Abstract:
The present invention discloses a method for driving thin film transistor liquid crystal display (TFT-LCD) and the storage medium for storing computer program representative of the method thereof. The method utilizes a timing controller to send polarity control signals to a plurality of source drivers in a TFT-LCD panel for changing the polarity distribution of the liquid crystal molecules in the panel. The method is characterized by dynamically changing the positions of polarity inversion for alleviating the problem of undercharging under high resolution and high frequency conditions; utilizing both polar and reverse polar driving signals for solving the problem of color shift in “checker board” checking signals; and providing a mechanism for mending the problem of undercharging of the first horizontal line.

Description:
FIELD OF THE INVENTION 
     The present invention is generally related to the method for driving liquid crystal display (LCD) and, more particularly, to an improved polarity reversion driving method for thin film transistor liquid crystal display (TFT-LCD). 
     DESCRIPTION OF THE PRIOR ART 
     For improving the quality of displaying images from the LCD display panel, the alternating current (AC) driving approach is often utilized for preventing the liquid crystal molecules from being constantly polarized. Several driving approaches are often utilized, such as frame inversion, line inversion, dot inversion, etc. When frame inversion driving approach is utilized, several shortcomings, such as flicking and unbalance of images, are often accompanied due to all the LCD capacitors being charged with the same polarity in each frame. For overcoming the above-mentioned shortcomings, line inversion and dot invention driving approaches have been developed by the industry. For example, in a line inversion driving approach, because capacitors along every two neighboring lines in a frame are charged in opposite polarities of voltage, the flicking problem is alleviated by the averaging effect. In a dot inversion driving approach, because capacitors at every two neighboring dots are charged in opposite polarities, a better averaging effect than which provided by the frame inversion for lowering the flicking problem is thus provided. However, although the dot inversion driving approach provides a best averaging effect and a lowest flicking problem among the above-mentioned approaches, it consumes the electric power most. Therefore, the dot inversion approach may have problems when being applied to, for example, a portable device, for shortcomings of lower endurance of electric power and/or a larger volume and weight of the expected and needed batteries. 
     As it faces a trade-of between the electric power consumption and the averaging effect, the prior art provides a multi-line inversion technique, for trying to decrease the times of inversions and thus to lower the electric power consumption. However, the multi-line inversion technique does not overcome the shortcoming of undercharging (insufficiency of charging) occurred at the inversion positions. Therefore, several problems, such as the lines with unbalanced brightness and flicking images, are thus generated. 
     Nowadays, the “1 line” inversion and the “1+2 line” inversion modes are relatively common utilized in the industries, and their timing diagrams are illustrated in  FIGS. 1A and 1B .  FIG. 1A  shows the polarity distribution in frame “n−1” F(n−1), which comprising the information of start pulse vertical signal (STV)  111 , clock signal (CLKV)  112 , RGB data  113 , “1 line” polarity distribution signal  114   a , and “1+2 line” polarity distribution signal  114   b . Similarly,  FIG. 1B  shows the polarity distribution in frame F(n), which comprising the information of STV  121 , CLKV  122 , RGB data  123 , “1 line” polarity distribution signal  124   a , and “1+2 line” polarity distribution signal  124   b . The continuous frames comprise the alternate frames of F(n−1) and F(n). Take “1+2 line” as an example, the polarity at the positions of  116 / 126 ,  117 / 127 ,  118 / 128 , and  119 / 129  are continuously been inversing, and thus the problems of unbalanced brightness at corresponding lines are emerged due to undercharging of this polarity inversion positions. In addition, the above-mentioned approach consumes electric power badly. 
