Patent Document

BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a liquid crystal display.  
         [0003]     2. Description of the Related Art  
         [0004]     A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD includes two panels provided with field-generating electrodes such as pixel electrodes and a common electrode and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer, which determines orientations of LC molecules in the LC layer to adjust polarization of incident light.  
         [0005]     Among the LCDs, a vertical alignment (VA) mode LCD, which aligns LC molecules such that the long axes of the LC molecules are perpendicular to the panels in absence of electric field, is spotlighted because of its high contrast ratio and wide viewing angle.  
         [0006]     The wide viewing angle of the VA mode LCD can be realized by cutouts in the field-generating electrodes and protrusions on the field-generating electrodes. Since the cutouts and the protrusions can determine the tilt directions of the LC molecules, the tilt directions can be distributed into several directions by using the cutouts and the protrusions such that the viewing angle is widened.  
         [0007]     However, the VA mode LCD has relatively poor lateral visibility compared with front visibility.  
       SUMMARY OF THE INVENTION  
       [0008]     A liquid crystal display is provided, which includes: first and second panels facing each other, interposing a gap therebetween, and first and second field generating electrodes, respectively; a liquid crystal layer filled in the gap and including a plurality of liquid crystal molecules; first and second tilt direction defining members disposed on the first and the second panels, respectively, and giving a first tilt direction to a group of the liquid crystal molecules; and a third tilt direction defining member disposed on one of the first and the second panels and giving a second tilt direction oblique to the first tilt direction to the group of the liquid crystal molecules.  
         [0009]     The second tilt direction preferably makes an angle of about 40-50 degrees with the first tilt direction, and more preferably, it makes an angle of about 45 degrees with the first tilt direction.  
         [0010]     The liquid crystal display may further include a first polarizer disposed on the first panel and having a polarization axis substantially parallel to the second tilt direction. In this case, the third tilt direction defining member is preferably disposed on the first panel.  
         [0011]     The liquid crystal display may further include a fourth tilt direction defining member disposed on the second panel and giving a third tilt direction opposite the second tilt direction to the second the group of the liquid crystal molecules.  
         [0012]     The liquid crystal display may further include a second polarizer disposed on the second panel and having a polarization axis substantially perpendicular to the polarization axis of the first polarizer.  
         [0013]     One of the first and the second panels may further include: a thin film transistor connected to one of the first and the second field-generating electrodes; and a gate line and a data line connected to the thin film transistor.  
         [0014]     The first and the second tilt direction defining members may extend parallel to each other to define an area having two major edges and the group of the liquid crystal molecules are disposed in the area defined by the first and the second tilt direction defining members.  
         [0015]     The first tilt direction defining member may include one of at least one first cutout in the first field-generating electrode and at least one first protrusion on the first field-generating electrode, and the first tilt direction defining member may include one of at least one second cutout in the second field-generating electrode and at least one second protrusion on the second field-generating electrode.  
         [0016]     The third tilt direction defining member may include an alignment layer that experienced pretilt treatment.  
         [0017]     The alignment layer may be rubbed in the second tilt direction, or exposed to linearly polarized light, or it may have a plurality of depressions.  
         [0018]     The first panel may further include: a thin film transistor connected to the first field-generating electrode; and a gate line and a data line connected to the thin film transistor; and an insulating layer disposed under the first field-generating electrode. The third tilt direction defining member includes a plurality of trenches formed at the insulating layer and disposed in the area defined by the first and the second tilt direction defining members.  
         [0019]     The area defined by the first and the second tilt direction defining members may have a minor edge oblique to the major edges thereof and the trenches adjacent to the minor edge may extend perpendicular to the minor edge.  
         [0020]     The liquid crystal display may further include a first polarizer disposed on the first panel and having a polarization axis substantially parallel to the second tilt direction, and a second polarizer disposed on the second panel and having a polarization axis substantially perpendicular to the polarization axis of the first polarizer.  
         [0021]     The liquid crystal molecules may be vertically aligned.  
         [0022]     A liquid crystal display is provided, which includes: a first substrate having first and second surfaces; a common electrode formed on the first surface of the first substrate; a first tilt direction defining member formed on the first substrate and extending in a first direction; a first alignment layer formed on the common electrode; a first polarizer disposed on the second surface of the first substrate; a second substrate having a first surface facing the first surface of the first substrate and a second surface; a gate line formed on the first surface of the second substrate; a gate insulating layer formed on the gate line; a data line formed on the gate insulating layer; a passivation layer formed on the data line; a pixel electrode formed on the passivation layer; a second tilt direction defining member formed on the second substrate and extending in the first direction; a first alignment layer formed on the pixel electrode; a second polarizer disposed on the second surface of the second substrate; and a liquid crystal layer disposed between the first alignment layer and the second alignment layer and including a plurality of liquid crystal molecules. The first tilt direction defining member includes either at least one cutout in the common electrode or at least one protrusion on the common electrode, and the second tilt direction defining member has includes either at least one cutout in the pixel electrode or at least one protrusion on the pixel electrode. In addition, the passivation layer has a plurality of trenches extending in at least one extending direction oblique to the first direction and disposed between the first tilt direction defining member and the second tilt direction defining member, or at least one of the first and the second alignment layers has experienced pretilt treatment giving at least one pretilt direction oblique to the first direction to the liquid crystal molecules.  
         [0023]     The at least one extending direction and the at least one pretilt direction may make an angle of about 40-50 degrees, in particular, about 45 degrees.  
         [0024]     One of polarization axes of the first and the second polarizers may be parallel to the at least one extending direction and the at least one pretilt direction.  
         [0025]     The polarization axes of the first and the second polarizers may be crossed.  
         [0026]     The liquid crystal molecules may be vertically aligned.  
         [0027]     The pixel electrode may have a plurality of depressions formed by the trenches and the alignment layer may have a plurality of depressions formed the depressions of the pixel electrode.  
         [0028]     The trenches near an edge of the pixel electrode may extend perpendicular to the edge of the pixel electrode, and the edge of the pixel electrode may be parallel to the gate line or the data line.  
         [0029]     The pretilt treatment may include at least one of rubbing and light illumination.  
