KR20130026272A - Electro phoretic display device and method for manufacturing the same - Google Patents

Electro phoretic display device and method for manufacturing the same Download PDF

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KR20130026272A
KR20130026272A KR1020110089778A KR20110089778A KR20130026272A KR 20130026272 A KR20130026272 A KR 20130026272A KR 1020110089778 A KR1020110089778 A KR 1020110089778A KR 20110089778 A KR20110089778 A KR 20110089778A KR 20130026272 A KR20130026272 A KR 20130026272A
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South Korea
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electrode
hydrophobic
electronic ink
electrophoretic display
partition wall
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KR1020110089778A
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Korean (ko)
Inventor
민혜리
김진욱
김병걸
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엘지디스플레이 주식회사
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Publication of KR20130026272A publication Critical patent/KR20130026272A/en

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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 
    • G02F1/13—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 liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133377—Cells with plural compartments or having plurality of liquid crystal microcells partitioned by walls, e.g. one microcell per pixel
    • 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
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3433—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices
    • G09G3/344—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices based on particles moving in a fluid or in a gas, e.g. electrophoretic devices
    • 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

Abstract

The present invention relates to an electrophoretic display device and a method of manufacturing the same, wherein the electrophoretic display device prevents inter-cell contamination of ink including electrophoretic particles through surface treatment of a substrate. Forming a first electrode on the first electrode; and forming a plurality of partition walls defining a cell region on the first electrode; and forming a hydrophobic film on the first electrode including the partition wall; and Dotting the electronic ink liquid in the cell area; And adhering a second substrate having a second electrode on the surface thereof to face the first substrate.

Description

Electrophoretic Display Device and Method for Manufacturing the Same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display device, and more particularly, to an electrophoretic display device and a method of manufacturing the same, which prevent inter-cell contamination of ink including electrophoretic particles through surface treatment of a substrate.

An electrophoretic display device (EPD) is one of the flat panel display devices used in an e-book, and is formed between two display panels on which an electrode for generating an electric field is formed, and is formed between these two display panels. It consists of an electric ink which is white and black, respectively, and has the pigment particle positively and negatively charged.

In such an electrophoretic display, a voltage is applied to two opposite electrodes to generate a potential difference across the electrodes, thereby moving black and white charged pigment particles to electrodes having opposite polarities, respectively, to display an image.

Such an electrophoretic display has a high reflectivity and contrast ratio, and unlike a liquid crystal display, there is no dependency on a viewing angle, and thus an image can be displayed with a comfortable feeling like paper. It has a black and white bistable characteristic, so that the image can be maintained without applying a constant voltage, and thus power consumption is small. In addition, unlike a liquid crystal display device, a polarizing plate, an alignment layer, a liquid crystal, etc. are not required, which has advantages in terms of price competitiveness.

Such an electrophoretic display device may form a color electrophoretic display device capable of color display by corresponding a color filter substrate to an upper portion thereof, or may be formed by mixing a pigment that enables color display in electrophoretic particles.

An electrophoretic display (EPD) is an image display device using a phenomenon in which colloidal particles contained in an insulating fluid are moved to either polarity between a pair of electrodes to which an electric field is applied. The electrophoretic display applies a voltage to a pair of opposing electrodes to display white when the white ink particles collect on the display surface and black when the black ink particles collect.

Such an electrophoretic display device forms a partition on a substrate for internalization of the electronic ink, and injects the electronic ink between the partitions by a screen printing method or the like. However, in this case, due to the large surface energy of the partition material, the electronic ink spreads on the lower part of the cell defined as the partition wall during injection, and enters the partition wall and invades the surrounding cells, thereby causing inter-cell contamination.

The conventional electrophoretic display device has the following problems.

Because of the large surface energy of the barrier material, the injected electronic ink spreads from the lower part of the cell and rises up the barrier to be transferred to another cell. This causes contamination of the electronic ink between cells, changes in the number of particles injected per unit cell, adversely affects driving, and prevents perfect image implementation.

The present invention has been made to solve the above problems, and to provide an electrophoretic display device and a method of manufacturing the same, which prevents the inter-cell contamination of the ink including the electrophoretic particles through the surface treatment of the substrate, have.

