KR102047231B1 - Electrophoretic display device and method of fabricating thereof - Google Patents

Electrophoretic display device and method of fabricating thereof Download PDF

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KR102047231B1
KR102047231B1 KR1020120143119A KR20120143119A KR102047231B1 KR 102047231 B1 KR102047231 B1 KR 102047231B1 KR 1020120143119 A KR1020120143119 A KR 1020120143119A KR 20120143119 A KR20120143119 A KR 20120143119A KR 102047231 B1 KR102047231 B1 KR 102047231B1
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substrate
layer
electrophoretic
surface modification
display device
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KR1020120143119A
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Korean (ko)
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KR20140074775A (en
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이정원
백승한
김수필
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엘지디스플레이 주식회사
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/166—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect
    • G02F1/167—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect by electrophoresis
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
    • G02F1/1675—Constructional details
    • G02F2001/1678—Constructional details characterised by the composition or particle type

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  • Nonlinear Science (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display device capable of preventing a specific deterioration of an electrophoretic layer, comprising: a first substrate and a second substrate including an image display unit and a non-display unit including a plurality of pixels: on the first substrate. A formed thin film transistor; A protective layer on the substrate on which the thin film transistor is formed; Barrier ribs formed on the non-image display unit on the passivation layer to define pixels; A pixel electrode formed on the image display unit on the protective layer; An electrophoretic layer formed on the pixels between the partition walls; A common electrode formed on the second substrate; And a surface modification layer formed on at least one substrate of the first substrate and the second substrate and in contact with the electrophoretic layer.

Description

Electrophoretic display device and its manufacturing method {ELECTROPHORETIC DISPLAY DEVICE AND METHOD OF FABRICATING 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 having a simplified manufacturing process and a reduced manufacturing cost.

In general, an electrophoretic display device is an image display device using a phenomenon in which colloidal particles move to either polarity when a pair of electrodes to which voltage is applied is immersed in a colloidal solution. Since it has characteristics, such as an electric power, it is attracting attention as an electronic device, such as an 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 composed of an array substrate on which a driving element is formed, thereby reflecting input light. The image can be displayed in the reflective mode.

1 is a view showing the structure of a conventional electrophoretic display device (1).

As shown in FIG. 1, the electrophoretic display device 1 may include a first substrate 20 and a second substrate 40 including a plurality of pixel regions, and an image display portion of the first substrate 20. A partition wall formed between the pixel electrode 18, the common electrode 42 formed on the second substrate 40, and an image non-display portion between the pixel and the pixel area of the second substrate 40 to partition each pixel. 80 and an electrophoretic layer 60 formed between the first substrate 20 and the second substrate 40.

Although not shown in the drawing, a thin film transistor is formed in each pixel region, and an electric field is formed between the pixel electrode 18 and the common electrode 42 as a voltage is applied to the pixel electrode 18. The second substrate 40 including the 60 is bonded to the first substrate 20 by an adhesive layer. The electrophoretic layer 60 is composed of an electrophoretic material in which white particles 64 and black particles 65 having positive and negative charge characteristics, respectively, are dispersed in a dispersion medium 62.

In the electrophoretic display device having such a structure, since the white particles 164 have positive charge characteristics, when the positive voltage is applied to the pixel electrode 18 from the outside, the common electrode 42 has a relatively negative potential. Therefore, the white particles 64 having a positive charge move toward the common electrode 42. Therefore, when light is input from the outside, that is, the upper portion of the second substrate 40, the input light is mostly reflected by the white particles 64, so that white is implemented in the electrophoretic display device.

On the contrary, when a negative voltage is applied to the pixel electrode 18, the common electrode 42 has a (+) potential, and the white particles 64 having a (+) charge are transferred to the first substrate 20. When the light is input from the outside, the input light is hardly reflected, thereby realizing black.

A manufacturing method of the conventional electrophoretic display device 1 having the above structure is schematically described as follows.

2 is a flowchart schematically showing a method of manufacturing a conventional electrophoretic display device 1.

As shown in FIG. 2, first, a plurality of gate lines and data lines defining pixel regions are formed on a first substrate 20, and the gate lines and data are formed in each of the pixel regions. A thin film transistor which is a driving element connected to the line is formed (S101). Subsequently, the pixel electrode 18 is formed on the first substrate 20 on which the thin film transistor is formed (S102).

