Patent Publication Number: US-2015062521-A1

Title: Liquid crystal display

Description:
This application claims priority to Korean Patent Application No. 10-2013-0104982 filed on Sep. 2, 2013, and all the benefits accruing therefrom under 35 U.S.C. §119, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     (a) Field 
     The invention relates to a liquid crystal display (“LCD”), and more particularly, to an LCD capable of preventing a mixed color between adjacent pixels and enhancing transmittance. 
     (b) Description of the Related Art 
     A liquid crystal display (“LCD”) which is one of the most common types of flat panel displays currently in use, is a display device which rearranges liquid crystal molecules of a liquid crystal layer by applying voltages to electrodes to control an amount of transmitted light. 
     The LCD has an advantage of easily forming a thin film shape, for example, but has a disadvantage in that side visibility deteriorates compared with front visibility, and in order to solve the disadvantage, various types of alignments of the liquid crystal and driving methods have been developed. As a method for implementing a wide viewing angle, an LCD in which a pixel electrode and a common electrode are formed on one substrate has received attention. 
     In such a liquid crystal display, at least one of two field generating electrodes of the pixel electrode and a plurality of cutouts is defined in the common electrode, and a plurality of branch electrodes is defined by the plurality of cutouts. 
     SUMMARY 
     In a liquid crystal display (“LCD”) in which a pixel electrode and a common electrode are disposed on one substrate, since liquid crystal molecules move in a horizontal direction, a mixed color at a side between pixels displaying different colors may be generated. 
     When polarities of data voltages applied to pixel electrodes provided in adjacent pixels are different from each other, an unnecessary fringe field is generated between the data line and the common electrode around the data line, and as a result, transmittance at an edge of the pixel area is decreased. 
     The invention has been made in an effort to provide a liquid crystal display having advantages of preventing a mixed color between pixels displaying different colors and increasing transmittance. 
     In an exemplary embodiment, an exemplary embodiment of the invention provides a liquid crystal display, including an insulation substrate, a gate line and a data line disposed on the insulation substrate, a first passivation layer disposed on the gate line and the data line, a first common electrode which is disposed on the first passivation layer and overlaps with the data line, an insulating layer disposed on the first common electrode, a second common electrode disposed on the insulating layer, a second passivation layer disposed on the second common electrode, and a pixel electrode disposed on the second passivation layer. 
     In an exemplary embodiment, the first common electrode may overlap with the gate line, and the first common electrode may include a first portion overlapping with the gate line and a second portion overlapping with the data line. 
     In an exemplary embodiment, the LCD may further include a light blocking member and a color filter disposed below the insulating layer, in which the first portion of the first common electrode may overlap with the light blocking member. 
     In an exemplary embodiment, the LCD may further include a light blocking member and a color filter disposed below the insulating layer. The first common electrode may be disposed on or below the light blocking member and the color filter. 
     In an exemplary embodiment, the first common electrode may be disposed below the light blocking member, and at the overlapping portion of the first common electrode and the light blocking member, edges of the first common electrode and the light blocking member may coincide with each other. 
     In an exemplary embodiment, the first common electrode may be disposed on the entire surface of the insulation substrate, and the second common electrode may be disposed in a region overlapping with the pixel electrode. 
     In an exemplary embodiment, a first edge of the first common electrode and a second edge most adjacent to the first common electrode among edges of the pixel electrode may be separated from each other. 
     In an exemplary embodiment, a distance between the first edge and the second edge may be about 2.45 micrometers (μm) to about 3.45 μm. 
     In an exemplary embodiment, an edge adjacent to the data line among the edges of the pixel electrode may further protrude toward the data line than an edge adjacent to the data line among the edges of the second common electrode. 
     In an exemplary embodiment, the second common electrode may have a plate-like planar shape, the pixel electrode may include a plurality of branch electrodes, and the plurality of branch electrodes may overlap with the second common electrode. 
     According to the exemplary embodiment of the invention, it is possible to effectively prevent a mixed color between pixels displaying different colors and increase transmittance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other exemplary embodiments, advantages and features of this disclosure will become more apparent by describing in further detail exemplary embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1  is a plan view illustrating an exemplary embodiment of a liquid crystal display (“LCD”) according to the invention. 
         FIG. 2  is a cross-sectional view of the LCD of  FIG. 1  taken along line II-II. 
         FIG. 3  is a cross-sectional view illustrating the LCD of  FIG. 1  taken along line III-III. 
         FIGS. 4A and 4B  are schematic cross-sectional views for describing the exemplary embodiment of a structure and a simulation result of the LCD according to the invention. 
         FIGS. 5A and 5B  are schematic cross-sectional views for describing the exemplary embodiment of a structure and a simulation result of the LCD according to the invention. 
         FIG. 6  is a plan view illustrating another exemplary embodiment of an LCD according to the invention. 
         FIG. 7  is a cross-sectional view of the LCD of  FIG. 6  taken along line VII-VII. 
         FIG. 8  is a cross-sectional view of the LCD of  FIG. 6  taken along line VIII-VIII. 
         FIGS. 9 to 16  are cross-sectional views illustrating an exemplary embodiment of a part of a manufacturing method of an LCD according to the invention. 
         FIG. 17  is a plan view illustrating another exemplary embodiment of an LCD according to the invention. 
