Patent Publication Number: US-7907227-B2

Title: Liquid crystal display

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2006-0015478 filed in the Korean Intellectual Property Office on Feb. 17, 2006, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid crystal display. 
     2. Description of the Related Art 
     A liquid crystal display (LCD) includes a pair of display panels having field generating electrodes and polarizers and a liquid crystal layer interposed between the two display panels. Field generating electrodes generate an electric field of varying intensity thereby varying the arrangement of liquid crystal molecules and changing the polarization of light passing through the liquid crystal layer. A polarizer blocks or transmits the polarized light appropriately to make bright and dark regions, thereby displaying desired images. 
     Color filters corresponding to respective pixels are formed on one display panel of a liquid crystal display and light blocking members are formed around the boundaries of the respective pixels. The color filters represent three primary colors, red, green, and blue, and the light blocking members block light that passes through portions of the liquid crystal layer that are not controlled by pixel electrodes to improve the contrast ratio of the liquid crystal display. 
     Generally, a liquid crystal display is completed by forming color filters and light blocking members on one panel opposite to the other panel on which the pixel electrodes are formed, assembling the two completed display panels to face each other, and injecting liquid crystal between the two display panels. 
     When a gate-on voltage is applied to a thin film transistor of a liquid crystal display, the liquid crystal layer, which is an electro-optic active layer, is charged and the charge is maintained until the next time that a gate-on voltage is applied. When the gate-on voltage is changed to a gate-off voltage, the pixel voltage drops down slightly. A storage capacitor reduces the range of the fluctuation to maintain the pixel voltage constantly. 
     Therefore, it is desirable that the capacitance of a storage capacitor in a liquid crystal display be as large as possible. 
     However, as a storage electrode is formed to increase the capacitance of a storage capacitor in the liquid crystal display, the aperture ratio of the liquid crystal display is decreased. 
     Also, misalignment between the pixel electrodes and the color filters and light blocking members may occur in the process of assembling the two display panels of the liquid crystal display to face each other, and the misalignment may decrease color reproducibility and contrast ratio. 
     Therefore, it would be desirable to provide a liquid crystal display that can maintain a high contrast ratio of the liquid crystal display and raise the aperture ratio of the liquid crystal display while increasing the capacitance of storage capacitors. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, alignment error between the display panels is reduced and the aperture ratio of the liquid crystal display is increased in a liquid crystal display that includes a first substrate, a color filter formed on the first substrate, a first electrode formed on the color filter, an interlayer insulating layer formed on the first electrode, a light blocking member formed on the interlayer insulating layer and partially overlapped by the first electrode, a second substrate facing the first substrate, a second electrode formed on the second substrate, and a liquid crystal layer interposed between the first and second substrates. The light blocking member and the first electrode may be overlap each other with the interlayer insulating layer interposed therebetween to form a storage capacitor. 
     The liquid crystal display may further include a gate line formed on the first substrate having a gate electrode, a gate insulating layer formed on the first substrate, a semiconductor layer formed on the gate insulating layer, a data line and a drain electrode formed on the gate insulating layer and the semiconductor layer, and a passivation layer formed on the data line and the drain electrode. 
     A storage voltage may be applied to the light blocking member. 
     Another exemplary embodiment of the present invention provides a liquid crystal display including a first substrate, a first electrode formed on the first substrate, an interlayer insulating layer formed on the first electrode, a light blocking member formed on the interlayer insulating layer and partially overlapped with the first electrode, a second substrate facing the first substrate, a second electrode formed on the second substrate, a liquid crystal layer interposed between the first and second substrates, and a light source unit for providing the first and second substrates and the liquid crystal layer with light. The light source unit may include a plurality of light sources for representing respective primary colors, and the plurality of light sources may be sequentially switched off to represent a desired color with the temporal sum of the primary colors. 
     The light blocking member and the first electrode may be overlapped with each other with the interlayer insulating layer interposed therebetween to form a storage capacitor. 
     A storage voltage may be applied to the light blocking member. 
     The liquid crystal display may further include a gate line formed on the first substrate and including a gate electrode, a gate insulating layer formed on the first substrate, a semiconductor layer formed on the gate insulating layer, a data line and a drain electrode formed on the gate insulating layer and the semiconductor layer, and a passivation layer formed on the data line and the drain electrode 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a layout view of a liquid crystal display according to an exemplary embodiment of the present invention. 
         FIG. 2  and  FIG. 3  are cross-sectional views of the liquid crystal display taken along lines II-II and III-III of  FIG. 1 , respectively. 