Meanwhile, the common electrode 42 is formed on the second substrate 40 (S103). Subsequently, a partition wall is formed on the second substrate 40 to partition each pixel area, and then an electrophoretic material is filled in the pixel area partitioned by the partition wall to form an electrophoretic layer 60 (S105). Thereafter, a protective film is attached onto the second substrate 40 on which the electrophoretic layer 60 is formed (S105 and S106). At this time, although not shown in the figure, an adhesive layer is formed on the common electrode 42 so that the protective film is attached to the adhesive layer. In order to prevent the adhesion of the adhesive layer from deteriorating or the adhesion of the foreign matter to the adhesive layer when the second substrate 40 is transferred to the bonding process in order to bond the second substrate 40 to the first substrate 20. To be attached.

Typically, an electrophoretic display device manufacturer receives a second substrate 40 on which an electrophoretic layer 60 is formed, and attaches the second substrate 40 to the first substrate 20. That is, the second substrate 40 having the electrophoretic layer 60 formed thereon is transferred from the outside to the electrophoretic display element forming line, and then the first substrate 20 and the second substrate 40 are bonded to each other to form the electrophoretic display element. To complete.

Therefore, since the second substrate 40 on which the electrophoretic layer 60 is formed has to be transported a long distance by a conveying means such as a vehicle, the adhesive force of the adhesive layer decreases during the conveying process, so that the first substrate 20 and the second substrate ( When bonding the 40) may cause a defect, the protective film is to prevent the defect by preventing the adhesive force of the adhesive layer is weakened.

The second substrate 40 transferred to the manufacturing line of the electrophoretic display device manufacturer is peeled off, and then the protective film attached is aligned with the first substrate 20 and then bonded to complete the electrophoretic display device (S109).

However, the following problem occurs in the conventional electrophoretic display device 1 manufactured by the above method.

In the conventional electrophoretic display device 1, the first substrate 20 and the second substrate 40 are separately manufactured, and then the first and second substrates 20 and 40 are bonded to each other by an adhesive layer. .

However, since the unit pixels of the electrophoretic display element are formed to have a small size of less than 150 μm in width and length, it is very difficult to align the electrophoretic layer with the pixels so as to exactly fit 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 may not be correctly transferred to the electrophoretic particles, which may cause a driving error.

In addition, since the first substrate 20 and the second substrate 40 are each manufactured in different processes, they are transported by a conveying means and then bonded to each other in the bonding process, so that the manufacturing process cannot be formed inline. The manufacturing process is delayed and the manufacturing cost increases.

Meanwhile, the common electrode 42 is formed on the second substrate 40, the electrophoretic layer 60 is applied, and an adhesive layer is applied. Then, the second substrate 40 is transferred to a bonding process to transfer the first substrate 20. ) In order to prevent the adhesion of the adhesive layer from deteriorating or adhered to the adhesive layer, the adhesive film must be transported with the protective film attached to the adhesive layer, and the second substrate 40 transferred at the same time is transferred to the first substrate. In order to attach to the 20, the protective film must be peeled from the second substrate 40. Static electricity is generated during the peeling of the protective film, and the generated static electricity causes misalignment in the initial arrangement of the electrophoretic particles. During operation of the electrophoretic display element, a moire in the shape of a comb-pattern was caused.

As described above, in the conventional electrophoretic display device, since the first substrate 20 and the second substrate 40 are manufactured in different processes, the first substrate 20 and the second substrate 40 when the electrophoretic layer is bonded. There is a problem that misalignment occurs or the process becomes complicated, and static electricity is generated when the adhesive layer is peeled off, resulting in poor image quality.

The present invention is to solve the above problems, to provide an electrophoretic display device and a method for manufacturing the electrophoretic layer that can reduce the manufacturing cost and simplify the manufacturing process by directly forming the electrophoretic layer on the substrate on which the thin film transistor is formed The purpose.

Another object of the present invention is to form a surface modification layer on the surface of the surface in contact with the electrophoretic material electrophoretic display device and method for manufacturing the electrophoretic material which can prevent the characteristics of the electrophoretic material from deteriorating when contacted with the electrophoretic material To provide.