         FIG. 18  is a plan view for describing a shape of a first common electrode of the LCD of  FIG. 17 . 
         FIG. 19  is a cross-sectional view of the LCD of  FIG. 17  taken along line XIX-XIX. 
         FIG. 20  is a cross-sectional view of the LCD of  FIG. 17  taken along line XX-XX. 
         FIG. 21  is a plan view illustrating another exemplary embodiment of an LCD according to the invention. 
         FIG. 22  is a cross-sectional view of the LCD of  FIG. 21  taken along line XXII-XXII. 
         FIG. 23  is a cross-sectional view illustrating the LCD of  FIG. 21  taken along line XXIII-XXIII. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the invention. 
     In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
     It will be understood that, although the terms “first,” “second,” “third” etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, “a first element,” “component,” “region,” “layer” or “section” discussed below could be termed a second element, component, region, layer or section without departing from the teachings herein. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms, including “at least one,” unless the content clearly indicates otherwise. “Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. 
     Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element&#39;s relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower,” can therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below. 
     “About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10%, 5% of the stated value. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims. 
     First, a liquid crystal display (“LCD”) according to an exemplary embodiment of the invention will be described with reference to  FIGS. 1 to 3 .  FIG. 1  is a plan view illustrating an LCD according to an exemplary embodiment of the invention,  FIG. 2  is a cross-sectional view of the LCD of  FIG. 1  taken along line II-II, and  FIG. 3  is a cross-sectional view of the LCD of  FIG. 1  taken along line III-III. 
     The LCD according to the exemplary embodiment of the invention includes a lower panel  100  and an upper panel  200  facing each other, and a liquid crystal layer  3  interposed between the two panels  100  and  200 . 
     First, the lower panel  100  will be described. 
     A gate conductor including a gate line  121  is disposed on a first insulation substrate  110  including transparent glass, plastic, or the like. 
     The gate line  121  includes a gate electrode  124  and a wide end portion (not illustrated) for connection with another layer or an external driving circuit. In an exemplary embodiment, the gate line  121  may include aluminum-based metal such as aluminum (Al) or an aluminum alloy, silver-based metal such as silver (Ag) or a silver alloy, copper-based metal such as copper (Cu) or a copper alloy, molybdenum-based metal such as molybdenum (Mo) or a molybdenum alloy, chromium (Cr), tantalum (Ta), and titanium (Ti), for example. However, the invention is not limited thereto, and the gate line  121  may have a multilayered structure including at least two conductive layers having different physical properties. 
     A gate insulating layer  140  including silicon nitride (SiNx) or silicon oxide (SiOx) is disposed on the gate conductor. In an exemplary embodiment, the gate insulating layer  140  may have a multilayered structure including at least two insulating layers having different physical properties. 
     Semiconductors  151  and  154  including amorphous silicon or polysilicon are disposed on the gate insulating layer  140 . The semiconductors  151  and  154  may include oxide semiconductors. 
     The semiconductors  151  and  154  include a first portion  151  disposed below the data line  171 , and a second portion  154  disposed below the source electrode  173  and the drain electrode  175 . The first portion  151  and the second portion  154  are connected to each other. 
     Ohmic contacts  161 ,  163 , and  165  are disposed on the second portion  154  of the semiconductors  151  and  154 . In an exemplary embodiment, the ohmic contacts  161 ,  163 , and  165  may include a material such as n+ hydrogenated amorphous silicon in which n-type impurity such as phosphorus is doped at a high concentration or silicide, for example. Among the ohmic contacts  161 ,  163 , and  165 , the first ohmic contact  161  is disposed below the data line  171 , and the second and third ohmic contacts  163  and  165  make a pair to be disposed on the second portion  154  of the semiconductors  151  and  154 . The first ohmic contact  161  and the second ohmic contact  163  are connected to each other. In the case where the semiconductors  151  and  154  are the oxide semiconductors, the ohmic contacts  161 ,  163 , and  165  may be omitted. 
     A data conductor including a data line  171  including a source electrode  173  and a drain electrode  175  is disposed on the ohmic contacts  161 ,  163 , and  165  and the gate insulating layer  140 . 
     The data line  171  includes a wide end portion (not illustrated) for connection with another layer or an external driving circuit. The data line  171  transfers a data signal and substantially extends in a vertical direction to cross the gate line  121 . 
     In this case, the data line  171  may have a first curved portion  171   a  having a curved shape in order to acquire maximum transmittance of the liquid crystal display, and the first curved portion  171   a  may have a V-lettered shape which is disposed in a middle region of a pixel area in a plan view. A second curved portion (not illustrated) which is curved to provide a predetermined angle with the first curved portion  171   a  may be further included in the middle region of the pixel area. 
     In an exemplary embodiment, the first curved portion  171   a  of the data line  171  may be curved to provide an angle of about 7 degrees (°) with a vertical reference line which provides an angle of 90° with an extending direction of the gate line  121 . The second curved portion disposed in the middle region of the pixel area may be further curved to provide an angle of about 7° to about 15° with the first curved portion. 
     The source electrode  173  is a part of the data line  171 , and disposed on the same line as the data line  171 . The drain electrode  175  is provided to extend in parallel with the source electrode  173 . Accordingly, the drain electrode  175  is parallel with the part of the data line  171 . 
     However, the shapes of the source electrode and the drain electrode are not limited thereto, and the source electrode and the drain electrode may have various shapes. 
