KR101295096B1 - Display substrate and electro phoretic display device having the same - Google Patents

Abstract

A display substrate for improving brightness and an electrophoretic display device having the same are disclosed. A display substrate for an electrophoretic display device includes a gate wiring, a data wiring, a switching element, and a pixel electrode. The gate wiring is formed on the insulating substrate. The data line extends in the direction crossing the gate line. The switching element is connected to the gate wiring and the data wiring. The pixel electrode is electrically connected to the switching element, and includes a reflective electrode layer that reflects light and an opaque electrode layer that absorbs light. As a result, it is possible to prevent a decrease in luminance due to leakage light and to prevent leakage current of the thin film transistor due to leakage light.

Electrophoretic Display, Thin Film Transistor, Opaque Layer

Description

DISPLAY SUBSTRATE AND ELECTRO PHORETIC DISPLAY DEVICE HAVING THE SAME}

1 is a schematic diagram illustrating a driving principle of an electrophoretic display device according to an exemplary embodiment of the present invention.

2 is a cross-sectional view illustrating a manufacturing process of an electrophoretic display device according to an exemplary embodiment of the present invention.

3 is a plan view of an electrophoretic display device including a display substrate according to a first exemplary embodiment of the present invention.

4 is a cross-sectional view taken along the line IV-IV 'of FIG. 3.

5 is a plan view of an electrophoretic display device including a display substrate according to a second exemplary embodiment of the present invention.

FIG. 6 is a cross-sectional view taken along the line VI-VI 'of FIG. 5.

7 is a plan view of an electrophoretic display device including a display substrate according to a third exemplary embodiment of the present invention.

FIG. 8 is a cross-sectional view taken along the line VI-VI 'of FIG. 7.

9A and 9B illustrate manufacturing process diagrams of a first exemplary embodiment of the display substrate illustrated in FIG. 8.

10A and 10B illustrate manufacturing process diagrams according to a second exemplary embodiment of the display substrate illustrated in FIG. 8.

11A and 11B illustrate manufacturing process diagrams according to a third exemplary embodiment of the display substrate illustrated in FIG. 8.

<Explanation of symbols for the main parts of the drawings>

210: upper insulating substrate 200: opposing substrate

240: common electrode 100a, 100b, 100c: display substrate

121: gate wiring 150: semiconductor layer

154 organic semiconductor layer 172 data wiring

180: protective film 181: organic film

The present invention relates to a display substrate and an electrophoretic display (EPD) having the same, and more particularly, to a display substrate for improving brightness and an electrophoretic display having the same.

The electrophoretic display is one of the flat panel display devices that can be used in electronic books, and has white and black colors between the two substrates on which the field generating electrodes are formed and the substrate, respectively, and the positively and negatively charged pigment particles are minute. There is also a display device which is formed in a shape confined to a capsule.

An electrophoretic display generates an electric potential difference across two electrodes by applying a voltage to two opposite electrodes, thereby moving black and white charged pigment particles to electrodes having opposite polarities, respectively, to display an image.

The electrophoretic display has a high reflectance and contrast ratio, and unlike liquid crystal displays, has no dependence on viewing angle, and thus has an advantage of displaying an image with a comfortable feel like paper, and has a bistable characteristic. Therefore, it is possible to maintain the image even if a constant voltage is not applied, which has the advantage of low power consumption.

However, the electrophoretic display has a disadvantage in that it does not have a black matrix that blocks light incident from the outside or covers an area not controlled by the pixel electrode.

In addition, in the case of an electrophoretic display device having a microcapsule, a connection between the microcapsules and the capsules is a binder, and there is leakage of light between the binders, resulting in a decrease in the contrast ratio. Although a method of reducing the size of the microcapsules to reduce the light leakage space has been proposed, a collision problem occurs between the capsules.

An object of the present invention is to provide a display substrate for an electrophoretic display device for minimizing reflection by leakage light.

Another object of the present invention is to provide an electrophoretic display device having the display substrate.

