KR101702106B1 - Electrowetting display device - Google Patents

Abstract

The present invention relates to an electrowetting display device capable of improving reflectance, capable of realizing various colors, and capable of increasing brightness, and an electrowetting display device according to the present invention includes a first substrate; A gate line and a gate electrode formed on the first substrate; A gate insulating film formed on the gate line and the gate electrode; A semiconductor layer formed on the gate insulating film; A data line, a source electrode, and a drain electrode crossing the gate line; A protective film formed on the data line, the source electrode, and the drain electrode; A pixel electrode formed on the passivation layer and connected to the drain electrode; A second substrate facing the first substrate; A common electrode formed on the second substrate; And an electro-optical layer formed between the pixel electrode and the common electrode, wherein the drain electrode overlaps with the pixel electrode, and includes an upper drain electrode and a lower drain electrode, .

Description

ELECTROWATTING DISPLAY DEVICE [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrowetting display device, and more particularly, to an electrowetting display device capable of improving reflectance, various colors, and brightness.

Currently known flat panel display devices include a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting display (OLED), a field effect display display: FED, an electrophoretic display (EPD), and an electrowetting display (EWD).

Among these, an electrowetting display device is driven in such a manner that a screen is displayed by reflecting a light coming from the outside by changing a surface tension of a liquid by applying a voltage to an aqueous liquid which is an electrolyte.

The light incident on the electrowetting display device is partially absorbed by the other layers in the interior, and only the remaining light is reflected to display the screen, which causes a problem of low reflectance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrowetting display device capable of improving the reflectance of an electrowetting display device.

It is also an object of the present invention to provide a display device capable of realizing various colors, increasing brightness, and being warped like paper.

According to another aspect of the present invention, there is provided a flat panel display comprising: a first substrate having a plurality of pixel regions defined therein including a thin film transistor region and a display region; A gate line and a gate electrode formed on the first substrate; A gate insulating film formed on the gate line and the gate electrode; A semiconductor layer formed on the gate insulating film; A data line, a source electrode, and a drain electrode crossing the gate line; A protective film formed on the data line, the source electrode, and the drain electrode; A pixel electrode formed on the passivation layer and connected to the drain electrode; A second substrate facing the first substrate; A common electrode formed on the second substrate; And an electro-optical layer formed between the pixel electrode and the common electrode, wherein the drain electrode is formed to overlap the pixel electrode in the thin film transistor region and the display region, and the upper drain electrode and the lower drain electrode / RTI >

The upper drain electrode is made of a reflective material.

Wherein the electro-optical layer comprises: a hydrophobic insulating layer formed on the pixel electrode; A barrier disposed over the hydrophobic insulating layer and having an opening; And a black oil layer located in the opening.

The upper drain electrode may be formed of a metal including aluminum.

The lower drain electrode may be formed of a metal including at least one of molybdenum and titanium.

According to another aspect of the present invention, there is provided a flat panel display device, including a contact hole formed in the protective film and the upper drain electrode to expose the lower drain electrode, Electrode.

The protective film may include a lower protective film and an upper protective film, the lower protective film may be made of an inorganic insulating material, and the upper protective film may be made of an organic insulating material.

The flat panel display according to the present invention may further include a color filter formed between the protective layer and the pixel electrode.

The color filter may be formed of quantum dots.

The first substrate and the second substrate may be flexible substrates.

The first substrate and the second substrate may be made of plastic or glass fiber reinforced plastic (FRP).

According to another aspect of the present invention, there is provided a flat panel display comprising: a first substrate having a plurality of pixel regions defined therein including a thin film transistor region and a display region; A gate line and a gate electrode formed on the first substrate; A gate insulating film formed on the gate line and the gate electrode; A semiconductor layer formed on the gate insulating film; A data line, a source electrode, and a drain electrode crossing the gate line; A protective film formed on the data line, the source electrode, and the drain electrode; A white reflective film formed on the protective film; A pixel electrode formed on the white reflective layer and connected to the drain electrode; A second substrate facing the first substrate; A common electrode formed on the second substrate; And an electro-optical layer formed between the pixel electrode and the common electrode, wherein the drain electrode is formed to overlap the pixel electrode in the thin film transistor region and the display region, and the upper drain electrode and the lower drain electrode And the upper drain electrode is made of a reflective material.