According to another aspect of the present invention, there is provided a method of manufacturing an electrophoretic display device, the method including: forming a first electrode on a first substrate; and forming a plurality of partition walls defining a cell region on the first electrode. Forming a hydrophobic film on the surface of the first electrode including the partition wall; and doting an electronic ink liquid in the cell region; And opposingly bonding a second substrate having a second electrode opposite to the first electrode to the first substrate.

The partition is photosensitive resin. For example, the photosensitive resin may include an epoxy ring at an end thereof. Alternatively, the photosensitive resin may be made of SU-8 or dry film photoresist (DFR).

After formation of the hydrophobic film, it is preferable that a hydrophobic group is exposed on the partition wall and the surface of the first electrode.

The hydrophobic group may be a fluorine group.

The forming of the hydrophobic film may be performed by spraying a hydrophobic solution on the first electrode including the partition wall and curing the hydrophobic solution. In this case, the hydrophobic solution is cured by heating the first substrate on a hot plate. At this time, the heating in the hot plate is carried out at 80 ℃ to 200 ℃, 1 minute to 10 minutes. In this case, the hydrophobic solution may be perfluorootyltrichlorosilane (FOTS).

On the other hand, the hydrophobic film may be formed by performing a plasma surface treatment on the first electrode including the partition wall. At this time, the plasma surface treatment may proceed with a gas containing a large amount of fluorine groups. The gas containing a large amount of fluorine groups, for example, CF 4 Lt; / RTI >

In addition, the hydrophobic film may be formed by coating a hydrophobic chemical solution on the first electrode including the partition wall and then thermosetting the hydrophobic chemical solution. In this case, the hydrophobic chemical may be Hexamethyldisilane (HMDS).

On the other hand, the electronic ink liquid contains electrophoretic particles containing two or more charged particles expressing the contrast or color in the sacrificial solvent.

In addition, the method may further include a drying process of volatilizing the sacrificial solvent after dotting the electronic ink solution, and may leave only the electronic ink on the colloid including electrophoretic particles expressing light and shade.

The hydrophobic film functions to lower the surface energy of the barrier rib and the surface of the first electrode relative to the surface energy of the electronic ink liquid.

In addition, an electrophoretic display device of the present invention for achieving the same object includes: a first electrode formed on a first substrate; a plurality of partitions defining a cell region on the first electrode; A hydrophobic film treated to expose a fluorine group on an electrode surface, and an injected electronic ink including electrophoretic particles on the hydrophobic film in the cell region; And a second substrate having a second electrode on its surface and bonded to the first substrate.

The electrophoretic display of the present invention as described above has the following effects.

Hydrophobic surface treatment may be performed on the first electrode including the partition wall before the electronic ink liquid is doped into the cell, thereby preventing contamination due to interaction between the electronic ink liquid and the partition wall and other surfaces. Thus, the electronic ink liquid can be doped with a minimum contact area in the cell. This prevents a meniscus phenomenon of the electronic ink liquid, so that the same amount of the electronic ink liquid is injected into each cell to improve driving characteristics.

In addition, in the color electrophoretic display, the dotting is performed so that the electronic ink liquid contacts the minimum contact area in each cell area, and flows into the partition wall of the other cell area to prevent the ink of different colors in the cell from being mixed. The display can be performed.

1 is a cross-sectional view showing an electrophoretic display of the present invention.
2 is a cross-sectional view showing a state in which the electronic ink liquid compared to the present invention invades the partition wall.
3A and 3B are cross-sectional views illustrating a surface treatment before injection of an electronic ink liquid in the method of manufacturing an electrophoretic display device of the present invention.
4 is a view showing the properties of the substrate surface after the process of Figure 3b
5A and 5B are diagrams illustrating states after injection and after injection of an electronic ink liquid in the method of manufacturing an electrophoretic display device of the present invention.
6A and 6B are cross-sectional views illustrating a method of injecting an electronic ink liquid by a screen printing method in the method of manufacturing an electrophoretic display device of the present invention.
7 is a view showing an electronic ink liquid used in the method of manufacturing an electrophoretic display device of the present invention.
8A and 8B are photographs showing the contact angle and injection shape of the electronic ink liquid of the electrophoretic display device when the electronic ink liquid is injected into the partition wall without surface treatment;
9A and 9B are photographs showing an electronic ink liquid contact angle and an injection shape of the electrophoretic display device of the present invention.
10 is a graph showing surface energy and polarity changes before and after surface treatment of an electrophoretic display device of the present invention.