In order to realize the above object of the present invention, the display substrate for an electrophoretic display device according to the first embodiment includes a gate wiring, a data wiring, a switching element, and a pixel electrode. The gate wiring is formed on an insulating substrate. The data line extends in a direction crossing the gate line. The switching element is connected to the gate line and the data line. The pixel electrode is electrically connected to the switching element, and includes a reflective electrode layer that reflects light and an absorption electrode layer that absorbs light.

In order to achieve the above object of the present invention, the display substrate for an electrophoretic display device according to the second embodiment includes a gate wiring, a data wiring, a switching element, an organic film, and a pixel electrode. The gate wiring is formed on an insulating substrate. The data line extends in a direction crossing the gate line. The switching element is connected to the gate line and the data line. The organic layer is formed of an opaque organic material on the insulating substrate on which the switching element is formed. The pixel electrode is electrically connected to the switching element through a contact hole formed in the organic layer.

In accordance with a first embodiment of the present invention, an electrophoretic display device includes a display substrate, an opposing substrate, and electrophoretic particles. The display substrate includes a pixel electrode including a gate line and a switching element connected to the data line, a reflective electrode layer electrically connected to the switching element to reflect light, and an absorption electrode layer to absorb light. The opposing substrate is coupled to the display substrate. The electrophoretic particles are interposed between the display substrate and the counter substrate.

In accordance with a second exemplary embodiment for realizing another object of the present invention, an electrophoretic display includes a display substrate, an opposing substrate, and electrophoretic particles. A switching element connected to a gate wiring and a data wiring formed in a direction crossing each other on the display substrate insulating substrate; an organic layer formed of an opaque organic material on the insulating substrate on which the switching element is formed; And a connected pixel electrode. The opposite substrate is coupled to the display substrate. The electrophoretic particles are interposed between the display substrate and the counter substrate.

According to the display substrate and the electrophoretic display device having the same, display quality can be improved by minimizing reflection due to leakage of light between the microcapsules of the electrophoretic device.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: FIG. 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 by like reference numerals throughout the specification. When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right over", but also when there is another part in between. Conversely, when a part is "just above" another part, there is no other part in the middle. In addition, the same components will be described with the same reference numerals, and in the following detailed description, the switching elements will be referred to as "thin film transistors".

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

First, a driving principle of an electrophoretic display device and an attaching process of two substrates for an electrophoretic display device will be described with reference to FIGS. 1 and 2.

1 is a schematic diagram illustrating a driving principle of an electrophoretic display device according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a manufacturing process of the electrophoretic display device according to an exemplary embodiment of the present invention.

As shown in FIG. 1, an electrophoretic display device according to an exemplary embodiment of the present invention refers to a pixel electrode PE (see FIG. 4) and a common electrode 240 and FIG. 4 for generating an electric field (−, +). Microcapsules are disposed between them, which are white and black and contain positive and negatively charged electrophoretic particles. The electrophoretic particles may be particles having a color such as R, G, B, C, N, and Y in addition to white and black.

When a potential difference (+,-) is formed at both ends of an electrode by applying a voltage to two opposite electrodes of the electrophoretic display according to the exemplary embodiment of the present invention, the electrophoretic particles of black and white are respectively formed as electrodes having opposite polarities. As a result, the observer 300 sees an image made of black or white.

An electrophoretic display device according to an exemplary embodiment of the present invention provides an electric field facing a display substrate 100 and pixel electrodes on which signal lines, pixel electrodes, and thin film transistors electrically connecting the signal lines and the pixel electrodes are formed. The generation key includes an opposing substrate 200 including a plastic film 210 having a common electrode formed thereon and a capsule 220 formed thereon.

In this case, in order to attach the two substrates 100 and 200, the opposite substrate 200 is laminated on the display substrate 100 through a laminator 500, and the display substrate ( 100).

Next, a structure of two substrates for an electrophoretic display according to an exemplary embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

3 is a plan view of an electrophoretic display including a display substrate according to a first exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along the line IV-IV 'of FIG. 3.

As described above, the electrophoretic display device according to the exemplary embodiment of the present invention has a plurality of capsules 220 and two substrates 100a formed between the opposing substrate 200, the display substrate 100a, and the two substrates 100a and 200. Adhesive 230 to bond 200.