     Furthermore, when the line inversion driving approach is applied with “1×1” checker board signals which are generally utilized as testing signals in industries, a green color shift problem is occurred, as illustrated in  FIG. 2 . In  FIG. 2 , it is supposed that the LCD panel is in normally white (NW) mode and the common voltage V COM  is about 5V, and thus it is in biased state when each of the pixels is applied with about 0V or 10V. Consequently, pixels  214 ,  215 ,  216 ,  221 ,  222 ,  223 ,  234 ,  235 , and  236  are displayed with black (opaque, marked as “K”), and pixels  211 ,  212 ,  213 ,  224 ,  225 ,  226 ,  231 ,  232 , and  233 , marked with R (red), G (green) or B (blue), are light transmissible. Taking the first row and second for example, the electric voltage is varied from about 6V to 10V (increasing about 4V) between pixels  211  and  221 , and the electric voltage is varied from about 4V to 0V (decreasing about 4V) between pixels  212  and  222 . The above-mentioned variations of the electric voltages are in opposite trends and able to be balanced. Further, the electric voltage is varied from about 0V to 4V (increasing about 4V) between pixels  214  and  224 , and the electric voltage is varied from about 10V to 6V (decreasing about 6V) between pixels  215  and  225 . The above-mentioned variations of the electric voltages are also in opposite trends and thus able to be balanced. However, the electric voltage is varied from about 6V to 10V (increasing about 4V) between pixels  213  and  223 , and the electric voltage is varied from about 0V to 4V (increasing about 4V) between pixels  216  and  226 . Therefore, the above-mentioned variations of the electric voltages are in the same trend and thus not able to be balanced. Being balanced or not is related to the coupling effect caused by the voltage increasing of both pixels  213 / 223  and  216 / 226 , and the common voltage is thus lifted. Due to the increasing of the common voltage, the difference between the pixel  225  (green) and the common voltage is reduced. Thus, the voltage bias of the green pixel  225  is lowered, and the brightness of the green pixel  225  becomes stronger. In contrast, via the increasing of the common voltage, the differences between the pixel  224  (red)/pixel  226  (blue) and the common voltage are enlarged. Thus, the voltage biases of the red pixel  224  and blue pixel  226  are increased, and the brightness of each the red pixel  224  and blue pixel  226  becomes weaker. Thus, it results in the overall image showing green color shift (green color being excessive) under the checker board testing signals. The similar problems are happened in the second and the third rows. By the voltage decreasing of the pixel  223 / 233  and the pixel  226 / 236 , the common voltage is pulled down. Consequently, the brightness of the pixel  232  (green) is enlarged by a decreased voltage bias, the brightness of each the pixel  231  (red) and the pixel  233  (blue) is reduced by increased voltage biases. It results in the overall image showing green color shift under the checker board testing signals as well. 
     Therefore, it is needed to provide a method for driving LCD, for overcoming the existed problem of brightness unbalance and the problem of green color shift under the checker board testing signals, which providing unexpected effect in view of the prior art. 
     SUMMARY OF THE INVENTION 
     In one aspect of the embodiments, the present invention provides a method for driving liquid crystal display, utilizing a timing controller to send polarity control signals to a plurality of source drivers in a display panel. The method comprises: step (a), setting value of K; step (b), setting each of first pixels of 1 to R horizontal lines of frames F(2R−2) as first polarity, setting each of first pixels of R+1 to R+K horizontal lines of the frames F(2R−2) as second polarity, and alternating polarity of each of first pixels of every K horizontal lines thereafter of the frames F(2R−2) as alternate the first polarity and the second polarity, wherein R is natural number from 1 to K, and K is natural number which is smaller or equal to number of the horizontal lines subtracting 1; setting each of first pixels of 1 to R horizontal lines of frames F(2R−1) as the second polarity, setting each of first pixels of R+1 to R+K horizontal lines of the frames F(2R−1) as the first polarity, and alternating polarity of each of first pixels of every K horizontal lines thereafter of the frames F(2R−1) as alternate the second polarity and the first polarity; step (c), repeating step (b) while substituting R from 1 to K with interval of 1; and step (d), displaying the frames F(2R−2) and F(2R−1) according to sequence generated by comparing values of 2R−2 and 2R−1 substituted with different R. 
     In preferred embodiments of the present invention, the sequence is ascending order or descending order sequence. 