     The gate electrode  124 , the source electrode  173  and the drain electrode  175  provide one thin film transistor (“TFT”) together with the second portion  154  of the semiconductors  151  and  154 , and a channel of the TFT is disposed in the second portion  154  of the semiconductors  151  and  154  between the source electrode  173  and the drain electrode  175 . 
     The LCD according to the exemplary embodiment of the invention includes the source electrode  173  disposed on the same line with the data line  171  and the drain electrode  175  extending in parallel with the data line  171 , and as a result, a width of the TFT may be increased while an area occupied by the data conductor is not increased, thereby increasing an aperture ratio of the liquid crystal display. 
     In exemplary embodiments, the data line  171  and the drain electrode  175  may include refractory metal such as molybdenum, chromium, tantalum and titanium or an alloy thereof, and may have a multilayered structure including a refractory metal layer (not illustrated) and a low resistive conductive layer (not illustrated). An example of the multilayered structure may include a double layer including a chromium or molybdenum (alloy) lower layer and an aluminum (alloy) upper layer, and a triple layer including a molybdenum (alloy) lower layer, an aluminum (alloy) intermediate layer and a molybdenum (alloy) upper layer. However, the invention is not limited thereto, and the data line  171  and the drain electrode  175  may include various metals or conductors in addition to the metal. 
     A first passivation layer  180   a  is disposed on the data conductor  171 ,  173  and  175 , the gate insulating layer  140  and the second portion  154  of the exposed semiconductors  151  and  154 . In an exemplary embodiment, the first passivation layer  180   a  may include an organic insulating material or an inorganic insulating material. 
     A first common electrode  260  is disposed on the first passivation layer  180   a.    
     The first common electrode  260  is disposed in a region corresponding to the data line  171 , and a width of the first common electrode  260  taken in a plan view is larger than that of the data line  171 . 
     In the case of the LCD according to the exemplary embodiment, since the source electrode  173  is a part of the data line  171 , the first common electrode  260  is provided even at a position corresponding to the source electrode  173 . 
     The first common electrode  260  extends in a direction parallel to the data line  171 , and receives a common voltage from the outside of the display area. 
     A light blocking member  220  and a color filter  230  are disposed on the first passivation layer  180   a  and the first common electrode  260 . The light blocking member  220  is provided at a position corresponding to the gate line  121  and the TFT, does not overlap with the pixel electrode  191  except for a portion where the pixel electrode  191  and the drain electrode  175  are connected to each other, and does not overlap with the data line  171  except for a portion where the gate line  121  and the data line  171  overlap with each other. A first opening  221  is defined in the light blocking member  220  by removing a periphery of the light blocking member  220  at the first contact hole  185  where the drain electrode  175  and the pixel electrode  191  are connected to each other. 
     The color filter  230  may partially overlap with the light blocking member  220 , and is substantially disposed in a region corresponding to a region where the pixel electrode  191  is provided. 
     In exemplary embodiments, the color filter  230  may uniquely display one of the primary colors, and an example of the primary colors may include three primary colors such as red, green and blue, for example, or yellow, cyan, magenta, and the like. Although not illustrated, the color filters may further include a color filter displaying a mixed color of the primary colors or white in addition to the primary colors. 
     Although not illustrated, an overcoat (not illustrated) may be disposed on the light blocking member  220  and the color filter  230 . The overcoat prevents pigment components of the light blocking member  220  and the color filter  230  from being dispersed. 
     In the illustrated exemplary embodiment, the first common electrode  260  is disposed below the light blocking member  220  or the color filter  230 , but the invention is not limited thereto, and the first common electrode  260  may be disposed on the light blocking member  220  or the color filter  230 . 
     An insulating layer  80  is disposed on the first common electrode  260 , the color filter  230  and the light blocking member  220 . 
     In an exemplary embodiment, the insulating layer  80  may include an organic material, has a relative large thickness, and provides a flat surface. However, the invention is not limited thereto, and the insulating layer  80  may include an inorganic material. 
     A second common electrode  270  is disposed on the insulating layer  80 . In an exemplary embodiment, the second common electrode  270  has a planar shape, and is disposed in a region corresponding to most of the pixel area. The second common electrodes  270  disposed at the adjacent pixels are connected to each other to receive a common voltage having a predetermined magnitude supplied from the outside of the display area. 
     The second common electrode  270  includes a vertical portion  271  extending parallel to the data line  171  between the two adjacent data lines  171  and a connecting portion  272 . The second common electrodes  270  disposed in the pixels adjacent to each other in a pixel row direction are connected to each other through the connecting portion  272 . Accordingly, the second common electrodes  270  disposed in all the pixel areas to be connected to each other may receive a voltage having a predetermined magnitude from an external common voltage applying unit. A second opening  273  is defined in the second common electrode  270  around the first contact hole  185  where the pixel electrode  191  and the drain electrode  175  are connected to each other. 
     An LCD according to another exemplary embodiment of the invention may further include a common voltage line (not illustrated) disposed in and/or on the same layer as the gate line  121  or the data line  171  and the second common electrode  270  is connected to the common voltage line through a contact hole (not illustrated) defined in an insulating layer disposed on the common voltage line to receive the common voltage, thereby preventing signal delay of the common voltage. 