3 and 4, a plurality of gate lines 121 extending mainly in the horizontal direction are formed on the lower insulating substrate 110 in the display substrate 100a. The gate wires 121 may be formed of a single layer made of silver (Ag) or silver alloy (Ag) or aluminum (Al) or aluminum alloy (Al alloy), copper, or copper alloy having low resistivity. In addition to such a single film, it may be made of a multilayer film including other films made of materials such as chromium (Cr), titanium (Ti), and tantalum (Ta) having good physical and electrical contact properties. A portion of each gate line 121 extends to form the gate electrode 123 of the thin film transistor TFT. The gate wiring 121 is inclined in cross section, and the inclination angle is in a range of 20 to 80 ° from the horizontal plane.

A gate insulating layer 130 made of silicon nitride (SiNx) is formed on the gate wiring 121.

A semiconductor island 150 made of hydrogenated amorphous silicon is formed on the gate insulating layer 130. Each semiconductor layer 150 is formed on the corresponding gate electrode 123 to form a channel of the thin film transistor TFT. The first ohmic contact 163 and the second ohmic contact layer 165 made of n + hydrogenated amorphous silicon doped with a high concentration of silicide or n-type impurities are disposed on the semiconductor layer 150. Is formed. The second ohmic contact layer 165 is disposed on the opposite side of the first ohmic contact layer 163 with respect to the gate electrode 123 and spaced apart from each other. Cross sections of the semiconductor layer 150 and the first and second ohmic contacts 163 and 165 have a tapered structure, and the inclination angle is in a range of 20 to 80 °.

A plurality of data lines 172 and drain electrodes 175 of the thin film transistor TFT are formed on the first and second ohmic contacts 163 and 165 and the gate insulating layer 130. . The data line 172 and the drain electrode 175 may be made of Al or Ag with low specific resistance, and may include a conductive material having excellent contact properties with other materials, such as the gate line 121. The data line 172 mainly includes a source electrode 173 of the thin film transistor TFT extending in the vertical direction to cross the gate line 121 and extend from the data line 172. The source electrode 173 and the drain electrode 175 are formed on the corresponding first and second ohmic contacts 163 and 165, and are spaced apart from each other.

Cross sections of the data line 172 and the drain electrode 175 may have a tapered structure having an inclination angle in a range of 20 ° to 80 °.

The first and second ohmic contacts 163 and 165 lower the contact resistance between the semiconductor layer 150, the source electrode 173, and the drain electrode 175.

A passivation layer 180 made of an acrylic organic insulating material covering the semiconductor layer 150 and having a low dielectric constant for planarization on the insulating substrate 110 on which the data line 172, the source electrode 173, and the drain electrode 175 are formed. Is formed.

The passivation layer 180 may include a first contact hole 185 exposing the drain electrode 175, a second contact hole 188 exposing the end portion 128 of the gate wiring 121 together with the gate insulating layer 130, and It has a second contact hole 189 exposing the end portion 179 of the data line 172. The second and third contact holes 188 and 189 are for electrical connection between the gate wiring 121 and the data wiring 172 and respective driving circuits (not shown).

At this time, the sidewalls of the first, second and third contact holes 185, 188, and 189 of the passivation layer 180 are inclined, and the inclination angle is preferably in the range of 30 ° to 180 °.

An interlayer insulating film (not shown) made of an insulating material such as silicon oxide or silicon nitride may be added below the passivation layer 180 to cover a portion of the exposed semiconductor layer 150.

The pixel electrode PE including the reflective electrode layer 191a and the absorption electrode layer 191b is formed on the passivation layer 180. The reflective electrode layer 191a is formed directly on the passivation layer 180, and the absorption electrode layer 191b is formed directly on the reflective electrode layer 191a.

The reflective electrode layer 191a is formed of a metal material such as chromium (Cr) or molybdenum (Mo). The reflective electrode layer 191a serves to reflect light incident from the rear surface of the electrophoretic display. When reflecting back incident light, it is possible to block the light from leaking between the microcapsules 220 and not being viewed from the front surface.