         FIG. 4  is a layout view of a liquid crystal display according to another exemplary embodiment of the present invention. 
         FIG. 5  and  FIG. 6  are cross-sectional views of the liquid crystal display taken along the lines V-V and VI-VI of  FIG. 4 , respectively. 
         FIG. 7  is a layout view of a liquid crystal display according to a further exemplary embodiment of the present invention. 
         FIG. 8  and  FIG. 9  are cross-sectional views of the liquid crystal display taken along the lines VIII-VIII and IX-IX of  FIG. 7 , respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     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. 
     A liquid crystal display according to an exemplary embodiment of the present invention will now be described in detail with reference to  FIG. 1  to  FIG. 3 . 
       FIG. 1  is a layout view of a thin film transistor array panel according to an exemplary embodiment of the present invention, and  FIG. 2  and  FIG. 3  are cross-sectional views of the thin film transistor array panel taken along lines II-II and III-III of  FIG. 1 , respectively. 
     The liquid crystal display according to the present exemplary embodiment includes a thin film transistor array panel  100  and a common electrode panel  200  that face each other, and a liquid crystal layer  3  interposed between the two display panels  100  and  200 . 
     The thin film transistor array panel  100  of the liquid crystal display will now be described in detail with reference to  FIG. 1  to  FIG. 3 . 
     A plurality of gate lines  121  are formed on an insulation substrate  110  made of transparent glass or plastic. 
     The gate lines  121  include a plurality of gate electrodes  124  that are protruded upward and wide ends  129  for connecting with another layer or external driving circuits. A gate driving circuit (not shown) for generating a gate signal may be mounted on a flexible printed circuit film (not shown) attached on the substrate  110 , mounted directly on the substrate  110 , or integrated with the substrate  110 . If the gate driving circuit is integrated with the substrate  110 , it may be directly connected to the gate lines  121 . 
     The gate lines  121  are made of an aluminum (Al) group metal including Al or an Al alloy, a silver (Ag) group metal including Ag or a Ag alloy, a copper (Cu) group metal including Cu or a Cu alloy, a molybdenum (Mo) group metal including Mo or a Mo alloy, chromium (Cr), tantalum (Ta), and titanium (Ti). However, the gate lines  121  may have a multi-layered structure including two conductive layers (not shown) that have different physical properties each other. One of the two conductive layers is made of a low-resistive metal to reduce voltage drop, such as an Al group metal, an Ag group metal, and a Cu group metal. The other conductive layer is made of a material that has excellent physical, chemical, and electrical contact characteristics with other materials, particularly, with indium tin oxide (ITO) and indium zinc oxide (IZO), for example, a Mo group metal, chromium, tantalum, and titanium. An exemplary combination may be the combination of a chromium lower layer and an aluminum (alloy) upper layer, and the combination of an aluminum (alloy) lower layer and a molybdenum (alloy) upper layer. The gate lines  121 , however, may be made of other various metals or conductors. 
     The sides of the gate lines  121  are inclined to the surface of the substrate  110 , and it is preferable that the inclination angle be about 30 to 80 degrees. 
     A gate insulating layer  140  that is made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate lines  121 . 
     A plurality of semiconductor islands  152  and  154  that are made of hydrogenated amorphous silicon (a-Si) or polysilicon are formed on the gate insulating layer  140 . The semiconductors  154  are placed on the gate electrodes  124 , and the semiconductors  152  cover the boundaries of the gate lines  121  to prevent the disconnection of the gate lines  121 . 
     A plurality of ohmic contact islands  163  and  165  are formed on the semiconductors  154 . The ohmic contacts  163  and  165  may be made of silicide or n+ hydrogenated amorphous silicon in which an n-type impurity such as phosphorus is highly doped. The ohmic contacts  163  and  165  form pairs to be disposed on the semiconductors  154 . An additional ohmic contact island  162  is provided on the semiconductors  152 . 
     The sides of the semiconductors  152  and  154  and the ohmic contacts  162 ,  163 , and  165  are also inclined to the surface of the substrate  110  at about 30 to 80 degrees. 
     A plurality of data lines  171  and a plurality of drain electrodes  175  are formed on the ohmic contacts  162 ,  163 , and  165  and the gate insulating layer  140 . 