     A second passivation layer  180   b  is disposed on the second common electrode  270 . The second passivation layer  180   b  may include an organic insulating material or an inorganic insulating material. 
     A pixel electrode  191  is disposed on the second passivation layer  180   b . The pixel electrode  191  includes a curved edge which is substantially parallel with the first curved portion  171   a  of the data line  171 . A plurality of cutouts  92  is defined in the pixel electrode  191 , and the pixel electrode  191  includes a plurality of branch electrodes  192  defined by the plurality of cutouts  92 . 
     A first contact hole  185  exposing the drain electrode  175  is defined in the first passivation layer  180   a , the insulating layer  80  and the second passivation layer  180   b . The pixel electrode  191  is physically and electrically connected to the drain electrode  175  through the first contact hole  185  to receive a voltage from the drain electrode  175 . 
     As illustrated in  FIG. 3 , when viewed from a cross-sectional shape, an edge adjacent to two adjacent data lines  171  among edges of the second common electrode  270  is disposed inside the edge of the pixel electrode  191 . That is, as illustrated in  FIG. 1 , when viewed from a planar shape, an edge adjacent to two adjacent data lines  171  among edges of the pixel electrode  191  further protrudes toward the data line  171  than the edge adjacent to two adjacent data lines  171  among edges of the second common electrode  270 . 
     A spacer  325  and a colored member  326  are disposed on the lower panel  100 . The spacer  325  maintains a gap between the lower panel  100  and the upper panel  200 , and the colored member  326  covers the first contact hole  185  to effectively prevent light leakage in the first contact hole  185  which does not overlap with the light blocking member  220 . The spacer  325  and the colored member  326  may be disposed in and/or on the same layer. 
     However, according to an LCD according to another exemplary embodiment of the invention, the spacer  325  may be disposed on the upper panel  200 . 
     Although not illustrated, an alignment layer is coated on the pixel electrode  191  and the second passivation layer  180   b , and the alignment layer may be a horizontal alignment layer and be rubbed in a predetermined direction. However, in an LCD according to another exemplary embodiment of the invention, the alignment layer includes a photoreactive material to be photo-aligned. 
     Next, the upper panel  200  will be described. 
     The upper panel  200  includes a second insulation substrate  210  including transparent glass, plastic, or the like and an alignment layer (not illustrated) disposed on the second insulation substrate  210 . 
     The LCD according to the exemplary embodiment includes the light blocking member  220  and the color filter  230  disposed on the lower panel  100 , but in the case of an LCD according to another exemplary embodiment of the invention, at least one of the light blocking member  220  and the color filter  230  may be disposed on the upper panel  200 , not the lower panel  100 . 
     The liquid crystal layer  3  includes a liquid crystal material having positive dielectric anisotropy. The liquid crystal molecules of the liquid crystal layer  3  are aligned so that long-axial directions thereof are parallel to the panels  100  and  200  without applying the electric field to the liquid crystal layer  3 . However, according to an LCD according to another exemplary embodiment of the invention, the liquid crystal layer  3  may include a liquid crystal material having negative dielectric anisotropy. 
     The pixel electrode  191  receives a data voltage from the drain electrode  175 , and the first common electrode  260  and the second common electrode  270  receive a common voltage having a predetermined magnitude from a common voltage applying unit disposed outside the display area. 
     The pixel electrode  191  and the second common electrode  270  which are field generating electrodes generate an electric field and thus the liquid crystal molecules of the liquid crystal layer  3  disposed on the pixel electrode  191  and the second common electrode  270  rotate in a direction parallel to the direction of the electric field. Polarization of light passing through the liquid crystal layer varies according to the determined rotation directions of the liquid crystal molecules. 
     The edge of the first common electrode  260  does not overlap with the pixel electrode  191 , and adjacent edges among the edges of the first common electrode  260  and the edges of the pixel electrode  191  are separated from each other at a first distance W1 taken in a plan view. In an exemplary embodiment, the first distance W1 between the adjacent edges among the edges of the first common electrode  260  and the edges of the pixel electrode  191  may be about 2.45 micrometers (μm) to about 3.45 μm. 
     Next, referring to  FIGS. 4A   4 B,  5 A and  5 B, characteristics of the LCD according to the exemplary embodiment of the invention will be described.  FIG. 4A  is a schematic cross-sectional view for describing a structure of the LCD according to the exemplary embodiment of the invention, and  FIG. 4B  is a diagram illustrating a simulation result of the LCD of  FIG. 4A .  FIG. 5A  is a schematic cross-sectional view for describing a structure of the LCD according to the exemplary embodiment of the invention, and  FIG. 5B  is a diagram illustrating a simulation result of the LCD of  FIG. 5A . 
     In  FIGS. 4B and 5B , a first portion L1 is a schematic cross-sectional view of the liquid crystal display, and a second portion L2 represents arrangement of liquid crystal directors, and a third portion L3 represents transmittance. First, a case where respective data voltages are applied to a first pixel electrode  191   a , and a second pixel electrode  191   b  and a third pixel electrode  191   c  disposed at both sides of the first pixel electrode  191   a , will be described with reference to  FIGS. 4A and 4B . 
     Referring to  FIG. 4A , a first data line  171   a  and a second data line  171   b  are disposed on the first insulation substrate  110  to be adjacent to each other. 
