KR20040060701A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: An LCD device is provided to form a reflective electrode connected with a pixel electrode in an area where light emitted from a back light is not transmitted, and to reflect an outer light, thereby improving an opening ratio and brightness. CONSTITUTION: The first and second substrates(110,140) are faced to each other. Gate lines and data lines(122) cross each other, and define a pixel area. A TFT(T) is connected to the gate lines and the data lines(122). A protective layer(130) covers the gate lines, the data lines(122), and the TFT(T). A transparent pixel electrode(134) is connected with the TFT(T), and is overlapped with the data lines(122). An organic insulating film(136) is located as being relative to the data lines(122). A reflective electrode(138) is formed on the organic insulating film(136), and is connected to the pixel electrode(134). A black matrix(142) is located as being relative to the TFT(T). Color filters(144a-144c) sequentially form R, G, and B colors. A common electrode(146) is formed under the color filters(144a-144c). A liquid crystal layer(150) is located between the first substrate(110) and the second substrate(140).

Description

Liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a high aperture liquid crystal display.

Recently, with the rapid development of the information society, the need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption has emerged. Among flat panel displays, liquid crystal displays have been actively applied to notebooks and desktop monitors due to their excellent resolution, color display, and image quality.

In general, a liquid crystal display device is formed by arranging two substrates on which electric field generating electrodes are formed so that the surfaces on which two electrodes are formed face each other, injecting a liquid crystal material between the two substrates, and then applying voltage to the two electrodes. By moving the liquid crystal molecules by an electric field, the device expresses an image by the transmittance of light that varies accordingly.

However, the liquid crystal display does not emit light by itself and thus requires a separate light source.

Therefore, an image is displayed by arranging a backlight on the back of the liquid crystal panel and injecting light from the backlight into the liquid crystal panel to adjust the amount of light according to the arrangement of the liquid crystals. In this case, the field generating electrode of the liquid crystal display device is formed of a transparent conductive material, and both substrates should also be made of a transparent substrate.

Such a liquid crystal display is referred to as a transmission type liquid crystal display. Since the liquid crystal display uses an artificial back light source such as a backlight, a bright image may be realized even in a dark external environment.

Hereinafter, a general transmissive liquid crystal display will be described with reference to the accompanying drawings.

FIG. 1 illustrates a partial cross-sectional view of a general transmissive liquid crystal display, and the first substrate 10 and the second substrate 40 are disposed at regular intervals as shown. A gate electrode 12 is formed on an inner surface of the lower first substrate 10, and a gate insulating layer 14 is formed thereon. Next, the active layer 16 and the ohmic contact layer 18 are sequentially formed on the gate insulating layer 14 on the gate electrode 12. Source and drain electrodes 24 and 26 are formed on the ohmic contact layer 18, and the source and drain electrodes 24 and 26 form a thin film transistor T together with the gate electrode 12. Meanwhile, a data line 22 made of the same material as the source and drain electrodes 24 and 26 is formed on the gate insulating layer 14, and the data line 22 is connected to the source electrode 24. Next, a passivation layer 30 made of an organic material is formed on the data line 22 and the source and drain electrodes 24 and 26 to cover the thin film transistor T, and the passivation layer 30 is a drain electrode 26. Has a contact hole 32 exposing Next, a pixel electrode 34 is formed in the pixel area above the passivation layer 30, and is connected to the drain electrode 26 through the contact hole 32. Here, the pixel electrode 18 covers the thin film transistor T and overlaps the data line 22 to improve the aperture ratio. The protective layer 30 is made of an organic material having a low dielectric constant. Signal interference does not occur between the 34 and the data lines 22.

On the other hand, a black matrix 42 is formed on the inner surface of the second substrate 40, and the color filter 44a in which the colors of red (R), green (G), and blue (B) are sequentially repeated thereon. And 44b and 44c are formed, and a common electrode 46 made of a transparent conductive material is formed on the color filters 44a, 44b and 44c. Here, the black matrix 42 covers the thin film transistor T and covers the edge of the pixel electrode 18. In addition, the color filters 44a, 44b, and 44c have one color corresponding to one pixel electrode 34.

Next, the liquid crystal layer 50 is positioned between the pixel electrode 34 and the common electrode 46.

Next, first and second optical films 62 and 64 are disposed on the outer surfaces of the first and second substrates 10 and 40, respectively, and outer surfaces of the first and second optical films 62 and 64, respectively. The first and second polarizing plates 72 and 74 are disposed in each.

Subsequently, the backlight 80 is disposed on the outer surface of the first polarizing plate 72. The backlight includes a light guide plate 86 under the liquid crystal display, a light source 82 positioned on the side of the light guide plate 86, and a reflector plate 84 surrounding the light source.