The white reflective layer may be formed of a material containing at least one of titanium oxide (TiO2) and barium sulfate (BaSO4).

The content of titanium oxide (TiO 2) in the white reflective film may be 20 wt% to 80 wt%.

The content of barium sulfate (BaSO 4) in the white reflective film may be 20 wt% to 80 wt%.

Wherein the electro-optical layer comprises: a hydrophobic insulating layer formed on the pixel electrode; A barrier disposed over the hydrophobic insulating layer and having an opening; And a black oil layer located in the opening.

The upper drain electrode may be formed of a metal including aluminum.

The lower drain electrode may be formed of a metal including at least one of molybdenum and titanium.

According to another aspect of the present invention, there is provided a flat panel display including a contact hole formed in the protective layer, the upper drain electrode, and the white reflective layer to expose the lower drain electrode, To the lower drain electrode.

The protective film may include a lower protective film and an upper protective film, the lower protective film may be made of an inorganic insulating material, and the upper protective film may be made of an organic insulating material.

The flat panel display according to the present invention may further include a color filter formed between the white reflective layer and the pixel electrode.

The color filter may be formed of quantum dots.

The first substrate and the second substrate may be flexible substrates.

The first substrate and the second substrate may be made of plastic or glass fiber reinforced plastic (FRP).

The flat panel display according to the present invention as described above has the following effects.

The flat panel display according to the present invention has an effect of improving the reflectance of the flat panel display by forming the upper drain electrode as the reflective metal.

Further, by further forming a white reflective film and an organic insulating film, the reflectance of the flat panel display device can be further improved.

Further, by forming the color filter using quantum dots, it is possible to realize various colors and increase the luminance.

In addition, by forming the first and second substrates as flexible substrates, it is possible to realize a display device which can be bent like a paper.

1 is a cross-sectional view of a flat panel display according to a first embodiment of the present invention.
2 is a cross-sectional view illustrating a flat panel display according to a second embodiment of the present invention.
3 is a cross-sectional view of a flat panel display according to a third embodiment of the present invention.
4A to 4E are process plan views illustrating a method of manufacturing a flat panel display device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. Like parts are designated with like reference numerals throughout the specification. It will be understood that when an element such as a layer, film, region, plate, or the like is referred to as being "on" another, it includes not only the element directly over another element, Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

Hereinafter, a flat panel display according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a flat panel display according to a first embodiment of the present invention.

1, a flat panel display device according to a first embodiment of the present invention is a reflective electroless wet display device that includes a lower substrate 110, a lower substrate 110, And an electro-optical layer (310, 350) disposed between the lower substrate (110) and the upper substrate (210). The electro-optical layer (310, 350 includes a partition wall 350 having a plurality of openings 355 and a black oil layer 310 disposed inside the openings 355.

The lower substrate 110 and the upper substrate 210 may be a glass substrate or a flexible substrate made of plastic or glass fiber reinforced plastic (FRP). The lower substrate 110 defines a pixel region PD by intersecting a gate line (not shown) and a data line (not shown), and the pixel region PD includes a thin film transistor region TD and a display region PD ). The thin film transistor region TD is a region where a thin film transistor is formed at the intersection of the gate line and the data line and the display region PD is a portion of the pixel region PD excluding the thin film transistor region TD.

A gate electrode 124 connected to a plurality of gate lines extending mainly in a lateral direction is formed on the lower substrate 110. A gate insulating film 140 made of silicon nitride (SiNx) or the like is formed on the gate line and the gate electrode 124.

