KR20060130921A - Liquid crystal display and manufacturing method thereof - Google Patents

Abstract

An LCD and a method for manufacturing the same are provided to prevent the damage of a color filter due to irradiation of UV rays, thereby improving the reliability of the LCD, by covering the color filter with a photoresist layer and then exposing color filter remnants except the color filter to the UV rays. A thin film for a color filter(230) is formed on a substrate(210), wherein the substrate includes a first region and a second region disposed at the outside of the first region. The thin film is pattern-etched to form the color filter positioned on the first region. A photoresist layer is formed on the color filter. Color filter remnants(231,232), which remain in the second region, are removed by applying UV rays onto the substrate. The photoresist layer is removed.

Description

Liquid crystal display device and its manufacturing method {LIQUID CRYSTAL DISPLAY AND MANUFACTURING METHOD THEREOF}

1 is a perspective view of a liquid crystal display according to an exemplary embodiment of the present invention;

2 is a layout view of a thin film transistor array panel for a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a cross-sectional view taken along line III-III ′ of the liquid crystal display including the thin film transistor array panel and the common electrode panel illustrated in FIG. 2.

4 through 7 are cross-sectional views sequentially illustrating a method of manufacturing the common electrode display panel illustrated in FIGS. 2 and 3.

The present invention relates to a liquid crystal display device and a manufacturing method thereof.

The liquid crystal display is one of the most widely used flat panel displays, and includes a field generating electrode that generates an electric field such as a pixel electrode and a common electrode, and a liquid crystal layer filled in the gap between the display panel and the display panel having a gap therebetween. It includes. In such a liquid crystal display, an electric field is formed on the liquid crystal layer by applying a voltage to two field generating electrodes to determine the alignment of liquid crystal molecules and to adjust the polarization of incident light to display an image.

The liquid crystal display includes a plurality of pixels including a field generating electrode and a thin film transistor connected thereto and arranged in a matrix form, and a plurality of signal lines transferring signals thereto. The signal line includes a gate line for transmitting a scan signal and a data line for transmitting a data signal, and each pixel includes a color filter for displaying color in addition to the field generating electrode and the thin film transistor.

The gate line, the data line, the pixel electrode, and the thin film transistor are disposed on one of the two display panels, and this display panel is commonly referred to as a thin film transistor display panel. The other display panel is generally provided with a common electrode and a color filter. The display panel is generally called a common electrode display panel, and a liquid crystal layer exists between the thin film transistor array panel and the common electrode display panel.

Such a liquid crystal display forms an electric field by applying different potentials to the pixel electrode and the common electrode to change the arrangement of liquid crystal molecules, and thereby displays an image by adjusting the transmittance of light passing through each of the color filters.

In order to make a color filter of the common electrode panel, a process of irradiating ultraviolet rays on the common electrode panel is performed to remove exposure, development, and color filter residue.

Meanwhile, the ultraviolet irradiation process removes the residue of the color filter and roughens the surface of the color filter facing the pixel electrode and displaying the color of the liquid crystal display.

As a result, the surface of the common electrode formed on the color filter and the alignment layer thereon are roughened, and a large amount of ionic impurities present in the liquid crystal layer are accumulated on the alignment layer, resulting in an afterimage in the liquid crystal display.

Accordingly, an object of the present invention is to provide a method for manufacturing a liquid crystal display device which prevents afterimages of the liquid crystal display device and improves the reliability of the liquid crystal display device.

According to an exemplary embodiment of the present invention, a liquid crystal display includes stacking a thin film for color filters on a substrate including a first region and a second region outside the first region, and patterning the thin film to form a color filter positioned on the first region. Forming a photoresist film on the color filter; irradiating ultraviolet rays on the substrate to remove color filter residues remaining in the second region; and removing the photoresist film.

The first area may correspond to an area displaying an image.

The method may further include forming a light blocking member between the substrate and the color filter.

The method may further include forming a common electrode on the color filter.