     The first passivation layer  180   a  is disposed on the first data line  171   a  and the second data line  171   b , and the first common electrode  260  is disposed on the first passivation layer  180   a . The first common electrode  260  is provided at a position corresponding to the first data line  171   a  and the second data line  171   b , and a width of the first common electrode  260  taken in a plan view is larger than a width of each of the first data line  171   a  and the second data line  171   b.    
     The insulating layer  80  is disposed on the first common electrode  260 . The second common electrode  270  is disposed on the insulating layer  80 . The second common electrode  270  does not overlap with the first data line  171   a  and the second data line  171   b  except for the connecting portion  272 , and is disposed in a first pixel area PX1 between the first data line  171   a  and the second data line  171   b , and between a second pixel area PX2 and a third pixel area PX3. 
     The second passivation layer  180   b  is disposed on the second common electrode  270 . The first pixel electrode  191   a , the second pixel electrode  191   b  and the third pixel electrode  191   c  are disposed on the second passivation layer  180   b.    
     The first pixel electrode  191   a  is disposed in the first pixel area PX1, the second pixel electrode  191   b  is disposed in the second pixel area PX2 disposed next to the first pixel area PX1, and the third pixel electrode  191   c  is disposed in the third pixel area PX3 disposed next to the first pixel area PX1. 
     Edges adjacent to the data lines  171   a  and  171   b  among the edges of the second common electrodes  270  disposed in the respective pixel areas PX1, PX2 and PX3 are disposed inside the edges of the pixel electrodes  191   a ,  191   b  and  191   c . That is, when viewed from a planar shape, the edges adjacent to the data lines  171   a  and  171   b  among the edges of the pixel electrodes  191   a ,  191   b  and  191   c  further protrude toward the data lines  171   a  and  171   b  than the edges adjacent to the data lines  171   a  and  171   b  among the edges of the second common electrode  270 . 
     A first data voltage is applied to the first pixel electrode  191   a , a second data voltage is applied to the second pixel electrode  191   b , and a third data voltage is applied to the third pixel electrode  191   c.    
     A polarity of the first data voltage applied to the first pixel electrode  191   a  is different from a polarity of the second data voltage applied to the second pixel electrode  191   b  and a polarity of the third data voltage applied to the third pixel electrode  191   c , and the polarity of the second data voltage and the polarity of the third data voltage are the same as each other.  FIG. 4A  illustrates a case where the polarity of the first data voltage is a positive polarity (+), and the polarity of the second data voltage and the polarity of the third data voltage are negative polarities (−). However, the invention is not limited thereto, and the polarity of the first data voltage may be a negative polarity, and the polarity of the second data voltage and the polarity of the third data voltage may be positive polarities. 
     When the first data voltage is applied to the first pixel electrode  191   a , the second data voltage is applied to the second pixel electrode  191   b , and the third data voltage is applied to the third pixel electrode  191   c , a first fringe field F1 is generated between the first pixel electrode  191   a  and the second common electrode  270 , between the second pixel electrode  191   b  and the second common electrode  270 , and between the third pixel electrode  191   c  and the second common electrode  270 . 
     A second fringe field F2 is generated between a first branch electrode  191   a   1  of the first pixel electrode  191   a  disposed at an outermost side of the first pixel area PX1 adjacent to the second pixel area PX2 and a second branch electrode  191   b   1  of the second pixel electrode  191   b  disposed at an outermost side of the second pixel area PX2 adjacent to the first pixel area PX1, and between the first branch electrode  191   a   1  of the first pixel electrode  191   a  disposed at an outermost side of the first pixel area PX1 adjacent to the third pixel area PX3 and a third branch electrode  191   c   1  of the third pixel electrode  191   c  disposed at an outermost side of the third pixel area PX3 adjacent to the first pixel area PX1. 
     Further, a third fringe field F3 is generated between the first branch electrode  191   a   1  of the first pixel electrode  191   a  disposed at the outermost side of the first pixel area PX1 and the first common electrode  260 , between the second branch electrode  191   b   1  of the second pixel electrode  191   b  disposed at an outermost side of the second pixel area PX2 and the first common electrode  260 , and between the third branch electrode  191   c   1  of the third pixel electrode  191   c  disposed at an outermost side of the third pixel area PX3 and the first common electrode  260 . 
     As described above, the insulating layer  80  is disposed on the first common electrode  260 . Accordingly, a size of the third fringe field F3 generated between the first branch electrode  191   a   1  of the first pixel electrode  191   a  in the first pixel area PX1 disposed at the outermost side of the first pixel area PX1 and the first common electrode  260  is smaller than a size of the second fringe field F2 generated between the first branch electrode  191   a   1  of the first pixel electrode  191   a  and the second branch electrode  191   b   1  of the second pixel electrode  191   b , and between the first branch electrode  191   a   1  of the first pixel electrode  191   a  and the third branch electrode  191   c   1  of the third pixel electrode  191   c.    
     That is, at the outermost sides of the first pixel area PX1, the second pixel area PX2, and the third pixel area PX3, a size of the second fringe field F2 in a horizontal direction in a cross section is larger than a size of the third fringe field F3 in a vertical direction in a cross section. 
     Accordingly, since the liquid crystal molecules move by the fringe field in the horizontal direction even at the outermost sides of the first pixel area PX1, the second pixel area PX2, and the third pixel area PX3, like a portion A of  FIG. 4B , transmittance is not decreased even at the edges of the respective pixel areas PX1, PX2 and PX3. 