A semiconductor layer 154 made of hydrogenated amorphous silicon or the like is formed on the gate insulating layer 140. The semiconductor layer 154 forms a channel of the thin film transistor. A data line and a drain electrode 175 are formed on the gate insulating layer 140 and the semiconductor layer 154. The data lines extend mainly in the vertical direction and intersect with the gate lines, and the branches extending from the respective data lines form the source electrodes 173. A pair of the source electrode 173 and the drain electrode 175 are located at least partially on the semiconductor layer 154 and are separated from each other and opposite to each other with respect to the gate electrode 124.

The drain electrode 175 is formed to overlap the pixel electrode 190 in the thin film transistor region TD and the display region DD. That is, the drain electrode 175 may extend to the display region DD as well as the thin film transistor region TD to reflect light incident on the pixel electrode 190.

The drain electrode 175 includes a lower drain electrode 175a and an upper drain electrode 175b.

The lower drain electrode 175a may be formed of a material having good conductivity, for example, a metal such as molybdenum, titanium, or the like.

The upper drain electrode 175b may be formed of a material having a high reflectivity, and may be formed using a metal such as aluminum. Light incident from the outside to the reflection type electrowetting display device according to the present invention can be effectively reflected by the upper drain electrode 175b made of a metal having high reflectivity.

Since the data line, the source electrode 173 and the drain electrode 175 are formed on the same layer, the data line and the source electrode 173 as well as the drain electrode 175 can be formed as a double layer.

The pixel electrode 190 is formed to extend not only to the drain electrode 175 but also to the source electrode 173 and the source electrode 173 is formed of a double layer and the upper layer is made of a metal having a high reflectivity. TD), the light incident from the outside can be effectively reflected.

A resistive contact member may be disposed between the semiconductor layer 154 and the source electrode 173 and the drain electrode 175 to reduce contact resistance therebetween.

A protective film 180 made of an insulating material such as silicon oxide or silicon nitride covering a part of the exposed semiconductor layer 154 is formed on the source electrode 173, the drain electrode 173, the semiconductor layer 154 and the gate insulating film 140 Respectively.

A color filter 230 may be formed on the passivation layer 180. The color filter 230 may be formed of a quantum dot (semiconductor nanocrystal). A quantum dot is a semiconductor material having a crystal structure of a few nanometers in size, which is composed of several hundreds to thousands of atoms and has a very small surface area per unit volume and a quantum confinement effect. Thus, it exhibits unique physico-chemical properties that are different from those inherent to the semiconductor material itself. At present, various synthesis techniques are being developed by controlling the size, structure and uniformity of quantum dots having such superior characteristics and various application possibilities.

On the color filter 230, a pixel electrode 190 made of a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) is formed.

A contact hole 185 is formed in the color filter 230, the protective film 180 and the upper drain electrode 175b to expose the lower drain electrode 175a. The pixel electrode 190 is physically and electrically connected to the lower drain electrode 175a through the contact hole 185. [

The thickness of the lower drain electrode 175b can be made sufficiently thick in the etching process for forming the contact hole 185 as compared with the case where the lower drain electrode 175b is etched through the upper drain electrode 175b and further to the lower drain electrode 175b .

A hydrophobic insulating layer 90 is formed on the pixel electrode 190 and a barrier 350 is formed on the hydrophobic insulating layer 90. The barrier ribs 350 are formed in the form of a matrix having openings 355 to define pixels and are formed of an organic film containing black pigment. A black oil layer 310 is formed in the opening 355. An aqueous solution layer 320 is formed between the barrier rib 350 and the black oil layer 310 and the common electrode 270.

The surface tension of the aqueous solution layer 320 is not changed in the pixel B where no voltage is applied between the pixel electrode 190 and the common electrode 270. The black oil layer 310 covers the entire pixel B have. Therefore, the light P2 incident on the opening portion is absorbed by the black oil layer 310 before reaching the upper drain electrode 175b, and the pixel B displays black.