The absorbing electrode layer 191b is formed of an oxidizing material such as chromium oxide (CrOx) or molybdenum oxide (MoOx). In addition, the absorbing electrode layer 191b is formed of an opaque material that absorbs light reflected or scattered by the electrophoretic particles, and has an optical density of 3.6 or more. In the case of displaying white color by the light incident from the front surface, even if the light is reflected, the brightness is not greatly influenced, but when the electrophoretic display device displays black color, the luminance may be reduced. The absorption electrode layer 191b may absorb the light incident from the front surface thereof to improve luminance.

The reflective electrode layer 191a and the absorption electrode layer 191b are electrically connected to the drain electrode 175 of the thin film transistor TFT through the first contact hole 185. The reflective electrode layer 191a and the absorption electrode layer 191b do not have high resistance in comparison with ITO or IZO, which is a transparent conductive material forming a conventional pixel electrode, and thus may serve as a pixel electrode in a reflective display device.

In addition, the pixel electrode PE formed of the reflective electrode layer 191a and the absorption electrode layer 191b may extend to an upper portion of the channel portion of the thin film transistor TFT. As the opaque pixel electrode PE extends to the upper portion of the channel portion of the thin film transistor TFT, leakage light is prevented from entering the channel portion of the thin film transistor TFT.

Therefore, in the electrophoretic display device according to the first exemplary embodiment, there is no black matrix on the opposing substrate 200, so that the semiconductor layer 150 between the source electrode 173 and the drain electrode 175, which is a channel portion of the TFT, is formed. It is possible to prevent light from being incident on the outside to prevent the leakage current caused by the leaked light.

In the electrophoretic display device according to the first exemplary embodiment of the present invention, the pixel electrode PE overlaps the gate line 121 and the data line 172 to increase the aperture ratio, and thus the pixel electrode PE is not controlled between the pixel electrode PE. It is possible to minimize the area of the non-area. In this case, a passivation layer 180 made of an insulating material having a low dielectric constant is interposed between the pixel electrode PE, the gate wiring 121, and the data wiring 172, thereby minimizing parasitic capacitance generated therebetween. .

Meanwhile, first and second contact assistants 198 and 199 are formed on the passivation layer 180. The first and second contact electrodes 198 and 199 are connected to the exposed ends 128 and 179 of the gate line 121 and the data line 172 through the second and third contact holes 188 and 189. It is. The first and second contact electrodes 198 and 199 protect the exposed ends 125 and 179 of the gate line 121 and the data line 172 and compensate for the adhesion between the display substrate 100a and the driving circuit. It is meant to, and not required. The first and second contact electrodes 198 and 199 are formed of the same layer as the pixel electrode PE.

Meanwhile, the opposing substrate 200 facing the display substrate 100a is made of a transparent conductive material on the upper insulating substrate 210 facing the lower insulating substrate 110 and faces the pixel electrode PE. A common electrode 240 is formed over the entire surface to form an electric field for driving the positively and negatively charged pigment particles.

5 is a plan view of an electrophoretic display device including a display substrate according to a second exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along the line VI-VI ′ of FIG. 5.

5 and 6, the display substrate 100b includes a plurality of gate lines 121 on an insulating substrate 110 made of transparent glass, silicon, or plastic. ) Is formed.

The gate line 121 transmits a gate signal and extends in a horizontal direction. The gate wiring 121 includes a wide end portion 129 for connecting a gate electrode 123 protruding from the gate wiring 121 to another layer or an external driving circuit.

An interlayer insulating layer 143 is formed on the entire surface of the insulating substrate 110 including the gate wiring 121. The interlayer insulating layer 143 may be made of a photosensitive organic material capable of solution processing, and the thickness of the interlayer insulating layer 143 may be about 5000 μm to 4 μm.

The interlayer insulating film 143 has an opening 144 and a contact hole 148. The opening 144 includes a lower opening 144p exposing the gate electrode 123 and an upper opening 144q positioned over the lower opening 144p. The lower opening 144p and the upper opening 144q are formed stepwise, and the upper opening 144q is larger than the lower opening 144p. The contact hole 148 exposes the end portion 129 of the gate wiring 121.

The gate insulating layer 130 is formed in the lower opening 144p. The interlayer insulating layer 143 surrounding the lower opening 144p serves as a bank for trapping the gate insulating layer 130.