As described above, in the transmissive liquid crystal display, a black matrix is formed in this portion to prevent light leakage from occurring at the edge of the pixel electrode, that is, the region corresponding to the gate wiring and the data wiring. In this case, the width of the black matrix becomes about 10 μm to 20 μm in consideration of the bonding margin, which lowers the aperture ratio of the liquid crystal display. That is, the aperture ratio of the transmissive liquid crystal display is about 60 to 70%, which causes a problem of low luminance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a high-aperture-rate liquid crystal display device which can improve aperture ratio and increase luminance.

1 is a cross-sectional view of a typical transmissive liquid crystal display device.

2 is a cross-sectional view of a liquid crystal display according to a first embodiment of the present invention.

3 is a cross-sectional view illustrating a path of light output from a liquid crystal display according to a first exemplary embodiment of the present invention.

4 is a plan view schematically illustrating a liquid crystal display according to a first or second embodiment of the present invention.

5 is a cross-sectional view of a COT structure liquid crystal display device according to a second embodiment of the present invention.

6 is a plan view schematically illustrating a liquid crystal display according to a third or fourth embodiment of the present invention.

7 is a cross-sectional view of a liquid crystal display according to a third embodiment of the present invention.

8 is a cross-sectional view of a COT structure liquid crystal display device according to a fourth embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

110: first substrate 112: gate electrode

114 gate insulating film 116 semiconductor layer

118: ohmic contact layer 122: data wiring

124: source electrode 126: drain electrode

130: protective layer 132: first contact hole

134: pixel electrode 136: organic insulating film

137: second contact hole 138: reflective electrode

140: second substrate 142: black matrix

144a, 144b, and 144c: color filter 146: common electrode

150: liquid crystal layer 162, 164: first and second optical films

172, 174: first and second polarizer 180: backlight

In order to achieve the above object, the liquid crystal display device of the first aspect of the present invention is to define a pixel region formed on the inner surface of the first substrate and intersect the first and second substrates facing each other at regular intervals. A thin film transistor connected to the gate wiring and the data wiring, the gate wiring and the data wiring, a protective layer covering the gate wiring and the data wiring and the thin film transistor, formed on the protective layer and connected to the thin film transistor, A transparent pixel electrode overlapping the data line, an organic insulating layer formed on the pixel electrode and corresponding to the data line, a reflective electrode formed on the organic insulating layer and connected to the pixel electrode, and an inner surface of the second substrate. And formed at a position corresponding to the thin film transistor. And a first substrate including the black matrix, a color filter in which red, green, and blue colors are sequentially formed on the black matrix, a common electrode formed on the color filter, and the reflective electrode, and the common electrode. It includes a liquid crystal layer positioned between the second substrate.

The liquid crystal display according to the second aspect of the present invention includes first and second substrates facing each other at regular intervals, gate wirings and data wirings formed on the inner surface of the first substrate and crossing each other to define pixel regions, and the gate wirings. And a thin film transistor connected to the data line, a protective layer covering the gate line, the data line and the thin film transistor, a transparent pixel electrode formed on the protective layer and connected to the thin film transistor and overlapping the data line; An organic insulating layer formed on the pixel electrode and corresponding to the data line, a reflective electrode formed on the organic insulating layer and connected to the pixel electrode, and red, green, and blue formed on the reflective electrode and the pixel electrode. Color filter formed sequentially, thin film strip on the inner surface of the second substrate Common formed on the black matrix, the black matrix formed in the lower position corresponding to the register electrodes and a liquid crystal layer positioned between the second substrate including a first substrate and the common electrode, including the reflective electrode.

The liquid crystal display device according to the third aspect of the present invention includes first and second substrates facing each other at regular intervals, gate wirings and data wirings formed on the inner surface of the first substrate and crossing each other to define pixel regions, and the gate wirings. And a thin film transistor connected to the data line, a protective layer covering the gate line, the data line and the thin film transistor, a transparent pixel electrode formed on the protective layer and connected to the thin film transistor and overlapping the data line; An organic insulating layer formed on the pixel electrode and corresponding to the data line and the thin film transistor, a reflective electrode formed on the organic insulating layer and connected to the pixel electrode, and formed on an inner surface of the second substrate; Color filter in which green, green and blue colors are sequentially formed; Multiple filters the lower common electrode which is formed on, and a liquid crystal layer positioned between the second substrate including a first substrate and the common electrode, including the reflective electrode.