In order to achieve the above object, an electrophoretic display device according to the present invention includes a first substrate and a second substrate including an image display unit and a non-image display unit including a plurality of pixels: a thin film transistor formed on the first substrate; A protective layer on the substrate on which the thin film transistor is formed; Barrier ribs formed on the non-image display unit on the passivation layer to define pixels; A pixel electrode formed on the image display unit on the protective layer; An electrophoretic layer formed on the pixels between the partition walls; A common electrode formed on the second substrate; And a surface modification layer formed on at least one substrate of the first substrate and the second substrate and in contact with the electrophoretic layer.

The electrophoretic material includes white particles and black particles having charge characteristics or includes color particles having charge characteristics, and further includes a dispersion medium.

The surface modification layer is formed on at least one surface of the pixel electrode, the side wall of the partition wall, and the common electrode, wherein the surface modifier is formed of a material including a COOH group.

In addition, the electrophoretic display device manufacturing method according to the present invention comprises the steps of 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; Forming a partition on the non-image display unit on the protective layer; Forming a pixel electrode on the image display unit on the protective layer; Forming a surface modifier on the sidewalls of the partition and the pixel electrode; Forming an electrophoretic layer by filling an electrophoretic material in pixels between the barrier ribs above the protective layer; Forming a common electrode on the second substrate; And bonding the first substrate and the second substrate to each other.

The surface modification layer is formed by laminating a material containing a COOH group on the sidewall of the partition and the surface of the pixel electrode by a spray method.

In the present invention, since the electrophoretic layer is directly formed on the array substrate on which the thin film transistor is formed, the electrophoretic layer can be used to bond the electrophoretic layer to the array substrate, and a protective film for protecting the adhesive layer is not required, thereby reducing manufacturing costs. have. In addition, since the electrophoretic layer may be formed inline on the manufacturing line of the array substrate forming the thin film transistor, the manufacturing process may be simplified.

In addition, in the present invention, the surface in contact with the electrophoretic layer by the surface modification layer surface treatment, it is possible to effectively prevent defects due to deterioration of the characteristics of the electrophoretic layer.

1 is a view showing a conventional electrophoretic display device.
2 is a flow chart briefly showing a method of manufacturing a conventional electrophoretic display device.
3 is a flow chart briefly showing a method of manufacturing an electrophoretic display device according to the present invention.
4A-4G illustrate a method of manufacturing an electrophoretic display device according to the present invention.
5A and 5B are diagrams each illustrating a method of forming an electrophoretic layer of an electrophoretic display device according to the present invention.

Hereinafter, an electrophoretic display device and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart schematically illustrating a manufacturing process of an electrophoretic display device according to the present invention.

As shown in FIG. 3, first, a plurality of gate lines and data lines defining pixel regions are formed on a first substrate, and thin film transistors, which are driving elements connected to the gate lines and data lines, are formed in each of the pixel regions. (S201). Subsequently, barrier ribs are formed in the image non-display portion on the first substrate on which the thin film transistor is formed, and then pixel electrodes are formed in the image display portion (S202 and S203).

In this case, the barrier rib and the pixel electrode are processed by the same photo process. In general, the formation of a metal pattern or patterning of an insulating layer in a manufacturing process of an electrophoretic display device is performed by photolithography using a photo-mask. In the present invention, the barrier ribs and the pixel electrodes are formed in the same photomask. By the same process. In addition, the pixel electrode may be formed without a separate photo process. That is, a photoresist layer laminated to etch the metal layer is patterned without using a photomask, and the pixel layer is formed by etching the metal layer by the patterned photoresist layer.

Subsequently, an electrophoretic material is applied to the pixel region partitioned by the partition wall of the first substrate, that is, the image display unit to form an electrophoretic layer (S204).

On the other hand, a common electrode is formed on the second substrate (S205), the second substrate on which the common electrode is formed is aligned with the first substrate, and then bonded to complete the electrophoretic display device (S206, S207).

The common electrode is formed by laminating a transparent conductive material on a second substrate by deposition or the like, and is formed by the same manufacturing line as a thin film transistor or a pixel electrode formed on the first substrate. In other words, in the present invention, since the process of the second substrate can be carried out in the same manufacturing line as the process of the first substrate, the first substrate and the first substrate and the first substrate are manufactured by manufacturing and transferring the second substrate in another factory in the conventional electrophoretic display device. Compared to the bonding of the two substrates, the first substrate and the second substrate can be manufactured inline, and the first substrate and the second substrate can be bonded together.