The gate insulating layer 130 is made of an organic material or an inorganic material. Examples of such organic materials include soluble polymer compounds such as polyimide, polyvinyl alcohol, fluorane-containing compounds, and parylene, and examples of inorganic materials include octadecyl. And silicon oxide (SiO 2) surface-treated with octadecyl trichloro silane (OTS).

A data line 172, a pixel electrode PE, and a contact assistant 198 are formed on the gate insulating layer 130 and the interlayer insulating layer 143.

The data line 172 transmits a data signal and mainly extends in a vertical direction to cross the gate line 121. The data line 172 includes a wide end portion 199 for connecting a part of the source electrode 193 protruding from another layer or an external driving circuit.

The pixel electrode PE and the data line 172 are formed in a multilayer film structure. Specifically, the first and second transparent conductive layers 191 and 192 formed of a transparent conductive material directly on the interlayer insulating layer 143 and the reflective metal material formed on the first and second transparent conductive layers 191 and 192. The first and second reflective electrode layers 171a and 172a and the first and second absorption electrode layers 171b and 172b formed of an opaque material are formed on the first and second reflective electrode layers 171a and 172a.

That is, the pixel electrode PE includes the first transparent conductive layer 191, the first reflective electrode layer 171a, and the first absorption electrode layer 171b, and the data line 172 includes the second transparent conductive layer 192. And a second reflective electrode layer 172a and a second absorption electrode layer 172b.

 The source electrode 193 and the end portion 199 of the data line 172 have a single film structure formed of a transparent conductive material. The end portion 179 of the data line 172 may be formed in a multilayered film structure in the same manner as the data line 172.

The transparent conductive material is made of a transparent conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). Reflective metal material is formed of low-resistance metal such as molybdenum (Mo), molybdenum alloy, chromium (Cr), chromium alloy, aluminum (Al), aluminum alloy, copper (Cu), copper alloy, silver (Ag), silver alloy It is preferably formed of a metal material such as chromium (Cr) or mol (Mo). The opaque material is formed of a black material or a white material, preferably formed of an oxidizing material such as chromium oxide (CrOx) or molybdenum oxide (MoOx), and has an optical density of 3.6 or more. Preferably, the transparent conductive material and the reflective metal material are materials having different etching selectivity, and the reflective metal material and the opaque material are materials having similar etching selectivity.

The drain electrode 195 extends from the first transparent conductive layer 191 of the pixel electrode PE and is formed on the gate insulating layer 130, and the source electrode 193 is the second transparent conductive layer of the data line 172. The gate insulating layer 130 is formed on the gate insulating layer 130 to extend from 192 to face the drain electrode 195.

The pixel electrode PE receives a data signal from the drain electrode 195. The pixel electrode PE to which the data voltage is applied generates an electric field together with the common electrode (not shown) facing the pixel electrode PE and to which the common voltage is applied, thereby interposing the pixel electrode PE between the pixel electrode PE and the common electrode. Positive and negatively charged pigment particles are driven.

As a result, the first reflective electrode layer 171a of the pixel electrode PE reflects light incident from the rear surface of the electrophoretic display. When reflecting back incident light, it is possible to block the light from leaking between the microcapsules 220 and not being viewed from the front surface. The absorption electrode layer 171b of the pixel electrode PE does not significantly affect the luminance even when light is reflected when the electrophoretic display displays white light, but the electrophoretic display device is black. In the case of displaying, the luminance can be reduced. The absorbing electrode layer 171b may absorb light incident from the entire surface of the absorbing electrode layer 171b to improve luminance.

The contact electrode 198 is connected to the end portion 129 of the gate wiring 121 through the contact hole 148, and complements the adhesion between the end portion 129 of the gate wiring 121 and an external device and fixes them. Protect.

The organic semiconductor layer 154 is formed in the upper opening 144q. The organic semiconductor layer 154 is in contact with the source electrode 193 and the drain electrode 195 in the upper opening 144q and overlaps the gate electrode 123.

The organic semiconductor layer 154 may include a high molecular compound or a low molecular compound dissolved in an aqueous solution or an organic solvent.

The organic semiconductor layer 154 may include a derivative including a substituent of tetratracene or pentacene. The organic semiconductor layer 154 may also include oligothiophenes comprising 4 to 8 thiophenes linked at the 2 and 5 positions of the thiophene ring.