On the other hand, since the surface tension of the aqueous solution layer 320 is changed in the pixel A to which the voltage is applied between the pixel electrode 190 and the common electrode 270, the black oil layer 310 is compressed, Can be opened. Accordingly, the light P1a incident on the opening portion is reflected by the upper drain electrode 175b, and the pixel A displays the color corresponding to the color filter 230. [

The color filter 230 may be omitted, and when the flat panel display device according to the present invention does not include the color filter 230, the pixel A displays a white color and thus can be used as a monochrome display device.

Hereinafter, a flat panel display according to a second embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view illustrating a flat panel display according to a second embodiment of the present invention.

The second embodiment is substantially the same as the first embodiment except that a white reflective film 80 is further added, and repeated description is omitted.

2, in the flat panel display device according to the second embodiment of the present invention, a white reflective film 80 is formed between the protective film 180 and the pixel electrode 190. The white reflective layer 80 may include titanium oxide (TiO 2) and a resin, and may include barium sulfate (BaSO 4) and a resin. The content of titanium oxide (TiO 2) in the white reflecting film 80 is preferably 20 wt% to 80 wt%, or the content of barium sulfate (BaSO 4) in the white reflecting film 80 is preferably 20 wt% to 80 wt%.

When the content of titanium oxide (TiO 2) or barium sulfate (BaSO 4) is 20 wt% or less, the reflectance is decreased. When the content of titanium oxide (TiO 2) or barium sulfate (BaSO 4) is 80 wt% or more, patterning becomes difficult.

Since the auxiliary reflective film 177 is formed under the white reflective film 80, the reflectance does not decrease even if the thickness d of the white reflective film 80 is set to 2 탆 or less. Therefore, the thickness of the white reflecting film 80 can be made as thin as 2 탆 or less, and the contact hole 185 can be easily formed in the white reflecting film 80.

Table 1 below shows the reflectance depending on the thickness of the white reflective layer 80 when the auxiliary reflective layer 177 is formed of aluminum under the white reflective layer 80.

As shown in Table 1, even if the thickness of the white reflecting film 80 is 2 탆, the reflectance does not largely decrease.

Hereinafter, a flat panel display according to a third embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view illustrating a flat panel display according to a third embodiment of the present invention.

The third embodiment is substantially the same as the second embodiment except that the protective film 180 is composed of the lower protective film 180p and the upper protective film 180q.

3, in the flat panel display device according to the third embodiment of the present invention, the passivation layer 180 includes a lower passivation layer 180p and an upper passivation layer 180q.

The lower protective film 180p is formed on the source electrode 173, the drain electrode 173, the semiconductor layer 154 and the gate insulating film 140 with an inorganic insulating material such as silicon oxide or silicon nitride covering a part of the exposed semiconductor layer 154 Lt; / RTI >

The upper protective film 180q is formed on the lower protective film 180p and is made of an organic insulating material having excellent planarization characteristics.

Hereinafter, with reference to Table 2, the influence of the upper protective layer 180q made of an organic insulating material on the reflectance is further examined.

Table 2 is a table showing the reflectance in the case where there is no organic film and the case where there is an organic film.

When there is no organic film When organic film is present The upper drain electrode 175b, Aluminum 0.1um Aluminum 0.1um Shielding (180) The lower protective film 180p, Silicon nitride 0.2um Silicon nitride 0.2um The upper protective film 180q Organic insulating material 2um The white reflective film 80 3um 3um reflectivity 66/65 70/68

As in the second embodiment, the reflectance of a single-layer protective film made of an inorganic insulating material was measured to be 65-66, while a protective film using an organic insulating material was further formed as in the third embodiment The reflectance of the case was measured to be 68-70. That is, it can be confirmed that the reflectance can be further improved by further forming a protective film using an organic insulating material.

In the flat panel display device according to the first embodiment of the present invention, the drain electrode 175 is formed as a lower drain electrode 175a and the upper drain electrode 175b, and the upper drain electrode 175b is formed using a reflective material such as aluminum Thereby improving the reflectance.