The surface of the color filter may be flat.

Then, the liquid crystal display according to an exemplary embodiment of the present invention and a manufacturing method thereof will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. 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 the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

First, the structure of a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

1 is a perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, FIG. 2 is a layout view of a thin film transistor array panel for a liquid crystal display according to an exemplary embodiment, and FIG. 3 is a thin film transistor illustrated in FIG. 2. FIG. 2 is a cross-sectional view taken along line III-III '' of the liquid crystal display device including the display panel and the common electrode display panel.

1 to 3, the liquid crystal display according to the present exemplary embodiment includes a thin film transistor array panel 100, a common electrode display panel 200, a liquid crystal layer 3 interposed therebetween, and both display panels 100 and 200. It includes a sealing material 310 for bonding.

As shown in FIG. 3, the liquid crystal layer 3 may be aligned in a vertical alignment or twisted nematic alignment, and may have an arrangement that is symmetrically bent with respect to the center plane of the two display panels 100 and 200.

First, the thin film transistor array panel 100 will be described.

The thin film transistor array panel 100 is divided into a display area DA and a peripheral area PA positioned outside the display area DA, and the sealing material 310 is disposed at a boundary between the display area DA and the peripheral area DA. Is located.

A plurality of gate lines 121 and a plurality of storage electrode lines 131 are formed on the lower substrate 110 made of transparent glass or plastic.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes a plurality of gate electrodes 124 protruding downward and end portions 129 having a large area for connection with another layer or an external driving circuit. A gate driving circuit (not shown) for generating a gate signal may be mounted on a flexible printed circuit film (not shown) attached to the substrate 110 or directly mounted on the substrate 110, It may be integrated into the substrate 110. When the gate driving circuit is integrated on the substrate 110, the gate line 121 may extend to be directly connected to the gate driving circuit.

The storage electrode line 131 receives a predetermined voltage, and includes a stem line extending substantially in parallel with the gate line 121 and a plurality of pairs of first and second storage electrodes 133a and 133b separated therefrom. Each of the storage electrode lines 131 is positioned between two adjacent gate lines 121, and the stem line is closer to the lower side of the two gate lines 121. Each of the sustain electrodes 133a and 133b has a fixed end connected to the stem line and a free end opposite thereto. The fixed end of the first sustain electrode 133a has a large area, and its free end is divided into two parts, a straight portion and a bent portion. However, the shape and arrangement of the storage electrode line 131 may be modified in various ways.

The gate line 121 and the storage electrode line 131 may be formed of aluminum-based metal such as aluminum (Al) or aluminum alloy, silver-based metal such as silver (Ag) or silver alloy, copper-based metal such as copper (Cu) or copper alloy, or molybdenum ( It may be made of molybdenum-based metals such as Mo) or molybdenum alloy, chromium (Cr), tantalum (Ta) and titanium (Ti). However, they may have a multilayer structure including two conductive films (not shown) having different physical properties. One of the conductive films is made of a metal having low resistivity, such as aluminum-based metal, silver-based metal, or copper-based metal, so as to reduce signal delay or voltage drop. In contrast, other conductive films are made of other materials, particularly materials having excellent physical, chemical, and electrical contact properties with indium tin oxide (ITO) and indium zinc oxide (IZO), such as molybdenum-based metals, chromium, tantalum, and titanium. Good examples of such a combination include a chromium bottom film, an aluminum (alloy) top film, and an aluminum (alloy) bottom film and a molybdenum (alloy) top film. However, the gate line 121 and the storage electrode line 131 may be made of various other metals or conductors.

Side surfaces of the gate line 121 and the storage electrode line 131 are inclined with respect to the surface of the substrate 110, and the inclination angle is preferably about 30 ° to about 80 °.

A gate insulating layer 140 made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate line 121 and the storage electrode line 131.