A liquid crystal display device according to the fourth aspect of the present invention includes first and second substrates spaced apart at regular intervals, gate wirings and data wirings formed on the inner surface of the first substrate and crossing each other to define pixel regions, and the gate wirings. And a thin film transistor connected to the data line, a protective layer covering the gate line, the data line and the thin film transistor, a transparent pixel electrode formed on the protective layer and connected to the thin film transistor and overlapping the data line; An organic insulating layer formed on the pixel electrode and corresponding to the data line and the thin film transistor, a reflective electrode formed on the organic insulating layer and connected to the pixel electrode, and red, green, and blue colors on an inner surface of the second substrate. The color filter formed in this order, formed below the color filter It comprises a liquid crystal layer positioned between the common electrode, and a second substrate including a first substrate and the common electrode, including the reflective electrode.

Here, the reflective electrode has a wider width than the data wiring and covers the data wiring, and the organic insulating film and the reflective electrode may cover the gate wiring.

On the other hand, the thickness of the liquid crystal layer corresponding to the pixel electrode is preferably twice the thickness of the liquid crystal layer corresponding to the reflective electrode.

The organic insulating layer may be made of the same material as the protective layer.

In the present invention, the pixel electrode may be made of one of indium tin oxide and indium zinc oxide.

The liquid crystal display according to the present invention may further include a backlight positioned on an outer surface of the first substrate. The display device may further include a first polarizer positioned between the first substrate and the backlight, and a second polarizer positioned on an outer surface of the second substrate. The optical film may further include a first optical film positioned between the first substrate and the first polarizing plate, and a second optical film positioned between the second substrate and the second polarizing plate.

An overcoat layer may be further included between the red, green, and blue color filters under the second substrate and the common electrode.

In addition, the thickness of the color filter formed on the reflective electrode is preferably thinner than the thickness of the color filter formed on the pixel electrode.

As described above, in the present invention, by forming a reflective electrode connected to the pixel electrode in a region where light from the backlight is blocked and reflecting external light, the aperture ratio can be improved as compared with a general transmissive liquid crystal display.

Hereinafter, a high aperture liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Recently, in order to improve the aperture ratio of a transmissive liquid crystal display, a transmissive with micro reflective liquid crystal display incorporating the technique of a reflective liquid crystal display into a transmissive liquid crystal display has been proposed.

<First Embodiment>

FIG. 2 is a cross-sectional view of the liquid crystal display according to the first exemplary embodiment of the present invention, and FIG. 2 illustrates a liquid crystal display capable of increasing the aperture ratio by using the non-reflective portion.

As illustrated, the first substrate 110 and the second substrate 140 face each other at a predetermined interval. It is preferable that the first and second substrates 110 and 140 be made of a transparent insulating substrate.

A gate electrode 112 made of a material such as a metal is formed on an inner surface of the first substrate 110, and a gate insulating layer 114 made of a silicon nitride film or a silicon oxide film is formed on the gate electrode 112. Although not shown, a gate wiring connected to the gate electrode 112 is further formed under the gate insulating layer 114.

Next, an active layer 116 made of amorphous silicon is formed on the gate insulating layer 114 on the gate electrode 112, and an ohmic contact layer 118 made of amorphous silicon containing impurities on the active layer 116. Is formed.

Subsequently, source and drain electrodes 124 and 126 are formed on the ohmic contact layer 118 and are formed of a conductive material such as metal and face the gate electrode 112. In addition, a data line 122 made of the same material as the source and drain electrodes 124 and 126 is formed on the gate insulating layer 114. The data line 122 is connected to the source electrode 124 and is connected to the gate line. Intersect with to define the pixel area. Meanwhile, the source and drain electrodes 124 and 126 together with the gate electrode 112 form a thin film transistor T.

Next, a protective layer 130 is formed on the data line 122 and the source and drain electrodes 124 and 126. The protective layer 130 is preferably made of an organic material having a low dielectric constant. The protective layer 130 has a first contact hole 132 exposing the drain electrode 132.

Subsequently, a pixel electrode 134 made of a transparent conductive material is formed on the passivation layer 130, and the pixel electrode 134 is connected to the drain electrode 126 through the first contact hole 132. The pixel electrode 134 may be made of indium tin oxide or indium zinc oxide. The pixel electrode 134 covers the thin film transistor T and is formed to overlap the data line 122.

Next, an organic insulating layer 136 is formed on the pixel electrode 134. The organic insulating layer 136 is formed at a position corresponding to the data line 122 to cover the edge of the pixel electrode 134. It has a second contact hole 137 exposing 134. Here, the organic insulating layer 136 is formed of the same material as the protective layer 130, that is, an organic material having a low dielectric constant.

Next, a reflective electrode 138 is formed on the organic insulating layer 136, and the reflective electrode 138 is connected to the pixel electrode 134 through the second contact hole 137. Here, the reflective electrode 138 is not connected to the pixel electrode 134 of the neighboring pixel. In addition, the reflective electrode 138 has a wider width than the data line 122 and covers the data line 122. Accordingly, the reflective electrode 138 also serves as a black matrix to prevent light leakage at the edge of the pixel electrode 134.

