Patent Document

CROSS REFERENCE TO RELATED APPLICATION 
     This claims priority under 35 U.S.C. §119 of Taiwan Application No. 95123741, filed Jun. 30, 2006, which is hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present invention relates to a display panel, a driving method, and a display device. More particularly, the present invention relates to a liquid crystal display (LCD) panel, a method for driving a liquid crystal display panel, and a liquid crystal display. 
     BACKGROUND 
     In a conventional multi-domain vertical alignment (MVA) LCD, protrusions or slits on a color filter substrate or a thin film transistor (TFT) array substrate make liquid crystal molecules arrange in multiple directions. This creates different alignment domains which allow the conventional MVA LCD to have a wide viewing angle. However, the transmittance of the MVA LCDs changes along with the variation of the wide viewing angle, which results in a variation of gray level. In other words, when the viewing angle varies, the brightness of the MVA LCD changes, which causes color shift. 
       FIG. 1  is a characteristic curve diagram of voltage to transmittance of a conventional MVA LCD. Referring to  FIG. 1 , the curve  11  to the curve  13  indicates the light transmittance observed when viewing the MVA liquid crystal display panel from the front. The curve  11  is a transmittance of red light, the curve  12  is a transmittance of green light, and the curve  13  is a transmittance of blue light. However, when viewing the MVA LCD panel from an oblique angle (e.g., 60 degrees), under the same working voltage the observed light transmittance changes and drifts from the curves  11 ,  12 , and  13  to the curves  14 ,  15 , and  16  respectively. 
     It can be seen that in regions of a higher gray level and a lower gray level, the light transmittance of the curve  11  is approximate to that of the curve  14 , the light transmittance of the curve  12  is approximate to that of the curve  15 , and the light transmittance of the curve  13  is approximate to that of the curve  16 . However, in the middle gray level region, the light transmittances of the curves  11 ,  12 , and  13  are significantly different from those of the corresponding curves  14 ,  15 , and  16 . In other words, the color shift phenomenon of the higher and lower gray levels is slight, and the color shift phenomenon of the middle gray level is severe. 
     In order to eliminate or reduce the color shift phenomenon, the conventional art divides one pixel unit into two regions of different light transmittances. The light transmittance of one region is relatively higher, thus displaying the color of a higher gray level, and the light transmittance of the other region is lower, thus displaying the color of a lower gray level. The color of the higher gray level and the color of the lower gray level are then mixed into a color of a middle gray level. Therefore, regardless of whether the user views the improved MVA LCD panel from the front or at an oblique angle, he or she can view similar colors. 
     In order to achieve the above technology, CHIMEI Corporation has developed an MVA pixel structure (Taiwan Patent Application No. 93132909), as shown in  FIG. 2 . A protection layer  303  of silicon nitride covers a TFT array substrate  301 . Next, transparent electrodes  305  and  307  are disposed on the protection layer  303 , so as to divide the entire pixel region into display regions A and B. The transparent electrode  307  is electrically connected to the transparent electrode  309 , and the transparent electrode  305  is floated to the transparent electrode  309 . In addition, a liquid crystal layer  313  is filled between the TFT array substrate  301  and the opposite substrate  311 . 
     It can be seen from  FIG. 2  that in the display region A, since the electrode  307  is at the same potential as the source end  309 , and a common electrode  315  on the opposite substrate may be connected to a common voltage, a liquid crystal capacitor  313   a  may be formed in the liquid crystal layer  313 . In the display region B, a protection layer capacitor  303   a  may be formed in the protection layer  303  between the electrode  309  and the electrode  305 . Similar to the display region A, a liquid crystal capacitor  313   b  is also formed between the electrode  305  and the common electrode  315 . 
