KR20120092732A - Electrowetting display device - Google Patents

Abstract

PURPOSE: An electrowetting display device is provided to form a common voltage pad on an upper substrate, thereby simplifying manufacturing processes and reducing manufacturing costs. CONSTITUTION: A spacer(60) is formed on an external area of a second substrate. The spacer maintains the gap between a first substrate and the second substrate. A second electrode(36) is formed on a color filter layer of the second substrate and the spacer. The second electrode receives a voltage from the first substrate. The second electrode forms an electric field with a first electrode.

Description

Electrowetting Display {ELECTROWETTING DISPLAY DEVICE}

The present invention relates to an electrowetting display device.

Electrowetting refers to a phenomenon in which a contact angle changes between a solid and an electrolyte when a voltage is applied to a solid. Recently, a technique of an electrowetting display device using the electrowetting phenomenon has been proposed.

An electrowetting display device has a hydrophobic insulating material laminated on an electrode, and when water and oil are in contact with the insulating material, a voltage is applied to the water and the electrode to change the hydrophobic property of the water to become hydrophilic, thereby decreasing the contact angle of water. This lowering pushes the oil to the pixel wall, reflecting light from the reflective electrode to display the contrast. Since the reflective electrowetting display device using water and oil has fast response time and high reflectance characteristics, many studies have been made to replace existing electronic paper products and liquid crystal display devices.

The present invention has been made in view of the above, and an object thereof is to provide an electrowetting display device capable of forming a reliable partition wall.

In order to achieve the above object, an electrowetting display device according to the present invention comprises: a first substrate and a second substrate including an image display area and a non-display area; A first electrode formed on the first substrate; A first insulating layer formed on the first substrate; A second insulating layer made of a hydrophobic material and formed on the first insulating layer; Barrier ribs formed on the second insulating layer in the image non-display area of the first substrate; A color filter layer formed on the second substrate; An opaque first solution and a transparent second solution disposed between the first substrate and the second substrate, the arrangement of which is changed by an electric field between the first electrode and the second electrode to switch light; A spacer formed in an outer region of the second substrate to maintain a distance between the first substrate and the second substrate; And a second electrode formed on the color filter layer and the spacer of the second substrate to apply a voltage from the first substrate to form a first electrode and an electric field.

A common line is formed on the first substrate, and conductive balls are disposed between the common line and the spacer to apply a common voltage from the first substrate to the common electrode of the second substrate.

In addition, a sealing layer is disposed in the outer region between the first substrate and the second substrate to bond the first substrate and the second substrate, and at this time, fine conductive balls may be dispersed in the sealing layer.

In addition, an electrowetting display apparatus manufacturing method according to the present invention comprises the steps of providing a first substrate and a second substrate comprising an image display area and a non-display area; Forming a protective layer on the first substrate; Forming a first electrode on the protective layer; Forming an insulating layer made of a hydrophobic material on the protective layer; Forming a partition on the insulating layer of the non-image display area of the first substrate; Forming a spacer in an outer region of the second substrate; Forming a second electrode on a second substrate including an upper sidewall and a sidewall of the spacer; And providing a first liquid and a second liquid between the first substrate and the second substrate.

In the present invention, the common electrode is formed on the spacer and electrically connected to the lower common line to transfer the common voltage from the lower substrate to the common electrode of the upper substrate. Therefore, the process is simplified and manufacturing cost is reduced compared to the conventional electrowetting display device in which the common voltage pad is formed on the upper substrate to apply the common voltage, and the common voltage can be smoothly applied from the lower substrate to the upper substrate. .

1 is a schematic perspective view of an electrowetting display device according to a first embodiment of the present invention;
2 is a cross-sectional view of an electrowetting display device according to a first embodiment of the present invention.
3A and 3B illustrate an operation of an electrowetting display device according to a first embodiment of the present invention.
4A-4I illustrate a method of manufacturing an electrowetting display device according to a first embodiment of the present invention.
5 is a cross-sectional view of an electrowetting display device according to a second embodiment of the present invention.
6A and 6B illustrate an operation of an electrowetting display device according to a second embodiment of the present invention.
7A and 7B illustrate an operation of an electrowetting display device according to a third embodiment of the present invention.
8A and 8B illustrate an operation of an electrowetting display device according to a second embodiment of the present invention.

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

1 is a perspective view schematically illustrating a structure of an electrowetting display device according to a first embodiment of the present invention. The electrowetting display at this time is a reflective electrowetting display.

As shown in FIG. 1, the electrowetting display device 1 according to the first embodiment of the present invention is bonded in a form in which the first substrate 10 and the second substrate 30 face each other. A first liquid and a second liquid (not shown) are disposed between the substrate 10 and the second substrate 30.

The first substrate 10 is formed with a first electrode 18 that reflects light input from the outside while applying voltage to the first and second liquids, and an insulating layer 24 made of a hydrophobic material thereon. ) Is formed. In addition, a partition wall 28 is formed on the first substrate 10. The partition wall 28 partitions each pixel of the electrowetting display device 1, and the first liquid existing on the first substrate 10 and the second substrate 30 is formed by the partition wall 28. Separated by pixel.

As shown in FIG. 1, the electrowetting display device 1 has R (Red) -pixels, G (Green) -pixels, and B (Blue) -pixels repeatedly arranged in a matrix shape. The partition wall 28 is also formed in a matrix to separate each pixel. In this case, the partition wall 28 is formed in an image non-display area where an actual image is not implemented.

 The black matrix 32 and the color filter 34 are formed on the second substrate 30. The black matrix 32 is formed in the region of the second substrate 30 corresponding to the pixel and the pixel region of the first substrate 10 or the region in which the partition wall 28 is formed to prevent light from leaking to the corresponding region. do. The color filter 34 is formed between the black matrices 32 of the second substrate 30 corresponding to the pixels of the first substrate 10 to implement color.

The second electrode 36 is formed on the color filter 34. The second electrode 36 faces the first electrode 18 of the first substrate 10 so that an electric field is formed when a signal is applied from an external driving element to change the arrangement of the first liquid and the second liquid. To switch the light by the first liquid and the second liquid.