     Like an existing liquid crystal display, when the first common electrode  260  is not provided, and the second common electrode  270  provided throughout the pixel area is disposed on the insulating layer  80 , in the first branch electrode  191   a   1 , the second branch electrode  191   b   2  and the third branch electrode  191   c   1  disposed at the outermost sides of the respective pixel areas PX1, PX2 and PX3, the size of the fringe field in the vertical direction to the second common electrode  270  is relatively increased, and as a result, the liquid crystal molecules disposed at the edges of the respective pixel areas PX1, PX2 and PX3 are affected by both the fringe field generated in the horizontal direction and the fringe field generated in the vertical direction. Due to the effect of the fringe fields applied in different directions, directivity of the fringe field is reduced, and as a result, transmittance of the LCD may be decreased at the edges of the respective pixel areas PX1, PX2 and PX3. 
     However, according to the LCD according to the exemplary embodiment of the invention, since the first common electrode  260  is disposed below the insulating layer  80  and the second common electrode  270  disposed on the insulating layer  80  is not provided at the edge of the pixel area except for the connecting portion  272 , the liquid crystal molecules disposed at the edge of the pixel area are substantially affected by the fringe field in the horizontal direction, thereby preventing deterioration of transmittance which may occur at the edge of the pixel area. 
     Next, a case where a data voltage is applied to the first pixel electrode  191   a , and the data voltages are not applied to the second pixel electrode  191   b  and the third pixel electrode  191   c  disposed at both sides of the first pixel electrode  191   a  will be described with reference to  FIGS. 5A and 5B . 
     Referring to  FIG. 5A , a first data voltage is applied to the first pixel electrode  191   a , and the data voltages are not applied to the second pixel electrode  191   b  and the third pixel electrode  191   c  to be turned off. 
     When the first data voltage is applied to the first pixel electrode  191   a , the first fringe field F1 is generated between the first pixel electrode  191   a  and the second common electrode  270 . 
     The third fringe field F3 is generated between the first branch electrode  191   a   1  of the first pixel electrode  191   a  disposed at the outermost side of the first pixel area PX1 and the first common electrode  260 . 
     Further, a fourth fringe field F4 may be generated even between the first branch electrode  191   a   1  of the first pixel electrode  191   a  disposed at the outermost side of the first pixel area PX1 adjacent to the second pixel area PX2 and the third pixel area PX3 and the second common electrode  270  disposed in the second pixel area PX2 and the third pixel area PX3. However, according to the LCD according to the exemplary embodiment of the invention, since the second common electrode  270  is not provided at a position overlapping with the data lines  171   a  and  171   b  except for the connecting portion, a distance between the first branch electrode  191   a   1  of the first pixel electrode  191   a  disposed at the outermost side of the first pixel area PX1 adjacent to the second pixel area PX2 and the third pixel area PX3 and the second common electrode  270  disposed in the second pixel area PX2 and the third pixel area PX3 becomes large. Accordingly, an effect of the fourth fringe field F4 is substantially small. 
     As such, an effect of the fourth fringe field F4 provided between the second pixel area PX2 and the third pixel area PX3 adjacent to each other at the outermost side of the first pixel area PX1 is substantially small, and the transmittance at the outermost side of the first pixel area PX1 deteriorates due to the effect of the third fringe field F3 generated in the vertical direction like a portion B of  FIG. 5B . Accordingly, when an image is displayed in the first pixel area PX1, the liquid crystal molecules which is disposed between the first pixel area PX1 and the second pixel area PX2 or third pixel area PX3 which are adjacent to the first pixel area PX1 and which displays a different color from that of the first pixel area PX1 do not unnecessarily rotate. 
     When the first common electrode  260  is not provided and the second common electrode  270  provided throughout the pixel area is disposed on the insulating layer  80 , the first branch electrode  191   a   1 , the second branch electrode  191   b   2  and the third branch electrode  191   c   1  disposed at the outermost sides of the respective pixel areas PX1, PX2 and PX3 are affected by the fourth fringe field F4 generated between the second common electrodes  270  disposed in the adjacent pixel areas. Accordingly, when the image is displayed in the first pixel area PX1, due to the effect of the fourth fringe field F4 applied to the liquid crystal molecules disposed between the first pixel area PX1 and the second pixel area PX2 or third pixel area PX3 which is adjacent to the first pixel area PX1 and displays a different color, a color displayed by the second pixel area PX2 or third pixel area PX3 which is an adjacent pixel at the edge of the first pixel area PX1 may be recognized. As such, when the colors displayed by the adjacent colors are recognized, a mixed color may be generated. 
     However, according to the LCD according to the exemplary embodiment of the invention, since the first common electrode  260  is disposed below the insulating layer  80 , and the second common electrode  270  disposed on the insulating layer  80  is not provided at the edge of the pixel area except for the connecting portion  272 , the liquid crystal molecules disposed between the pixel area displaying the image and the adjacent pixel area which is adjacent to the pixel area displaying the image and displays a different color are prevented from unnecessarily rotating, thereby preventing the mixed color generated between the adjacent pixels. 