A plurality of linear semiconductors 151 made of hydrogenated amorphous silicon (hereinafter referred to as a-Si) or polysilicon are formed on the gate insulating layer 140. The linear semiconductor 151 mainly extends in the longitudinal direction and includes a plurality of projections 154 extending toward the gate electrode 124. The linear semiconductor 151 has a wider width in the vicinity of the gate line 121 and the storage electrode line 131 and covers them widely.

A plurality of linear and island ohmic contacts 161 and 165 are formed on the semiconductor 151. The ohmic contacts 161 and 165 may be made of a material such as n + hydrogenated amorphous silicon in which n-type impurities such as phosphorus are heavily doped, or may be made of silicide. The linear ohmic contact 161 has a plurality of protrusions 163, and the protrusion 163 and the island-type ohmic contact 165 are paired and disposed on the protrusion 154 of the semiconductor 151.

Side surfaces of the semiconductor 151 and the ohmic contacts 161, 163, and 165 are also inclined with respect to the substrate 110, and the inclination angle is about 30 ° to about 80 °.

A plurality of data lines 171 and a plurality of drain electrodes 175 are formed on the ohmic contacts 161, 163, and 165 and the gate insulating layer 140.

The data line 171 transmits a data signal and mainly extends in the vertical direction to cross the gate line 121. Each data line 171 also crosses the storage electrode line 131 and runs between adjacent sets of storage electrodes 133a and 133b. Each data line 171 includes a plurality of source electrodes 173 extending toward the gate electrode 124 and a wide end portion 179 for connection with another layer or an external driving circuit. A data driving circuit (not shown) for generating a data signal is mounted on a flexible printed circuit film (not shown) attached to the substrate 110, directly mounted on the substrate 110, or integrated in the substrate 110. Can be. When the data driving circuit is integrated on the substrate 110, the data line 171 may be extended to be directly connected to the data driving circuit.

The drain electrode 175 is separated from the data line 171 and faces the source electrode 173 around the gate electrode 124.

Each drain electrode 175 includes one wide end and the other end having a rod shape. The wide end portion overlaps the storage electrode line 131, and the rod-shaped end portion is partially surrounded by the bent source electrode 173.

One gate electrode 124, one source electrode 173, and one drain electrode 175 together with the protrusion 154 of the semiconductor 151 form one thin film transistor (TFT). A channel of the transistor is formed in the protrusion 154 between the source electrode 173 and the drain electrode 175.

The data line 171 and the drain electrode 175 are preferably made of a refractory metal such as molybdenum, chromium, tantalum, and titanium, or an alloy thereof, and include a refractory metal film (not shown) and a low resistance conductive film. It may have a multilayer structure including (not shown). Examples of the multilayer structure include a double layer of chromium or molybdenum (alloy) lower layer and an aluminum (alloy) upper layer, and a triple layer of molybdenum (alloy) lower layer, aluminum (alloy) interlayer and molybdenum (alloy) upper layer. However, the data line 171 and the drain electrode 175 may be made of various metals or conductors.

The side of the data line 171 and the drain electrode 175 may also be inclined at an inclination angle of about 30 ° to about 80 ° with respect to the surface of the substrate 110.

The ohmic contacts 161, 163, and 165 exist only between the semiconductor 151 below and the data line 171 and the drain electrode 175 thereon, thereby lowering the contact resistance therebetween. Although the linear semiconductor 151 is narrower than the data line 171 in most places, as described above, the width of the linear semiconductor 151 is widened at the portion where it meets the gate line 121 to smooth the profile of the surface, thereby disconnecting the data line 171. prevent. The semiconductor 151 has an exposed portion between the source electrode 173 and the drain electrode 175, and not covered by the data line 171 and the drain electrode 175.

A passivation layer 180 is formed on the data line 171, the drain electrode 175, and the exposed semiconductor 151. The passivation layer 180 may be made of an inorganic insulator or an organic insulator, and may have a flat surface. Examples of the inorganic insulator include silicon nitride and silicon oxide. The organic insulator may have photosensitivity and the dielectric constant is preferably about 4.0 or less. However, the passivation layer 180 may have a double layer structure of the lower inorganic layer and the upper organic layer so as not to damage the exposed portion of the semiconductor 151 while maintaining excellent insulating properties of the organic layer.