The organic semiconductor layer 154 may be polythienylenevinylene, poly-3-hexylthiophene, polythiophene, phthalocyanine, metallized phthalocyanine, or Halogenated derivatives thereof. The organic semiconductor layer 154 may also include perylenetetracarboxylic dianhydride (PTCDA), naphthalenetetracarboxylic dianhydride (NTCDA), or imide derivatives thereof. . The organic semiconductor layer 154 may include a derivative including perylene or coronene and substituents thereof.

The thickness of the organic semiconductor layer 154 is about 300 mW to 1 m.

The organic thin film transistor OTFT includes a gate electrode 123, a source electrode 193, and a drain electrode 195, and a channel formed of the organic semiconductor layer 154 between the source electrode 193 and the drain electrode 195. It includes a channel. The opposing portions of the source electrode 193 and the drain electrode 195 may be formed to bend, thereby making fun of the channel width to improve current characteristics.

The passivation layer 180 is formed on the organic semiconductor layer 154. The passivation layer 180 is formed of an opaque organic insulating material or an inorganic insulating material that blocks light. The passivation layer 180 prevents the organic semiconductor layer 154 from being damaged during the manufacturing process. As the passivation layer 180 is formed of an opaque material, light may enter the channel portion of the organic thin film transistor OTFT to prevent leakage current.

FIG. 7 is a plan view of an electrophoretic display including a display substrate according to a third exemplary embodiment of the present invention, and FIG. 8 is a cross-sectional view taken along the line VI-VI 'of FIG. 7.

Referring to FIGS. 7 and 8, the display substrate 100c includes gate lines 121 formed on an insulating substrate 110 made of transparent glass, silicon, or plastic. Is formed. The gate wiring 121 includes a wide end portion 129 for connecting a gate electrode 123 protruding from the gate wiring 121 to another layer or an external driving circuit. The storage wiring 127 is formed in a direction parallel to the gate wiring 123.

The gate wirings 121 may be formed of a single film made of silver (Ag) or silver alloy (Ag) or aluminum (Al) or aluminum alloy (Al alloy), copper, or a copper alloy having low resistivity, In addition to such a single film, it may be made of a multilayer film including other films made of materials such as chromium (Cr), titanium (Ti), and tantalum (Ta) having good physical and electrical contact properties.

A gate insulating layer 130 made of silicon nitride (SiNx) or the like is formed on the gate wiring 121, the gate electrode 123, and the storage wiring 127.

A semiconductor island 150 made of hydrogenated amorphous silicon is formed on the gate insulating layer 130. The semiconductor layer 150 is formed on the corresponding gate electrode 123 to form a channel portion of the thin film transistor TFT. A first ohmic contact layer 163 and a second ohmic contact layer 165 made of n + hydrogenated amorphous silicon doped with silicide or n-type impurities at a high concentration are formed on the semiconductor layer 150. The first and second ohmic contacts 163 and 165 are spaced apart from each other with respect to the gate electrode 123.

Data lines 172 and drain electrodes 175 of the thin film transistor TFT are formed on the first and second ohmic contacts 163 and 165 and the gate insulating layer 130. The data line 172 and the drain electrode 175 may be made of Al or Ag with low specific resistance, and may include a conductive material having excellent contact properties with other materials, such as the gate line 121. The data line 172 extends in a direction crossing the gate line 121 and includes a source electrode 173 of the thin film transistor TFT extending from the data line 172. The source electrode 173 and the drain electrode 175 are formed on the corresponding first and second ohmic contacts 163 and 165, and are spaced apart from each other. In addition, the storage electrode 177 overlapping the storage wiring 127 is formed of the same metal layer as the data wiring 172.

The passivation layer 140 for protecting the semiconductor layer 150 is formed on the insulating substrate 110 on which the data line 172, the source electrode 173, the drain electrode 175, and the storage electrode 177 are formed. An opaque organic film 181 made of an organic material absorbing light is formed on the passivation layer 140. The opaque organic layer 181 is formed of a black material or a white material to a thickness of about 3 μm to 4 μm.