       FIG. 3  is an equivalent circuit diagram of the pixel structure in  FIG. 2 . Referring to  FIGS. 2 and 3  together, a drain end of the TFT  321  is electrically connected to the data line  31 , and a gate end is electrically connected to the scan line  33 . Furthermore, a source end of the TFT  321  is electrically connected to the storage capacitor  323 , the liquid crystal capacitor  313   a  in the display region A, the protection layer capacitor  303   a , and the liquid crystal capacitor  313   b  in the display region B. The voltage of the liquid crystal capacitor  313   a  in the display region A is V 1 , and the voltages of the protection layer capacitor  303   a  and the liquid crystal capacitor  313   b  in the display region B are V 2  and V 3  respectively. Considering the voltages of the liquid crystal capacitors in the display region A and in the display region B are different, the light transmittances at each display region may be different. For example, display region A may have a high gray level and display region B may have a low gray level. Mixing the high and low gray levels may produce a middle gray level when viewing the MVA LCD panel from different angles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, incorporated in and constituting a part of this specification, illustrate one or more implementations consistent with the principles of the invention and, together with the description of the invention, explain such implementations. The drawings are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the invention. 
         FIG. 1  is a characteristic curve diagram of voltage to transmittance of a conventional MVA LCD. 
         FIG. 2  is a side view of a cross-section of a pixel structure in a conventional MVA LCD. 
         FIG. 3  is an equivalent circuit diagram of the pixel structure of  FIG. 2 . 
         FIG. 4A  is a partial top view of an active device array substrate of a liquid crystal display panel according to an embodiment of the present invention. 
         FIG. 4B  is a side cross-sectional view of a liquid crystal display panel according to an embodiment of the present invention. 
         FIG. 4C  is an equivalent circuit diagram of a liquid crystal display panel according to an embodiment of the present invention. 
         FIG. 4D  is a view of a drive waveform and relation curve in an embodiment of the invention. 
         FIG. 4E  is a view of a drive waveform and relation curve in an embodiment of the invention. 
         FIG. 4F  is a view of a drive waveform and relation curve in an embodiment of the invention. 
         FIG. 4G  is a view of a drive waveform and relation curve in an embodiment of the invention. 
         FIG. 4H  is a view of a drive waveform and relation curve in an embodiment of the invention. 
         FIG. 5  is a top view of a LCD according to an embodiment of the present invention. 
         FIG. 6  is a partial top view of an active device array substrate according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following description refers to the accompanying drawings. Among the various drawings the same reference numbers may be used to identify the same or similar elements. While the following description provides a thorough understanding of the various aspects of the claimed invention by setting forth specific details such as particular structures, architectures, interfaces, and techniques, such details are provided for purposes of explanation and should not be viewed as limiting. Moreover, those of skill in the art will, in light of the present disclosure, appreciate that various aspects of the invention claimed may be practiced in other examples or implementations that depart from these specific details. At certain junctures in the following disclosure descriptions of well known devices, circuits, and methods have been omitted to avoid clouding the description of the present invention with unnecessary detail. 
       FIG. 4A  is a partial top view of an active device array substrate of a liquid crystal display panel according to an embodiment of the present invention.  FIG. 4B  is a cross-sectional view of a partial structure of the liquid crystal display panel according to an embodiment of the present invention. The cross-sectional view of the active device array substrate in  FIG. 4B  is taken along the sectional lines A-A′ and B-B′ in  FIG. 4A . Referring to  FIGS. 4A and 4B  together, the liquid crystal display panel  400  is, for example, but not limited to, an MVA LCD. The liquid crystal display panel  400  may include a plurality of pixel units  410  arranged in an array. Each pixel unit  410  may have a plurality of sub-pixel regions  411  and includes a plurality of active devices  413 , a plurality of liquid crystal capacitors  415 , and a plurality of storage capacitors  417 . One of the active devices  413  may be disposed in one of the sub-pixel regions  411  and electrically connected to a scan line  420  and a data line  430 . The liquid crystal capacitors  415  are respectively disposed in the sub-pixel regions  411 , and each liquid crystal capacitor  415  is electrically connected to the corresponding active device  413 . The storage capacitors  417  are respectively disposed in the sub-pixel regions  411 , and each storage capacitor  417  is electrically connected to the corresponding active device  413 . In the same pixel unit  410 , the ratio of the capacitance of the storage capacitor  417  to that of the liquid crystal capacitor  415  of any sub-pixel region  411  is unequal to the ratio of the capacitance of the storage capacitor  417  to that of the liquid crystal capacitor  415  of any other sub-pixel regions  411 . 