The electrowetting display device according to the first embodiment of the present invention having the above configuration will be described in more detail with reference to FIG. 2. In this case, although a plurality of pixels are formed in the electrowetting display device, only one pixel is described in the drawing for convenience of description. Since the pixel structures formed on the electrowetting display are substantially the same, only one pixel will be described so that the overall structure of the electrowetting display may be described.

As shown in Fig. 2, the electrowetting display device 1 of this embodiment comprises a first substrate 10 and a second substrate 30 made of glass or plastic and including an image display area and an image non-display area; A thin film transistor formed on the first substrate 10, a protective layer 22 formed on the first substrate 10 on which the thin film transistor is formed, and an image display area on the protective layer 22 to be externally driven. The first electrode 18 into which the image signal is input from the device, the insulating layer 24 of the hydrophobic material formed on the protective layer 22 and the first electrode 18, and the aspect ratio on the insulating layer 24. A partition 28 formed of a hydrophilic material formed in the display area, a black matrix 32 formed in the image non-display area of the second substrate 30 to block light leakage from the corresponding area, and a second substrate ( 30 is formed on the color filter layer 34 to implement color, and the second substrate 30 is formed of the first substrate 10 The second electrode 36 forming the first electrode 18 and the electric field, and the first liquid 42 and the second liquid 44 disposed between the first substrate 10 and the second substrate 30. Is made of.

The thin film transistor may include a gate electrode 11 formed on the first substrate 10, a gate insulating layer 12 formed on the gate electrode 11, and amorphous silicon (a-Si) formed on the gate insulating layer 12. And a source layer 14 and a drain electrode 15 formed on the semiconductor layer 13.

Although not shown in the drawing, a plurality of gate lines and data lines are vertically arranged on each other (ie, the gate lines and the data lines are arranged in a matrix) on the first substrate 10 by the gate lines and the data lines. The partitioned region is defined as a pixel, and a thin film transistor is disposed in each partitioned pixel. The gate electrode 11 of the thin film transistor is electrically connected to the gate line and the source electrode 14 is electrically connected to the data line. When the scan signal is input to the gate electrode 11 through the gate line, the semiconductor layer 13 ) Is activated and the thin film transistor is turned on and at the same time an image signal is input to the first electrode 18 through the source electrode 14 and the drain electrode 15 through the data line.

The protective layer 22 is made of an organic insulating material such as BCB (Benzo Cyclo Butene) or photo acryl, and at this time, a contact hole is formed in the protective layer 22 on the drain electrode 15 of the thin film transistor. The first electrode 18 formed on the protective layer 22 is electrically connected to the drain electrode 15 of the thin film transistor through the contact hole. In addition, an inorganic insulating material such as SiO ₂ and SiN ₂ may be used as the protective layer 22.

The first electrode 18 is a pixel electrode, and forms an electric field with the second electrode 36 of the second substrate 30 as an image signal is input, and is made of a metal having good reflectivity to receive light incident from the outside. Reflect. That is, the first electrode 18 functions not only as an electrode for applying a signal but also as a reflective layer.

The first electrode 18 may be formed of a transparent conductive material. In this case, the incident light must be reflected to the outside by disposing a separate reflective layer under the first electrode 18.

The insulating layer 24 is formed of a hydrophobic material or hydrophobic treatment of the surface. The partition 28 is made of a hydrophilic material. The height of the partition wall 28 may be higher than the height of the first liquid 42 that is molten when the first liquid 42 is driven to the partition wall 28 by the second liquid 44.

The black matrix 32 is for preventing light from leaking into an image non-display area, that is, an area in which the partition wall 28 is formed, and is made of a metal oxide such as CrO, CrO ₂ , or a black resin. The color filter layer 34 is formed in the image display area to implement actual colors. The R, G, and B pixels are repeatedly arranged, and the second electrode 36 is a common electrode to which a common voltage is applied. An electric field is formed to face the pixel electrode 18 formed on the substrate 10. In this case, the second electrode 36 may be formed of a transparent conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a transparent conductive material such as a conductive polymer and carbon nanotubes. have.

The first liquid 42 and the second liquid 44 are formed between the first substrate 10 and the second substrate 30. As the non-polar liquid, the first liquid 42 mainly uses black oil, for example, but an opaque organic solvent such as silicon oil, mineral oil, carbon tetrachloride (CCl ₄ ) in a black state may be used. The second liquid 44 may be, for example, a transparent aqueous solution as a polar liquid. In this case, the aqueous solution mainly consists of water, and may include an electrolyte such as NaCl.

At this time, since the first liquid 42 and the second liquid 44 do not mix with each other, a boundary is formed. The second liquid 44 is an aqueous solution, and the first substrate 10 has a hydrophobic insulating layer 24. Since the partition wall 28 is formed of a hydrophilic material and the first liquid 42 and the second liquid 44 are filled between the first substrate 10 and the second substrate 30, the first liquid 42 ) Is positioned at the lower side, that is, the first substrate 10 side, and the second liquid 44 is positioned at the upper side, that is, the second substrate 30 side.

In the outer regions of the first substrate 10 and the second substrate 30, spacers 60 are formed along the outer regions of the first substrate 10 and the second substrate 30 to form the first substrate 10 and the first substrate 10. The gap between the two substrates 30 can be kept constant. In the present embodiment, the spacer 60 is formed on the second substrate 30, but the spacer 60 may be formed on the first substrate 10. The common electrode 36 is formed on the sidewalls and the upper surface of the spacer 60, and a sealing layer 66 is formed on the outside thereof to bond the first substrate 10 and the second substrate 30 and seal them at the same time. do.

The common line 62 or the common voltage pad is formed on the first substrate 10 facing the spacer 60. The common voltage is applied to the common line 62 from an external driving element, and a conductive ball 64 having good conductivity is positioned between the common line 62 and the common electrode 36 formed on the spacer 60. The voltage applied to the line 62 is supplied to the common electrode 36.

The sealing layer 66 is formed of a thermosetting resin or an ultraviolet curable resin, and is formed by applying a sealing material to an outer region of the first substrate 10 or the second substrate 30 and then applying heat or ultraviolet rays to cure the sealing material. do.