         [0030]     Both the first and the second alignment layer may have experienced the pretilt treatment giving opposite pretilt directions. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]     The present invention will become more apparent by describing embodiments thereof in detail with reference to the accompanying drawings in which:  
         [0032]      FIG. 1  is a layout view of a TFT array panel of an LCD according to an embodiment of the present invention;  
         [0033]      FIG. 2  is a sectional view of the TFT array panel shown in  FIG. 1  taken along the lines II-II′-II″-III′″;  
         [0034]      FIG. 3  is a layout view of a common electrode panel of an LCD according to an embodiment of the present invention;  
         [0035]      FIG. 4  is a layout view of an LCD including the TFT array panel shown in  FIGS. 1 and 2  and the common electrode panel shown in  FIG. 3 ;  
         [0036]      FIG. 5  is a sectional view of the LCD shown in  FIG. 4  taken along the line V-V′;  
         [0037]      FIGS. 6-9  are sectional views of the TFT array panel shown in  FIGS. 1-5  in intermediate steps of a manufacturing method thereof according to an embodiment of the present invention;  
         [0038]      FIG. 10A  is a layout view of a TFT array panel for an LCD according to another embodiment of the present invention;  
         [0039]      FIG. 10B  is a sectional view of the TFT array panel shown in  FIG. 10A  taken along the line XB-XB′;  
         [0040]      FIG. 10C  is a sectional view of the LCD shown in  FIG. 10A  taken along the lines XC-XC′ and XC′-XC″;  
         [0041]      FIGS. 11A and 11B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in a first step of a manufacturing method thereof according to an embodiment of the present invention;  
         [0042]      FIGS. 12A and 12B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 11A and 11B ;  
         [0043]      FIGS. 13A and 13B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 12A and 12B ;  
         [0044]      FIGS. 14A and 14B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 13A and 13B ;  
         [0045]      FIGS. 15A and 15B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 14A and 14B ;  
         [0046]      FIG. 16  is a sectional view of an LCD shown in  FIG. 4  taken along the line V-V′ according to another embodiment of the present invention;  
         [0047]      FIG. 17  is a sectional view of an LCD shown in  FIG. 4  taken along the line V-V′ according to another embodiment of the present invention;  
         [0048]      FIG. 18  is a layout view of a TFT array panel of an LCD according to an embodiment of the present invention;  
         [0049]      FIG. 19  is a layout view of a common electrode panel of an LCD according to an embodiment of the present invention;  
         [0050]      FIG. 20  is a layout view of an LCD including the TFT array panel shown in  FIG. 18  and the common electrode panel shown in  FIG. 19 ;  
         [0051]      FIG. 21  is a sectional view of the LCD shown in  FIG. 20  taken along the line XXI-XXI′;  
         [0052]      FIGS. 22 and 23  show two different types of pretilt directions for a pair of crossed polarization axes POL;  
         [0053]      FIG. 24  is a layout view of a TFT array panel of an LCD according to an embodiment of the present invention;  
         [0054]      FIG. 25  is a layout view of a common electrode panel of an LCD according to an embodiment of the present invention;  
         [0055]      FIG. 26  is a layout view of an LCD including the TFT array panel shown in  FIG. 24  and the common electrode panel shown in  FIG. 25 ;  
         [0056]      FIG. 27  is a sectional view of the LCD shown in  FIG. 26  taken along the line XXVII-XXVII′;  
         [0057]      FIG. 28  show exemplary pretilt directions, tilt directions of the LC molecules, and a pair of crossed polarization axes POL of the LCD shown in  FIGS. 24-27 ; and  
         [0058]      FIG. 29  shows exemplary pretilt directions, tilt directions of LC molecules, and a pair of crossed polarization axes POL of an LCD according to another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0059]     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.  
         [0060]     In the drawings, the thickness of layers, films and regions are exaggerated for clarity. Like numerals refer to like elements throughout. 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.  
         [0061]     Now, liquid crystal displays and thin film transistor (TFT) array panels for LCDs according to embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0062]     An LCD according to an embodiment of the present invention will be described in detail with reference to  FIGS. 1-5 .  
         [0063]      FIG. 1  is a layout view of a TFT array panel of an LCD according to an embodiment of the present invention,  FIG. 2  is a sectional view of the TFT array panel shown in  FIG. 1  taken along the lines II-II′-II″-III′″,  FIG. 3  is a layout view of a common electrode panel of an LCD according to an embodiment of the present invention,  FIG. 4  is a layout view of an LCD including the TFT array panel shown in  FIGS. 1 and 2  and the common electrode panel shown in  FIG. 3 , and  FIG. 5  is a sectional view of the LCD shown in  FIG. 4  taken along the line V-V′.  
         [0064]     An LCD according to an embodiment of the present invention includes a TFT array panel  100 , a common electrode panel  200 , and a LC layer  3  interposed between the panels  100  and  200  and containing a plurality of LC molecules  31  aligned substantially vertical to surfaces of the panels  100  and  200 .  
         [0065]     The TFT array panel  100  is now described in detail with reference  FIGS. 1, 2 ,  4  and  5 .  
         [0066]     A plurality of gate lines  121  and a plurality of storage electrode lines  131  are formed on an insulating substrate  110  such as transparent glass.  
         [0067]     The gate lines  121  extend substantially in a transverse direction and are separated from each other and transmit gate signals. Each gate line  121  includes a plurality of projections forming a plurality of gate electrodes  124  and an end portion  129  having a large area for connection with an external driving circuit.  
         [0068]     Each storage electrode line  131  extends substantially in the transverse direction and includes a plurality of sets of branches. Each branch set includes a pair of longitudinal branches forming first and second storage electrodes  133   a  and  133   b . Each of the first storage electrodes  133   a  has a free end portion and a fixed end portion connected to the storage electrode line  131 , and the fixed end portion has a projection. The storage electrode lines  131  are supplied with a predetermined voltage such as a common voltage, which is applied to a common electrode  270  on the common electrode panel  200  of the LCD. Each storage electrode line  131  may include a pair of stems extending in the transverse direction and it may further include a plurality of connections (not shown) connected between the first storage electrodes  133   a  and the second storage electrodes  133   b  respectively in adjacent sets of the storage electrodes  133   a  and  133   b.    
         [0069]     The gate lines  121  and the storage electrode lines  131  is preferably made of Al containing metal such as Al and Al alloy, Ag containing metal such as Ag and Ag alloy, Cu containing metal such as Cu and Cu alloy, Mo containing metal such as Mo and Mo alloy, Cr, Ti or Ta. The gate lines  121  and the storage electrode lines  131  may have a multi-layered structure including two films having different physical characteristics, a lower film (not shown) and an upper film (not shown). The upper film is preferably made of low resistivity metal including Al containing metal such as Al and Al alloy for reducing signal delay or voltage drop in the gate lines  121  and the storage electrode lines  131 . On the other hand, the lower film is preferably made of material such as Cr, Mo and Mo alloy, which has good contact characteristics with other materials such as indium tin oxide (ITO) or indium zinc oxide (IZO). A good exemplary combination of the lower film material and the upper film material is Cr and Al—Nd alloy.  
         [0070]     In addition, the lateral sides of the gate lines  121  and the storage electrode lines  131  are inclined relative to a surface of the substrate, and the inclination angle thereof ranges about 20-80 degrees.  
         [0071]     A gate insulating layer  140  preferably made of silicon nitride (SiNx) is formed on the gate lines  121  and the storage electrode lines  131 .  
         [0072]     A plurality of semiconductor stripes  151  preferably made of hydrogenated amorphous silicon (abbreviated to “a-Si”) or polysilicon are formed on the gate insulating layer  140 . Each semiconductor stripe  151  extends substantially in the longitudinal direction and has a plurality of projections  154  branched out toward the gate electrodes  124 .  
         [0073]     A plurality of ohmic contact stripes and islands  161  and  165  preferably made of silicide or n+ hydrogenated a-Si heavily doped with n type impurity such as phosphorous are formed on the semiconductor stripes  151 . Each ohmic contact stripe  161  has a plurality of projections  163 , and the projections  163  and the ohmic contact islands  165  are located in pairs on the projections  154  of the semiconductor stripes  151 .  
         [0074]     The lateral sides of the semiconductor stripes  151  and the ohmic contacts  161  and  165  are inclined relative to a surface of the substrate, and the inclination angles thereof are preferably in a range between about 30-80 degrees.  
         [0075]     A plurality of data lines  171 , a plurality of drain electrodes  175  separated from the data lines  171 , and a plurality of isolated metal pieces  172  are formed on the ohmic contacts  161  and  165  and the gate insulating layer  140 .  
         [0076]     The data lines  171  for transmitting data voltages extend substantially in the longitudinal direction and intersect the gate lines  121  and the storage electrode lines  131 . Each data line  171  is disposed between the first and the second storage electrodes  133   a  and  133   b  in adjacent sets of the branches  133   a  and  133   b  of the storage electrode lines  131  and it includes an end portion  179  having a large area for contact with another layer or an external device. A plurality of branches of each data line  171 , which project toward the drain electrodes  175 , form a plurality of source electrodes  173 . Each drain electrode  175  includes an end portion having a large area for contact with another layer and each source electrode  173  is curved to partly enclose another end portion of the drain electrode  175 . A gate electrode  124 , a source electrode  173 , and a drain electrode  175  along with a projection  154  of a semiconductor stripe  151  form a TFT having a channel formed in the projection  154  disposed between the source electrode  173  and the drain electrode  175 .  