     For the convenience of illustrating the structure of the liquid crystal display panel  400 , in this embodiment, each pixel unit  410  only has two sub-pixel regions  411   a  and  411   b , and only includes two active devices  413   a  and  413   b , two liquid crystal capacitors  415   a  and  415   b , and two storage capacitors  417   a  and  417   b  in one embodiment of the invention. Other embodiments of the invention may include more or fewer of any or all of these devices. The active device  413   a  is disposed in the sub-pixel region  411   a , the active device  413   b  is disposed in the sub-pixel region  411   b , and both the active device  413   a  and the active device  413   b  are electrically connected to the same scan line  420  and the same data line  430 . The liquid crystal capacitor  415   a  is disposed in the sub-pixel region  411   a  and electrically connected to the active device  413   a , and the liquid crystal capacitor  415   b  is disposed in the sub-pixel region  411   b  and electrically connected to the active device  413   b . The storage capacitor  417   a  is disposed in the sub-pixel region  411   a  and electrically connected to the active device  413   a , and the storage capacitor  417   b  is disposed in the sub-pixel region  411   b  and electrically connected to the active device  413   b . The ratio of the capacitance of the storage capacitor  417   a  to that of the liquid crystal capacitor  415   a  of sub-pixel region  411   a  is unequal to the ratio of the capacitance of the storage capacitor  417   b  to that of the liquid crystal capacitor  415   b  of the sub-pixel region  411   b.    
     Each pixel unit  410  further includes two pixel electrodes  419   a  and  419   b  in one embodiment of the invention. More or fewer electrodes may be included in other embodiments of the invention. The pixel electrodes  419   a  and  419   b  are disposed in the sub-pixel region  411   a  and  411   b  respectively. The part of each of the pixel electrodes  419   a ,  419   b  that extends to a storage capacitor line  440  serves as storage capacitor opposite electrode  419   c ,  419   d  respectively. The storage capacitor opposite electrodes  419   c ,  419   d  are respectively coupled with the storage capacitor line  440  to form the storage capacitor  417   a  and the storage capacitor  417   b  respectively. The pixel electrodes  419   a ,  419   b  further have a plurality of main slits L for defining four alignment domains I, II, III, IV respectively. For example, a plurality of protrusions P 10  is disposed above the pixel electrodes  419   a ,  419   b . When the pixel unit  410  is not driven, the liquid crystal molecules in the liquid crystal layer  450  are arranged vertically. When the pixel unit  410  is driven, the liquid crystal molecules in the liquid crystal layer  450  are inclined towards the horizontal direction. Particularly, in one of the specific alignment domains I, II, III, IV, the inclined directions of the liquid crystal molecules are consistent. However, in different alignment domains I, II, III, IV, the inclined direction of the liquid crystal molecules are different from one another. By means of making the liquid crystals inclined towards different directions, the liquid crystal molecules in different alignment domains can compensate for the optical effects generated by a change of viewing angles, such that the liquid crystal display panel  400  has a wider viewing area. 
     In view of the above, the active devices  413   a ,  413   b  are, for example, TFTs, switching elements with three terminals or another suitable switch element (e.g., diode). The storage capacitor line  440  may be parallel to the scan line  420  and arranged between two adjacent scan lines (e.g.,  420 ). Furthermore, pixel electrode  419   a , liquid crystal layer  450 , and common electrode  460  help form a liquid crystal capacitor  415   a , and pixel electrode  419   b , liquid crystal layer  450 , and common electrode  460  help form liquid crystal capacitor  415   b.    
       FIG. 4C  is an equivalent circuit diagram of a liquid crystal display panel according to an embodiment of the present invention. Referring to  FIGS. 4A and 4C , in each pixel unit  410  the active device  413   a  has a parasitic capacitor  414   a  of a capacitance C gd (A), and the active device  413   b  has a parasitic capacitor  414   b  of a capacitance C gd (B). The capacitance C gd (A) may be equal to or different from the capacitance C gd (B). 