In addition, a fine size conductive ball may be dispersed in the sealing layer 66. As such, as the fine conductive balls are dispersed in the sealing layer 66, the sealing layer 66 becomes conductive, and as a result, the conductivity between the common electrode 36 and the common line 62 is improved. At this time, the conductive ball 64 is disposed between the common electrode 36 and the common line 62 of the partition 28, but the voltage is reduced by the fine conductive ball of the sealing layer 66 without the conductive ball 64. It may be applied to the common electrode 36.

The reason why the common electrode 36 is formed on the sidewall and the upper region of the spacer 60 as described above is as follows.

There may be various methods for applying a common voltage to the common electrode 36 of the second substrate 30 in the electrowetting display device. For example, a common voltage applying pad may be formed on the second substrate 30 to apply the common voltage directly to the common electrode 36. However, in this case, the number of parts of the second substrate 30 is increased and the process is complicated, thereby increasing the manufacturing cost. As another example, there is a method of applying a common voltage to the common electrode 36 of the second substrate 30 through the first substrate 10. In this method, the first substrate 10 and the second substrate 30 must be electrically connected by Ag dots or conductive balls. However, in the case of an electrowetting display device, the first substrate 10 and the second substrate 30 are electrically connected to each other. Since the interval of is 100 micrometers or more, it was impossible to electrically connect the space | interval of 100 micrometers or more by these Ag dots and a conductive ball.

However, in the present invention, since the first substrate 10 and the second substrate 30 are electrically connected to each other by forming the spacer 60 and forming the common electrode 36 thereon, the spacer 60 allows the first substrate. Since the gap of the electrical connection between the substrate 10 and the second substrate 30 is greatly reduced, the first substrate 10 and the second substrate 30 can be electrically connected smoothly.

Referring to the operation of the electrowetting display device having the above configuration is as follows.

3A and 3B are diagrams illustrating electrowetting display devices when signals are applied to and not applied to the first electrode 18, respectively, in which a detailed configuration such as a thin film transistor is omitted. ), Only the second substrate 30, the first electrode 18 and the second electrode 36, the partition 28, the insulating layer 24, the first liquid 42 and the second liquid 44 are shown. . In addition, three adjacent R, G, and B pixels are shown in the figure.

As shown in FIG. 3A, when no signal is applied to the first electrodes 18a, 18b, and 18c formed on the R, G, and B pixels, the first electrodes 18a, 18b, and 18c and the second electrode 36 are not applied. Since no electric field is formed between the first and second, the opaque first liquid 42 is evenly spread on the first substrate 10 of the R, G, and B pixels. In this state, when light is incident from the outside (that is, from the top of the second substrate 30), the light is absorbed by the opaque first liquid 42 and the light is not reflected to the outside so that the light of the electrowetting display device is The screen is black.

As shown in FIG. 3B, no signal is applied to the first electrode 18a of the R-pixel and the first electrode 18c of the B-pixel, and the signal is applied only to the first electrode 18b of the G-pixel. In this case, no electric field is formed in the R-pixel and B-pixel, whereas an electric field is formed in the G-pixel. In this case, a common voltage is applied to the common electrode 36 of the second substrate 30. That is, a common voltage applied from the outside through the common line formed on the first substrate 10 is formed on the spacer 60 through the conductive ball 64 (or the microconductive ball of the sealing layer 68). 36, an electric field is formed between the pixel electrode 18b and the common electrode 36 in the G-pixel.

As such, as the electric field is formed in the G-pixel, the opaque first liquid 42 in the R- and B-pixels is spread evenly on the first substrate 10 of the R- and B-pixels. In the G-pixel, an electric field is applied to improve the wettability characteristic of the insulating layer 24 due to the electrowetting phenomenon, so that the insulating layer 24 has a hydrophilic characteristic, and the second liquid of the G-pixel is caused by the hydrophilic characteristic. 44 is spread on the first substrate 10 of the G-pixel. Therefore, the first liquid 42 is pushed to the side in the G-pixel by spreading the second liquid 44 onto the first substrate 10, so that on the first substrate 10 of the G-pixel. The transparent second liquid 44 is spread and the opaque first liquid 42 is driven toward the partition 28.

When light is incident from the outside in this state, since the opaque first liquid 42 is uniformly spread on the first substrate 10 in the R-pixel and B-pixel, the light incident from the outside is transmitted to the first liquid ( Is absorbed by 42) and black is displayed on the screen. On the other hand, in the G-pixel, since the light incident from the outside is transmitted by the transparent second liquid 44 and reflected by the first electrode 18, the light is transmitted through the G-color filter layer 34b and output to the outside. Green color is realized. As a result, when a signal is applied only to the G-pixel, a green color is implemented on the screen.

By applying a voltage to the first electrodes 18a and 18c of the R-pixel and B-pixel, respectively, a red color and a blue color can be realized on the screen, and a desired color can be realized by adjusting the luminance of these colors. .

As described above, in the first embodiment of the present invention, an image is realized by blocking and reflecting light by applying a voltage to the second liquid 44 composed of the opaque first liquid 42 and the aqueous solution to change its distribution. It becomes possible. Such an electrowetting device has advantages of low power consumption and good contrast ratio by the existing liquid crystal display or organic light emitting display device.

Hereinafter, a method of manufacturing an electrowetting display device according to a first embodiment of the present invention will be described with reference to FIGS. 4A to 4H.

First, as shown in FIG. 4A, a sputtering method is performed on an opaque metal having good conductivity such as Cr, Mo, Ta, Cu, Ti, Al, or Al alloy on the first substrate 10 made of a transparent material such as glass or plastic. After stacking by sputtering process and etching by photolithography process to form gate electrode 11, CVD (Chemicla Vapor) is formed over the entire first substrate 10 on which the gate electrode 11 is formed. The gate insulating layer 12 is formed by stacking an inorganic insulating material such as SiO ₂ or SiNx by a deposition method.

Subsequently, a semiconductor material such as amorphous silicon (a-Si) is deposited on the entire first substrate 10 by CVD and then etched to form a semiconductor layer 13. In addition, although not shown in the drawing, an ohmic contact for ohmic-contacting the source electrode and the drain electrode to be subsequently formed with a semiconductor layer 13 by doping impurities or stacking amorphous silicon with impurities added to a part of the semiconductor layer 13 To form an ohmic contact layer.