     The data lines  171  transfer data signals and extend mainly in a vertical direction to cross the gate lines  121 . The data lines  171  have a plurality of U-shaped source electrodes  173  extending toward the gate electrodes  124  and wide ends  179  for connecting with another layer or external driving circuits. A data driving circuit (not shown) for generating the data signals may be mounted on a flexible printed circuit film (not shown) attached on the substrate  110 , mounted directly on the substrate  110 , or integrated with the substrate  110 . If the data driving circuit is integrated with the substrate  110 , it may be directly connected to the data lines  171 . 
     The drain electrodes  175  are separated from the data lines  171  and face the source electrodes  173  with the gate electrodes  124  interposed therebetween. Each of the drain electrodes  175  has one wide end and one rod-shaped end. The wide end is connected to a pixel electrode  191  through a contact hole  185 , and the rod-shaped end is partially surrounded by a source electrode  173 . 
     A thin film transistor (TFT) consists of one gate electrode  124 , one source electrode  173 , and one drain electrode  175  together with the semiconductor  154 , and the channel of the TFT is formed on the semiconductor  154  between the source electrode  173  and the drain electrode  175 . 
     It is preferable that the data lines  171  and the drain electrodes  175  be made of a refractory metal such as molybdenum, chromium, tantalum, titanium, and alloys thereof, and have a multi-layered structure having a refractory metal layer (not shown) and a low-resistance conductive layer (not shown). An exemplary multi-layered structure may be a double-layered structure of a chromium or molybdenum (alloy) lower layer and an aluminum (alloy) upper layer, or a triple-layered structure of a molybdenum (alloy) lower layer, an aluminum (alloy) middle layer, and a molybdenum (alloy) upper layer. The data lines  171  and drain electrodes  175 , however, may be made of other various metals or conductors. 
     The sides of the data lines  171  and the drain electrodes  175  are inclined to the surface of the substrate  110 , and it is preferable that the inclination angle be about 30 to 80 degrees. 
     The ohmic contacts  162 ,  163 , and  165  are disposed only between the semiconductors  152  and  154 , and the data lines  171  and drain electrodes  175  to reduce the contact resistance between them. 
     A passivation layer  180  that is made of an inorganic material such as silicon nitride or silicon oxide is formed on the data lines  171  and drain electrodes  175 , and exposed regions of the semiconductors  154 . The passivation layer  180  may be made of an organic material and may have a double-layered structure composed of a lower inorganic layer and an upper organic layer to protect the exposed regions of the semiconductors  152  and  154  and to provide excellent insulating characteristics of the layers. 
     A plurality of contact holes  182  and  185  are formed on the passivation layer  180  to expose ends  179  of the data lines  171  and the drain electrodes  175 , respectively. Also, a plurality of contact holes  181  are formed on the passivation layer  180  and the gate insulating layer  140  to expose ends  129  of the gate lines  121 . 
     A plurality of pixel electrodes  191  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. 
     An interlayer insulating layer  187  is formed on the pixel electrodes  191  and the passivation layer  180 , and it may be made of a transparent inorganic insulator including silicon nitride or silicon oxide. The interlayer insulating layer  187  may be removed at the ends  129  of the gate lines  121  or the ends  179  of the data lines  171  to connect such to an external device. 
     Light blocking members  220  that are made of a conductive material are formed on the interlayer insulating layer  187 . The light blocking members  220  are also called a black matrix. The light blocking members  220  may consist of one portion corresponding to the pixel electrodes  191 , the gate lines  121 , and the data lines  171 , and another portion corresponding to the thin film transistors, and they are overlapped with the boundaries of the pixel electrodes  191 , the gate lines  121 , and the data lines  171 . The light blocking members  220  prevent light leakage from between the pixel electrodes  191  and receive a storage voltage from the outside. 
     The pixel electrodes  191  are physically and electrically connected to the drain electrodes  175  through the contact holes  185  and receive data voltages from the drain electrodes  175 . The pixel electrode  191  on which a data voltage is applied generates an electric fields together with a common electrode  270  of the common electrode panel  200  on which a common voltage is applied, so as to determine the orientation of the liquid crystal molecules in the liquid crystal layer  3  between the two electrodes. The polarization of light that passes through the liquid crystal layer varies depending on the orientation of the liquid crystal molecules. The pixel electrodes  191  and common electrode  270  form capacitors (hereinafter, referred to as liquid crystal capacitors) that maintain some of the applied voltage even after the thin film transistors are turned off. 