In the passivation layer 180, a plurality of contact holes 182 and 185 exposing the end portion 179 and the drain electrode 175 of the data line 171 are formed, respectively, and the passivation layer 180 and the gate insulating layer are formed. In the 140, a plurality of contact holes 181 exposing the end portion 129 of the gate line 121 and a plurality of contact holes 183a exposing a part of the storage electrode line 131 near the fixed end of the first storage electrode 133a. And a plurality of contact holes 183b exposing the protruding portion of the free end of the first storage electrode 133a.

A plurality of pixel electrodes 191, a plurality of overpasses 83, and a plurality of contact assistants 81 and 82 are formed on the passivation layer 180. They may be made of a transparent conductive material such as ITO or IZO or a reflective metal such as aluminum, silver, chromium or an alloy thereof.

The pixel electrode 191 is physically and electrically connected to the drain electrode 175 through the contact hole 185 and receives a data voltage from the drain electrode 175. The pixel electrode 191 to which the data voltage is applied generates an electric field together with the common electrode (not shown) 270 of another display panel (not shown) 200 to which a common voltage is applied. Thus, the direction of the liquid crystal molecules of the liquid crystal layer (not shown) 3 between the two electrodes 191 and 270 is determined. The polarization of light passing through the liquid crystal layer 3 varies according to the direction of the liquid crystal molecules determined as described above. The pixel electrode 191 and the common electrode 270 form a capacitor (hereinafter, referred to as a "liquid crystal capacitor") to maintain an applied voltage even after the thin film transistor is turned off.

The pixel electrode 191 and the drain electrode 175 connected to the pixel electrode 191 overlap with the storage electrode line 131 including the storage electrodes 133a and 133b. A capacitor formed by the pixel electrode 191 and the drain electrode 175 electrically connected to the pixel electrode 191 overlapping the storage electrode line 131 is called a storage capacitor, and the storage capacitor enhances the voltage holding capability of the liquid crystal capacitor.

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 and the external device.

The connecting leg 83 crosses the gate line 121 and exposes the exposed portion of the storage electrode line 131 and the storage electrode through contact holes 183a and 183b positioned on opposite sides with the gate line 121 interposed therebetween. 133b) is connected to the exposed end of the free end. The storage electrode lines 131 including the storage electrodes 133a and 133b may be used together with the connecting legs 83 to repair defects in the gate line 121, the data line 171, or the thin film transistor.

An alignment layer 11 is formed on the pixel electrode 190, the contact auxiliary members 81 and 82, and the passivation layer 180.

Next, the common electrode display panel 200 will be described with reference to FIGS. 1 to 3.

A plurality of light blocking members 220 are formed on the upper substrate 210 made of transparent glass or plastic. The light blocking member 220 is called a black matrix and blocks light. The light blocking member 220 has a plurality of openings facing the pixel electrode 191 and having substantially the same shape as the pixel electrode 191. However, the light blocking member 220 may include a portion corresponding to the gate line 121 and the data line 171 and a portion corresponding to the thin film transistor.

A plurality of color filters 230 is also formed on the substrate 210. The color filters 230 are separated from each other, and an edge portion thereof overlaps with the adjacent light blocking member 220 and extends in the vertical direction along the column of the pixel electrodes 191. The color filter 230 may display one of primary colors such as three primary colors of red, green, and blue. Here, the surface of the color filter 230 is flat.

The common electrode 270 is formed on the color filter 230. The common electrode 270 is made of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO).

On the other hand, as described above, since the surface of the color filter 230 is flat, the common electrode 270 present thereon is made flat along the color filter 230. Therefore, the ionic impurities contained in the liquid crystal layer 3 can be almost eliminated from being accumulated on the surface of the common electrode 270, and thus, an afterimage of the liquid crystal display device can be prevented.