Subsequently, an electrically conductive opaque metal such as Cr, Mo, Ta, Cu, Ti, Al, or Al alloy is laminated on the first substrate 10 by sputtering, and then etched, and then etched on the semiconductor layer 113. In other words, the source electrode 14 and the drain electrode 15 are formed on the ohmic contact layer, and then BCenzo (Benzo Cyclo Butene) is formed over the entire first substrate 10 having the source electrode 14 and the drain electrode 15 formed thereon. ) Or a protective layer 22 is formed by stacking an organic insulating material such as photo acryl or an organic insulating layer such as SiO ₂ or SiN ₂ .

In addition, although not shown, the protective layer 22 may be formed of a plurality of layers. For example, the protective layer 22 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, or inorganic 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 22 is formed to be flat, and the interface characteristic with the protective layer 22 is improved by applying the inorganic insulating layer. In addition, a contact hole is formed in the protective layer 22 to expose the drain electrode 15 of the thin film transistor to the outside.

Subsequently, as shown in FIG. 4B, a metal having good reflectivity and good conductivity, such as Al or Al alloy, is laminated and etched on the protective layer 22 by a sputtering process d to etch the first electrode 18. ). In this case, the first electrode 18 is electrically connected to the drain electrode 15 of the thin film transistor through a contact hole formed in the protective layer 22.

Subsequently, as shown in FIG. 4C, a hydrophobic material such as fluoropolymer or silicon is coated on the protective layer 22 and the first electrode 18 to form the insulating layer 24. On top of that, as shown in FIG. 4D, a hydrophilic material is applied and patterned to form a partition wall 28 in the image non-display area on the insulating layer 24.

Next, as shown in FIG. 4E, an opaque first liquid 42 such as black oil or the like is applied onto the hydrophobic insulating layer 24 of the pixel partitioned by the image display area, that is, the partition wall 28.

Thereafter, as shown in FIG. 4F, the black matrix 32 and the color filter layer 34 are formed on the second substrate 30 made of glass or plastic, and the second electrode 36 is formed thereon. The black matrix 32 is formed by laminating metal oxides such as CrO or CrO ₂ and then etching them by a photolithography process or by coating and etching black resin, and the color filter layer 34 is formed by the black matrix 32. It is formed by laminating red, green and blue inks and resists.

Subsequently, as shown in FIG. 4G, an organic insulating material is applied and patterned over the entire second substrate 30 to form a spacer 60 in the outer region of the second substrate 30, and then shown in FIG. 4H. As described above, the common electrode 36 is formed by stacking a transparent conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO) or a transparent conductive material such as a conductive polymer and carbon nanotubes. . In this case, the common electrode 36 is formed not only on the color filter layer 34 in the pixel region but also on the sidewall and the top of the spacer 60.

Thereafter, as shown in FIG. 4I, the sealing layer 66 is formed in the outer region of the first substrate 10 or the second substrate 30, and the first substrate 10 and the second substrate 30 are formed. After the first substrate 10 and the second 30 are bonded to each other in an aligned state, the second liquid 44 made of an aqueous solution is injected between the first and second substrates 10 and 30. In addition, ultraviolet light and heat are applied to the sealing layer 66 to cure the sealing layer 66 to complete the electrowetting display device.

5 is a diagram illustrating an electrowetting display device according to a second exemplary embodiment of the present invention. In this case, the electrowetting display device of this embodiment is a transmissive display device, which is provided with a backlight for supplying light to the display device although not shown in the drawing. Since the electrowetting display device of this embodiment is similar in structure to the display device of the first embodiment, a similar structure will be briefly described and only the other parts will be described in detail.

As shown in FIG. 5, the dry wet display device of this embodiment includes a first substrate 110 and a second substrate 130 including an image display area and an image non-display area, and a first liquid (between). 142 and the second liquid 144 is filled.

The first substrate 110 is a thin film transistor array substrate, in which a gate line and a data line (not shown) defining a plurality of pixels are arranged, and a thin film transistor is disposed in each pixel. The thin film transistor may include a gate electrode 111 formed on the first substrate 110, a gate insulating layer 112 formed on the gate electrode 111, a semiconductor layer 113 formed on the gate insulating layer 112, A source electrode 114 and a drain electrode 115 formed on the semiconductor layer 13.

A protective layer 122 made of an organic insulating material or an inorganic insulating material is formed on the first substrate 110 on which the thin film transistor is formed, and a first electrode 122 is formed on the protective layer 122. The first electrode is formed by stacking a transparent conductive oxide such as ITO or IZO or a transparent polymer such as a conductive polymer and a carbon nanotube, and a thin film transistor through a contact hole formed in the protective layer 122. It is electrically connected to the drain electrode 115.

An insulating layer 124 made of a hydrophobic material is disposed on the passivation layer 122 and the first electrode 118, and a partition 128 made of a hydrophilic material is formed in an image non-display area on the insulating layer 124. .

The second substrate 130 includes a black matrix 132 formed in an image non-display area to block light leakage to the corresponding area, a color filter layer 134 formed on the second substrate 30 to implement color; The second electrode 136 is formed on the second substrate 30 to form an electric field with the first electrode 118 of the first substrate 110.

The first liquid 142 and the second liquid 144 are filled between the first substrate 110 and the second substrate 130. In this case, the first liquid 142 is a non-polar liquid and the second liquid 144 is a polar liquid and forms a boundary without mixing with each other due to different properties. In this case, since the second liquid 144 is an aqueous solution, the hydrophobic insulating layer 124 is formed on the first substrate 110, and the partition 128 is made of a hydrophilic material, the first liquid 142 is positioned below the second liquid. Liquid 144 is placed on top.

In the outer regions of the first substrate 110 and the second substrate 130, spacers 160 are formed along the outer sides of the first substrate 110 and the second substrate 130 to form the first substrate 110 and the first substrate 110. The distance between the two substrates 130 can be kept constant. The common electrode 136 is formed on the sidewalls and the upper surface of the spacer 160, and a sealing layer 166 is formed on the outside thereof to bond the first substrate 110 and the second substrate 130 and seal them at the same time. do.

A common line 162 or a common voltage pad is formed on the first substrate 110 facing the spacer 160, and at this point, conductivity is established between the common line 162 and the common electrode 136 formed on the spacer 160. A good conductive ball 164 is positioned to supply a voltage applied to the common line 162 from an external driving device to the common electrode 136.