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

1 is a cross-sectional view of an electrophoretic display device of the present invention.

As shown in FIG. 1, the electrophoretic display device of the present invention includes first and second substrates 100 and 200 facing each other, first and second electrodes 110 and 210 formed on each substrate, and first and second electrodes. It includes a partition wall 120 formed to separate the cells in the space between the two electrodes and the electronic ink 130 injected into each cell.

Here, the electronic ink 130 has a minimum contact area between the first electrode 110 and the partition wall 120 in the partition wall 120, and aggregates and is injected into a spherical shape.

Electrophoretic particles including black and white charged particles are dispersed in the electronic ink 130, or red / green / blue or yellow / magenta / cyan Electrophoretic particles containing colored charged particles such as cyan are included. The electronic ink 130 is injected in a liquid form including a sacrificial solvent when injected into the cell, and the sacrificial solvent is dried through a drying process to leave only electrophoretic particles.

In addition, a hydrophobic modification treatment is performed on the surface of the partition wall 120 including the first electrode 110 before the injection of the electronic ink liquid, and the surface is hydrophobized so that the electronic ink 130 adheres to the surface with a minimum area. For example, it aggregates in spherical shape.

Here, the first and second electrodes 110 and 210 are made of transparent electrodes such as indium tin oxide (ITO) and indium zinc oxide (IZO), and the partition wall 120 is a photoresist, such as a photoresist. It consists of materials, such as chemical resin. In addition, the partition wall 120 has a solidified pattern through photocuring after patterning.

In the electrophoretic display of the present invention, the surfaces of the partition wall 120 and the first electrode 110 are lower than the surface energy of the electronic ink liquid into which surface energy is injected after the hydrophobic reforming treatment is performed. The electronic ink liquid remains in contact with the minimum area in the cell similarly to a spherical shape by maintaining the property of aggregation without being dispersed after injection into the cell region.

In this case, the first and second substrates 100 and 200 are bonded to each other with the partition wall 120 interposed therebetween, and cells are defined around the partition wall 120, and an electric ink is formed in each cell. 130 is injected.

Fig. 2 is a cross-sectional view showing a state in which an electronic ink liquid compared to the present invention invades a partition wall.

As shown in FIG. 2, when the electronic ink liquid is injected without surface treatment, the electronic ink liquid 13 is dispersed on the surface of the first electrode 11 and the partition wall 12 on the substrate 10. This is shown to occur because the surface energy of the material of the partition 12 is relatively larger than the surface energy of the electronic ink liquid 13, and therefore, the injected electronic ink liquid 13 is formed between the partitions 12. A phenomenon occurs that flows on the surface of the first electrode 11 in the cell and passes over the surface of the partition 12 to the adjacent cell. This causes the inter-cell contamination of the electronic ink liquid 13, and there is a risk of incomplete image display such as weak gradation or dark spots in a specific cell (pixel) due to the difference in the amount of injected electronic ink liquid for each cell. have.

In the state in which the electrophoretic particles are dispersed in the sacrificial solvent during injection into the electronic ink liquid, the phenomenon of overflowing the above-described electronic ink liquid is because the surface energy of the material of the partition wall is larger than that of the sacrificial solvent. It is understood that the property to be dispersed is large.

In order to prevent such invasion of the electronic ink liquid, and to inject the electronic ink liquid in a state of good cohesion without being dispersed in the cell, the manufacturing method of the electrophoretic display device of the present invention proceeds with the surface pretreatment before the electronic ink liquid injection, This will be described below.

3A and 3B are cross-sectional views illustrating the surface treatment before injection of an electronic ink liquid in the method of manufacturing an electrophoretic display device of the present invention.