     It should be mentioned that in the liquid crystal display panel  400  of this embodiment, each pixel unit  410  includes two sub-pixel regions  411   a  and  411   b  and the ratio of the storage capacitance C St (A) to the liquid crystal capacitance C LC (A) of the sub-pixel region  411   a  is unequal to the ratio of the storage capacitance C St (B) to the liquid crystal capacitance C LC (B) of the sub-pixel region  411   b , i.e., C St (A)/C LC (A)≠C St (B)/C LC (B). Other embodiments of the invention may include more or fewer subpixel regions. If the characteristic that the ratio of the capacitance of the sub-pixel region  411   a  is unequal to that of the sub-pixel region  411   b  is utilized together with an appropriate driving method, the voltage V A  on the pixel electrode  419   a  can be adjusted to be different from the voltage V B  on the pixel electrode  419   b . If the pixel electrode voltage V A  and the pixel electrode voltage V B  are different, the voltage difference at both ends of the liquid crystal capacitor  415   a  may be different from that at both ends of the liquid crystal capacitor  415   b . Therefore, the liquid crystal molecules in the sub-pixel region  411   a  and that in the sub-pixel region  411   b  may be inclined to different extents. In other words, the liquid crystal molecules in a same pixel unit  410  may have, for example, eight inclining angles based on the number of different alignment domains. Consequently, the light transmittances of the sub-pixel region  411   a  and the sub-pixel region  411   b  may be different (e.g.,  411   a  has a high gray level and  411   b  has a low gray level), and the liquid crystal molecules in two sub-pixel regions  411   a ,  411   b  can compensate the optical effects (e.g., form a middle gray level), thereby eliminating or reducing the color shift phenomenon of the liquid crystal display panel  400 . 
     In order to achieve C St (A)/C LC (A)≠C St (B)/C LC (B), in one embodiment, the storage capacitance C St (A) of the storage capacitor  417   a  is different from the storage capacitance C St (B) of the storage capacitor  417   b . The method of achieving C St (A)/C LC (A)≠C St (B)/C LC (B), however, is not limited to the above method. In another embodiment, the liquid crystal capacitance C LC (A) of the liquid crystal capacitor  415   a  may be unequal to the liquid crystal capacitance C LC (B) of the liquid crystal capacitor  415   b , so as to achieve C St (A)/C LC (A)≠C St (B)/C LC (B). There are various methods for making the liquid crystal capacitance C LC (A) unequal to the liquid crystal capacitance C LC (B). For example, the layout of the mask may be changed to make the pixel electrode  419   a  and the pixel electrode  419   b  have different areas. Furthermore, an insulating layer (not shown) may be formed below the pixel electrode  419   a  or the pixel electrode  419   b , such that the sub-pixel region  411   a  and the sub-pixel region  411   b  have different cell gaps. In other embodiments, C St (A)/C LC (A)≠C St (B)/C LC (B) may be obtained by having C St (A)≠C St (B) and C LC (A)≠C LC (B). Hereinafter, the driving method for the liquid crystal display panel  400  is described. 
       FIG. 4D  is a schematic view of a drive waveform in a certain time sequence of the liquid crystal display panel in  FIG. 4C . Referring to  FIGS. 4C and 4D , in the driving method, firstly, a scan signal V S  is applied to the scan line  420 . Then, a data signal V D  is applied to the data line  430 . After that, a compensation signal V St  remains applied to the storage capacitor line  440 . Furthermore, a common voltage V com  is applied to the common electrode  460 , and the high level voltage of the data signal V D  is greater than the value of the common voltage V com . 
       FIG. 4D  further shows a relation curve between the pixel electrode voltage V A  of the pixel electrode  419   a  and the pixel electrode voltage V B  of the pixel electrode  419   b . The relation curve is shown below the drive waveform and does not share, for example, a Y axis (V) with the drive waveform plot. It can be seen from  FIG. 4D  that when the scan signal V S  is switched from a high level to a low level, the compensation signal V St  is switched to a high level. Specifically, when the scan signal V S  is switched from the high level to the low level, the pixel electrode voltage V A  and the pixel electrode voltage V B  are slightly dropped due to a feed-through effect of the parasitic capacitor  414   a  and the parasitic capacitor  414   b . However, after the compensation signal V St  is switched from a low level to a high level, the pixel electrode voltage V A  and the pixel electrode voltage V B  rises due to the feed-through effects. 
     Also, since C St (A)/C LC (A)≠C St (B)/C LC (B), the amounts of rising respectively for the pixel electrode voltage V A  and the pixel electrode voltage V B  due to the feed-through effect caused by the variation of the compensation signal V St  are different, and the magnitude of the rising voltage ΔV (i.e., “feedthrough voltage”) for either ΔV A  or ΔV B  is expressed by the following equation: 
     