     In preferred embodiments of the present invention, the polarity control signals are AC control signals. 
     In preferred embodiments of the present invention, the method further comprises a frame initial position setting step, to present the frames F(2R−2) and F(2R−1) as F(n+(2R−2)) and F(n+(2R−1)), for identifying frame initial positions. 
     In preferred embodiments of the present invention, the method further comprises a frame recurring step, to reiteratively display frames for satisfying a renew frequency M while M&gt;K. 
     In preferred embodiments of the present invention, the method further comprises a horizontal line pixel distribution step, to set polarities of second pixels of each of the horizontal lines of the frames F(2R−2) and F(2R−1) as opposite to polarities of the first pixels, to set polarities of third pixels as opposite to the polarities of the second pixels, and to set polarities of pixels thereafter with the same pattern, for generating polarity distribution comprising alternate the first polarity and the second polarity; wherein if the first pixels are set as the first polarity, then the second pixels are set as the second polarity. 
     In preferred embodiments of the present invention, the method further comprises a polarity distribution setting step, for assigning add ones and even ones of the plurality of source drivers with polar driving signals and reverse polar driving signals. 
     In preferred embodiments of the present invention, the method further comprises an undercharging improving step, for changing the polarity of polarity control signals to be the same with polarity of the first pixels before the polarity of first pixels are generated. 
     In preferred embodiments of the present invention, the method further comprises an undercharging improving step comprising: providing a plurality of data storage unit; providing a data enable signal (or data initiating signal); storing polarity data of the first pixels of the first horizontal lines of the frames F(2R−2) and (2R−1) into first data storage unit of the plurality of data storage unit; setting first pixels of next horizontal lines of the frames F(2R−2) and F(2R−1) as identical to the first pixels of the first horizontal lines and storing into the first data storage unit; delaying start pulse vertical signal one unit time according to the data enable signal; storing polarity data of first pixels of second horizontal lines of the frames F(2R−2) and (2R−1) into second data storage unit of the plurality of data storage unit; transmitting data stored in the first data storage unit to the plurality of source drivers when the starting pulse vertical signal is started; transmitting data stored in the second data storage unit to the plurality of source drivers in next timing unit; and reiteratively storing polarity data of first pixels of horizontal lines thereafter to the plurality of data storage units, and transmitting the polarity data of first pixels of horizontal lines thereafter to the plurality of source drivers in the next timing unit. 
     In another aspect of the embodiments, the present invention provides a storage medium readable by a timing controller. The storage medium stores a program of instructions executable by the timing controller to perform a method for driving a panel of a liquid crystal display, for sending polarity control signals to a plurality of source drivers in the panel. The method comprises the steps mentioned above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  illustrate the timing diagram according to a prior art; 
         FIG. 2  illustrates the green color shift with “1×1” checker board testing signals according to a prior art; 
         FIGS. 3A-3F  illustrate the timing diagram of the driving method according to the embodiments of the present invention; 
         FIG. 4  illustrates the sequential diagram of the frames of the driving method according to the embodiments of the present invention; 
         FIGS. 5A-5D  illustrate the schematic diagram of the dynamically polarity inversion according to the embodiments of the present invention; 
         FIGS. 6A and 6B  illustrate the displaying frames under “1×1” checker board testing signals according to the embodiments of the present invention; and 
         FIGS. 7A and 7B  illustrate the schematic diagram of method for improving the undercharging problem according to the embodiments of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the embodiments of the present invention, an improved driving method for TFT-LCD is provided. The method utilizes a timing controller to transmit polarity control signals to a plurality of source drivers, for changing the polarity distribution of the liquid crystal molecules within the panel. An AC power is coupled to the timing controller for generating AC control signals.  FIGS. 3A-3F  illustrate the timing diagram of the improved driving method according to the embodiments of the present invention. In  FIG. 3A , it illustrates the information of STV  311 , CLKV  312 , RGB data  313 , and “1+K” polarity distribution signal  314 . In frame F(n+0), if the polarity of the first horizontal line is positive, then the polarities of the second to the “K+1” horizontal lines are negative, the polarities of the “K+2” to the “2K+1” horizontal lines are positive, and the other horizontal lines are distributed according to the same pattern, as shown in  FIG. 3A . In frame F(n+1), if the polarity of the first horizontal line is negative, then the polarities of the second to the “K+1” horizontal lines are positive, the polarities of the “K+2” to the “2K+1” horizontal lines are negative, and the other horizontal lines are distributed according to the same pattern, as shown in  FIG. 3B . Based on the illustration shown in  FIGS. 3A and 3B , frames of F(n+0) and F(n+1) form a polarity distribution “1+K” ( 314  and  324 ). In other words, the first horizontal line is given a first polarity, and every K lines thereafter changes to the second or to the first polarity, alternatively. Besides, the frames of F(n+0) and F(n+1) comprise opposite polarity distributions. 