     Next, an LCD according to another exemplary embodiment of the invention will be described with reference to  FIGS. 6 to 8 .  FIG. 6  is a plan view illustrating an LCD according to another exemplary embodiment of the invention,  FIG. 7  is a cross-sectional view of the LCD of  FIG. 6  taken along line VII-VII, and  FIG. 8  is a cross-sectional view of the LCD of  FIG. 6  taken along line VIII-VIII. 
     Referring to  FIGS. 6 to 8 , the LCD according to the exemplary embodiment is similar to the LCD according to the exemplary embodiment illustrated in  FIGS. 1 to 3 . Accordingly, the description for like constituent elements may be omitted. 
     However, in the LCD according to the exemplary embodiment, unlike the LCD according to the exemplary embodiment illustrated in  FIGS. 1 to 3 , the first common electrode  260  is disposed in a region corresponding to the data line  171  and even in a region corresponding to the gate line  121  and the TFT. The first common electrode  260  includes a first portion  260 A disposed in the region corresponding to the gate line  121  and the TFT, and a second portion  260 B disposed at a position corresponding to the data line  171 . 
     Like the LCD according to the exemplary embodiment illustrated in  FIGS. 1 to 3 , even in the LCD according to the exemplary embodiment, the light blocking member  220  is provided at a position corresponding to the gate line  121  and the TFT, does not overlap with the pixel electrode  191  except for a portion where the pixel electrode  191  and the drain electrode  175  are connected to each other, and does not overlap with the data line  171  except for a portion where the gate line  121  and the data line  171  overlap with each other. A third opening  222  is defined in the light blocking member  220  by removing a periphery of the light blocking member  220  at the first contact hole  185  where the drain electrode  175  and the pixel electrode  191  are connected to each other. Further, the first portion  260 A of the first common electrode  260  overlaps with the light blocking member  220 , and the second portion  260 B of the first common electrode  260  does not overlap with the light blocking member  220 . The first portion  260 A of the first common electrode  260  and the light blocking member  220  around the first contact hole  185  where the drain electrode  175  and the pixel electrode  191  are connected are removed to define the third opening  222 . 
     The first portion  260 A of the first common electrode  260  and the light blocking member  220  which overlap with each other have edges overlapping with each other. That is, the first common electrode  260  and the light blocking member  220  may be simultaneously provided by one photolithography process by using one mask. This will be described with reference to  FIGS. 9 to 16 .  FIGS. 9 to 16  are cross-sectional views illustrating a manufacturing method of an LCD device according to an exemplary embodiment of the invention in sequence. 
     First, referring to  FIGS. 9 and 10 , a transparent conductive layer  10  providing the first common electrode  260  and an opaque layer  20  providing the light blocking member  220  are sequentially laminated, and a photosensitive film is laminated thereon. Thereafter, by performing exposure using a photomask having a translucent area in addition to a light transmitting area and a light blocking area, a first photosensitive film pattern  400   a  and a second photosensitive film pattern  400   b  having different thicknesses according to a position are provided. In this case, the first photosensitive film pattern  400   a  is provided at a portion where the first portion  260 A of the first common electrode  260  and the light blocking member  220  overlapping with each other are provided, and the second photosensitive film pattern  400   b  is provided at a position where the second portion  260 B of the first common electrode  260  is provided. In an exemplary embodiment, a thickness of the first photosensitive film pattern  400   a  is larger than that of the second photosensitive film pattern  400   b.    
     As a method of varying the thickness of the photosensitive film according to a position, various methods are included, and for example, a method of positioning the translucent area in addition to the light transmitting area and the light blocking area in the photomask is included. A slit pattern, a lattice pattern, or a thin film having medium transmittance or a medium thickness is provided in the translucent area. In the case of using the slit pattern, a width of the slit or a distance between the slits in a plan view may be smaller than resolution of an exposer used in a photolithography process. As another example, a method of using a photosensitive film capable of reflowing is included. That is, the photosensitive film capable of reflowing is provided by a general exposure mask having only the light transmitting area and the light blocking area and then reflows, and flows down to a region where the photosensitive film does not remain to provide a thin portion. As such, a manufacturing method is simplified by omitting one photolithography process. 
     Next, as illustrated in  FIGS. 11 and 12 , by using the first photosensitive film pattern  400   a  and the second photosensitive film pattern  400   b  as an etching mask, by etching the opaque layer  20  and the transparent conductive layer  10 , the first portion  260 A and the second portion  260 B of the first common electrode  260 , and the light blocking member  220  disposed on the first portion  260 A of the first common electrode  260  and a dummy light blocking member  220   c  disposed on the second portion  260 B of the first common electrode  260  are provided. In this case, a third opening  222  defined on and/or around the drain electrode  175  is defined in the first portion  260 A of the first common electrode  260  and the light blocking member  220 . 
     Referring to  FIGS. 13 and 14 , a third photosensitive film pattern  400   c  is provided by decreasing a height of the first photosensitive film pattern  400   a , and the second photosensitive film pattern  400   b  is removed to expose the dummy light blocking member  220   c  disposed on the second portion  260 B of the first common electrode  260 . 
     As illustrated in  FIGS. 15 and 16 , by using the third photosensitive film pattern  400   c  as an etching mask, the dummy light blocking member  220   c  disposed on the second portion  260 B of the common electrode  260  is removed, and the third photosensitive film pattern  400   c  is removed. 
     As such, by providing the photosensitive film patterns having different heights according to a position, the first common electrode  260  and the light blocking member  220  may be provided by one photolithography process. 