       
         
           
             
               
                 
                   
                     
                       Δ 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       V 
                     
                     = 
                     
                       
                         
                           C 
                           gd 
                         
                         ⁡ 
                         
                           ( 
                           
                             
                               V 
                               StH 
                             
                             - 
                             
                               V 
                               StL 
                             
                           
                           ) 
                         
                       
                       
                         ( 
                         
                           
                             C 
                             LC 
                           
                           + 
                           
                             C 
                             St 
                           
                           + 
                           
                             C 
                             gd 
                           
                         
                         ) 
                       
                     
                   
                   , 
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   1 
                 
               
             
           
         
       
     
     where V StH  is a high level voltage of the compensation signal, V StL  is a low level voltage of the compensation signal. It can be seen from Equation 1 that as the storage capacitance C St (A) and the storage capacitance C St (B) are different, the extent of rising (e.g., ΔV A , ΔV B ) of the pixel electrode voltage V A  and the pixel electrode voltage V B  respectively in different sub-pixel regions is different. Therefore, the voltage difference at two ends of the liquid crystal capacitor  415   a  is different from that at two ends of the liquid crystal capacitor  415   b , such that the liquid crystal molecules in the sub-pixel region  411   a  and the sub-pixel region  411   b  are inclined to different extents. As a result, the light transmittance of the sub-pixel region  411   a  is different from that of the sub-pixel region  411   b . If the above driving method is used to adjust the pixel electrode voltage V A  and the pixel electrode voltage V B  to change the light transmittances of the sub-pixel region  411   a  and the sub-pixel region  411   b , the color shift phenomenon of the liquid crystal display panel  400  can be eliminated or reduced. 
     It should be noted that the above driving method is suitable for the circumstance when the value of the high level voltage of the data signal V D  is greater than the value of the common voltage V com . However, if the value of the high level voltage of the data signal V D  is smaller than the common voltage V com , the switching of the compensation signal V St  may be different, in one embodiment of the invention, from that described above. 
     For example,  FIG. 4E  is a schematic view of a drive waveform of the liquid crystal display panel in  FIG. 4C  under another circumstance. When the value of the high level voltage of the data signal V D  is smaller than the value of the common voltage V com  and after the scan signal V S  is switched from the high level to the low level, the pixel electrode voltage V A  and the pixel electrode voltage V B  are dropped due to the feed-through effect of the parasitic capacitor  414   a  and the parasitic capacitor  414   b . Then, the compensation signal V St  is switched to the low level, and the pixel electrode voltage V A  and the pixel electrode voltage V B  are dropped again, instead of rising. The dropping extents of the pixel electrode voltage V A  and the pixel electrode voltage V B  are different, so that the light transmittance of the sub-pixel region  411   a  is different from that of the sub-pixel region  411   b , which further eliminates the color shift phenomenon of the liquid crystal display panel  400 . 
     However, when taking the frame with a positive polarity (e.g.,  FIG. 4D ) and the frame with a negative polarity (e.g.,  FIG. 4E ) into account, if the feedthrough voltage is different in different sub-pixel regions due to the parasitic capacitor (i.e., parasitic capacitance), the sub-pixel regions cannot have the same common voltage V com . In each sub-pixel region, the feedthrough voltage equation caused by the parasitic capacitor is expressed by Equation 1. In one embodiment of the present invention, the capacitance C gd (A) and the capacitance C gd (B) may be adjusted to be different according to the above Equation 1, such that the pixel electrode voltage V A  and the pixel electrode voltage V B  respectively located in different sub-pixel regions have the same feedthrough voltage regardless of whether the frame has a positive polarity (e.g.,  FIG. 4D ) or a negative polarity (e.g.,  FIG. 4E ). That is, ΔV A1  (positive frame) is equal to ΔV A2  (negative frame), and ΔV B1  (positive frame) is equal to ΔV B2  (negative frame, as shown in  FIG. 4F ), thereby making each of the sub-pixel regions have the same common voltage V com . 
     If a frame with a low gray level is displayed in the liquid crystal display, the frame with a low gray level must be ensured to have a minimum dark-state brightness, so as to achieve a frame with a high contrast.  FIG. 4G  is a schematic view of a drive waveform of the liquid crystal display panel in  FIG. 4C  according to another embodiment of the present invention. In a frame with a low gray level, the data signal V D  with a low gray level of a positive polarity can be adjusted to be smaller than the value of the common voltage V com . As the compensation signal V St  is switched from a low level to a high level, the pixel electrode voltage V A  and the pixel electrode voltage V B  can be increased such that the pixel electrode voltage V A  is greater than the common voltage V com , and the pixel electrode voltage V B  is still smaller than the common voltage V com . Therefore, the average visual effect may be equal to the original low gray level display of a positive polarity and thereby achieve a low color shift effect. 