Next, a black matrix 142 is formed on the inner surface of the second substrate 140. The black matrix 142 covers the thin film transistor T to prevent photocurrent from occurring in the thin film transistor T. As mentioned above, since the reflective electrode 138 also serves as a black matrix, the black matrix 142 may be formed to correspond only to the thin film transistor T, and may be omitted at portions corresponding to the edges of the pixel electrode 134. have.

Next, color filters 144a, 144b, and 144c are formed on the black matrix 142, in which red, green, and blue colors are sequentially repeated. Each of the color filters 144a, 144b, and 144c has one color. Corresponds to the pixel electrode 134.

Next, a common electrode 146 made of a transparent conductive material is formed on the color filters 144a, 144b, and 144c. The common electrode 146 may be made of the same transparent conductive material as the pixel electrode 138, and may be made of a material such as indium tin oxide or indium zinc oxide.

Next, the liquid crystal layer 150 is positioned between the first substrate 110 including the reflective electrode 138 and the common electrode 146, and the liquid crystal molecules of the liquid crystal layer 150 are the pixel electrode 134 and the common electrode. When a voltage is applied to 146, the arrangement state is changed by the electric field generated between the two electrodes 134 and 146. In this case, the signal applied to the pixel electrode 134 is also transmitted to the reflective electrode 138, so that the liquid crystal molecules of the liquid crystal layer 150 corresponding to the reflective electrode 138 also move. Although not shown, an alignment layer is formed between the pixel electrode 134 and the reflective electrode 138 and the liquid crystal layer 150, and between the common electrode 146 and the liquid crystal layer 150, respectively, and thus the initial arrangement state of the liquid crystal molecules. Determine.

Subsequently, first and second optical films 162 and 164 are disposed on outer surfaces of the first and second substrates 110 and 140, respectively, and outer surfaces of the first and second optical films 162 and 164, respectively. The first and second polarizing plates 172 and 174 are respectively disposed therein. The first and second optical films 162 and 164 may be formed of a quarter wave plate (QWP) having a phase difference of λ / 4, and the light transmission axis of the first polarizing plate 172 is light transmission of the second polarizing plate 174. It is perpendicular to the axis.

Subsequently, the backlight 180 is disposed on the outer surface of the first polarizing plate 172. The backlight 180 includes a light guide plate 186 under the liquid crystal display, a light source 182 positioned on the side of the light guide plate 186, and a reflecting plate 184 surrounding the light source. The light guide plate 186 converts linear light from the light source 182 into planar light, and the light from the light source 182 is reflected by the reflector 184 and is incident on the light guide plate 186.

As described above, in the present invention, the reflective electrode is formed in a region where light is blocked in the transmissive liquid crystal display to form an unreflected region.

3 illustrates a path of light output from the liquid crystal display. As shown in FIG. 3, the first light L1 from the backlight 180 passes through the first polarizing plate 172 and the first optical film 162, and then the pixel electrode 134 and the liquid crystal layer 150. ), The common electrode 146, the color filter 144b, the second optical film 164, and the second polarizing plate 174, are sequentially output. In this case, the light incident from the backlight 180 to the area corresponding to the data line 122 and the reflective electrode 138 is blocked by the data line 122 and the reflective electrode 138 and cannot be transmitted.

Meanwhile, the second light L2 from the outside is reflected after passing through the second polarizing plate 174, the second optical film 162, the color filter 144b, the common electrode 146, and the liquid crystal layer 150. The light is reflected by the electrode 138 and then passed through the liquid crystal layer 150, the common electrode 146, the color filter 144b, the second optical film 164, and the second polarizing plate 174 in order.

In this case, in order to optimize the optical characteristics of the first light L1 and the second light L2, the thickness of the liquid crystal layer 150 corresponding to the pixel electrode 134 is the liquid crystal layer 150 corresponding to the reflective electrode 138. ) To be twice the thickness. The thickness of the liquid crystal layer 150 may be adjusted by the thickness of the organic insulating layer 136.

Therefore, in the present invention, a reflective electrode connected to the pixel electrode is formed on the data line, and external light is reflected by the reflective electrode and output.

In the case of a general transflective liquid crystal display device, the reflective part and the transmissive part are provided under a constant aperture ratio. The liquid crystal display according to the present invention forms a reflective electrode in a region which is not used as a transmissive part in the general transmissive liquid crystal display device and uses the reflective part. Therefore, since the reflection part is further formed while maintaining the aperture ratio of the general transmissive liquid crystal display device as it is, the aperture ratio can be improved and the luminance can be increased as compared with the general transmissive liquid crystal display device.

In addition, since the liquid crystal display according to the present invention uses the non-reflective area, the luminance can be further improved in a bright external environment.