     The pixel electrodes  191  are overlapped by the light blocking members  220  to receive a storage voltage from the outside to form the capacitors. The capacitors formed by overlapping the pixel electrodes  191  and the light blocking members  220  are called storage capacitors, and the storage capacitors enhance the voltage maintaining ability of the liquid crystal capacitors. 
     The common electrode panel  200  will now be described with reference to  FIG. 2  and  FIG. 3 . 
     The common electrode  270  is formed on an insulation substrate  210  made of transparent glass or plastic, and the common electrode  270  is made of a transparent conductor such as ITO or IZO. 
     Alignment layers (not shown) are applied on the inner surfaces of the display panels  100  and  200 , and they may be a horizontal alignment layer or a vertical alignment layer. Polarizers (not shown) are provided on the outer surfaces of the display panels  100  and  200 . The polarization axes of the two polarizers are perpendicular to each other, and it is desirable that one of the two polarization axes runs parallel to the gate lines  121 . In the case of a reflective liquid crystal display, one of the two polarizers 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. 
     In addition, the liquid crystal display according to an exemplary embodiment of the present invention may further include a backlight unit  900  for providing the polarizers, phase retardation film, display panels  100  and  200 , and liquid crystal layer  3  with light. The backlight unit  900  of the liquid crystal display according to an exemplary embodiment of the present invention is made of light emitting diodes (LEDs) or the like, and includes a plurality of light sources for representing primary colors. The example of the primary colors may be three primary colors, red, green, and blue. The light sources for red, green, and blue colors are sequentially switched off, and each pixel alternatively represents the primary colors with time, recognizing a desired color by the spatial and temporal sum of these primary colors. 
     In the case of a liquid crystal display in which color filters are formed on the common electrode panel  200  corresponding to the thin film transistor array panel  100 , light blocking members are generally formed on the common electrode panel  200 . However, when the light blocking members are formed on the common electrode panel  200  opposite to the thin film transistor array panel  100 , an alignment error may occur in assembling the two display panels  100  and  200 , and may cause the contrast ratio of the liquid crystal display to reduce because light is not blocked at the portions that the pixel electrodes cannot control. 
     Also, a storage capacitor of a liquid crystal display is generally formed by overlapping the drain electrode  175  that is electrically connected to the pixel electrode  191  with a storage electrode that is formed on the substrate with the gate insulating layer  140  interposed therebetween. 
     On the contrary, in the liquid crystal display according to the present exemplary embodiment, three primary colors are represented by using the backlight unit, not color filters. The light blocking members  220  are formed on the thin film transistor array panel  100 , preventing the deterioration of color reproducibility and the reduction of screen contrast ratio caused by an alignment error between the two display panels  100  and  200 . Also, the storage capacitor of the liquid crystal display according to the present exemplary embodiment is formed by overlapping the pixel electrodes  191  and the light blocking members  220  that receive a storage voltage, with the interlayer insulating layer  187  interposed therebetween. 
     That is, the light blocking members  220  made of a conductive material are formed on the thin film transistor array panel  100 , and function as not only a light blocking member but also as a storage electrode, increasing the aperture ratio of the liquid crystal display compared with a liquid crystal display including a storage electrode formed on the thin film transistor array panel. 
     A liquid crystal display according to another exemplary embodiment of the present invention will now be described in detail with reference to  FIG. 4  to  FIG. 6 . 
       FIG. 4  is a layout view of the liquid crystal display according to another exemplary embodiment of the present invention, and  FIG. 5  and  FIG. 6  are cross-sectional views of the liquid crystal display taken along the lines V-V and VI-VI of  FIG. 4 , respectively. 
     The liquid crystal display according the present exemplary embodiment also includes a thin film transistor array panel  100  and a common electrode panel  200  that face each other, and a liquid crystal layer  3  interposed between the two display panels  100  and  200 . 
     In the thin film transistor array panel  100 , a plurality of gate lines  121  including gate electrodes  124  are formed on a substrate  110 . A gate insulating layer  140 , a plurality of semiconductor islands  152  and  154 , and a plurality of ohmic contact islands  162 ,  163 , and  165  are sequentially formed on the gate lines  121 . A plurality of data lines  171 , including source electrodes  173  and ends  179 , and a plurality of drain electrodes  175  are formed on the ohmic contacts  162 ,  163 , and  165 . 
     A first protection layer  801  is formed on the gate insulating layer  140 , the data lines  171 , and the drain electrodes  175 . The first protection layer  801  prevents pigments of color filters  230 R,  230 G, and  230 B that will be formed later from flowing into the semiconductor layer  154 . 