       FIG. 4H  is a schematic view of a drive waveform of the liquid crystal display panel in  FIG. 4C  according to still another embodiment of the present invention. In the low gray level display of a negative polarity, the low gray level data signal V D  of a negative polarity can be adjusted to be greater than the value of the common voltage V com . The compensation signal V St  may be switched from a high level to a low level and the pixel electrode voltage V A  and the pixel electrode voltage V B  may be dropped as a result, the pixel electrode voltage V A  may be lower than the common voltage V com  and the pixel electrode voltage V B  may still be higher than the common voltage V com . Therefore, the average visual effect is equal to the original low gray level display of a negative polarity, thereby achieving a low color shift effect. 
     The above liquid crystal display panel  400  can be used to assemble a liquid crystal display.  FIG. 5  is a schematic structural view of an LCD according to an embodiment of the present invention. Referring to  FIG. 5 , the liquid crystal display  600  may include a liquid crystal display panel  400 , a backlight module  510 , and an optical film  520 . The backlight module  510  may be a cold cathode fluorescence lamp (CCFL) backlight module, and may include a back frame  512 , a reflector  514 , a plurality of cold cathode fluorescence lamps (CCFLs)  516 , and a diffuser  518 . The diffuser  518  may be disposed above the back frame  512 , the CCFLs  516  may be disposed between the diffuser  518  and the back frame  512 , and the reflector  514  may be disposed between the CCFLs  516  and the back frame  512 . Similarly, the liquid crystal display panel  400  may be disposed above the backlight module  510 . The optical film  520  may be disposed between the liquid crystal display panel  400  and the backlight module  510 . In this embodiment, the backlight module  510  is a CCFL backlight module, but in another embodiment, the backlight module  510  can also be a light emitting diode (LED) backlight module or another suitable backlight source. 
     Since the liquid crystal display  600  is assembled using the liquid crystal display panel  400 , the liquid crystal display  600  not only has a relatively large viewing angle, but the color shift phenomenon can also be eliminated. 
     In one embodiment of the invention, the liquid crystal display panel may employ a row inversion driving method. In other words, in the same frame time data signals applied to the pixel units  410  in the same row have the same polarity and data signals applied to the pixel units  410  in two adjacent rows have opposite polarities. In a liquid crystal display panel  400  adopting a driving method of row inversion, the storage capacitor line  440  may be parallel to the scan line  420  and arranged between two adjacent scan lines  420  in one embodiment of the invention. In other words, pixel units  410  sharing the same common scan line  420  may also share the same common storage capacitor line(s)  440 . Particularly, any two adjacent pixel units  410  in the same row may share the same common storage capacitor line(s)  440 . Thus, as for two adjacent pixel units  410 , the compensation signals V St  may have the same value, and the writing voltage of the two pixel units  410  may have the same polarity. 
     The storage capacitor line  440  is not limited to the shape as shown in  FIG. 4B . For example, in another embodiment of the invention ( FIG. 6 ), the driving method of the liquid crystal display panel may also be the row inversion mode. The storage capacitor line  440  may extend on the liquid crystal display panel in a direction substantially the same as that of the data line  430 . Also, the storage capacitor line  440  may further have a plurality of extension lines  440   a ′ disposed along the main slit L of the pixel electrode  410 . Since the area above the main slit L is a “no effect” area and the extension line  440   a ′ is made of an opaque material, the aperture ratio of the pixel unit  410  may not be reduced after the extension line  440   a ′ is disposed along the main slit L of the pixel electrodes  419   a ,  419   b.    
     Also, the driving method is not limited to the row inversion mode, but can also be, for example but without limitation, column inversion, pixel inversion, dot inversion mode or “many dot” inversion mode. Specifically, the liquid crystal display panel of  FIG. 6  can adopt the driving method of dot inversion. In this embodiment of the invention, the compensation signals V St  can be different since the pixel units  410  in any two adjacent columns use different storage capacitor lines  440 . Therefore, the writing voltages of two pixel units  410  can have opposite polarities. 
     In addition, the liquid crystal display panel  400  may be a normally dark display apparatus. That is, when no voltage is applied to the liquid crystal capacitor  415   a  and the liquid crystal capacitor  415   b , the display is normally dark. When the pixel unit  410  is lightened abnormally, one can weld the pixel electrode  419   a  (or the pixel electrode  419   b ) and the storage capacitor line  440  together by means of, for example, a laser. Considering the characteristic that the average compensation signal V St  of the storage capacitor line  440  equals the common voltage V com , coupling the storage capacitor or line to the pixel electrode  419   a ,  419   b  may make the lightened pixel unit  410  become a dark dot so as to reduce the sensation of human eyes to dead spots and thereby enhance the display quality. 
     The process for manufacturing the aforementioned liquid crystal display panel and the liquid crystal display of the present invention is compatible with the current manufacturing processes in this field, without requiring additional manufacturing equipments. Also, the driving method of the present invention is not limited to be applied to the MVA LCD, but can also be applied to other kinds of liquid crystal displays, for example, twisted nematic (TN) LCD, in-plane switching (IPS) LCD, optically compensated bend (OCB) LCD, etc. 
     While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.

Technology Category: 3