         [0077]     The metal pieces  172  are disposed on the gate lines  121  near the end portions of the storage electrodes  133   a.    
         [0078]     The data lines  171 , the drain electrodes  175 , and the metal pieces  172  are preferably made of refractory metal such as Cr, Mo containing metal, Ti and Ti, or Al containing metal and they may also have a multilayered structure including a lower film (not shown) preferably made of refractory metal and an upper film (not shown) located thereon and preferably made of low resistivity material.  
         [0079]     Like the gate lines  121  and the storage electrode lines  131 , the data lines  171 , the drain electrodes  175 , and the metal pieces  172  have tapered lateral sides, and the inclination angles thereof range about 30-80 degrees.  
         [0080]     The ohmic contacts  161  and  165  are interposed only between the underlying semiconductor stripes  151  and the overlying data lines  171  and the overlying drain electrodes  175  thereon and reduce the contact resistance therebetween. The semiconductor stripes  151  include a plurality of exposed portions, which are not covered with the data lines  171  and the drain electrodes  175 , such as portions located between the source electrodes  173  and the drain electrodes  175 .  
         [0081]     A passivation layer  180  is formed on the data lines  171 , the drain electrodes  175 , and the exposed portions of the semiconductor stripes  151 . The passivation layer  180  is preferably made of photosensitive organic material having a good flatness characteristic, low dielectric insulating material having dielectric constant lower than 4.0 such as a-Si:C:O and a-Si:O:F formed by plasma enhanced chemical vapor deposition (PECVD), or inorganic material such as silicon nitride. The passivation layer  180  may include a lower film of inorganic insulator and an upper film of organic insulator.  
         [0082]     The passivation layer  180  has a plurality of contact holes  182  and  185  exposing the end portions  179  of the data lines  171  and the end portions of the drain electrodes  175 , respectively. The passivation layer  180  and the gate insulating layer  140  have a plurality of contact holes  181 ,  183  and  184  exposing the end portions  129  of the gate lines  121 , the projections of the free end portions of the first storage electrodes  133   a , and portions of the storage electrode lines  131  near the fixed end portions of the first storage electrodes  133   a , respectively.  
         [0083]     In addition, the passivation layer  180  and the gate insulating layer have a number of rectilinear trenches  186 .  
         [0084]     A plurality of pixel electrodes  190 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84 , which are preferably made of a transparent conductor such as ITO and IZO or a reflective conductor such as Al, are formed on the passivation layer  180 .  
         [0085]     The pixel electrodes  190  are physically and electrically connected to the drain electrodes  175  through the contact holes  185  such that the pixel electrodes  190  receive the data voltages from the drain electrodes  175 .  
         [0086]     The pixel electrodes  190  supplied with the data voltages generate electric fields in cooperation with the common electrode  270 , which reorient liquid crystal molecules  31  in the liquid crystal layer  3 .  
         [0087]     A pixel electrode  190  and the common electrode  270  form a liquid crystal capacitor, which stores applied voltages after turn-off of the TFT. An additional capacitor called a “storage capacitor,” which is connected in parallel to the liquid crystal capacitor, is provided for enhancing the voltage storing capacity. The storage capacitors are implemented by overlapping the pixel electrodes  190  with the storage electrode lines  131  including the storage electrodes  133   a  and  133   b.    
         [0088]     Each pixel electrode  190  is chamfered at its left corners and the chamfered edges of the pixel electrode  190  make an angle of about 45 degrees with the gate lines  121 .  
         [0089]     Each pixel electrode  190  has a plurality of upper cutouts  91  and  92 , lower cutouts  95  and  96 , and center cutouts  93  and  94 , which partition the pixel electrode  190  into a plurality of partitions. The upper and the lower cutouts  91 ,  92 ,  95  and  96  are disposed at upper and lower halves of the pixel electrode  190 , respectively, and the center cutouts  93  and  94  are located between the upper cutouts  91  and  92  and the lower cutouts  95  and  96 . The cutouts  91 - 96  substantially have inversion symmetry with respect to an imaginary transverse center line bisecting the upper and the lower halves of the pixel electrode  190 .  
         [0090]     The upper and the lower cutouts  91 ,  92 ,  95  and  96  make an angle of about 45 degrees to the gate lines  121 , and the upper cutouts  91  and  92 , which extend substantially parallel to each other and to the chamfered upper left edge of the pixel electrode  190 , extend substantially perpendicular to the lower cutouts  95  and  96 , which extend substantially parallel to each other and to the chamfered lower left edge of the pixel electrode  190 .  
         [0091]     The cutouts  91  and  96  extend approximately from a left longitudinal edge of the pixel electrode  190  approximately to transverse edges of the pixel electrode  190 . The cutouts  92  and  95  extend approximately from the left edge of the pixel electrode  190  approximately to a right longitudinal edge of the pixel electrode  190 .  
         [0092]     The center cutout  93  includes a transverse portion extending approximately from the left edge of the pixel electrode  190  along the transverse center line of the pixel electrode  190  and a pair of oblique portions extending from the transverse portion to the right edge of the pixel electrode  190  and extending substantially parallel to the upper cutouts  91  and  92  and the lower cutouts  95  and  96 , respectively. The center cutout  94  extends along the transverse center line of the pixel electrode  190  and has an inlet from the right edge of the pixel electrode  190 , which has a pair of inclined edges substantially parallel to the upper cutouts  91  and  92  and the lower cutouts  95  and  96 , respectively.  
         [0093]     Accordingly, the upper half of the pixel electrode  190  is also partitioned into four upper partitions by the upper cutouts  91  and  92  and the center cutout  93 , and the lower half of the pixel electrode  190  is partitioned into four lower partitions by the lower cutouts  95  and  96  and the center cutout  93 . The number of partitions or the number of the cutouts is varied depending on the design factors such as the size of pixels, the ratio of the transverse edges and the longitudinal edges of the pixel electrodes, the type and characteristics of the liquid crystal layer  3 , and so on.  
         [0094]     In addition, each pixel electrode  190  has a number of depressions forming along the trenches  186  of the passivation layer  180  and the gate insulating layer  140  and contacting the substrate  110 .  
         [0095]     In the meantime, the storage electrode lines  131  may further include a plurality of branches (not shown) overlapping the cutouts  91 - 96  and lower edges of the pixel electrodes  190 .  
         [0096]     The contact assistants  81  and  82  are connected to the end portions  129  of the gate lines  121  and the end portions  179  of the data lines  171  through the contact holes  181  and  182 , respectively. The contact assistants  81  and  82  are not requisites but preferred to protect the end portions  129  and  179  and to complement the adhesiveness of the end portions  129  and  179  and external devices.  
         [0097]     The storage connections  84  cross over the gate lines  121  and they are connected to the exposed projection of the fixed end portions of the first storage electrodes  133   a  and the exposed portions of the storage electrode lines  131  respectively through the contact holes  183  and  184  opposite each other with respect to the gate lines  121 . The storage connections  84  overlaps the metal pieces  172  and they may be electrically connected to the metal pieces  172 . The storage electrode lines  131  including the storage electrodes  133   a  and  133   b  along with the storage connections  84  and the metal pieces  172  are used for repairing defects in the gate lines  121 , the data lines  171 , or the TFTs. The electrical connection between the gate lines  121  and the storage electrode lines  131  for repairing the gate lines  121  is obtained by illuminating the cross points of the gate lines  121  and the storage connections  84  by a laser beam to electrically connect the gate lines  121  to the storage connections  84 . In this case, the metal pieces  172  enhance the electrical connection between the gate lines  121  and the storage connections  84 .  