       FIG. 3C  illustrates the frame F(n+2), which comprising information of STV  331 , CLKV  332 , RGB data  333 , and “2+K” polarity distribution signal  334 . If the polarities of the first to the second horizontal lines are positive, then the polarities of the third to the “K+2” horizontal lines are negative, the polarities of the “K+3” to the “2K+2” horizontal lines are positive, and the other horizontal lines are distributed according to the same pattern, as shown in  FIG. 3C .  FIG. 3D  illustrates the frame F(n+3), which comprising information of STV  341 , CLKV  342 , RGB data  343 , and “2+K” polarity distribution signal  334 . If the polarities of the first to the second horizontal line are negative, then the polarities of the third to the “K+2” horizontal lines are positive, the polarities of the “K+3” to the “2K+2” horizontal lines are negative, and the other horizontal lines are distributed according to the same pattern, as shown in  FIG. 3D . Based on the illustration shown in  FIGS. 3C and 3D , frames of F(n+2) and F(n+3) form a polarity distribution “2+K” ( 334  and  344 ). In other words, the first and second horizontal lines are given the first polarity, and every K lines thereafter changes to the second or to the first polarity, alternatively. Besides, the frames of F(n+2) and F(n+3) comprise opposite polarity distributions. 
       FIG. 3E  illustrates the frame F(n+(2K−2)), which comprising information of STV  351 , CLKV  352 , RGB data  353 , and “K” polarity distribution signal  354 . If the polarities of the first to the “K” horizontal lines are positive, then the polarities of the “K+1” to the “2K” horizontal lines are negative, the polarities of the “2K+1” to the “3K” horizontal lines are positive, and the other horizontal lines are distributed according to the same pattern, as shown in  FIG. 3E .  FIG. 3F  illustrates the frame F(n+(2K−1)), which comprising information of STV  361 , CLKV  362 , RGB data  363 , and “K” polarity distribution signal  364 . If the polarities of the first to the “K” horizontal lines are negative, then the polarities of the “K+1” to the “2K” horizontal lines are positive, the polarities of the “2K+1” to the “3K” horizontal lines are negative, and the other horizontal lines are distributed according to the same pattern, as shown in  FIG. 3F . Based on the illustration shown in  FIGS. 3E and 3F , frames of F(2K−2) and F(2K−1) form a polarity distribution “K” ( 354  and  364 ). In other words, the first to “K” horizontal lines are given the first polarity, and every K lines thereafter changes to the second or to the first polarity, alternatively. Besides, the frames of F(n+(2K−1)) and F(n+(2K−1)) comprise opposite polarity distributions. In above description, “n” means that the initial position to be selected, “n+1”, “n+2”, etc. refer to the sequential relationship, and “K” should be natural numbers. If the resolution of the panel is “1024×768”, the value of K should be smaller than or equal to “768−1”. For example, K can be assigned as “50”. Further, as shown in  FIGS. 3A and 3B , the polarity inversing positions in “1+K” mode (frame F(n+0) and F(n+1)) are at positions  315 / 325 ,  316 / 326 ,  317 / 327 ,  318 / 328 , and other positions beyond the illustration. Similarly, as shown in  FIGS. 3C and 3D , the polarity inversing positions in “2+K” mode (frame F(n+2) and F(n+3)) are at positions  335 / 345 ,  336 / 346 ,  337 / 347 ,  338 / 348 , and other positions beyond the illustration. Similarly, as shown in  FIGS. 3E and 3F , the polarity inversing positions in “K” mode (frame