As described above, in the present invention, since the manufacturing process of the first substrate and the second substrate is performed inline, the adhesive layer or the adhesive layer for attaching the substrate on which the transfer of the second substrate or the electrophoretic layer is formed to the thin film transistor substrate is protected. To avoid the need for a protective film, the process of aligning the two substrates, the process of peeling off the protective film for protecting the adhesive layer of the substrate on which the electrophoretic layer is formed, etc., it is possible to simplify the manufacturing process.

Furthermore, in the present invention, since the partition wall and the pixel electrode can be formed by one photomask, the manufacturing process can be further simplified and the manufacturing cost can be greatly reduced.

Hereinafter, a method of manufacturing an electrophoretic display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 4A to 4I. In this case, 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.

First, as shown in FIG. 4A, a Cr, Mo, Ta, Cu, Ti, Al, or Al alloy is formed on a first substrate 120 including an image display unit and an image non-display unit and made of a transparent material such as glass or plastic. After laminating a highly conductive opaque metal by a sputtering process and etching by a photolithography process to form a gate electrode 111, the substrate 120 having the gate electrode 111 formed thereon. The gate insulating layer 122 is formed by stacking an inorganic insulating material such as SiO 2 or SiNx by CVD (Chemicla Vapor Deposition).

Subsequently, as illustrated in FIG. 4B, 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. In addition, although not shown in the drawing, an ohmic contact that ohmic-contacts the source electrode and the drain electrode to be subsequently formed with a semiconductor layer 113 by doping impurities or stacking amorphous silicon added with impurities to a part of the semiconductor layer 113. To form an ohmic contact layer.

Thereafter, as shown in FIG. 4C, an electrically conductive opaque metal such as Cr, Mo, Ta, Cu, Ti, Al, or Al alloy is laminated on the first substrate 120 by sputtering and then etched. The first substrate 120 on which the source electrode 115 and the drain electrode 116 are formed on the semiconductor layer 113 and, strictly speaking, on the ohmic contact layer, is formed on the source electrode 115 and the drain electrode 116. A protective layer 124 is formed by stacking an organic insulating material such as BCB (Benzo Cyclo Butene) or photo acryl.

In addition, although not shown, the protective layer 124 may be formed of a plurality of layers. For example, the protective layer 124 may be formed of a double layer of an organic insulating layer made of an organic insulating material such as BCB or photoacryl and an inorganic insulating layer made of an inorganic insulating material such as SiO 2 or SiNx. It may be formed of 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 to be flat, and the interface property with the protective layer 124 is improved by applying the inorganic insulating layer.

A portion of the protective layer 124 is removed to form a contact hole 117 through which the drain electrode 116 is exposed to the outside.

Subsequently, as shown in FIG. 4D, the photosensitive organic material is stacked and etched over the entire first substrate 120 to form a barrier 180 made of an organic insulating material on the non-display portion on the protective layer 124. . In this case, the partition wall 180 may be formed of a negative photosensitive organic material or a positive photosensitive organic material.

Although not illustrated in the drawing, the partition wall 180 is formed along a boundary area of pixels arranged in a matrix shape on the first substrate 120, so that the partition wall 180 also has a matrix shape on the first substrate 120. Is formed.

Thereafter, as illustrated in FIG. 4E, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), Mo, AlNd, or the like is formed over the entire first substrate 120 on which the partition wall 180 is formed. Metals are stacked and etched to form pixel electrodes 118 electrically connected to the drain electrodes 116 through the contact holes 117. In this case, the pixel electrode 118a may be formed of a plurality of metal layers. That is, a plurality of metal layers such as Cu and MoTi may be sequentially stacked and then etched. In addition, the pixel electrode 118 may be formed using carbon nanotubes or water-soluble conductive polymers.

In the drawing, the pixel electrode 118 is formed only on the passivation layer 124, but the pixel electrode 118 may be formed to extend to the sidewall of the partition wall 180.

Subsequently, as shown in FIG. 4F, after the surface modification layer 184 is formed on the upper side of the pixel electrode 118 and the sidewalls of the partition wall 180, the electrophoresis is performed on the pixel electrode 118 between the partition walls 180. The electrophoretic layer 160 is formed by filling the material. The electrophoretic material is composed of particles having positive and negative charge characteristics. In this case, the particles may be white particles 164 and black particles 165, color particles such as cyan, magenta, yellow, or R (Red), G (Green), B It may be a color particle such as (Blue).