Alignment layers 11 and 21 are coated on inner surfaces of the display panels 100 and 200, and they may be vertical alignment layers. In addition, polarizers 12 and 22 are provided on the outer surfaces of the display panels 100 and 200, and polarization axes of the two polarizers 12 and 22 are orthogonal and one polarization axis is parallel to the gate line 121. It is preferable. In the case of a reflective liquid crystal display, one of the two polarizers 12 and 22 may be omitted.

The liquid crystal display according to the present exemplary embodiment may further include a phase retardation film (not shown) for compensating for the delay of the liquid crystal layer 3.

The liquid crystal display may include a polarizer 12 and 22, a phase retardation film, display panels 100 and 200, and a backlight unit (not shown) for supplying light to the liquid crystal layer 3.

Next, a method of manufacturing the common electrode panel for the liquid crystal display shown in FIGS. 2 and 3 according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 4 to 7.

4 through 7 are cross-sectional views sequentially illustrating a method of manufacturing the common electrode display panel illustrated in FIGS. 2 and 3.

First, as shown in FIG. 4, a substrate 210 made of transparent glass or plastic is prepared, a light shielding member 220 is formed thereon, and the color filter thin film 235 is coated thereon.

Subsequently, as illustrated in FIG. 5, the color filter thin film 235 is patterned to form the color filter 230. In this case, the color filter 230 is formed in an area facing the display area DA of the thin film transistor array panel 100, and residues are formed in an area other than an area facing the display area DA of the thin film transistor array panel 100. (231, 232) remains. The residues 231 and 232 deteriorate the characteristics of the liquid crystal display.

Accordingly, in order to solve such a problem, as illustrated in FIG. 6, the photosensitive film 60 is formed thick on the common electrode panel 200 facing the display area DA of the thin film transistor array panel 100.

Subsequently, ultraviolet rays are irradiated onto the common electrode display panel 200 to remove the residues 231 and 232. At this time, the surface of the photosensitive film 60 is roughened under the influence of ultraviolet rays. However, the color filter 230 under the photoresist layer 60 is not damaged by ultraviolet rays and thus has a flat surface.

Next, as shown in FIG. 7, the photosensitive film 60 is removed and a common conductor 270 is formed by coating a transparent conductor such as ITO or IZO on the entire surface of the common electrode display panel 200.

On the other hand, as described above, since the surface of the color filter 230 is flat, the common electrode 270 present thereon is made flat along the color filter 230. Therefore, the ionic impurities contained in the liquid crystal layer 3 can be almost eliminated from being accumulated on the surface of the common electrode 270, and thus, an afterimage of the liquid crystal display device can be prevented.

According to the present invention, the color filter facing the display area of the thin film transistor array panel is covered with a photosensitive film during the color filter manufacturing process of the common electrode display panel, and the residue of the color filter remaining in the other area is exposed to ultraviolet rays and removed. The color filter representing the color of the liquid crystal display device can be prevented from being damaged by ultraviolet rays. Accordingly, by making the surface of the common electrode formed on the surface of the common electrode flat along the color filter structure, almost no ionic impurities accumulate on the surface of the common electrode, thereby preventing afterimages of the liquid crystal display and improving reliability. have.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the 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 rights.

Claims (5)

Stacking a thin film for a color filter on a substrate including a first region and a second region outside the first region, Patterning the thin film to form a color filter positioned on the first region; Forming a photoresist film on the color filter; Irradiating ultraviolet light on the substrate to remove the color filter residue remaining in the second region, and Removing the photoresist Method of manufacturing a liquid crystal display comprising a. In claim 1, And the first area corresponds to an area for displaying an image. In claim 1, And forming a light blocking member between the substrate and the color filter. In claim 1, And forming a common electrode on the color filter. In claim 1, A manufacturing method of a liquid crystal display device having a flat surface of the color filter.

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