     The color filters  230 R,  230 G, and  230 B are formed on the first protection layer  801 . The color filters  230 R,  230 G, and  230 B extend longitudinally to run parallel to the data lines  171  along pixel columns divided by the data lines  171 , and are alternatively formed along with the pixel columns. The color filters  230 R,  230 G, and  230 B are removed at regions in which contact holes will be formed to expose ends  129  of the gate lines  121  or ends  179  of the data lines  171  connected to external circuits. Also, they are removed at regions  235  in which contact holes will be formed to expose the drain electrodes  175 . 
     A second protection layer  802  is provided on the color filters  230 R,  230 G, and  230 B, and it prevents the pigments of the color filters from flowing into the liquid crystal layer  3 . 
     Herein, the second protection layer  802  may be omitted. 
     Contact holes  181 ,  182 , and  185  are formed on the first and second protection layers  801  and  802  to expose the ends  129  of the gate lines, the ends  179  of the data lines  171 , and the drain electrodes  175 , respectively. 
     A plurality of pixel electrodes  191  made of ITO or IZO and a plurality of contact assistants  81  and  82  are formed on the second protection layer  802 . 
     An interlayer insulating layer  187  that is made of a transparent inorganic insulator including silicon nitride or silicon oxide is formed on the pixel electrodes  191  and the second protection layer  802 , and it may be removed at ends  129  of the gate lines  121  or ends  179  of the data lines  171  that are connected to external circuits. 
     Light blocking members  220  made of a conductive material are formed on the interlayer insulating layer  187 . The light blocking members  220  prevent light leakage from between the pixel electrodes  191 , and overlap the pixel electrodes  191  to form storage capacitors. 
     The pixel electrodes  191  are physically and electrically connected to the drain electrodes  175  through contact holes  185  and receive a data voltage from the drain electrodes  175 . The pixel electrode  191  on which a data voltage is applied generates an electric field together with a common electrode  270  of the display panel  200  on which a common voltage is applied, so as to determine the orientation of the liquid crystal molecules in the liquid crystal layer  3  between the two electrodes. The polarized light that passes through the liquid crystal layer varies depending on the orientation of the liquid crystal molecules determined by the applied electric field. The pixel electrodes  191  and the common electrode  270  form capacitors (hereinafter, referred to as liquid crystal capacitors) to maintain the applied voltage even after the thin film transistors are turned off. 
     The pixel electrodes  191  are overlapped by the light blocking members  220  that receive a storage voltage from the outside to form capacitors. The capacitors formed by overlapping the pixel electrodes  191  and the light blocking members  220  are called storage capacitors, and the storage capacitors enhance the voltage maintaining ability of the liquid crystal capacitors. 
     A common electrode panel  200  will now be explained. In the common electrode panel  200 , a common electrode  270  that is made of a transparent conductor is formed on an insulation substrate  210  that is made of transparent glass or plastic. 
     In the liquid crystal display according to the present exemplary embodiment, the color filters  230 R,  230 G, and  230 B and the light blocking members  220  made of a conductive material are formed on the thin film transistor array panel  100 , preventing the deterioration of color reproducibility and the reduction of the screen contrast ratio caused by an alignment error between the two display panels  100  and  200 . 
     Also, the liquid crystal display according to the present exemplary embodiment includes the storage capacitors that are formed by overlapping the pixel electrodes  191  that receive data signals with the light blocking members  220  that receive a storage voltage with the gate insulating layer  140  interposed therebetween. Therefore, the light blocking members  220  function as not only a light blocking member but also as a storage electrode, increasing the aperture ratio of the liquid crystal display compared with a liquid crystal display including additional storage electrodes. 
     A liquid crystal display according to a further exemplary embodiment of the present invention will now be described in detail with reference to  FIG. 7  to  FIG. 9 . 
       FIG. 7  is a layout view of the liquid crystal display according to a further exemplary embodiment of the present invention, and  FIG. 8  and  FIG. 9  are cross-sectional views of the liquid crystal display taken along the lines VIII-VIII and IX-IX of  FIG. 7 , respectively. 
     The liquid crystal display according to the present exemplary embodiment also includes a thin film transistor array panel  100  and a common electrode panel  200  that face each other, and a liquid crystal layer  3  interposed between the two display panels  100  and  200 . 
     In the thin film transistor array panel  100 , a plurality of gate lines  121  including gate electrodes  124  are formed on a substrate  110 . 