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

In addition, in the case of color particles as a dye having a charge characteristic, the color particles may have a negative charge or may have a negative charge.

The electrophoretic material may include a dispersion medium such as a liquid polymer. The dispersion medium is a black particle, a white particle, and a color particle are distributed, and may be a liquid such as a liquid polymer or air itself. As described above, that the dispersion medium is air itself means that the particles move in the air as voltage is applied even 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. When using a black dispersion medium absorbs light incident from the outside, it is possible to improve the contrast by displaying a clear black when implementing black. In addition, the color dispersion medium is used when the color is implemented by the electrophoretic material, each color pixel includes a dispersion medium of the corresponding color, it is possible to express a more vivid color when implementing the color.

In addition, the electrophoretic material may be a material in which a capsule filled with an electron ink is distributed in a polymer binder. At this time, the electron ink distributed in the capsule is composed of white particles (or white ink) and black particles (or black ink). In this case, 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 be used not only a specific material but all currently known particles.

The filling of the electrophoretic material into the partition wall 180 may be performed by various methods, which will be described below.

5A and 5B illustrate a method of forming the electrophoretic layer 160 by filling an electrophoretic material into the partition wall 180 formed on the substrate 120.

The method illustrated in FIG. 5A relates to an inkjet method or a nozzle method. As shown in FIG. 5A, an electrophoretic material 160a is filled in a syringe (or nozzle) 185 and then the substrate 120 is filled. Position the syringe 185 on the top. Subsequently, the syringe 185 is moved on the substrate 120 in a state where a pressure is applied to the syringe 185 by an external air supply device (not shown). The electrophoretic material 160a is dropped to form the electrophoretic layer 160 on the substrate 120.

The method illustrated in FIG. 5B relates to a squeeze method, and as shown in FIG. 5B, after the electrophoretic material 160a is coated on the substrate 120 on which the plurality of partition walls 180 are formed, the squeeze bar 187 is provided. By moving on the substrate 120 by the pressure of the squeeze bar 187 is filled with the electrophoretic material 160a into the partition 180 in the unit pixel to form the electrophoretic layer 160.

Of course, the present invention is not limited to the method as described above. The method described above shows an example of the 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 electrophoretic layer 160 forming processes such as casting printing, bar coating printing, screen printing, and mold printing may be applied to the present invention.

The surface modification layer 184 is to prevent the electrophoretic layer from deteriorating when the filled electrophoretic layer 160 contacts the pixel electrode 118 and the partition wall 180. The reason for forming) is described in detail as follows.

As described above, the electrophoretic layer 160 is composed of a dispersion medium such as a liquid polymer in which black particles, white particles, and color particles are distributed. The electrophoretic layer 160 is in contact with a metal or metal oxide such as the pixel electrode 118, or an organic material such as the partition wall 180. When the electrophoretic layer 160 is formed, the liquid polymer is formed of a metal oxide or organic material. Will be combined. The combination of the liquid polymer causes deterioration of the properties of the electrophoretic material, and as a result, it is an important cause of deterioration of the properties when the electrophoretic display device is manufactured.

On the other hand, in the present invention, since the surface modification layer 184 is formed, the electrophoretic material does not directly contact the barrier 180 and the pixel electrode 118, so that the electrophoretic material is generated by combining with an organic material and a metal oxide. Can solve the problem.

In this case, the surface modification layer 184 is formed by spraying on the sidewalls of the barrier 180 and the upper portion of the pixel electrode 118 by a spray method. Various materials are used as the surface modification layer 184, but it is preferable to use a material including a -COOH group. According to the present invention, it can be seen that when the polyester and the positive photoresist including the -COOH group are used, the electrical bistable stability of the particles included in the electrophoretic layer 160 is improved.

Although the surface modification layer 184 is formed only on the sidewall of the barrier 180, the surface modification layer 184 may be formed on an upper surface of the barrier 180 of the surface modification layer 184. However, since the upper surface of the partition wall 180 does not substantially contact the electrophoretic layer 160, the surface modification layer 184 may not be formed. In other words, in the present invention, it is preferable to form the surface modification layer 184 on all the components in contact with the electrophoretic layer 160 in addition to the electrode or the partition 180.

Subsequently, as shown in FIG. 4G, a common electrode 142 made of a transparent metal oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the second substrate 140 as described above. After the surface modification layer 184 is formed on the electrode 142, the first substrate 120 and the second substrate 140 are bonded together to complete the electrophoretic display device. In this case, a surface modification layer 184 may be formed on the common electrode 142 to prevent defects caused by the electrophoretic material directly contacting the common electrode 142.