The operation of the electrowetting display device according to the second embodiment of the present invention having the above configuration will now be described with reference to FIGS. 6A and 6B.

First, as shown in FIG. 6A, when a signal is not applied to the first electrodes 118a, 118b, and 118c formed in the R, G, and B pixels, the first electrodes 118a, 118b, 118c, and the second electrode. Since no electric field is formed between the 136, the opaque first liquid 142 is evenly spread on the first substrate 110 of the R, G, and B pixels.

In this state, when light is incident from a backlight (not shown) disposed below the first substrate 110, the light is blocked by the opaque first liquid 142 and the upper portion of the second substrate 130. Since light is not transmitted, black is implemented on the screen of the electrowetting display device.

As shown in FIG. 6B, the signal is not applied to the first electrode 118a of the R-pixel and the first electrode 118c of the B-pixel, and the signal is applied only to the first electrode 118b of the G-pixel. In this case, no electric field is formed in the R-pixel and B-pixel, whereas an electric field is formed in the G-pixel. In this case, a common voltage is applied to the common electrode 136 of the second substrate 130. That is, the common voltage applied from the outside through the common line formed on the first substrate 110 is supplied to the common electrode 136 formed on the spacer 160 through the conductive ball 164, so that the pixel electrode 118b is applied to the G-pixel. ) And the common electrode 136.

As such, as the electric field is formed in the G-pixel, the opaque first liquid 142 spreads evenly on the first substrate 110 of the R-pixel and the B-pixel in the R-pixel and the B-pixel. In the G-pixel, an electric field is applied to improve the wettability characteristic of the insulating layer 124 due to the electrowetting phenomenon, so that the insulating layer 124 has a hydrophilic characteristic, and the second liquid of the G-pixel is caused by the hydrophilic characteristic. 144 is spread on the first substrate 110 of the G-pixel. Therefore, the first liquid 142 is pushed to the side in the G-pixel by the spread of the second liquid 144 on the first substrate 110 on the first substrate 110 of the G-pixel. The transparent second liquid 144 is present and the opaque first liquid 142 is driven toward the partition 128.

When light is incident from the backlight in this state, since the opaque first liquid 142 is uniformly spread on the first substrate 110 in the R-pixel and the B-pixel, the light incident from the outside is transmitted to the first liquid ( Blocked by 142, black is displayed on the screen. On the other hand, in the G-pixel, since light incident from the outside passes through the transparent second liquid 144 and then passes through the G-color filter layer 134b, a green color is realized. As a result, when a signal is applied only to the G-pixel, a green color is implemented on the screen.

By applying a voltage to the first electrodes 118a and 118c of the R-pixel and B-pixel, respectively, a red color and a blue color can be realized on the screen, and a desired color can be realized by adjusting the luminance of these colors. .

As described above, in the second embodiment of the present invention, the second liquid 144 composed of the opaque first liquid 142 and the aqueous solution is applied with a voltage to change the distribution thereof, thereby blocking and transmitting light to implement an image. It becomes possible.

7A and 7B illustrate an electrowetting display device according to a third embodiment of the present invention, with reference to this drawing, a driving method of the electrowetting display device of the third embodiment will be described. At this time, the electrowetting display device of this embodiment is a reflective display device, and the specific structure of the thin film transistor and the like is the same as that of the first and second embodiments, so that the configuration thereof will be omitted and only other configurations and operations will be mainly described. do.

As shown in FIG. 7A, first electrodes 218, 218b, and 218c are formed on R, G, and B pixels of the first substrate 210, and an insulating layer 224 made of a hydrophobic material is disposed thereon. A partition 228 made of a hydrophilic material is formed in an image non-display area between the pixel and the pixel.

Although not shown in the drawing, a plurality of gate lines and data lines are vertically and horizontally arranged on the first substrate 210 to define a plurality of pixels, and thin film transistors are disposed in each pixel to turn the thin film transistors on and off. Image signals are externally applied to the first electrodes 218a, 218b, and 218c through the thin film transistors.

The first electrodes 218a, 218b, and 218c are formed of a metal having good reflectance, and thus form a electric field as a signal is applied, and at the same time, reflect the light incident from the outside. In addition, the first electrodes 218a, 218b, and 218c may be formed of a transparent conductive material. In this case, a reflective layer is provided below the first electrodes 218a, 218b, and 218c to reflect light incident from the outside.

The black substrate 232 is formed on the second substrate 230 to block light leakage to the corresponding region, and the first electrode of the first substrate 210 is formed on the second substrate 230. 218 and a second electrode 236 forming an electric field are formed. In this case, the second electrode 230 is formed by stacking a transparent conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a transparent conductive material such as a conductive polymer and carbon nanotubes. .

The first liquid 242 and the second liquid 244 are filled in the first substrate 210 and the second substrate 230. In this case, the first liquid 242 may be used as a non-polar color liquid, silicon oil, mineral oil, carbon tetrachloride (CCl ₄ ) containing the dyes of R, G, B, the second liquid 244 is a polar liquid, Mainly using aqueous solution, such as water.

When the first liquid 242 and the second liquid 244 are filled between the first substrate 210 and the second substrate 230, the first liquid 242 and the second liquid 244 have different properties. The second liquid 244 is an aqueous solution, the hydrophobic insulating layer 224 is formed on the second substrate 210, and the partition wall 228 is made of a hydrophilic material. ) Is located at the bottom and the second liquid 244 is located at the top.

In the outer regions of the first substrate 210 and the second substrate 230, spacers 260 are formed along the outer sides of the first substrate 210 and the second substrate 230 to form the first substrate 210 and the first substrate 210. The gap between the two substrates 230 can be kept constant. The common electrode 236 is formed on the sidewalls and the upper surface of the spacer 260, and a sealing layer 266 is formed on the outside thereof to bond the first substrate 210 and the second substrate 230 and seal the same. do.

A common line 262 or a common voltage pad is formed on the first substrate 210 facing the spacer 260. In this case, conductivity is established between the common line 262 and the common electrode 236 formed on the spacer 260. A good conductive ball 264 is positioned to supply a voltage applied to the common line 262 from an external driving device to the common electrode 236.