The reflective electrode may be formed not only on the data line but also on the gate line. In addition, the liquid crystal display includes a storage capacitor, and the reflective electrode may be formed on the storage capacitor.

4 is a plan view schematically illustrating a liquid crystal display according to a first exemplary embodiment of the present invention. As illustrated, the gate line 111 and the data line 122 cross each other to define a pixel area, and the pixel electrode 134 is formed in the pixel area. The pixel electrode 134 overlaps the gate wiring 111 and the data wiring 122. Subsequently, an organic insulating layer 136 is formed, and the organic insulating layer 136 is formed to cover the edge of the pixel electrode 134, the gate wiring 111, and the data wiring 122. Next, a reflective electrode 138 is formed, and the reflective electrode 138 covers the edge of the pixel electrode 134, the gate wiring 111, and the data wiring 122, and is formed to be separated from neighboring pixels. . In this case, as mentioned above, the reflective electrode 138 is connected to the pixel electrode 134.

As described above, when the reflective electrode is formed over the gate wiring and the data wiring, the opening ratio is about 91%.

Second Embodiment

The second embodiment of the present invention relates to a color filter on TFT array (COT) structure liquid crystal display device which can increase the aperture ratio by using the non-reflective portion.

FIG. 5 illustrates a COT structure liquid crystal display device which can increase an aperture ratio by using an unreflective portion. The polarizing plate, the retardation plate, and the backlight outside the liquid crystal panel except for the liquid crystal panel have the same role as those in the first embodiment and thus will not be described.

As shown in the drawing, the first substrate 210 and the second substrate 240 made of a transparent insulating substrate face each other at a predetermined interval.

A gate electrode 212 is formed on an inner surface of the first substrate 210, and an active layer 216 made of amorphous silicon and a gate insulating layer 214 on the gate electrode 212 and an upper portion of the active layer 216. An ohmic contact layer 218 made of amorphous silicon containing impurities is formed on the substrate. In addition, source and drain electrodes 224 and 226 facing the gate electrode 212 are formed on the ohmic contact layer 218. At the same time, a data line 222 formed of the same material as the two electrodes 224 and 226 is formed on the gate insulating layer 214. The data line 222 is connected to the source electrode 224 and the gate line ( Not shown) to define the pixel area. Meanwhile, the source and drain electrodes 224 and 226 together with the gate electrode 212 form a thin film transistor T.

Next, a passivation layer 230 is formed on the data line 222 and the source and drain electrodes 224 and 226. The passivation layer 230 is preferably made of an organic material having a low dielectric constant. The protective layer 230 has a first contact hole 232 exposing the drain electrode 226.

Next, a pixel electrode 234 made of a transparent conductive material is formed on the passivation layer 230, and the pixel electrode 234 is connected to the drain electrode 226 through the first contact hole 232. The pixel electrode 234 may be made of indium tin oxide or indium zinc oxide. Here, the pixel electrode 234 is formed to include a thin film transistor T so as to overlap a part of the data line 222.

Next, an organic insulating layer 236 is formed on the pixel electrode 234. The organic insulating layer 236 is formed at a position corresponding to the data line 222 to cover the edge of the pixel electrode 234. And a second contact hole 237 exposing 234. Here, the organic insulating layer 236 is made of the same material as the protective layer 230, that is, an organic material having a low dielectric constant.

Next, a reflective electrode 238 is formed on the organic insulating layer 236, and the reflective electrode 238 is connected to the pixel electrode 234 through the second contact hole 237. In this case, the reflective electrode 238 is formed not to be connected to the pixel electrode 234 of the neighboring pixel. In addition, the reflective electrode 238 has a width wider than that of the data line 222 and covers the data line 222. Accordingly, the reflective electrode 238 serves as a black matrix to prevent light leakage at the edge of the pixel electrode 234.