     In the illustrated exemplary embodiment, the first common electrode  260  is disposed below the light blocking member  220  or the color filter  230 , but the first common electrode  260  may be disposed on the light blocking member  220  or the color filter  230 . 
     The second common electrode  270  may not be disposed in a region corresponding to the gate line  121  and the data line  171 . However, as illustrated in  FIG. 6 , a connecting portion for connecting the second common electrodes  270  disposed in the adjacent pixels may overlap with the data line  171 . 
     An LCD according to another exemplary embodiment of the invention may further include a common voltage line disposed on the same layer as the gate line  121  or the data line  171 , and the second common electrode  270  is connected to the common voltage line through a contact hole defined in an insulating layer disposed on the common voltage line to receive the common voltage. 
     Many features of the LCD according to the exemplary embodiment described above with reference to  FIGS. 1 to 3  may be all applied to the LCD according to the exemplary embodiment. Accordingly, the LCD according to the exemplary embodiment has characteristics and effects as described with reference to  FIGS. 4A and 4B  and  FIGS. 5A and 5B . 
     Next, an LCD according to another exemplary embodiment of the invention will be described with reference to  FIGS. 17 to 20 .  FIG. 17  is a plan view illustrating an LCD according to another exemplary embodiment of the invention,  FIG. 18  is a plan view for describing a shape of a first common electrode of the LCD of  FIG. 17 ,  FIG. 19  is a cross-sectional view of the LCD of  FIG. 17  taken along line XIX-XIX, and  FIG. 20  is a cross-sectional view of the LCD of  FIG. 17  taken along line XX-XX. 
     Referring to  FIGS. 17 to 20 , the LCD according to the exemplary embodiment is similar to the LCD according to the exemplary embodiment illustrated in  FIGS. 1 to 3 , and the LCD according to the exemplary embodiment illustrated in  FIGS. 6 to 8 . The detailed description for like constituent elements is omitted. 
     However, referring to  FIGS. 17 to 20 , the first common electrode  260  of the LCD according to the exemplary embodiment is disposed on the entire surface of the first insulation substrate  110 . 
     In more detail, the first common electrode  260  is disposed on the entire surface of the first insulation substrate  110 , and is removed around the first contact hole  185  where the drain electrode  175  and the pixel electrode  191  are connected to each other to define a fourth opening  261 . 
     In the illustrated exemplary embodiment, the first common electrode  260  is disposed below the light blocking member  220  or the color filter  230 , but the first common electrode  260  may be disposed on the light blocking member  220  or the color filter  230 . 
     The second common electrode  270  may not be disposed in a region corresponding to the gate line  121  and the data line  171 . However, as illustrated in  FIG. 17 , a connecting portion for connecting the second common electrodes  270  disposed in the adjacent pixels may overlap with the data line  171 . 
     An LCD according to another exemplary embodiment of the invention may further include a common voltage line disposed on the same layer as the gate line  121  or the data line  171 , and the second common electrode  270  is connected to the common voltage line through a contact hole defined in an insulating layer disposed on the common voltage line to receive the common voltage. 
     Many features of the liquid crystal displays according to the exemplary embodiments described with reference to  FIGS. 1 to 3  and  6  to  8  may all be applied to the LCD according to the exemplary embodiment. Accordingly, the LCD according to the exemplary embodiment has characteristics and effects as described with reference to  FIGS. 4A and 4B  and  FIGS. 5A and 5B . 
     Next, an LCD according to another exemplary embodiment of the invention will be described with reference to  FIGS. 21 to 23 .  FIG. 21  is a plan view illustrating an LCD according to another exemplary embodiment of the invention,  FIG. 22  is a cross-sectional view of the LCD of  FIG. 21  taken along line XXII-XXII, and  FIG. 23  is a cross-sectional view illustrating the LCD of  FIG. 21  taken along line XXIII-XXIII. 
     Referring to  FIGS. 21 to 23 , the LCD according to the exemplary embodiment is similar to the LCD according to the exemplary embodiment illustrated in  FIGS. 1 to 3 . The detailed description for like constituent elements is omitted. 
     However, in the LCD according to the exemplary embodiment, unlike the LCD according to the exemplary embodiment illustrated in  FIGS. 1 to 3 , the first common electrode  260  is disposed on the light blocking member  220  or the color filter  230 . That is, the first common electrode  260  is provided between the light blocking member  220  or the color filter  230  and the insulating layer  80 . 
     Further, the second common electrode  270  may not be disposed in a region corresponding to the gate line  121  and the data line  171 . However, as illustrated in  FIG. 21 , a connecting portion for connecting the second common electrodes  270  disposed in the adjacent pixels may overlap with the data line  171 . 
     An LCD according to another exemplary embodiment of the invention may further include a common voltage line disposed on the same layer as the gate line  121  or the data line  171 , and the second common electrode  270  is connected to the common voltage line through a contact hole provided in an insulating layer disposed on the common voltage line to receive the common voltage. 
     Many features of the liquid crystal displays according to the exemplary embodiments described with reference to  FIGS. 1 to 3 ,  6  to  8  and  17  to  20  may all be applied to the LCD according to the exemplary embodiment. Accordingly, the LCD according to the exemplary embodiment has characteristics and effects as described with reference to  FIGS. 4A and 4B  and  FIGS. 5A and 5B . 
     While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.