When the signal is not applied to the first electrodes 218a, 218b, and 218c formed on the R, G, and B pixels in the electrowetting display device configured as described above, the first electrodes 218a, 218b, and 218c and the second electrode ( Since no electric field is formed between the 236, the first liquids 242 of R, G, and B colors are spread evenly on the first substrate 210 of the R, G, and B pixels, respectively.

In this state, when light is incident from the outside (that is, from the top of the second substrate 230), the light passes through the first liquid 242 of R, G, and B colors, and then the lower first electrode 218a. Since it is reflected by 218b) and outputted to the outside, colors of R, G, and B can be implemented in each of the R, G, and B pixels.

As shown in FIG. 7B, a signal is not applied to the first electrode 218a of the R-pixel and the first electrode 218c of the B-pixel, and only a signal is applied to the first electrode 218b of the G-pixel. In this case, no electric field is formed in the R-pixel and B-pixel, whereas an electric field is formed in the G-pixel. In this case, a common voltage is applied to the common electrode 236 of the second substrate 230. That is, the common voltage applied from the outside through the common line formed on the first substrate 210 is supplied to the common electrode 236 formed on the spacer 260 through the conductive ball 264, so that the pixel electrode 218b is applied to the G-pixel. ) And the common electrode 236.

As such, as the electric field is formed in the G-pixel, the first liquid 242 of red color is spread evenly on the first substrate 210 in the R-pixel and the first liquid 242 of blue color in the B-pixel. Is spread evenly on the first substrate 210, while an electric field is applied in the G-pixel to improve the wettability characteristic of the hydrophobic insulating layer 224 due to the electrowetting phenomenon, and thus the insulating layer 224 has hydrophilic characteristics. Due to this hydrophilic property, the second liquid 244 is spread on the first substrate 210 of the G-pixel. Accordingly, the first liquid 242 of green color is pushed to the side surface in the G-pixel by spreading the second liquid 244 onto the first substrate 210. The transparent second liquid 244 is spread on the 210, and the green first liquid 242 is driven toward the partition wall 228.

In this state, when light is incident from the outside, the first liquid 242 of red color is evenly spread on the first substrate 210 in the R-pixel, and the first liquid 242 of blue color is first in the B-pixel. Since it spreads evenly on the substrate 210, the light incident from the outside passes through the red first liquid 242 and the blue first liquid 242, respectively, and then again at the first electrodes 218a and 218b. Since it is reflected and output to the outside, red and blue colors are implemented in the R-pixel and B-pixel, respectively. On the other hand, in the G-pixel, white is realized because light incident from the outside is transmitted through the transparent second liquid 244 to be reflected by the first electrode 218 and then output to the outside. As a result, when a signal is applied only to the G-pixel, a mixed color of red color and blue color is implemented on the screen.

By applying a voltage to the first electrodes 218a and 218c of the R-pixel and B-pixel, respectively, a mixed color of green and blue colors or a mixed color of red and blue colors can be realized on the screen. By adjusting the luminance of the color it is possible to achieve the desired color.

8A and 8B illustrate an electrowetting display device according to a fourth embodiment of the present invention. The electrowetting display device of this embodiment is a transmissive display device, and the specific structure of the thin film transistor is shown in the first embodiment and the first embodiment. Since it is the same as 2nd Embodiment, these structures are abbreviate | omitted and only a different structure and operation | movement are demonstrated mainly.

As shown in FIG. 8A, first electrodes 318, 318b, and 318c are formed on the R, G, and B pixels of the first substrate 310, and an insulating layer 324 made of a hydrophobic material is disposed thereon. A partition 328 made of a hydrophilic material is formed in the non-display region between the pixel and the pixel.

Although not shown in the drawing, a plurality of gate lines and data lines are vertically and horizontally arranged on the first substrate 310 to define a plurality of pixels, and a thin film transistor is disposed in each pixel to turn the thin film transistor on and off. Image signals are externally applied to the first electrodes 318a, 318b, and 318c through the thin film transistors.

The first electrodes 318a, 318b, and 318c are formed by stacking a transparent conductive oxide such as ITO or IZO, a conductive polymer, and a transparent conductive material such as carbon nanotubes.

The second substrate 330 includes a black matrix 332 formed in an image non-display area to block leakage of light to the corresponding area, color filter layers 334a, 334b, and 334c for real color, and a second substrate. A second electrode 336 is formed on the 330 to form an electric field with the first electrode 318 of the first substrate 310. In this case, the second electrode 330 is formed by stacking a transparent conductive oxide such as ITO or IZO, a conductive polymer, and a transparent conductive material such as carbon nanotubes.

The first liquid 342 and the second liquid 344 are filled in the first substrate 310 and the second substrate 330.

At this time, the first liquid 242 is a non-polar liquid, silicon oil, a mineral oil, carbon tetrachloride (CCl ₄ ) containing a phosphor therein can be used, the second liquid 344 is a polar liquid, mainly water An aqueous solution is used.

When the first liquid 342 and the second liquid 344 are filled between the first substrate 310 and the second substrate 330, the first liquid 342 and the second liquid 344 have different properties. Due to this, a boundary is formed without mixing, in which case the second liquid 344 is an aqueous solution, an insulating layer 324 is formed on the second substrate 310, and the partition wall 328 is made of a hydrophilic material. Is located at the bottom and the second liquid 344 is located at the top.

In the outer regions of the first substrate 310 and the second substrate 330, spacers 360 are formed along the outer sides of the first substrate 310 and the second substrate 330 to form the first substrate 310 and the first substrate 310. The gap between the two substrates 330 can be kept constant. The common electrode 336 is formed on the sidewalls and the upper surface of the spacer 360, and a sealing layer 266 is formed on the outside thereof to bond the first substrate 310 and the second substrate 330 and seal the same. do.

A common line 362 or a common voltage pad is formed on the first substrate 310 facing the spacer 360. In this case, conductivity is established between the common line 362 and the common electrode 336 formed on the spacer 360. A good conductive ball 364 is positioned to supply a voltage applied to the common line 362 from an external driving device to the common electrode 336.