The structure of the electrophoretic display device manufactured by the above method will be described in detail with reference to FIG. 4G.

As shown in FIG. 4G, the electrophoretic display device according to the present invention includes a gate electrode 111, a semiconductor layer 113, a source electrode 115, and a drain electrode 116 in an image non-display portion of the first substrate 120. A thin film transistor is formed and a protective layer 124 is formed thereon. A partition wall 180 is formed in the image non-display portion on the passivation layer 124, and the electrophoretic layer 160 is also disposed on the image display portion of the first substrate 120, that is, the pixel electrode 118 between the partition walls 180. The electrophoretic layer 160 is in direct contact with the pixel electrode 118.

In addition, in the present invention, since the surface modification layer 184 is formed in all the spaces in which the electrophoretic layer 160 is formed, that is, the electrophoretic layer 160 is formed, the electrophoretic material of the electrophoretic layer 160 is Since only the surface modification layer 184 is in contact with other structures, the surface modification layer 184 may be prevented from deteriorating characteristics due to contact with organic materials or metal oxides.

Looking at the driving of the electrophoretic display device of such a structure is as follows. When the electrophoretic material 160 is formed of the white particles 164 and the black particles 165, since the white particles 164 have a positive charge or negative charge characteristics, a signal is input from the outside and formed on the first substrate 120. When a signal is applied to the pixel electrode 118 through the thin film transistor, 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 pixel electrode 118, the common electrode 142 of the second substrate 140 has a relatively negative potential. Since the white particles 164 having a (+) charge is moved toward the second substrate 140. Therefore, when light is input from the outside, that is, the upper portion of the second substrate 140, the input light is mostly reflected by the white particles 164, so that white is implemented in the electrophoretic display device.

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

On the contrary, when a negative voltage is applied to the pixel electrode 118, the common electrode 142 of the second substrate 140 has a (+) potential, so that the white particles 164 having a (+) charge are charged. When the light is input from the outside by moving to the first substrate 120, the input light is hardly reflected, thereby implementing black.

Meanwhile, when the white particles 164 have a negative charge, when a positive voltage is applied to the pixel electrode 118, the common electrode 142 of the second substrate 140 may have a relatively negative potential. Therefore, the white particles 164 having a negative charge are moved toward the first substrate 120. Therefore, when light is input from the outside, that is, the upper portion of the second substrate 140, since most of the input light is not reflected, black is implemented in the electrophoretic display device.

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

When the electrophoretic material is formed of color particles, color particles such as R, G, B color particles, cyan, magenta, yellow, etc. may be formed according to a signal applied to the pixel electrode 118. The substrate 140 may be moved 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 pixel electrode 118, the white particles and the black particles are separated in the capsule by an electric field generated between the pixel electrode 118 and the common electrode 142. For example, when a negative voltage is applied to the pixel electrode 118, the common electrode 142 of the second substrate 140 has a relatively positive potential, so that white particles having a positive charge The black particles moving toward the first substrate 120 and having a (-) charge move toward the second substrate 140. In this state, when light is input from the outside, that is, the upper portion of the second substrate 140, the input light is reflected by the black particles, so that black is implemented in the electrophoretic display device.

On the contrary, when a positive voltage is applied to the pixel electrode 118, the common electrode 142 of the second substrate 140 has a negative potential, so that white particles having a positive charge are formed on the second substrate. Moving to 140, the black particles having a negative charge is moved to the first substrate 140.

In this state, when light is input from the outside, that is, the upper portion of the second substrate 140, the input light is reflected by the white particles, thereby implementing white.

In this case, when the white particles and the black particles in the capsule have negative charge and positive charge characteristics, respectively, white and black may be realized in the opposite operation.

As described above, in the present invention, since the electrophoretic layer 160 is directly formed on the first substrate 120, the electrophoretic layer 160 may be removed as compared to the conventional art in which the electrophoretic layer is formed on the second substrate 140. The adhesive layer for attaching to the second substrate 140 or the protective film for protecting the adhesive layer is not required. In addition, in the present invention, since the electrophoretic layer 160 may be formed in a conventional thin film transistor forming process line, for example, an insulation layer forming process line, a separate process line is not required, thus further reducing manufacturing costs. You can do it.