As shown in FIG. 3A, the first electrode 110 is formed on the first substrate 100. Here, the first electrode 110 is made of a transparent electrode such as ITO, IZO, ITZO (Indium Tin Zinc Oxide).

Subsequently, a plurality of partition walls 120 for separating the plurality of cells are formed on the first electrode 110.

The partition wall 120 is formed of an epoxy-based negative photoresist, for example, as shown in SU-8 having the following Chemical Formula 1. The material SU-8 is one example, and the present invention is not limited thereto, and the partition wall 120 may be formed by selecting any one of the photosensitive materials. For example, it may also be formed by a dry film photoresist (DFR).

Figure pat00001

As shown in Formula 1, the material of SU-8 has an epoxy ring at its end, and this epoxy ring is divided into a polar part and a central benzene ring connection part into a disperse part. . When equipped with such an epoxy ring, the surface energy is higher than that of the general solvent. Therefore, when the partition wall 120 is formed of an epoxy resin having an epoxy ring at the end, the electronic ink liquid tends to disperse to the partition wall 120 when the electronic ink liquid including a sacrificial solvent composed of a general solvent is injected into the liquid phase. Has In the manufacturing method of the electrophoretic display of the present invention, in order to prevent this, the surface pretreatment before injection of the electronic ink liquid is performed.

Subsequently, the surface of the first electrode 110 and the partition wall 120 is sprayed onto the first electrode 110 including the partition wall 120 using a hydrophobic solution 135.

In this case, for example, the hydrophobic solution is sprayed with a perfluorooctyltrichlorosilane (FOTS) solution containing a large amount of fluorine groups, and then cured in the hot plate 300 for a predetermined time as shown in FIG. 3B to form the partition wall 120 and the first. The hydrophobic film 135a to which a large amount of fluorine groups are exposed is formed on the surface of the electrode 110. In the experiment, the curing process was performed for 5 minutes at a temperature of about 110 ° C. In some cases, the heating temperature and time may vary. In this case, it is preferable to proceed with a heating temperature and time at about 80 to 200 degreeC for about 1 to 10 minutes.

Chemical formula of the FOTS is the same as the formula (2). That is, since a large amount of fluorine groups are contained, the fluorine groups are exposed to the outside on the partition walls and the first electrode surfaces after the surface treatment.

Figure pat00002

4 is a view showing the properties of the substrate surface after the process of Figure 3b.

As shown in FIG. 4, the hydrophobic film 135a is exposed to a large amount of fluorine groups. The fluorine groups cause superhydrophobicity on the surface to lower the surface energy so that the liquid ink is injected into the liquid phase without being dispersed to the partition walls. Allow aggregation in the cell. This prevents the invasion of the inter-cell electronic ink liquid.

On the other hand, the surface pretreatment using the above-described FOTS has been described an example of forming a hydrophobic film, it can be replaced by a surface pretreatment process that makes a variety of hydrophobic. As long as the material includes a large amount of the fluorine group described above, and a material capable of exposing hydrophobic groups other than the fluorine group to the partition and the first electrode outside, a solvent or gas containing no fluorine group can be used.

For example, the hydrophobic film may be formed by plasma surface treatment on the first electrode including the partition wall. At this time, the plasma surface treatment is CF 4 containing a large amount of fluorine groups Proceed to gas or the like.

In addition, the hydrophobic film may be formed by coating a hydrophobic chemical solution on the first electrode including the partition wall and then thermosetting the hydrophobic chemical solution. In this case, the hydrophobic chemical may be Hexamethyldisilane (HMDS).

5A and 5B are diagrams illustrating states after injection and injection of an electronic ink liquid in the method of manufacturing an electrophoretic display device of the present invention.

As shown in FIG. 5A, in the state in which the hydrophobic film 135a is formed on the surfaces of the first electrode 110 and the partition wall 120, black and white inks for contrast display or red / green / blue inks or yellow / magenta for color display. The electronic ink liquid 130a containing the cyan ink (reactive monomer) in the sacrificial solvent is injected into each cell. In this case, the hydrophobic film 135a is formed on the surface of the first electrode 110 and the partition wall 120 of the cell, so that the hydrophobic film 135a is not dispersed in the cell of the electronic ink liquid 130a.