The backlight is disposed under the display panel including the first substrate 310 and the second substrate 330. The backlight is an ultraviolet (UV) backlight, which is disposed on one side or both sides of the light source 360 to emit ultraviolet rays, and is disposed below the first substrate 310 to guide ultraviolet rays input to one side or both sides to the display panel. Light guide plate 362. The light guide plate 362 is a plate for storing ultraviolet rays, and a material having a refractive index of about 1.5 may be used.

In the electrowetting display device configured as described above, when no signal is applied to the first electrodes 318a, 318b, and 318c formed on the R, G, and B pixels, the first electrodes 318a, 318b, and 318c and the second electrode ( Since no electric field is formed between the 336, the first liquid 342 is evenly spread on the first substrate 310 of the R, G, and B pixels, respectively.

In this state, when ultraviolet light is incident on the first liquid 342 of the R, G, and B pixels from the backlight, the phosphor contained in the first liquid 342 emits light, and visible light is output from the first liquid 342. The output visible light passes through the color filter layers 324a, 324b, and 324c of the R, G, and B colors, respectively, so that red, green, and blue colors may be implemented in the respective R, G, and B pixels.

As shown in FIG. 8B, no signal is applied to the first electrode 318a of the R-pixel and the first electrode 318c of the B-pixel, and a signal is applied only to the first electrode 318b of the G-pixel. In this case, no electric field is formed in the R-pixel and B-pixel, whereas an electric field is formed in the G-pixel. In this case, a common voltage is applied to the common electrode 336 of the second substrate 330. That is, the common voltage applied from the outside through the common line formed on the first substrate 310 is supplied to the common electrode 336 formed on the spacer 360 through the conductive ball 364 to the pixel electrode 318b in the G-pixel. ) And the common electrode 336.

As such, as the electric field is formed in the G-pixel, the first liquid 342 is evenly spread on the first substrate 210 in the R-pixel and the B-pixel, while in the G-pixel, the electric field is applied to the electric field. Wetting improves the wettability of the insulating layer 324, so that the hydrophobic insulating layer 324 has a hydrophilic property, and the second liquid 344 is the first substrate 310 of the G-pixel by the hydrophilic property. It will spread to the phase. Therefore, the first liquid 342 including the phosphor is pushed to the side surface in the G-pixel by spreading the second liquid 344 onto the first substrate 310 so that the first substrate of the G-pixel ( The transparent second liquid 244 is spread on the 310, and the first liquid 342 including the phosphor is driven toward the partition wall 328.

When ultraviolet light is incident from the backlight in this state, since the first liquid 342 is evenly spread on the R-pixel and B-pixel on the first substrate 310, the light incident from the outside is R-pixel and B-pixel. When incident on the first liquid 342, the phosphor in the first liquid 342 emits visible light from the first liquid 342, and the output visible light is R-pixel and B-, respectively. Through the color filter layers 324a and 324c of the pixel, red and blue colors may be realized in each of the R-pixel and the B-pixel, respectively.

On the other hand, in the G-pixel, since the second liquid 344 is in contact with the insulating layer 324, ultraviolet rays incident from the backlight are reflected by the second liquid 344. Since water constituting the second liquid 344 generally has a refractive index of about 1.33, ultraviolet light incident from the backlight to the second liquid 344 is reflected from the second liquid 344 to the backlight. Thus, black is realized in the G-pixel because no visible light is emitted in the G-pixel. As a result, when a signal is applied only to the G-pixel, a mixed color of red color and blue color is implemented on the screen.

By applying a voltage to the first electrodes 318a and 318c of the R-pixel and B-pixel, respectively, a mixed color of green and blue colors or a mixed color of red and blue colors can be realized on the screen. By adjusting the luminance of the color it is possible to achieve the desired color.

As described above, in the electrowetting display device according to the present invention, an image may be embodied in a reflection type or a transmission type by using an electrowetting property of a liquid. In this case, since the common electrode is formed on the sidewalls and the upper portions of the spacers disposed in the outer regions of the first substrate and the second substrate and contacts the lower electrode, the common voltage is smoothly supplied from the first substrate to the common electrode.

In the above description, the electrowetting display device having the specific structure is described, but the present invention is not limited to the electrowetting display device having the specific structure. If the common electrode is formed on the top and sidewalls of the spacer to electrically connect the first substrate and the second substrate, the present invention can be applied to an electrowetting display device having any structure.

In addition, in the above description, the insulating layer on the protective layer is made of a hydrophobic material and the partition is made of a hydrophilic material. However, the insulating layer on the protective layer is made of a hydrophilic material and the partition may be made of a hydrophobic material. In this case, the first liquid is composed of a polar liquid such as an aqueous solution and the second liquid is composed of a nonpolar liquid such as an oil. When the first liquid and the second liquid are filled between the first substrate and the second substrate, the first substrate is filled. The first liquid is present on the side and the second liquid is present on the second substrate side. The electrowetting display of this structure will also be driven by the same method as described above.

10,20: substrate 18,36: electrode
24 hydrophobic insulating layer 28 partition wall
32: Black matrix `34: Color filter layer
42,44: Liquid 60: Spacer

Claims (30)