In the flat panel display device according to the second embodiment of the present invention, a white reflective film 80 including titanium oxide (TiO 2) or barium sulfate (BaSO 4) is additionally formed to form the upper drain electrode 175b and the white reflective film 80) can further improve the reflectance.

In addition, in the flat panel display device according to the third embodiment of the present invention, the passivation layer 180 is formed of the lower passivation layer 180a and the upper passivation layer 180b, and the lower passivation layer 180a is formed of the upper passivation layer 180b, The upper drain electrode 175b, the white reflective film 80, and the upper protective film 180b can further improve the reflectivity.

Unlike the flat panel display device according to the third embodiment of the present invention, the white reflective layer 80 may be omitted, and reflection is caused by the upper drain electrode 175b and the upper protective layer 180b.

Hereinafter, a method of manufacturing a flat panel display according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4A to 4E are process plan views illustrating a method of manufacturing a flat panel display device according to an embodiment of the present invention.

First, as shown in FIG. 4A, a conductive material is deposited on a substrate (not shown) and patterned to form a gate electrode 121 and a gate electrode 124 protruding from the gate line 121 extending in one direction. At the same time, the sustain electrodes 133 protruding from the sustain electrode lines 131 and the sustain electrode lines 131 substantially parallel to the gate lines 121 are formed.

The entire surface of the substrate including the gate line 121, the gate electrode 124, the sustain electrode lines 131 and the sustain electrode 134 is covered with a gate insulating film (not shown) using an insulating material such as silicon oxide or silicon nitride 140 are formed.

Next, a semiconductor layer 150 is formed on the gate insulating layer 140 so as to overlap with the gate electrode 124.

4C, a conductive material such as molybdenum, titanium, or the like and a highly reflective material such as aluminum are stacked and patterned on the gate insulating layer 140 and the semiconductor layer 150, A source electrode 173 projecting from the data line 171 onto the semiconductor layer 150 and a drain electrode 175 spaced apart from the source electrode 173 are formed.

The data line 171, the source electrode 173, and the drain electrode 175 are formed as a double layer by stacking and patterning two materials.

The gate line 121 and the data line 171 intersect each other to define a pixel region PD and the pixel region PD includes a thin film transistor region TD and a display region DD. The drain electrode 175 is formed in both the thin film transistor region TD and the display region DD.

A protective film (not shown) is formed by laminating an inorganic insulating material and an organic insulating material on the entire surface of the substrate including the data line 171, the source electrode 173, and the drain electrode 175. A material including titanium oxide (TiO 2) and resin or a material including barium sulfate (BaSO 4) and a resin is coated on a protective film to form a white reflective film (not shown). A color filter (not shown) is formed on the white reflecting film. At this time, the color filter may be formed as a quantum dot.

As shown in FIG. 4D, a contact hole 181 is formed by patterning in a state where a protective film, a white reflective film, and a color filter are laminated.

ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) is deposited on the entire surface of the substrate and patterned to form a pixel electrode 190 connected to the drain electrode 175 through the contact hole 181.

4E, the barrier 350 is formed to surround the outer periphery of the pixel region, and the black oil layer 310 is formed in the inner portion of the barrier 350, that is, the pixel region. The barrier ribs 350 are formed in the form of a matrix having openings that expose pixel regions, and are formed of an organic film containing black pigment.

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

80: white reflective film 90: hydrophobic insulating layer
175a: lower drain electrode 175b: upper drain electrode
180p: lower protective film 180q: upper protective film
190: pixel electrode 270: common electrode
310: black oil layer 320: aqueous solution layer
350: partition wall

Claims (19)