For example, the surface energy after the hydrophobic surface treatment of the partition wall made of SU-8 is maintained at a level lower than the sacrificial solvent contained in the electronic ink at about 18.00 F / m.

As shown in FIG. 5B, the sacrificial solvent is evaporated through a drying process to leave only the electronic ink 130 in the cell.

Here, the sacrificial solvent is, for example, dodecane (dodecane), the surface energy is about 23.35mN / m, less than the surface energy 31.49mN / m when the partition wall 120 is SU-8. Therefore, when the electronic ink liquid 130a is injected without surface treatment before the electronic ink liquid 130a is injected, the electronic ink liquid 130a spreads on the surface of the first electrode 110 to rise up the partition wall 120. In other words, the contact area becomes wide during injection, and a meniscus phenomenon occurs, and the electronic ink liquid rises on the partition like a crescent moon.

However, in the method of manufacturing the electrophoretic display of the present invention, hydrophobic treatment is performed on the surface of the first electrode 110 and the partition wall 120 by using a FOTS solution or the like before the injection of the electronic ink liquid 130a to inject surface energy. It is made lower than the electronic ink liquid used, and the property which makes electronic ink liquids gather is enlarged. That is, the injection area of the electronic ink liquid can be minimized to minimize the contact area, so that the quantitative ink injected per unit cell after the sacrificial solvent in the electronic ink liquid is volatilized can be positioned inside the cell to improve driving characteristics.

Here, the hydrophobic film 135a functions to lower the surface energy of the surface of the partition wall 120 and the first electrode 11 relative to the surface energy of the electronic ink liquid 130a.

Therefore, contamination by the interaction between the electronic ink liquid 130a and the partition wall 120 can be prevented.

The hydrophobic film described above is exaggerated in the form of a film, but after the actual curing, the hydrophobic groups such as fluorine groups remain on the barrier ribs and the first electrode to remain functional groups, and the components do not increase the thickness of the surface. Therefore, in the following description of the implantation step, the hydrophobic film is omitted for illustration.

For example, the injection of the electronic ink liquid is performed by a screen printing method or the like.

6A and 6B are cross-sectional views illustrating a method of injecting an electronic ink liquid by a screen printing method in the method of manufacturing an electrophoretic display device of the present invention.

As shown in FIG. 6A, after the plurality of partitions 120 are formed to be spaced apart from each other, the first substrate 100 may include a mask 250 having an opening 250a that opens only a part of the cells between the partitions 120. Align on top. For example, in the illustrated example, the partition walls 120 are spaced at intervals of 100 μm, and the openings 250a of the mask 250 have an opening 250a having a width of 80 μm.

Subsequently, after preparing the electronic ink liquid 130a including black and white charged ink components for contrast display or red / green / blue charged ink components for color display or yellow / magenta / cyan charged ink components in the sacrificial solvent, The electronic ink liquid 135a is moved into a squeegee 350 so that the electronic ink liquid 130a is doped into the cell between the partition walls 120 through the opening 250a.

The electronic ink liquid 130a contains electrophoretic particles including two or more charged particles, which express the contrast or the color, in the sacrificial solvent.

As shown in FIG. 6B, when the drying is performed after the electronic ink liquid 130a is doped, the electronic ink 130 in which the sacrificial solvent is volatilized due to the hydrophobicity of the surfaces of the partition wall 120 and the first electrode 110 is in the cell. The contact state is maintained in the minimum area, and the electronic ink 130 is spaced apart from the partition wall 120.

Through this drying process, only the electronic ink on the colloid can be left in the cell, including electrophoretic particles expressing the contrast or color.

FIG. 7 is a diagram showing an electronic ink liquid used in the method of manufacturing the electrophoretic display device of the present invention. FIG.