The opaque organic layer 181 absorbs the leaked light when the light leaks between the electrophoretic particles of the electrophoretic display device. Accordingly, the leaked light may be prevented from being reflected or scattered on the display substrate 100c, thereby improving luminance. That is, the lowering of the contrast ratio can be prevented. In addition, since the opaque organic film 181 covers the channel portion of the thin film transistor TFT, leakage current of the thin film transistor TFT due to leakage light can be prevented.

First, second, and third contact holes 185, 188, and 189 are formed in the passivation layer 140 and the opaque organic layer 181. The first contact hole 185 exposes the drain electrode 175 of the TFT, the second contact hole 188 exposes the end portion 129 of the gate wiring 121, and the third contact hole 189. ) Exposes the end portion 179 of the data line 172.

The pixel electrode 191, the first contact electrode 198, and the second contact electrode (eg, a transparent conductive material) are formed on the opaque organic layer 181 on which the first, second, and third contact holes 185, 188, and 189 are formed. 199).

9A and 9B are diagrams illustrating manufacturing processes of the first exemplary embodiment of the display substrate illustrated in FIG. 8.

8 and 9A, the thin film transistor layer TL including the thin film transistor TFT is formed on the insulating substrate 110. The passivation layer 140 is formed on the thin film transistor layer TL. The first photomask 410 is formed on the passivation layer 140. The first photomask 410 includes first and second and third transmission portions 415, 418, and 419 corresponding to the first, second, and third contact holes 185, 188, and 189.

The passivation layer 140 is etched using the first photomask 410 to form first, second, and third holes H1, H2, and H3 in the passivation layer 140.

8 and 9B, an opaque organic film 181 is formed on the insulating substrate 110 on which the first, second, and third holes H1, H2, and H3 are formed to have a thickness of about 5000 μm to 4 μm. Form. The second photomask 420 is formed on the opaque organic layer 181. The second photomask 420 also includes first and second and third transmission portions 425, 428, 429 corresponding to the first, second and third contact holes 185, 188, 189. First and second portions of the opaque organic layer 181 may be etched using the second photomask 420 to expose the drain electrode 175, the end portion 128 of the gate line, and the end portion 179 of the data line. And third contact holes 185, 188, 189.

The pixel electrode 191, the first contact electrode 198, and the second electrode may be coated and patterned on the insulating substrate 110 on which the first, second, and third contact holes 185, 188, and 189 are formed. The contact electrode 199 is formed.

10A and 10B illustrate manufacturing holes according to the second embodiment of the display substrate illustrated in FIG. 8.

8 and 10A, the passivation layer 140 and the opaque organic layer 181 are sequentially formed on the insulating substrate 110 on which the thin film transistor layer TL is formed.

The first photomask 430 is formed on the opaque organic layer 181. The first photomask 430 includes first and second and third transmission portions 435, 438, and 439 corresponding to the first, second, and third contact holes 185, 188, and 189.

The opaque organic layer 181 is etched using the first photomask 430 to form first, second and third holes H1, H2, and H3 in the opaque organic layer 181.

8 and 10B, a second photomask for removing the passivation layer 140 exposed on the opaque organic layer 181 having the first, second, and third holes H1, H2, and H3 formed therein. 440 is formed. The second photomask 440 includes first, second, and third transmission parts 445, 448, and 449 corresponding to the first, second, and third holes H1, H2, and H3.

The passivation layer 140 is removed using the second photomask 440 to form first, second, and third contact holes 185, 188, and 189.

11A and 11B illustrate manufacturing process diagrams according to a third exemplary embodiment of the display substrate illustrated in FIG. 8.

8 and 11A, the passivation layer 140 and the opaque organic layer 181 are sequentially formed on the insulating substrate 110 on which the thin film transistor layer TL is formed.

The first photomask 450 is formed on the opaque organic layer 181. The first photomask 450 includes first and second and third transmission portions 455, 458, and 459 corresponding to the first, second, and third contact holes 185, 188, and 189.

The opaque organic layer 181 is etched using the first photomask 450 to form first, second and third holes H1, H2, and H3 in the opaque organic layer 181.