In addition, the present invention compared to the conventional manufacturing and transporting the electrophoretic layer in a separate factory or manufacturer attached to the second substrate 140 and bonding the second substrate 140 and the first substrate 120 again, In the process, such as the transfer of the substrate on which the electrophoretic layer is formed or the attachment of the electrophoretic layer is unnecessary, so that the manufacturing process can be simplified.

Furthermore, in the present invention, the surface-modified layer 184 is formed by surface-treating most of the regions (possibly all regions) in which the electrophoretic layer 160 contacts, so that the electrophoretic layer 160 is the surface-modified layer 184. Since contact with other areas is minimized, defects due to deterioration of the characteristics of the electrophoretic layer 160 may be prevented.

As described above, in the method of manufacturing the electrophoretic display device according to the present invention, the partition wall is directly formed on the first substrate and the electrophoretic layer is also directly filled between the partition walls of the first substrate so that the electrophoretic layer is directly pixel electrode. Unlike the conventional electrophoretic display, a separate adhesive layer for attaching the electrophoretic layer is not required between the electrophoretic layer, the pixel electrode, and the protective layer. Therefore, the electrophoretic display device of this embodiment can simplify the manufacturing process, thereby reducing the manufacturing cost.

In addition, in the present invention, the surface in contact with the electrophoretic layer by the surface modification layer surface treatment, it is possible to effectively prevent defects due to deterioration of the characteristics of the electrophoretic layer.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

120,140 substrate 111 gate electrode
113: semiconductor layer 115: source electrode
116: drain electrode 118: pixel electrode
124: protective layer 142: common electrode
160: electrophoretic layer 164: white particles
165 black particles 180 bulkhead
184: surface modification layer

Claims (12)

First and second substrates including an image display unit and a non-image display unit including a plurality of pixels:
A thin film transistor formed on the first substrate;
A protective layer on the substrate on which the thin film transistor is formed;
Barrier ribs formed on the non-image display unit on the passivation layer to define pixels;
A pixel electrode formed on the image display unit on the protective layer;
An electrophoretic layer formed on the pixels between the partition walls;
A common electrode formed on the second substrate; And
A surface modification layer formed on a surface of the pixel electrode, a sidewall of the partition wall, and a surface of the common electrode;
And the electrophoretic layer is in contact with the surface modification layer, and the electrophoretic layer is not in contact with the pixel electrode, the partition wall, and the common electrode by the surface modification layer. The method of claim 1, wherein the thin film transistor,
A gate electrode formed on the substrate;
A semiconductor layer formed on the gate electrode; And
An electrophoretic display device comprising a source electrode and a drain electrode formed on the semiconductor layer. The electrophoretic display device of claim 1, wherein the electrophoretic layer comprises white particles and black particles having charge characteristics. The electrophoretic display device of claim 1, wherein the electrophoretic layer comprises color particles having charge characteristics. The electrophoretic display device of claim 3 or 4, wherein the electrophoretic layer further comprises a dispersion medium. delete delete The electrophoretic display device of claim 1, wherein the surface modification layer is polyester or a positive photoresist. Providing a first substrate and a second substrate including an image display unit including a plurality of pixels and an image non-display unit;
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;
Forming a partition on the non-image display unit on the protective layer;
Forming a pixel electrode on the image display unit on the protective layer;
Forming a surface modification layer on the sidewalls of the partition and the pixel electrode;
Forming an electrophoretic layer by filling an electrophoretic material in a pixel between the barrier ribs on the protective layer on which the surface modification layer is formed;
Forming a common electrode on the second substrate;
Forming a surface modification layer formed of a material including a COOH group on the common electrode; And
Comprising the step of bonding the first substrate and the second substrate,
And the electrophoretic layer is in contact with the surface modification layer and the electrophoretic layer is not in contact with the pixel electrode, the partition wall and the common electrode by the surface modification layer. 10. The method of claim 9, wherein the step of forming the electrophoretic layer is electrophoretic material inside the partition wall using one of dropping method, squeeze method, casting printing method, bar coating printing method, screen printing method, mold printing method. Electrophoretic display device manufacturing method comprising the step of filling. delete The method of claim 9, wherein the forming of the surface modification layer comprises stacking the surface modification layer on the sidewalls of the barrier ribs and the surface of the pixel electrode by a spray method.
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