On the other hand, as shown in FIG. 7, the electrophoretic particles 1310 are dispersed in the sacrificial solvent 1320 in the electronic ink solution, and each of the electrophoretic particles 1310 is a black and white two-color charged ink component or color display. The three-color red / green / blue charged ink component or yellow / magenta / cyan three-color charged ink component is included therein. These charged ink components vary the degree of aggregation depending on the electric field formed between the electrodes of both substrates, whereby contrast display and gradation display can be performed.

8A and 8B are photographs showing the contact angle and injection shape of the electronic ink liquid of the electrophoretic display device when the electronic ink liquid is injected into the partition wall without surface treatment, and FIGS. 9A and 9B are electronic ink of the electrophoretic display device of the present invention. The photograph shows the liquid contact angle and the injection shape.

As shown in FIG. 8A, when the hydrophobic surface treatment before the electronic ink liquid injection is not performed on the first electrode including the partition wall, the contact angle of the electronic ink liquid is about 73.15 °, and the injected electronic ink liquid has a wide width. The height is dispersed in a thin state, and a phenomenon of rising up through the partition wall around the cell of FIG. 8B (a black lump around the partition wall) is observed.

However, as shown in Fig. 9A, when the hydrophobic surface treatment is performed on the first electrode including the partition wall before the injection of the electronic ink liquid, the injected electronic ink liquid remains in a nearly spherical shape and the contact angle is weak. It is close to 90 °. In this case, as shown in Fig. 9B, the electronic ink liquid is rolled into the partition wall with the electronic ink liquid and the electronic ink liquids are agglomerated with each other, which is observed in the profile as a round liquid phase in the partition wall.

10 is a graph showing surface energy and polarity changes before and after the surface treatment of the electrophoretic display of the present invention, and Table 1 summarizes the surface energy values before and after the surface treatment and after the lapse of time.

Figure 10 looks at the change in polarity of the surface energy of the partition wall before and after reforming.

Figure pat00003

In the first experiment, the surface energy was 31.14 mN / m and 18.36 mN / m, respectively, before and immediately after surface treatment. In this case, the partition material is SU-8, and as shown in Formula 1 above, the polar part means terminal epoxy rings, and the disperse part has central benzene rings except the epoxy ring. And their connections. At this time, before the surface treatment, the surface energy of the polar part and the dispersion part is divided into 5.35 mN / m and 25.79 mN / m, respectively, accounting for 17.2% and 82.8% of the total partitions, respectively.

In addition, immediately after the surface treatment, the polar part of the partition disappears, and the dispersion part or 100% remains, so that the surface of the partition becomes hydrophobic.

After 48 hours, 72 hours, and 144 hours of surface treatment, the surface energy of the bulkhead is 11.8 mN / m, 12.7 mN / m, and 11.9 mN / m. It can be seen that the state is maintained. In addition, it can be seen that the polar portion is maintained within 5% of the overall configuration, so that the surface energy of the polar portion alone is maintained at a level of 0.5 mN / m.

In the second experiment, the surface energy was 31.88 mN / m and 18.26 mN / m, respectively, before and immediately after surface treatment. In this case, the partition material is SU-8, which is the same material as above.

At this time, the surface energy of the polar portion and the dispersion portion before the surface treatment is divided into 5.89mN / m, 25.99mN / m, respectively, it can be seen that occupies 18.5%, 81.5% of the configuration of the entire partition, respectively.

The surface energy of the bulkhead after 48 hours, 72 hours, and 144 hours after the surface treatment was measured after 1 hour, and the surface energy of the partition wall was 12.0 mN / m, 12.3 mN / m, and 11.6 mN / m. It can be seen that the energy remains more reduced than immediately after the surface treatment. In addition, it can be seen that the polar portion is maintained within 8.6% of the overall configuration, so that the surface energy of the polar portion alone is maintained at a level of 1.0 mN / m or less.

These experiments confirm that the surface remains hydrophobic even after surface treatment. This is because even when the barrier is made of SU-8 or when other materials with high surface energy are used, after the surface treatment, the surface energy of the barrier and the first electrode surface is lowered to agglomerate with each other rather than to disperse the electronic ink liquid. It can be expected to be injected with a minimum contact area in the cell.