         [0098]     The description of the common electrode panel  200  follows with reference to  FIGS. 3-5 .  
         [0099]     A light blocking member  220  called a black matrix for preventing light leakage is formed on an insulating substrate  210  such as transparent glass. The light blocking member  220  may include a plurality of openings that face the pixel electrodes  190  and it may have substantially the same shape as the pixel electrodes  190 . The light blocking member  220  is preferably made of a single Cr layer, double layers of Cr and Cr oxide, or an organic layer containing black die.  
         [0100]     A plurality of color filters  230  are formed on the substrate  210  and they are disposed substantially in the areas enclosed by the light blocking member  220 . The color filters  230  may extend substantially along the longitudinal direction along the pixel electrodes  190 . The color filters  230  may represent one of the primary colors such as red, green and blue colors.  
         [0101]     An overcoat  250  for preventing the color filters  230  from being exposed and for providing a flat surface is formed on the color filters  230  and the light blocking member  220 .  
         [0102]     A common electrode  270  preferably made of transparent conductive material such as ITO and IZO is formed on the overcoat  250 .  
         [0103]     The common electrode  270  has a plurality of sets of cutouts  271 - 276 .  
         [0104]     A set of cutouts  271 - 276  face a pixel electrode  190  and include a plurality of upper and lower cutouts  271  and  272  and  275  and  276  and center cutouts  273  and  274 . Each of the cutouts  271 - 276  is disposed between adjacent cutouts  91 - 96  of the pixel electrode  190  or between a cutout  91  or  96  and a chamfered edge of the pixel electrode  190 . In addition, each of the cutouts  271 - 276  has at least an oblique portion extending parallel to the upper cutouts  91  and  92  or the lower cutouts  95  and  96  of the pixel electrode  190 , and the distances between adjacent two of the cutouts  271 - 276  and  91 - 96 , the oblique portions thereof, the oblique edges thereof, and the chamfered edges of the pixel electrode  190 , which are parallel to each other, are substantially the same. The cutouts  271 - 276  substantially have inversion symmetry with respect to an imaginary transverse center line of the pixel electrode  190 .  
         [0105]     Each of the cutouts  271  and  276  has an oblique portion extending approximately from a left edge of the pixel electrode  190  approximately to an upper or lower edge of the pixel electrode  190  and transverse and longitudinal portions extending from respective ends of the oblique portion along edges of the pixel electrode  190 , overlapping the edges of the pixel electrode  190 , and making obtuse angles with the oblique portion.  
         [0106]     Each of the cutouts  272  and  275  has an oblique portion, a longitudinal portion connected to an end of the oblique portion, and an expansion connected to the other end of the oblique portion. The oblique portion extends approximately from the left edge of the pixel electrode  190  approximately to upper right or lower right corner of the pixel electrode  190 . The longitudinal portion extends from the end of the oblique portion along the left edge of the pixel electrode  190 , overlaps the left edge of the pixel electrode  190 , and makes an obtuse angle with the oblique portion. The expansion covers the respective corner of the pixel electrode  190 .  
         [0107]     The cutout  273  has a pair of oblique portions extending approximately from the center of the left edge of the pixel electrode  190  to the right edge of the pixel electrode  190 , a transverse portion extending from a meeting point of the oblique portions to the left, and a pair of longitudinal portions extending from the respective oblique portions along the right edge of the pixel electrode  190 , overlapping the right edge of the pixel electrode  190 , and making an obtuse angle with the respective oblique portions. The cutout  274  has a transverse portion extending along the transverse center line of the pixel electrode  190 , a pair of oblique portions extending from the transverse portion approximately to the right edge of the pixel electrode  190  and making obtuse angles with the transverse portion, and a pair of longitudinal portions extending from the respective oblique portions along the right edge of the pixel electrode  190 , overlapping the right edge of the pixel electrode  190 , and making an obtuse angle with the respective oblique portions.  
         [0108]     The number of the cutouts  271 - 276  may be varied depending on the design factors, and the light blocking member  220  may also overlap the cutouts  271 - 276  to block the light leakage through the cutouts  271 - 276 .  
         [0109]     In the meantime, the cutouts  271 - 276  may expose portions of the color filters  230  if there is no overcoat  250 , and the exposed portions of the color filters  230  may contaminate the LC layer  3 .  
         [0110]     Retardation films  13  and  23  for compensating the retardation of the LC layer  3  are disposed on outer surfaces of the panels  100  and  200 , and crossed polarizers  12  and  22  are provided on the retardation films  13  and  23 , respectively, such that a transmissive axis of the polarizer  12  is parallel to the transverse direction. However, the transmissive axis of the polarizer  12  may be parallel to the longitudinal axis. One of the polarizers may be omitted when the LCD is a reflective LCD.  
         [0111]     The LCD may further include homeotropic alignment films (not shown) and these films have depressions forming along the trenches  186  and the depressions of the pixel electrodes  190 .  
         [0112]     The LC layer  3  has negative dielectric anisotropy and the LC molecules  310  in the LC layer  3  are aligned such that their long axes are substantially vertical to the surfaces of the panels in absence of electric field.  
         [0113]     As shown in  FIG. 4 , a set of the cutouts  91 - 96  and  271 - 276  divides a pixel electrode  190  into a plurality of subareas and each subarea has two major edges and is full of the trenches  186 . The trenches  186  make an oblique angle, preferably of about 45 degrees, with oblique edges of the cutouts  91 - 96  and  271 - 276 . It is preferable that the trenches  186  extend parallel to a transmissive (or absorptive) axis of the polarizers  12  and  22  and they are aligned substantially perpendicular to transverse and longitudinal edges of the cutouts  91 - 96  and  271 - 276  and of the pixel electrodes  190 . In detail, the trenches  186  in each of four parallelogrammic subareas, which has substantially two oblique edges and two longitudinal edges, are aligned in the transverse direction. On the other hand, the trenches  186  in each of twelve trapezoidal subareas, which has substantially two oblique edges, a transverse edge, and a longitudinal edge, have two extending directions depending on the relative distances from the transverse edge and the longitudinal edge. The trenches  186  closer to transverse edge than the longitudinal edge are aligned perpendicular to the transverse edge, while those closer to the longitudinal edge are aligned perpendicular to the longitudinal edge.  
         [0114]     The cutouts  91 - 96  and  271 - 276  as well as the trenches  186  control the tilt directions of the LC molecules  31  in the LC layer  3 . This will be described in detail.  
         [0115]     Upon application of the common voltage to the common electrode  270  and a data voltage to the pixel electrodes  190 , an electric field substantially perpendicular to the surfaces of the panels  100  and  200  is generated. The LC molecules  31  tend to change their orientations in response to the electric field such that their long axes are perpendicular to the field direction. In addition, the LC molecules  31  near the depressions of the alignment layers generated by the trenches  186  tend to align themselves to the length directions of the depressions.  
         [0116]     The cutouts  91 - 96  and  271 - 276  of the electrodes  190  and  270  and the edges of the pixel electrodes  190  distort the electric field to have a first horizontal component. The first horizontal component of the electric field is perpendicular to the edges of the cutouts  91 - 96  and  271 - 276  and the edges of the pixel electrodes  190 .  