A first substrate on which a plurality of pixel regions including a thin film transistor region and a display region are defined;
A gate line and a gate electrode formed on the first substrate;
A gate insulating film formed on the gate line and the gate electrode;
A semiconductor layer formed on the gate insulating film;
A data line, a source electrode, and a drain electrode crossing the gate line;
A protective film formed on the data line, the source electrode, and the drain electrode;
A contact hole formed in the protective film;
A pixel electrode formed on the passivation layer and connected to the drain electrode through the contact hole;
A second substrate facing the first substrate;
A common electrode formed on the second substrate; And
And an electro-optical layer formed between the pixel electrode and the common electrode,
Wherein the drain electrode is formed to overlap the pixel electrode in the thin film transistor region and the display region, and includes an upper drain electrode and a lower drain electrode,
Wherein the upper drain electrode is made of a reflective material,
The electro-
A hydrophobic insulating layer formed on the pixel electrode;
A barrier disposed over the hydrophobic insulating layer and having an opening; And
And a black oil layer located in the opening,
Wherein the contact hole is formed in the protection film and the upper drain electrode so as to expose the lower drain electrode and the pixel electrode is connected to the lower drain electrode through the contact hole,
Electropneumatic display device.
delete The method according to claim 1,
Wherein the upper drain electrode is made of a metal containing aluminum,
Electropneumatic display device.
The method of claim 3,
Wherein the lower drain electrode is made of a metal containing at least one of molybdenum and titanium,
Electropneumatic display device.
delete The method according to claim 1,
Wherein the protective film comprises a lower protective film and a top protective film,
Wherein the lower protective film is made of an inorganic insulating material,
Wherein the upper protective film is made of an organic insulating material,
Electropneumatic display device.
The method according to claim 1,
And a color filter formed between the protective film and the pixel electrode.
Electropneumatic display device.
8. The method of claim 7,
Wherein the color filter comprises a quantum dot,
Electropneumatic display device.
A first substrate on which a plurality of pixel regions including a thin film transistor region and a display region are defined;
A gate line and a gate electrode formed on the first substrate;
A gate insulating film formed on the gate line and the gate electrode;
A semiconductor layer formed on the gate insulating film;
A data line, a source electrode, and a drain electrode crossing the gate line;
A protective film formed on the data line, the source electrode, and the drain electrode;
A white reflective film formed on the protective film;
A contact hole formed in the protective film and the white reflective film;
A pixel electrode formed on the white reflective film and connected to the drain electrode through the contact hole;
A second substrate facing the first substrate;
A common electrode formed on the second substrate; And
And an electro-optical layer formed between the pixel electrode and the common electrode,
Wherein the drain electrode is formed to overlap the pixel electrode in the thin film transistor region and the display region, and includes an upper drain electrode and a lower drain electrode,
Wherein the upper drain electrode is made of a reflective material,
The electro-
A hydrophobic insulating layer formed on the pixel electrode;
A barrier disposed over the hydrophobic insulating layer and having an opening; And
And a black oil layer located in the opening,
Wherein the contact hole is formed in the protective film, the upper drain electrode, and the white reflective film so as to expose the lower drain electrode, and the pixel electrode is connected to the lower drain electrode through the contact hole,
Electropneumatic display device.
10. The method of claim 9,
Wherein the white reflective film is made of a material containing at least one of titanium oxide (TiO2) and barium sulfate (BaSO4)
Electropneumatic display device.
11. The method of claim 10,
The content of titanium oxide (TiO 2) in the white reflective film is 20 wt% to 80 wt%
Electropneumatic display device.
11. The method of claim 10,
Wherein the content of barium sulfate (BaSO4) in the white reflective film is 20 wt% to 80 wt%
Electropneumatic display device.
delete 10. The method of claim 9,
Wherein the upper drain electrode is made of a metal containing aluminum,
Electropneumatic display device.
15. The method of claim 14,
Wherein the lower drain electrode is made of a metal containing at least one of molybdenum and titanium,
Electropneumatic display device.
delete 10. The method of claim 9,
Wherein the protective film comprises a lower protective film and a top protective film,
Wherein the lower protective film is made of an inorganic insulating material,
Wherein the upper protective film is made of an organic insulating material,
Electropneumatic display device.
10. The method of claim 9,
Further comprising a color filter formed between the white reflective film and the pixel electrode,
Electropneumatic display device.
19. The method of claim 18,
Wherein the color filter comprises a quantum dot,
Electropneumatic display device.

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