Referring to FIG. 11B, the exposed passivation layer 140 is removed using the opaque organic layer 181 having the first, second, and third holes H1, H2, and H3 formed thereon as a mask. Accordingly, first, second and third contact holes 185, 188 and 189 are formed.

According to the manufacturing process according to the third embodiment, the number of masks can be reduced as compared with the manufacturing process according to the first and second embodiments.

As described in detail above, according to the present invention, by forming a protective film covering the thin film transistor layer with an opaque pixel electrode and an opaque material, it is possible to prevent a decrease in luminance due to leakage light, and furthermore, a thin film due to leakage light. The leakage current of the transistor can be prevented.

In detail, first, the pixel electrode including the reflective electrode layer and the absorption electrode layer may be formed to cover the channel portion of the thin film transistor to completely block light incident from the front and rear surfaces thereof. Second, incident light can prevent reflection and scattering by forming a protective film of an opaque material on the thin film transistor layer. As a result, it is possible to prevent a decrease in luminance and a leakage current of the thin film transistor.

The display substrate and the electrophoretic display including the same according to the exemplary embodiment of the present invention may have various modified forms.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of right.

Claims (30)

A gate wiring formed on an insulating substrate; A data line extending in a direction crossing the gate line; A switching element connected to the gate line and the data line; And And a pixel electrode electrically connected to the switching element, the pixel electrode including a reflective electrode layer reflecting light and an absorption electrode layer formed of an opaque material absorbing light. The display substrate of claim 1, wherein the reflective electrode layer is made of chromium (Cr) or molybdenum (Mo). The display substrate of claim 1, wherein an optical density of the absorbing electrode layer is 3.6 or more. The display substrate of claim 3, wherein the absorption electrode layer is formed of chromium oxide (CrOx) or molybdenum oxide (MoOx). The display substrate of claim 1, wherein the switching element comprises a channel portion formed of a semiconductor layer. The display substrate of claim 5, wherein the pixel electrode is formed on the switching element to cover the channel portion. The display substrate of claim 6, wherein the reflective electrode layer is directly connected to the switching element, and the absorption electrode layer is formed on the reflective electrode layer. The display substrate of claim 1, wherein the switching element comprises a channel portion formed of an organic semiconductor layer. The display substrate of claim 8, further comprising a passivation layer formed to cover the organic semiconductor layer. The display substrate of claim 9, wherein the passivation layer is made of an opaque organic insulating material. The display substrate of claim 8, wherein the pixel electrode further comprises a transparent electrode layer formed of a transparent conductive material. The display substrate of claim 11, wherein the transparent electrode layer is directly connected to the switching element, the reflective electrode layer is formed on the transparent electrode layer, and the absorption electrode layer is formed on the reflective electrode layer. delete delete delete delete And a pixel electrode including a switching element connected to a gate line and a data line formed in a direction crossing each other, a reflective electrode layer electrically connected to the switching element to reflect light, and an absorption electrode layer formed of an opaque material to absorb light. Display substrates; An opposite substrate coupled to the display substrate; And An electrophoretic display device comprising electrophoretic particles interposed between the display substrate and the opposite substrate. The electrophoretic display of claim 17, wherein the opposing substrate further comprises a common electrode facing the pixel electrode. 18. The electrophoretic display of claim 17, wherein the reflective electrode layer is made of chromium (Cr) or molybdenum (Mo). 18. The electrophoretic display of claim 17, wherein an optical density of the absorbing electrode layer is 3.6 or more. 21. The electrophoretic display of claim 20, wherein the absorption electrode layer is made of chromium oxide (CrOx) or molybdenum oxide (MoOx). 18. The electrophoretic display of claim 17, wherein the switching element comprises a channel portion formed of a semiconductor layer. The electrophoretic display of claim 22, wherein the pixel electrode is formed on the switching element to cover the channel portion. 18. The electrophoretic display of claim 17, wherein the switching element comprises a channel portion formed of an organic semiconductor layer. 25. The electrophoretic display of claim 24, further comprising a protective film formed of an opaque organic insulating material covering the organic semiconductor layer. The electrophoretic display of claim 24, wherein the pixel electrode further comprises a transparent electrode layer formed of a transparent conductive material. delete delete delete delete

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