A first substrate and a second substrate including an image display area and a non-display area;
A first electrode formed on the first substrate;
A first insulating layer formed on the first substrate;
A second insulating layer made of a hydrophobic material and formed on the first insulating layer;
Barrier ribs formed on the second insulating layer in the image non-display area of the first substrate;
A color filter layer formed on the second substrate;
An opaque first solution and a transparent second solution disposed between the first substrate and the second substrate, the arrangement of which is changed by an electric field between the first electrode and the second electrode to switch light;
A spacer formed in an outer region of the second substrate to maintain a distance between the first substrate and the second substrate; And
And a second electrode formed on the color filter layer and the spacer of the second substrate to apply a voltage from the first substrate to form a first electrode and an electric field. The electrowetting display device according to claim 1, wherein the first liquid is a nonpolar black liquid and the second liquid is a polar transparent liquid solution. The electrowetting display device according to claim 1, wherein the first electrode is made of a metal having good reflectivity and the second electrode is made of a transparent conductive material. The electrowetting display device of claim 1, further comprising a reflective layer formed under the first electrode to reflect light incident from the outside. The method of claim 3 or 4, wherein when no electric field is applied between the first electrode and the second electrode, light input from the upper portion of the second substrate is absorbed by the first liquid, and the first electrode and the second electrode. The electrowetting display device of claim 1, wherein the first liquid is pushed toward the partition wall as an electric field is applied between the electrodes, and the light applied from the outside is not absorbed by the first liquid and is reflected to the upper portion of the second substrate. The electrowetting display device of claim 1, wherein the first electrode is made of a transparent conductive material. The method of claim 6, wherein when no electric field is applied between the first electrode and the second electrode, light input from the lower portion of the first substrate is absorbed by the first liquid, and an electric field is formed between the first electrode and the second electrode. The first liquid is pushed toward the partition wall as is applied, the light applied from the outside is transmitted by the first liquid is not absorbed by the first liquid is output to the upper portion of the second substrate. The method of claim 1,
A common line formed on the first substrate; And
And a conductive ball disposed between the common line and the spacer. 2. The electrowetting display device of claim 1, further comprising a sealing layer disposed in an outer region between the first and second substrates to bond the first and second substrates together. The electrowetting display device of claim 9, wherein fine sealing balls are dispersed in the sealing layer. A first substrate and a second substrate including an image display area and a non-display area;
A first electrode formed on the first substrate;
A first insulating layer formed on the first substrate;
A second insulating layer made of a hydrophobic material and formed on the first insulating layer;
Barrier ribs formed on the second insulating layer in the image non-display area;
A first solution and a transparent second solution disposed between the first substrate and the second substrate, the arrangement of which is changed by an electric field between the first electrode and the second electrode to switch light;
A spacer formed in an outer region of the second substrate to maintain a distance between the first substrate and the second substrate; And
And a second electrode formed on the color filter layer and the spacer of the second substrate to apply a voltage from the first substrate to form a first electrode and an electric field. The electrowetting display device according to claim 11, wherein the first liquid is a non-polar color liquid to which R, G, and B dyes are added, and the second liquid is a transparent polar aqueous solution. The electrowetting display device according to claim 11, wherein the first electrode is made of a metal having good reflectivity and the second electrode is made of a transparent conductive material. The electrowetting display device of claim 11, further comprising a reflective layer formed under the first electrode to reflect light incident from the outside. 15. The method of claim 13 or 14, wherein when no electric field is applied between the first electrode and the second electrode, the light input from the upper portion of the second substrate is transmitted through the first liquid and then reflected and output to the outside. The color corresponding to the first liquid is realized, and as the electric field is applied between the first electrode and the second electrode, the first liquid is pushed toward the partition wall, and the light applied from the outside is reflected without being transmitted through the first liquid and is output to the outside. And an electrowetting display device to implement white. The method of claim 11,
A common line formed on the first substrate; And
And a conductive ball disposed between the common line and the spacer. 12. The electrowetting display device according to claim 11, further comprising a sealing layer disposed in an outer region between the first substrate and the second substrate to bond the first substrate and the second substrate together. 18. The electrowetting display device according to claim 17, wherein fine sealing balls are dispersed in the sealing layer. A first substrate and a second substrate including an image display area and a non-display area;
A first electrode formed on the first substrate;
A first insulating layer formed on the first substrate;
A second insulating layer formed of a hydrophobic material and formed on the first insulating layer and having an opening through which a portion of the first insulating layer is exposed;
Barrier ribs formed in said second insulating layer and said opening in an image non-display area of a first substrate;
A color filter layer formed on the second substrate;
A first solution and a transparent second solution disposed between the first substrate and the second substrate, the first solution and a second solution including phosphors whose arrangement is changed by an electric field between the first electrode and the second electrode to switch light;
A spacer formed in an outer region of the second substrate to maintain a distance between the first substrate and the second substrate;
A second electrode formed on the color filter layer and the spacer of the second substrate to apply a voltage from the first substrate to form a first electrode and an electric field; And
And an backlight disposed under the first substrate, the backlight configured to supply ultraviolet rays to the first and second solutions. 20. The electrowetting display device of claim 19, wherein the first electrode and the second electrode are made of a transparent conductive material. The method of claim 19, wherein the backlight,
At least one light source emitting ultraviolet light;
An electrowetting display device comprising a light guide plate for guiding ultraviolet light emitted from a light source disposed on one or both sides to a first liquid and a second liquid. 20. The method of claim 19, wherein when no electric field is applied between the first electrode and the second electrode, ultraviolet rays input from the upper portion of the second substrate are incident on the first liquid, and the phosphor contained in the first liquid emits light and emits light. Gas light rays pass through the color filter layer, and as the electric field is applied between the first electrode and the second electrode, the first liquid is pushed toward the partition wall, and the light applied from the outside is reflected from the surface of the second liquid and is not output to the outside. An electrowetting display device. Providing a first substrate and a second substrate including an image display area and a non-display area;
Forming a protective layer on the first substrate;
Forming a first electrode on the protective layer;
Forming an insulating layer made of a hydrophobic material on the protective layer;
Forming a partition on the insulating layer of the non-image display area of the first substrate;
Forming a spacer in an outer region of the second substrate;
Forming a second electrode on a second substrate including an upper sidewall and a sidewall of the spacer; And
A method of manufacturing an electrowetting display device comprising the step of providing a first liquid and a second liquid between a first substrate and a second substrate. 24. The method of claim 23, wherein providing a first substrate comprises forming a thin film transistor on the first substrate. 24. The method of claim 23,
Forming a common line on the first substrate; And
And placing a conductive ball in contact with the common electrode on the spacer on the common line. The method of claim 23, wherein the step of providing the first liquid and the second liquid between the first substrate and the second substrate,
Applying a first liquid to the first substrate;
Bonding the first substrate and the second substrate to each other by a sealing layer; And
And injecting a second liquid between the first substrate and the second substrate. 27. The method of claim 26, wherein the first liquid is nonpolar black oil and the second liquid is a transparent polar aqueous solution. 27. The method of claim 26, wherein the first liquid is nonpolar black oil and the second liquid is a transparent polar aqueous solution. 27. The method of claim 26, wherein the first liquid is a nonpolar color liquid and the second liquid is a transparent polar aqueous solution. 27. The method of claim 26, wherein the first liquid is a non-polar liquid containing phosphors and the second liquid is a transparent polar aqueous solution.

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