         [0117]     Like the cutouts  91 - 96  and  271 - 276 , the depressions of the pixel electrodes  190  generated by the trenches  186  also distort the electric field to have second horizontal components. Since the depressions make angles of about 45 degrees with the cutouts  91 - 96  and  272 - 276 , the second horizontal components of the electric field make an angle of about 45 degrees with the first component.  
         [0118]     Accordingly, the orientations of the LC molecules  31  on each subarea have an azimuthal distribution determined by balancing the aligning forces caused by the geometry of the trenches  186  and caused by the cutouts  91 - 96  and  271 - 276 , and the azimuthal distribution improves lateral visibility as well as front visibility.  
         [0119]     In addition, the trenches  186  themselves contribute to the improvement of the lateral visibility since they scatter the light, which is expected to go to the front side, to go to the lateral side.  
         [0120]     In the meantime, the parallelism between the trenches  186  and the transmission (or the absorption) axis is required for maintaining the luminance in a black state where there is no electric field and the perpendicularity between the trenches  186  and the transverse and the longitudinal edges of each subarea is required for preventing textures due to the conflict of the tilt directions given by the trenches  186  and the edges.  
         [0121]     At lease one of the cutouts  91 - 96  and  271 - 276  can be substituted with protrusions or depressions.  
         [0122]     The shapes and the arrangements of the cutouts  91 - 96  and  271 - 276  may be modified.  
         [0123]     A method of manufacturing the TFT array panel shown in  FIGS. 1-5  according to an embodiment of the present invention will be now described in detail with reference to  FIGS. 6-9  as well as  FIGS. 1-5 .  
         [0124]      FIGS. 6-9  are sectional views of the TFT array panel shown in  FIGS. 1-5  in intermediate steps of a manufacturing method thereof according to an embodiment of the present invention.  
         [0125]     Referring to  FIG. 6 , a conductive layer preferably made of Al containing metal, Ag containing metal, Cu containing metal, Mo containing metal, Cr, Ti or Ta are sputtered and wet or dry etched by photolithography to form a plurality of gate lines  121  including a plurality of gate electrodes  124  and end portions  129  and a plurality of storage electrode lines  131  including a plurality of storage electrodes  133   a  and  133   b.    
         [0126]     The conductive layer may include a Mo alloy lower film and an Ag alloy upper film. Both the upper and lower films can be simultaneously etched by an Al etchant containing phosphoric acid, nitric acid, acetic acid and deionized water. In addition, the conductive layer can have an inclined lateral surface making an angle of about 30 degrees since the etching rate of the above-described Al etchant is faster for Al alloy than for Mo alloy.  
         [0127]     Referring to  FIG. 7 , after sequential CVD of a gate insulating layer  140  preferably made of silicon nitride or silicon oxide, an intrinsic a-Si layer, and an extrinsic a-Si layer, the extrinsic a-Si layer and the intrinsic a-Si layer are photo-etched to form a plurality of extrinsic semiconductor stripes  164  and a plurality of intrinsic semiconductor stripes  151  including a plurality of projections  154  on the gate insulating layer  140 .  
         [0128]     Referring to  FIG. 8 , a conductive layer preferably made of refractory metal is sputtered and photo-etched to form a plurality of date lines  171  including a plurality of source electrodes  173  and end portions  179 , a plurality of drain electrodes  175 , and a plurality of metal pieces  172 .  
         [0129]     Thereafter, portions of the extrinsic semiconductor stripes  164 , which are not covered with the data lines  171  and the drain electrodes  175 , are removed to complete a plurality of ohmic contact stripes  161  including a plurality of projections  163  and a plurality of ohmic contact islands  165  and to expose portions of the intrinsic semiconductor stripes  151 . Oxygen plasma treatment preferably follows in order to stabilize the exposed surfaces of the semiconductor stripes  151 .  
         [0130]     Referring to  FIG. 9 , a passivation layer  180  is formed by chemical vapor deposition of a-Si:C:Q or a-Si:O:F, by deposition of an inorganic insulator such as silicon nitride, or by coating of an organic insulator such as acrylic material.  
         [0131]     The passivation layer  180  and the gate insulating layer  140  are photo-etched to form a plurality of trenches  186  exposing the substrate  110  and a plurality of contact holes  181 - 185  exposing the end portions  129  of the gate lines  121 , the end portions  179  of the data lines  171 , the storage electrodes  133   a , and the storage electrode lines  131 , and the drain electrodes  175 .  
         [0132]     Finally, a plurality of pixel electrodes  190  having a plurality cutouts  91 - 96 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84  are formed on the passivation layer  180  and on the exposed portions of the substrate  110 , the drain electrodes  175 , the end portions  129  and  179 , the storage electrodes  133   a , the storage electrode lines  131  by sputtering and photo-etching an IZO or ITO layer.  
         [0133]     A TFT array panel for an LCD according to another embodiment of the present invention will be described in detail with reference to  FIGS. 10A-10C .  
         [0134]      FIG. 10A  is a layout view of a TFT array panel for an LCD according to another embodiment of the present invention,  FIG. 10B  is a sectional view of the TFT array panel shown in  FIG. 10A  taken along the line XB-XB′, and  FIG. 10C  is a sectional view of the LCD shown in  FIG. 10A  taken along the lines XC-XC′ and XC′-XC″.  
         [0135]     Referring to  FIGS. 10A-10C , a layered structure of the TFT array panel according to this embodiment is almost the same as that shown in  FIGS. 1-5 .  
         [0136]     In detail, a plurality of gate lines  121  including a plurality of gate electrodes  124  and end portions  129  and a plurality of storage electrode lines  131  including a plurality of storage electrodes  133   a  and  133   b  are formed on a substrate  110 , and a gate insulating layer  140 , a plurality of semiconductor stripes  151  including a plurality of projections  154 , and a plurality of ohmic contact stripes  161  including a plurality of projections  163  and a plurality of ohmic contact islands  165  are sequentially formed thereon. A plurality of data lines  171  including a plurality of source electrodes  173  and end portions  179 , a plurality of drain electrodes  175 , and a plurality of isolated metal pieces  172  are formed on the ohmic contacts  161  and  165 , and a passivation layer  180  is formed thereon. A plurality of contact holes  181 - 185  and a plurality of trenches  186  are provided at the passivation layer  180  and the gate insulating layer  140 . A plurality of pixel electrodes  190  having a plurality of cutouts  91 - 96 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84  are formed on the passivation layer  180 .  
         [0137]     Different from the TFT array panel shown in  FIGS. 1-5 , the TFT array panel according to this embodiment further provides a plurality of semiconductor islands (not shown) and a plurality of ohmic contact islands (not shown) disposed under the metal pieces  172  and having substantially the same planar shape as the metal pieces  172 .  
         [0138]     In addition, the semiconductor stripes  151  have almost the same planar shapes as the data lines  171  and the drain electrodes  175  as well as the underlying ohmic contacts  161  and  165 . However, the projections  154  of the semiconductor stripes  151  include some exposed portions, which are not covered with the data lines  171  and the drain electrodes  175 , such as portions located between the source electrodes  173  and the drain electrodes  175 .  
         [0139]     Many of the above-described features of the TFT array panel shown in  FIGS. 1-5  may be appropriate to the LCD shown in  FIGS. 10A-10C .  
         [0140]     Now, a method of manufacturing the TFT array panel shown in  FIGS. 10A-10C  according to an embodiment of the present invention will be described in detail.  