Next, red, green, and blue color filters 243, 244, and 245 are formed on the pixel electrode 234 and the reflective electrode 238 on which the organic insulating layer 236 is not formed. In this case, the red, green, and blue color filters 243, 244, and 245 are formed so that one color corresponds to one pixel electrode 234 and the reflective electrode 238 in contact with the pixel electrode 234. The color filters 243, a 244a, and 245a formed on the pixel electrode 234 are thicker than the color filters 243b, 244b (not shown) formed on the reflective electrode 238. . The reason why the color electrodes 243b, 244b (not shown) formed in the reflective electrode 236 are formed and the color filters 243, a 244a, 245a in the region consisting only of the pixel electrode 234 is different from each other is formed. This is to make the color characteristics similar. In the portion where the reflective electrode 236 is formed and reflected, external light passes through the color filters 243b and 244b twice (not shown), but in the portion where the reflective electrode 236 is not formed, the light is emitted from the backlight 286. Since light passes through the color filters 243, a 244a, and 245a only once, the color characteristics of the two parts appear differently. Therefore, by configuring the thickness of the color filters (243, 244, 245) in duplicate, the above problems can be overcome to some extent. In this case, the color filters 243, 244, and 245 are formed by coating and patterning a color filter resin. The pixel electrodes overlapping the organic insulating material with the gate wiring (not shown) and the data wiring 222 and spaced apart from each other ( 234 is applied to form an organic insulating film 236, and then a reflective electrode 238 is formed thereon. Therefore, an inclined step occurs in a portion where the reflective electrode 238 is formed and a non-formed portion, and the color filter resin applied by the inclined step flows down so that the thickness of the reflective electrode 238 is increased. The formed part is formed thin. In this case, the thickness of the color filter resin may be adjusted by the viscosity and the step height. At this time, it is preferable that the thickness of the color filters 243b, 244b (not shown) on the reflective electrode 238 is 1/2 the thickness of the color filters 243a, 244a, 245a where the reflective electrode 238 is not formed. However, even if thicker than 1/2, the color characteristics are improved rather than being formed with the same thickness.

Next, a black matrix 242 is formed on the inner surface of the second substrate 240. The black matrix 242 covers the thin film transistor T to prevent abnormal light from leaking due to the photocurrent generated in the thin film transistor T.

Next, a common electrode 246 made of a transparent conductive material is formed under the black matrix 242. The common electrode 246 is preferably made of the same transparent conductive material as the pixel electrode 238, and may be made of a material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

In the above-described COT structure liquid crystal display device having the non-reflective region, the non-reflective portion is formed on the gate wiring and the data wiring to increase the aperture ratio and the brightness, and the color filter and the thin film transistor shown in the first embodiment are respectively the second substrate and the first. In the liquid crystal display having the general structure of each of the substrates, the error occurring when the two substrates are bonded may be reduced to further reduce the color characteristic and the brightness. In addition, the color filter thickness is formed differently in the non-reflective portion and the transmissive portion has the advantage of further improving the color characteristics.

Next, the third and fourth embodiments of the present invention are variations of the first and second embodiments, respectively, and do not constitute a black mattress on the color filter substrate, which is located above the thin film transistors in the pixel to prevent abnormal light leakage. Instead, the reflective electrode is formed on the array substrate to provide a liquid crystal display device which is utilized as an unreflected area to further increase the aperture ratio in an external stepped environment.

Since the basic structure is the same as in the first and second embodiments, only the color filter substrate, the array substrate, and the liquid crystal layer therebetween are shown, and other components such as backlight, polarizer, and retardation plate are the same as in the first embodiment. Description is omitted. In addition, only the part inside which differs is demonstrated using reference numeral.

6 is a plan view schematically illustrating a liquid crystal display device according to third and fourth embodiments. As shown in the drawing, the gate line 311 and the data line 322 cross each other to define a pixel area, and a pixel electrode 334 is formed in the pixel area. In this case, the pixel electrode 334 overlaps the gate wiring 311 and the data wiring 322. Subsequently, an organic insulating layer 336 is formed, and the organic insulating layer 336 is formed at the edge of the pixel electrode 334 and the gate line 311 and the data line 322 and the intersection of the two lines. It is formed so as to cover (not shown).

Next, a reflective electrode 338 is formed, and the reflective electrode 338 is formed on the organic insulating layer 336 to cover the gate wiring 311, the data wiring 322, and the thin film transistor (not shown). Formed. The reflective electrode 338 is formed separately from each other, and the thin film transistor (not shown) is formed at the intersection of the data line 311 positioned on the left side of the pixel, the gate line 322 positioned below the pixel, and the two lines. The reflection electrode 338 is electrically connected to each other. Therefore, the pixel area driven by the substantially same pixel signal is indicated by A on the drawing.

The reflective electrode 338 was formed in the data wiring 322, the gate wiring 311, and the thin film transistor region to provide the non-reflective portion, so that the liquid crystal display device was configured so that the aperture ratio reached almost 100%.

Third Embodiment

7 is a cross-sectional view of a liquid crystal display according to a third exemplary embodiment of the present invention.

As shown in the drawing, the first substrate 310 and the second substrate 340 made of a transparent insulating substrate face each other at a predetermined interval.

The thin film transistor T including the gate electrode 312, the active layer 316, the ohmic contact layer 318, and the source and drain electrodes 324 and 326 is formed on the inner surface of the first substrate 310. At the same time, a data line 322 connected to the source electrode 324 is formed on the gate insulating layer 314.

Next, a passivation layer 330 made of an organic material having a low dielectric constant is formed on the data line 322 and the thin film transistor T. The protective layer 330 has a first contact hole 332 exposing the drain electrode 326.