     A gate insulating layer  140 , a plurality of semiconductor islands  152  and  154 , and a plurality of ohmic contact islands  162 ,  163 , and  165  are sequentially formed on the gate lines  121 . 
     A plurality of data lines  171 , each including source electrodes  173   10  and an end  179 , and a plurality of drain electrodes  175  are formed on the ohmic contacts  162 ,  163 , and  165 . 
     A passivation layer  180  is formed on the gate insulating layer  140 , the data lines  171 , and the drain electrodes  175 . The passivation layer  180  may have an excellent planarization characteristic and photosensitivity, and its dielectric constant is preferably less than about 4.0. The passivation layer  180  may be made of an inorganic material and have a double-layered structure composed of a lower inorganic layer and an upper organic layer to protect the exposed regions of the semiconductors  152  and  154  and to provide the excellent insulating characteristics of the layers. 
     An interlayer insulating layer  187  is formed on the pixel electrodes  191  and the passivation layer  180 , and it may be made of a transparent inorganic insulator including silicon nitride or silicon oxide. The interlayer insulating layer  187  may be removed at ends  129  of the gate lines  121  or ends  179  of the data lines  171  to connect such to external circuits. 
     Light blocking members  220  that are made of a conductive material are formed on the interlayer insulating layer  187 . The light blocking members  220  prevent light leakage from between the pixel electrodes  191  and are overlapped with the pixel electrodes  191  to form storage capacitors. 
     The pixel electrodes  191  are physically and electrically connected to the drain electrodes  175  through contact holes  185  and receive a data voltage from the drain electrodes  175 . The pixel electrode  191  on which a data voltage is applied generates an electric field together with a common electrode  270  of the other display panel  200  on which a common voltage is applied, so as to determine the orientation of liquid crystal molecules of the liquid crystal layer  3  between the two electrodes. The polarization of light that passes through the liquid crystal layer varies depending on the determined orientation of the liquid crystal molecules. 
     The pixel electrodes  191  are overlapped with the light blocking members  220  that receive the storage voltage from the outside to form capacitors. The capacitors formed by overlapping the pixel electrodes  191  and the light blocking members  220  are called storage capacitors, and the storage capacitors enhance the voltage maintaining ability of the liquid crystal capacitors. 
     The common electrode panel  200  will now be explained. In the common electrode panel  200 , a plurality of color filters  230  are formed on an insulation substrate  210  that is made of transparent glass or plastic. The color filters may extend in a vertical direction along the columns of pixel electrodes  191 . Each of the color filters  230  may represent one of three primary colors, red, green, and blue. 
     An overcoat  250  is formed on the color filters  230 . The overcoat  250  may be made of an (organic) insulator and prevents the color filters from being exposed to provide a flat surface. The overcoat  250  may be omitted. 
     The common electrode  270  is formed on the overcoat  250 . The common electrode  270  is made of a transparent conductor such as ITO or IZO. 
     The liquid crystal display according to the present exemplary embodiment includes the light blocking members  220  that are formed on the thin film transistor array panel  100 , thereby preventing the reduction of the screen contrast ratio by an alignment error of the two display panels  100  and  200 . Also, the liquid crystal display includes the storage capacitors that are formed by overlapping the pixel electrodes  191  that receive a data signal with the light blocking members that receive a storage voltage with the interlayer insulating layer  187  interposed therebetween, thereby increasing the aperture ratio of the liquid crystal display. 
     In the liquid crystal display according to the present invention, the color filters and the light blocking members  220  made of a conductive material are formed on the thin film transistor array panel, thereby preventing the deterioration of the color reproducibility and the reduction of the screen contrast ratio by an alignment error of the two display panels. Also, the storage capacitors are formed by overlapping the pixel electrodes with the light blocking members, thereby increasing the aperture ratio of the liquid crystal display compared with a liquid crystal display including additional storage electrodes. 
     In the liquid crystal display according to the present invention, three primary colors are represented by using the backlight unit, rather than color filters, and the light blocking members are simultaneously formed on the thin film transistor array panel, thereby preventing the deterioration of the color reproducibility and the reduction of the screen contrast ratio by an alignment error of the two display panels  100 . Also, the storage electrodes are formed by overlapping the pixel electrodes with the light blocking members that receive a storage voltage, increasing the aperture ratio of the liquid crystal display. 
     As described above, the liquid crystal display according to the present invention can prevent the deterioration of the color reproducibility and the reduction of the screen contrast ratio by an alignment error of the two display panels, and can increase the aperture ratio of the liquid crystal display. 
     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 embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.