         [0141]      FIGS. 11A and 11B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in a first step of a manufacturing method thereof according to an embodiment of the present invention;  FIGS. 12A and 12B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 11A and 11B ;  FIGS. 13A and 13B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 12A and 12B ;  FIGS. 14A and 14B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 13A and 13B ; and  FIGS. 15A and 15B  are sectional views of the TFT array panel shown in  FIGS. 10A-10C  taken along the line XB-XB′ and the lines XC-XC′ and XC′-XC″, respectively, in the step of the manufacturing method following the step shown in  FIGS. 14A and 14B .  
         [0142]     Referring to  FIGS. 11A and 11B , a conductive layer is sputtered on an insulating substrate  110  and they are wet or dry etched in sequence to form a plurality of gate lines  121 , each including a plurality of gate electrodes  124  and an expansion  129 , and a plurality of storage electrode lines  131  including a plurality of storage electrodes  133   a  and  133   b.    
         [0143]     Referring to  FIGS. 12A and 12B , a gate insulating layer  140 , an intrinsic a-Si layer  150 , and an extrinsic a-Si layer  160  are sequentially deposited by CVD and a conductive layer  170  is deposited by sputtering, and a photoresist film PR with the thickness of about 1-2 microns is coated on the conductive layer  170 .  
         [0144]     Referring to  FIGS. 13A and 13B , the photoresist film PR is exposed to light through a slit photo-mask (not shown) including slit areas (not shown), and developed such that the developed photoresist PR has a position dependent thickness. The photoresist shown in  FIGS. 13A and 13B  includes a plurality of first to third portions with decreased thickness. The first portions are located on first areas B (referred to as “wire areas” hereinafter) and the second portions are located on second areas A (referred to as “channel areas” hereinafter), respectively, while the third portions located on remaining third areas C are not illustrated in the figures since they have substantially zero thickness to expose underlying portions of the conductive layer  170 . The thickness of the second portions on the channel areas A is preferably smaller than half of that of the first portions on the wire areas B, and more preferably, it is smaller than about 4,000 Å.  
         [0145]     The different thickness of the photoresist PR enables to selectively etch the underlying layers when using suitable process conditions. Therefore, a plurality of data lines  171  including a plurality of source electrodes  173 , a plurality of drain electrodes  175 , and a plurality of isolated metal pieces  172  as well as a plurality of ohmic contact stripes  161  including a plurality of projections  163 , a plurality of ohmic contact islands  165 , a plurality of semiconductor stripes  151  including a plurality of projections  154 , and a plurality of semiconductor and ohmic contact islands (not shown) disposed under the metal pieces  172  are obtained by a series of etching steps as shown in  FIGS. 14A and 14B .  
         [0146]     For descriptive purpose, portions of the conductive layer  170 , the extrinsic a-Si layer  160 , and the intrinsic a-Si layer  150  on the wire areas B are called first portions, portions of the conductive layer  170 , the extrinsic a-Si layer  160 , and the intrinsic a-Si layer  150  on the channel areas A are called second portions, and portions of the conductive layer  170 , the extrinsic a-Si layer  160 , and the intrinsic a-Si layer  150  on the third areas C are called third portions.  
         [0147]     An exemplary sequence of forming such a structure is as follows:  
         [0148]     (1) Removal of third portions of the conductive layer  170 , the extrinsic a-Si layer  160  and the intrinsic a-Si layer  150  on the wire areas B;  
         [0149]     (2) Removal of the second portions of the photoresist;  
         [0150]     (3) Removal of the second portions of the conductive layer  170  and the extrinsic a-Si layer  160  on the channel areas A; and  
         [0151]     (4) Removal of the first portions of the photoresist.  
         [0152]     Another exemplary sequence is as follows:  
         [0153]     (1) Removal of the third portions of the conductive layer  170 ;  
         [0154]     (2) Removal of the second portions of the photoresist;  
         [0155]     (3) Removal of the third portions of the extrinsic a-Si layer  160  and the intrinsic a-Si layer  150 ;  
         [0156]     (4) Removal of the second portions of the conductive layer  170 ;  
         [0157]     (5) Removal of the first portions of the photoresist; and  
         [0158]     (6) Removal of the second portions of the extrinsic a-Si layer  160 .  
         [0159]     The first example is described in detail.  
         [0160]     At first, the exposed third portions of the conductive layer  170  on the third areas C are removed by wet etching or dry etching to expose the underlying third portions of the extrinsic a-Si layer  160 .  
         [0161]     Next, the third portions of the extrinsic a-Si layer  160  on the third areas C and of the intrinsic a-Si layer  150  are removed preferably by dry etching and the second portions of the photoresist PR are removed by ashing to expose the second portions of the conductors  170 . The removal of the second portions of the photoresist PR are performed either simultaneously with or independent from the removal of the third portions of the extrinsic a-Si layer  160  and of the intrinsic a-Si layer  150 . Residue of the second portions of the photoresist PR remained on the channel areas A is removed by ashing.  
         [0162]     The semiconductor stripes  151  and the metal pieces  172  as well as the semiconductor and ohmic contact islands under the metal pieces  172  are completed in this step.  
         [0163]     Next, the second portions of the conductors  170  and the extrinsic a-Si layer  160  on the channel areas A as well as the first portion of the photoresist PR are removed. At this time, the second portions of the semiconductor stripes  151  may be subject to thickness reduction.  
         [0164]     In this way, each conductor  170  is divided into a data line  171  and a plurality of drain electrodes  175  to be completed, and the extrinsic a-Si layer  160  is divided into an ohmic contact stripe  161  and a plurality of ohmic contact islands  165  to be completed.  
         [0165]     Referring to  FIGS. 15A and 15B , a passivation layer  180  is deposited and patterned along with the gate insulating layer  140  to form a plurality of contact holes  181 - 185  and a plurality of trenches  186 .  
         [0166]     Finally, a plurality of pixel electrodes  190 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84  are formed on the passivation layer  180  and the substrate  110  and on the exposed portions of the gate insulating layer  140 , the drain electrodes  175 , the expansions  129  of the gate lines  121 , and the expansions  179  of the data lines  171  by sputtering and photo-etching an IZO or ITO film with thickness of about 400-500 Å as shown in  FIGS. 10A-10C .  
         [0167]     As a result, the manufacturing process is simplified by omitting a photolithography step.  
         [0168]     An LCD according to another embodiment of the present invention will be described in detail with reference to  FIG. 16 .  
         [0169]      FIG. 16  is a sectional view of an LCD shown in  FIG. 4  taken along the line V-V′ according to another embodiment of the present invention. It is noted that reference numerals  91 - 96  and  271 - 276  shown in  FIG. 4  should be changed into  101 - 106  and  281 - 286 .  
         [0170]     Referring to  FIG. 16 , an LCD according to this embodiment also includes a TFT array panel  100 , a common electrode panel  200 , and a LC layer  3  interposed therebetween and including a number of LC molecules  31 .  
         [0171]     Layered structures of the panels  100  and  200  according to this embodiment are almost the same as those shown in  FIG. 5 .  
         [0172]     Regarding the TFT array panel  100 , a plurality of gate lines  121  including a plurality of gate electrodes  124  and end portions  129  and a plurality of storage electrode lines  131  including a plurality of storage electrodes  133   a  and  133   b  are formed on a substrate  110 , and a gate insulating layer  140 , a plurality of semiconductor stripes  151  including a plurality of projections  154 , and a plurality of ohmic contact stripes  161  including a plurality of projections  163  and a plurality of ohmic contact islands  165  are sequentially formed thereon. A plurality of data lines  171  including a plurality of source electrodes  173  and end portions  179 , a plurality of drain electrodes  175 , and a plurality of isolated metal pieces  172  are formed on the ohmic contacts  161  and  165 , and a passivation layer  180  is formed thereon. A plurality of contact holes  181 - 185  and a plurality of trenches  186  are provided at the passivation layer  180  and the gate insulating layer  140 . A plurality of pixel electrodes  190 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84  are formed on the passivation layer  180 .  