Subsequently, a pixel electrode 334 made of a transparent conductive material and connected to the drain electrode 326 through the first contact hole 332 is formed on the passivation layer 330. In this case, the pixel electrode 334 is formed to partially overlap the data line 322 including the thin film transistor T. The pixel electrode 334 is preferably selected from indium tin oxide or indium zinc oxide, which are transparent conductive materials.

Next, an organic insulating layer 336 is formed on the pixel electrode 334 corresponding to the data line 322 and formed to be spaced apart from each other to cover the pixel electrode 334 and the spaced area wider than the width of the data line. At the same time, an organic insulating film 336 is also formed on the pixel electrode on the thin film transistor T. The organic insulating layer 336 has a second contact hole 337 exposing the pixel electrode 334. The reflective electrode 338 is formed on the upper side. The reflective electrode 338 is connected to the pixel electrode 334 through the second contact hole 337 and is not connected to the pixel electrode 334 of the neighboring pixel. In addition, the reflective electrode 338 has a wider width than the data line 322 and the thin film transistor T and covers the data line 322 and the thin film transistor T. In this case, the reflective electrode 338 serves as a black matrix to prevent abnormal light leakage.

In addition, the thickness of the liquid crystal layer 350 corresponding to the pixel electrode 334 is adjusted in the organic insulating layer 336 under the reflective electrode 338 so that the thickness of the liquid crystal layer 350 corresponding to the reflective electrode 338. It is desirable to double the thickness.

Next, color filters 343, 344, and 345 are sequentially formed on the inner surface of the second substrate 340. The color filters 343, 344, and 345 have one color. It corresponds to this one pixel electrode 334. In more detail, each of the red, green, and blue color filters 343, 344, and 345 is positioned to include a portion where the reflective electrode 338 of the first substrate 310 is formed and a portion that is not formed. That is, the boundary of each of the color filters 343, 344, and 345 of red, green, and blue is disposed at the left end of the data line 322.

Next, a common electrode 346 made of a transparent conductive material is formed under the color filters 343, 344, and 345. The common electrode 346 is preferably selected from indium tin oxide or indium zinc oxide, which is the same transparent conductive material as the pixel electrode 338. In this case, an overcoat layer may be formed between the color filters 344a, 344b, and 344c and the common electrode 346.

Fourth Example

8 is a cross-sectional view of a COT structure liquid crystal display device according to a fourth embodiment of the present invention.

Since the structure of the liquid crystal display according to the fourth embodiment is the same as that of the second embodiment except that there is no black mattress corresponding to the thin film transistor and instead an organic insulating film and a reflective electrode are formed thereon, only the portions that differ are described. .

As illustrated, the first substrate 410 on which the thin film transistor T and the color filters 443, 444, and 445 are formed, and the second substrate 440 on which the common electrode 446 is formed are spaced apart from each other. .

The thin film transistor T is formed on the first substrate 410, and the data line 422 is formed on the gate insulating layer 414. In addition, a passivation layer 430 is formed on the thin film transistor T and the data line 422, and the pixel is in contact with the drain electrode 426 of the thin film transistor T through the first contact hole 432. An electrode 434 is formed. The pixel electrode 434 is formed in the pixel area between the data line 422 and the wire, and is formed to be spaced apart from the neighboring pixel electrode 434 by a predetermined interval on the data line 422.

Next, an organic insulating layer 436 formed of the same material as the passivation layer 430 is formed on the data line 422 and the pixel electrode 434 on the thin film transistor T. The organic insulating layer 436 corresponding to the data line 422 has a width wider than that of the data line 422. In addition, the organic insulating layer 436 has a second contact hole 437 exposing the lower pixel electrode 434. The reflective electrode 438 is formed on the organic insulating layer 436 in contact with the pixel electrode 434 through the second contact hole 437.

Next, red, green, and blue color filters 443, 444, and 445 are formed to correspond to the reflective electrode 438 and the pixel electrode 434, respectively. At this time, the color filters (444b, 445b) formed on the reflective electrode 438 have a color filter 443a having a thickness formed on the pixel electrode 434 due to the inclined step of the organic insulating layer 436 below. It is formed thinner than the thickness of 444a, 445a). Preferably, the thickness is 1/2 of the thickness of the color filters 443a, 444a, and 445a on the pixel electrode 434. However, since the thickness is controlled by the level difference and the viscosity of the color filter resin, accurate thickness adjustment is difficult. However, since the thickness is thinner than that of the color filters 443a, 444a, and 445a on the pixel electrode 434, color characteristics may be improved.

Since the second substrate is the same as the second embodiment except that there is no black matrix corresponding to the thin film transistor T, the description thereof is omitted.

The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit of the present invention.