In the above experimental example, the partition wall is specifically referred to as SU-8, and the surface pretreatment is performed by FOTS to show the result, but the present invention is not limited to such a material. Basically, the hydrophobic treatment is performed before the injection of the electronic ink liquid into the cell, thereby lowering the surface energy of the barrier ribs and the first electrode than the surface energy of the electronic ink liquid, thereby increasing the property of collecting the electronic ink liquids, thereby increasing the electronic ink liquid. The significance of the present invention is that the contact angle of is increased.

In addition, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

100: first substrate 110: first electrode
120: partition 130: electronic ink
130a: Electronic Ink Liquid 135: Hydrophobic Solution
135a: hydrophobic film 250: mask
250a: opening 300: hot plate
1310: electrophoretic particles 1320: sacrificial solvent

Claims (19)

Forming a first electrode on the first substrate;
Forming a plurality of partition walls defining a cell region on the first electrode;
Forming a hydrophobic film on a surface of the first electrode including the partition wall;
Dotting electronic ink liquid in said cell area; And
And bonding the second substrate having the second electrode to face the first electrode so as to face the first substrate. The method of claim 1,
The partition wall is a method of manufacturing an electrophoretic display device, characterized in that the photosensitive resin. The method of claim 2,
The photosensitive resin is a manufacturing method of an electrophoretic display device characterized in that it comprises an epoxy ring (epoxy ring) at the end. The method of claim 2,
The photosensitive resin is a manufacturing method of an electrophoretic display device, characterized in that consisting of SU-8 or dry film photoresist (DFR). The method of claim 1,
And a hydrophobic group is exposed on the barrier rib and the surface of the first electrode after the hydrophobic film is formed. 6. The method of claim 5,
And the hydrophobic group is a fluorine group. The method of claim 1,
The forming of the hydrophobic layer is performed by spraying a hydrophobic solution on the first electrode including the partition and curing the hydrophobic layer. 8. The method of claim 7,
The hardening of the hydrophobic solution is a method of manufacturing an electrophoretic display, characterized in that by heating the first substrate on a hot plate. The method of claim 8,
The heating on the hot plate is performed at 80 ° C to 200 ° C for 1 minute to 10 minutes. 8. The method of claim 7,
The hydrophobic solution is a manufacturing method of an electrophoretic display, characterized in that the perfluorootyltrichlorosilane (FOTS). The method of claim 1,
The formation of the hydrophobic film is performed by plasma surface treatment on the first electrode including the partition wall. 12. The method of claim 11,
The plasma surface treatment is performed with a gas containing a large amount of fluorine groups. 13. The method of claim 12,
The gas containing a large amount of fluorine groups is CF 4 The manufacturing method of the electrophoretic display apparatus characterized by the above-mentioned. The method of claim 1,
The hydrophobic film is formed by coating a hydrophobic chemical solution on the first electrode including the partition wall and then thermosetting the electrophoretic display device. The method of claim 14,
The hydrophobic chemical is HMDS (Hexamethyldisilane) manufacturing method of an electrophoretic display device. The method of claim 1,
And the electrophoretic particles including two or more charged particles expressing contrast or color in the sacrificial solvent. 17. The method of claim 16,
And a drying step of volatilizing the sacrificial solvent after the electronic ink liquid is doped. The method of claim 1,
And the hydrophobic layer lowers surface energy of the barrier ribs and the surface of the first electrode relative to the surface energy of the electronic ink liquid. A first electrode formed on the first substrate;
A plurality of partitions defining a cell region on the first electrode;
A hydrophobic film treated to expose a fluorine group on the partition wall and the surface of the first electrode;
An injected electronic ink comprising electrophoretic particles on the hydrophobic film in the cell region; And
And a second substrate having a second electrode facing the first electrode and bonded to the first substrate.
KR1020110089778A 2011-09-05 2011-09-05 Electro phoretic display device and method for manufacturing the same KR20130026272A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9477110B2 (en) 2013-11-21 2016-10-25 Samsung Display Co., Ltd. Display device and manufacturing method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9477110B2 (en) 2013-11-21 2016-10-25 Samsung Display Co., Ltd. Display device and manufacturing method thereof

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