         [0173]     Regarding the common electrode panel  200 , a light blocking member  220 , a plurality of color filters  230 , an overcoat  250 , and a common electrode  270  are formed on an insulating substrate  210 .  
         [0174]     Retardation films  13  and  23  for compensating the retardation of the LC layer  3  are disposed on outer surfaces of the panels  100  and  200 , and a pair of polarizers  12  and  22  are provided on the retardation films  13  and  23 .  
         [0175]     Different from the LCD shown in  FIG. 5 , a plurality of protrusions  101 - 106  are provided on the pixel electrodes  190  instead of the cutouts  91 - 96  shown in  FIG. 5 , and a plurality of protrusions  281 - 286  are provided on the common electrode  270  instead of the cutouts  271 - 276  shown in  FIG. 5 .  
         [0176]     The protrusions  101 - 106  and  281 - 286  play substantially the same role as the cutouts  91 - 96  and  271 - 276 . That is, the protrusions  101 - 106  and  281 - 286  cause a horizontal component in an electric field generated in the LC layer  3 . In addition, the protrusions  101 - 106  and  281 - 286  cause pretilt of the LC molecules  31  that is perpendicular to edges of the protrusions. As described above, the trenches  186  induce the LC molecules  31  to align their length directions. Accordingly, the orientations of the LC molecules  31  on each subarea enclosed by the protrusions  101 - 106  and  281 - 286  and chamfered edges of the pixel electrodes  190  have an azimuthal distribution made by balancing the aligning forces caused by the geometry of the trenches  186  and caused by the protrusions  101 - 106  and  281 - 286 , which improves lateral visibility as well as front visibility.  
         [0177]     Many of the above-described features of the LCD shown in  FIGS. 1-5  may be appropriate to the LCD shown in  FIG. 16 .  
         [0178]     An LCD according to another embodiment of the present invention will be described in detail with reference to  FIG. 17 .  
         [0179]      FIG. 17  is a sectional view of an LCD shown in  FIG. 4  taken along the line IV-IV′ according to another embodiment of the present invention. It is noted that reference numerals  271 - 276  shown in  FIG. 4  should be changed into  281 - 286 .  
         [0180]     Referring to  FIG. 17 , an LCD according to this embodiment also includes a TFT array panel  100 , a common electrode panel  200 , and a LC layer  3  interposed therebetween and including a number of LC molecules  31 .  
         [0181]     Layered structures of the panels  100  and  200  according to this embodiment are almost the same as those shown in  FIGS. 5 and 16 . More exactly, the structure of the LCD shown in  FIG. 17  is a hybrid of those shown in  FIGS. 5 and 16 .  
         [0182]     Regarding the TFT array panel  100 , a plurality of gate lines  121  including a plurality of gate electrodes  124  and end portions  129  and a plurality of storage electrode lines  131  including a plurality of storage electrodes  133   a  and  133   b  are formed on a substrate  110 , and a gate insulating layer  140 , a plurality of semiconductor stripes  151  including a plurality of projections  154 , and a plurality of ohmic contact stripes  161  including a plurality of projections  163  and a plurality of ohmic contact islands  165  are sequentially formed thereon. A plurality of data lines  171  including a plurality of source electrodes  173  and end portions  179 , a plurality of drain electrodes  175 , and a plurality of isolated metal pieces  172  are formed on the ohmic contacts  161  and  165 , and a passivation layer  180  is formed thereon. A plurality of contact holes  181 - 185  and a plurality of trenches  186  are provided at the passivation layer  180  and the gate insulating layer  140 . A plurality of pixel electrodes  190 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84  are formed on the passivation layer  180 .  
         [0183]     Regarding the common electrode panel  200 , a light blocking member  220 , a plurality of color filters  230 , an overcoat  250 , and a common electrode  270  are formed on an insulating substrate  210 .  
         [0184]     Retardation films  13  and  23  for compensating the retardation of the LC layer  3  are disposed on outer surfaces of the panels  100  and  200 , and a pair of polarizers  12  and  22  are provided on the retardation films  13  and  23 .  
         [0185]     The LCD according to this embodiment provides a plurality of cutouts  91 - 96  at the pixel electrodes  190  like  FIG. 5 , while it provides a plurality of protrusions  281 - 286  on the common electrode  270  like  FIG. 16 .  
         [0186]     Accordingly, the orientations of the LC molecules  31  on each subarea enclosed by the cutouts  91 - 96 , the protrusions  281 - 286  and chamfered edges of the pixel electrodes  190  have an azimuthal distribution made by balancing the aligning forces caused by the geometry of the trenches  186  and caused by the cutouts  91 - 96  and the protrusions  281 - 286 , which improves lateral visibility as well as front visibility.  
         [0187]     Many of the above-described features of the LCD shown in  FIGS. 5 and 16  may be appropriate to the LCD shown in  FIG. 17 .  
         [0188]     An LCD according to another embodiment of the present invention will be described in detail with reference to  FIGS. 18-21  as well as  FIGS. 22 and 23 .  
         [0189]      FIG. 18  is a layout view of a TFT array panel of an LCD according to an embodiment of the present invention,  FIG. 19  is a layout view of a common electrode panel of an LCD according to an embodiment of the present invention,  FIG. 20  is a layout view of an LCD including the TFT array panel shown in  FIG. 18  and the common electrode panel shown in  FIG. 19 , and  FIG. 21  is a sectional view of the LCD shown in  FIG. 20  taken along the line XXI-XXI′.  
         [0190]     Referring to  FIGS. 18-21 , an LCD according to this embodiment also includes a TFT array panel  100 , a common electrode panel  200 , and a LC layer  3  interposed therebetween and including a number of LC molecules  31 .  
         [0191]     Layered structures of the panels  100  and  200  according to this embodiment are almost the same as those shown in  FIGS. 1-5 .  
         [0192]     Regarding the TFT array panel  100 , a plurality of gate lines  121  including a plurality of gate electrodes  124  and end portions  129  and a plurality of storage electrode lines  131  including a plurality of storage electrodes  133   a  and  133   b  are formed on a substrate  110 , and a gate insulating layer  140 , a plurality of semiconductor stripes  151  including a plurality of projections  154 , and a plurality of ohmic contact stripes  161  including a plurality of projections  163  and a plurality of ohmic contact islands  165  are sequentially formed thereon. A plurality of data lines  171  including a plurality of source electrodes  173  and end portions  179 , a plurality of drain electrodes  175 , and a plurality of isolated metal pieces  172  are formed on the ohmic contacts  161  and  165 , and a passivation layer  180  is formed thereon. A plurality of contact holes  181 - 185  are provided at the passivation layer  180  and the gate insulating layer  140 . A plurality of pixel electrodes  190  having a plurality of cutouts  91 - 96 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84  are formed on the passivation layer  180 .  
         [0193]     Regarding the common electrode panel  200 , a light blocking member  220 , a plurality of color filters  230 , an overcoat  250 , and a common electrode  270  having a plurality of cutouts  271 - 276  are formed on an insulating substrate  210 .  
         [0194]     Retardation films  13  and  23  for compensating the retardation of the LC layer  3  are disposed on outer surfaces of the panels  100  and  200 , and crossed polarizers  12  and  22  are provided on the retardation films  13  and  23 , respectively, such that one of their polarization axes is parallel to the transverse direction or the longitudinal direction.  
         [0195]     A pair of alignment layers  11  and  21 , which are not shown in  FIG. 5  but may be also provided, are coated on inner surfaces of the panels  100  and  200 .  