In the liquid crystal display according to the present invention, an unreflected region may be formed on the gate wiring and the data wiring of the general transmissive liquid crystal display or the COT structure liquid crystal display, and optionally on the thin film transistor, thereby improving the aperture ratio and increasing the luminance.

Claims (14)

First and second substrates facing each other at regular intervals; A gate line and a data line formed on an inner surface of the first substrate and crossing the gate line to define a pixel area; A thin film transistor connected to the gate line and the data line; A protective layer covering the gate line, the data line, and the thin film transistor; A transparent pixel electrode formed on the passivation layer and connected to the thin film transistor and overlapping the data line; An organic insulating layer formed on the pixel electrode and formed at a position corresponding to the data line; A reflective electrode formed on the organic insulating layer and connected to the pixel electrode; A black matrix formed on an inner surface of the second substrate and formed at a position corresponding to the thin film transistor; A color filter in which red, green, and blue colors are sequentially formed below the black matrix; A common electrode formed under the color filter; And A liquid crystal layer positioned between the first substrate including the reflective electrode and the second substrate including the common electrode. Liquid crystal display comprising a. First and second substrates facing each other at regular intervals; A gate line and a data line formed on an inner surface of the first substrate and crossing the gate line to define a pixel area; A thin film transistor connected to the gate line and the data line; A protective layer covering the gate line, the data line, and the thin film transistor; A transparent pixel electrode formed on the passivation layer and connected to the thin film transistor and overlapping the data line; An organic insulating layer formed on the pixel electrode and formed at a position corresponding to the data line; A reflective electrode formed on the organic insulating layer and connected to the pixel electrode; A color filter sequentially formed of red, green, and blue formed on the reflective electrode and the pixel electrode; A black matrix formed at a position corresponding to the thin film transistor on an inner surface of the second substrate; A common electrode formed under the black matrix; And A liquid crystal layer positioned between the first substrate including the reflective electrode and the second substrate including the common electrode. Liquid crystal display comprising a. First and second substrates facing each other at regular intervals; A gate line and a data line formed on an inner surface of the first substrate and crossing the gate line to define a pixel area; A thin film transistor connected to the gate line and the data line; A protective layer covering the gate line, the data line, and the thin film transistor; A transparent pixel electrode formed on the passivation layer and connected to the thin film transistor and overlapping the data line; An organic insulating layer formed on the pixel electrode and formed at a position corresponding to the data line and the thin film transistor; A reflective electrode formed on the organic insulating layer and connected to the pixel electrode; A color filter formed on an inner surface of the second substrate and having red, green, and blue colors sequentially formed; A common electrode formed under the color filter; And A liquid crystal layer positioned between the first substrate including the reflective electrode and the second substrate including the common electrode. Liquid crystal display comprising a. First and second substrates facing each other at regular intervals; A gate line and a data line formed on an inner surface of the first substrate and crossing the gate line to define a pixel area; A thin film transistor connected to the gate line and the data line; A protective layer covering the gate line, the data line, and the thin film transistor; A transparent pixel electrode formed on the passivation layer and connected to the thin film transistor and overlapping the data line; An organic insulating layer formed on the pixel electrode and formed at a position corresponding to the data line and the thin film transistor; A reflective electrode formed on the organic insulating layer and connected to the pixel electrode; A color filter in which red, green, and blue colors are sequentially formed on the inner surface of the second substrate; A common electrode formed under the color filter; And A liquid crystal layer positioned between the first substrate including the reflective electrode and the second substrate including the common electrode. Liquid crystal display comprising a. The method according to any one of claims 1 to 4, The reflective electrode has a width wider than that of the data line and covers the data line. The method according to any one of claims 1 to 4, And the organic insulating film and the reflective electrode cover the gate wiring. The method according to any one of claims 1 to 4, The thickness of the liquid crystal layer corresponding to the pixel electrode is twice the thickness of the liquid crystal layer corresponding to the reflective electrode. The method according to any one of claims 1 to 4, The organic insulating layer is formed of the same material as the protective layer. The method according to any one of claims 1 to 4, The pixel electrode is one of indium tin oxide and indium zinc oxide. The method according to any one of claims 1 to 4, And a backlight disposed on an outer surface of the first substrate. The method according to any one of claims 1 to 4, And a second polarizer disposed between the first substrate and the backlight, and a second polarizer positioned on an outer surface of the second substrate. The method according to any one of claims 1 to 4, And a first optical film positioned between the first substrate and the first polarizing plate, and a second optical film positioned between the second substrate and the second polarizing plate. The method according to any one of claims 1 to 3, And an overcoat layer between the red, green, and blue color filters below the second substrate and the common electrode. The method according to any one of claims 2 to 4, The thickness of the color filter formed on the reflective electrode is thinner than the thickness of the color filter formed on the pixel electrode.