         [0196]     Different from the LCD shown in  FIGS. 1-5 , there is no trench at the passivation layer  180 .  
         [0197]     Instead, the alignment layers  11  and  21  preferably made of polyimide or polyamide are rubbed in a direction making an oblique angle, preferably of about 40-50 degree and more preferably of about 45 degrees, with oblique edges of the cutouts  91 - 96  and  271 - 276 . It is preferable that the rubbing directions are parallel to a polarization axis POL of the polarizers  12  and  22  such that the luminance in a black state of the LCD is minimized. It is also preferable that the rubbing directions are antiparallel but they may be parallel. The rubbing makes the LC molecules  31  near the alignments layers  11  and  21  tilt along the rubbing directions upon application of an electric field to the LC layer  3 , and antiparallel rubbing directions make the LC molecules  31  tilt in opposite directions.  
         [0198]     The predetermined tilt direction is referred to as “the pretilt direction” hereinafter and the treatment for providing the pretilt direction such as the rubbing is referred to as “the pretilt treatment.” 
         [0199]     The provisions of the above-described trenches  186  can be also considered as a kind of the pretilt treatment. The pretilt direction may be also obtained by illuminating a polarized light onto the alignment layers  11  and  21 . The pretilt treatment may cause the LC molecules  31  to be slightly inclined relative to a direction normal to surfaces of the alignment layers  11  and  21 .  
         [0200]     The pretilt treatment may be performed to only one of the alignment layers  11  and  21 . When pretilt treatment is performed to the alignment layer  11 , the pretilt direction is preferably parallel to the polarization axis POL of the polarizer  12 . On the contrary, the pretilt direction is preferably parallel to the polarization axis POL of the polarizer  22  when the pretilt treatment is performed at the alignment layer  21 . As described above, the parallelism between the pretilt direction and one of the polarization axes POL minimizes the light leakage in the black state.  
         [0201]      FIGS. 22 and 23  show two different types of pretilt directions, one in the longitudinal direction and the other in the transverse direction, for a pair of crossed polarization axes POL. The pretilt directions shown in  FIGS. 22 and 23  are antiparallel to each other. The nails shown in  FIGS. 22 and 23  indicate four different tilt directions of the LC molecules  31 .  
         [0202]     Accordingly, the orientations of the LC molecules  31  on each subarea enclosed by the cutouts  91 - 96  and  271 - 276  and chamfered edges of the pixel electrodes  190  have an azimuthal distribution made by balancing the aligning forces caused by the provision of the pretilt directions and caused by the cutouts  91 - 96  and  271 - 276 , which improves lateral visibility as well as front visibility.  
         [0203]     The pretilt treatment such as rubbing or the light illumination can be localized by using photoresist pattern. For example, the pretilt directions formed by the local pretilt treatment may be equal to the extending directions of the trenches  186  shown in  FIG. 4 .  
         [0204]     Many of the above-described features of the LCD shown in  FIGS. 1-5  may be appropriate to the LCD shown in  FIGS. 18-21 .  
         [0205]     An LCD according to another embodiment of the present invention will be described in detail with reference to  FIGS. 24-27 .  
         [0206]      FIG. 24  is a layout view of a TFT array panel of an LCD according to an embodiment of the present invention,  FIG. 25  is a layout view of a common electrode panel of an LCD according to an embodiment of the present invention,  FIG. 26  is a layout view of an LCD including the TFT array panel shown in  FIG. 24  and the common electrode panel shown in  FIG. 25 , and  FIG. 27  is a sectional view of the LCD shown in  FIG. 26  taken along the line XXVII-XXVII′.  
         [0207]     Referring to  FIGS. 24-27 , an LCD according to this embodiment also includes a TFT array panel  100 , a common electrode panel  200 , and a LC layer  3  interposed therebetween and including a number of LC molecules  31 .  
         [0208]     Layered structures of the panels  100  and  200  according to this embodiment are almost the same as those shown in  FIGS. 18-21 .  
         [0209]     Regarding the TFT array panel  100 , a plurality of gate lines  121  including a plurality of gate electrodes  124  and end portions  129  and a plurality of storage electrode lines  131  including a plurality of storage electrodes  133   a  and  133   b  are formed on a substrate  110 , and a gate insulating layer  140 , a plurality of semiconductor stripes  151  including a plurality of projections  154 , and a plurality of ohmic contact stripes  161  including a plurality of projections  163  and a plurality of ohmic contact islands  165  are sequentially formed thereon. A plurality of data lines  171  including a plurality of source electrodes  173  and end portions  179 , a plurality of drain electrodes  175 , and a plurality of isolated metal pieces  172  are formed on the ohmic contacts  161  and  165 , and a passivation layer  180  is formed thereon. A plurality of contact holes  181 - 185  are provided at the passivation layer  180  and the gate insulating layer  140 . A plurality of pixel electrodes  190 , a plurality of contact assistants  81  and  82 , and a plurality of storage connections  84  are formed on the passivation layer  180 , and an alignment layer  11  is coated thereon.  
         [0210]     Regarding the common electrode panel  200 , a light blocking member  220 , a plurality of color filters  230 , an overcoat  250 , a common electrode  270 , and an alignment layer  21  are formed on an insulating substrate  210 .  
         [0211]     Retardation films  13  and  23  for compensating the retardation of the LC layer  3  are disposed on outer surfaces of the panels  100  and  200 , and crossed polarizers  12  and  22  are provided on the retardation films  13  and  23 , respectively.  
         [0212]     Different from the LCD shown in  FIGS. 18-21 , each pixel electrode  190  has a cutout  98  extending in a longitudinal direction and bisecting the pixel electrode  190  into left and right halves. In addition, the common electrode  270  has a plurality of pairs of cutouts  277  and  279  and each pair of cutouts  277  and  279  faces a pixel electrode  190  and is disposed between the cutout  98  of the pixel electrode  190  and longitudinal edges of the pixel electrode  190 . The cutouts  98 ,  277  and  279  make an electric field generated by the electrodes  190  and  270  to have a horizontal component in a transverse direction.  
         [0213]     Furthermore, the polarization axes of the polarizers  12  and  22  make an angle of about 45 degrees with the gate lines  121  and the data lines  171  and the alignment layers  11  and  21  are subject to pretilt treatment giving a pretilt direction parallel to one of the polarization axes POL of the polarizers  12  and  22 .  
         [0214]      FIG. 28  show exemplary pretilt directions, the tilt directions of the LC molecules, and a pair of crossed polarization axes POL of the LCD shown in  FIGS. 24-27 . The pretilt directions shown in  FIG. 28  are antiparallel to each other. The nails shown in  FIGS. 22 and 23  indicate two different tilt directions of the LC molecules  31 .  
         [0215]     When the cutouts  98 ,  277  and  279  extend in the transverse direction, the tilt directions may be longitudinal as shown in  FIG. 29 , which shows pretilt directions, tilt directions of LC molecules, and a pair of crossed polarization axes POL of such an LCD.  
         [0216]     Accordingly, the orientations of the LC molecules  31  on each subarea enclosed by the cutouts  98 ,  277  and  279  and the longitudinal edges of the pixel electrodes  190  have an azimuthal distribution made by balancing the aligning forces caused by the provision of the pretilt directions and caused by cutouts  98 ,  277  and  279 , which improves lateral visibility as well as front visibility.  
         [0217]     Many of the above-described features of the LCD shown in  FIGS. 18-21  may be appropriate to the LCD shown in  FIGS. 24-27 .  
         [0218]     While the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that various modifications and substitutions can be made thereto without departing from the spirit and scope of the present invention as set forth in the appended claims.

Technology Category: 3