F(n+(2K−2)) and F(n+(2K−1))) are at positions  355 / 365 ,  356 / 366 ,  357 / 367 , and other positions beyond the illustration. In prior arts, the brightness at each of the polarity inversing positions are unbalanced due to undercharging. The problem is more critical in a panel with better specification such as resolution of “1920×1080” and renew frequency of “120” Hz. In prior arts, line inversion or multi-line inversion approach inverses the polarity at fixed line positions, thereby the capacitors at same positions are always being undercharged and the unbalance of brightness should be obvious. In contrast, in the embodiments of the present invention, utilizing the above-mentioned driving method that the polarity inversing positions are dynamically changed, the above-mentioned problem can be obviously alleviated. For example, in  FIGS. 3A and 3B , the polarities are inversed at positions  316 / 326 ,  317 / 327 ,  318 / 328 ,  319 / 329 , etc. In  FIGS. 3C and 3D , the polarities are inversed at positions  336 / 346 ,  337 / 347 ,  338 / 348 , etc. In  FIGS. 3E and 3F , the polarities are inversed at  356 / 366 ,  357 / 367 , etc. Accordingly, in dynamical polarity inversion comprising modes of “1+K”, “2+K”, “K”, etc., the polarity inversing positions are always switched with different positions, and thus the positions currently being undercharged can be immediately fully charged in the next mode. Further, the problem of brightness unbalance caused by undercharging of capacitors is eased by averaging effect upon the dynamically switching processes.  FIG. 4  shows the sequential diagram of the frames according to the embodiments of the present invention. In step  411 , frame F(n+0) is implemented. Then, in step  412 ,  421 ,  422 ,  431 ,  441 ,  442 , etc., F(n+1), F(n+2), F(n+3), F(n+4), F(n+5), F(n+6), etc. are implemented, respectively. Wherein step  431  may comprise implementing of F(n+4), F(n+5), F(n+6), and/or other possible candidates, and it is dependent on the predetermined value K. Further, frames F(n+0) and F(n+1) are classified as “1+K” (polarity distribution) mode  410 , frames F(n+2) and F(n+3) are classified as “2+K” mode, F(n+(2K−2)) and F(n+(2K−1)) are classified as “K” mode, and the possible candidates F(n+4) and F(n+5) are classified as  430  (other modes).  FIGS. 5A-5D  illustrate part of the displaying frame (comprising a plurality of pixels) in mode “1+K” and “2+K”. In  FIG. 5A , for example, the polarity distribution of the first vertical line which is marked with “F(n+0)” is arranged according to the “1+K” polarity distribution  314  shown in  FIG. 3A , and each of the pixels on the second vertical line are arranged with polarities opposite to each of the pixels on the first vertical line, respectively. The vertical lines thereafter are arranged according to the same pattern. 
     The description above may be alternatively represented as frames of F(2R−2) and F(2R−1), wherein R is natural number from 1 to K, and K is natural number which is smaller or equal to the horizontal line number of the panel minus one. This can be implemented by a method comprising: step (a), setting value of K; step (b), setting each of first pixels on 1 to R horizontal lines of frame F(2R−2) as positive polarity, setting each of first pixels on R+1 to R+K horizontal lines of frame F(2R−2) as negative polarity, and setting each of first pixels on every K lines thereafter as alternate positive and negative polarities; setting each of first pixels on 1 to R horizontal lines of frame F(2R−1) as negative polarity, setting each of first pixels on R+1 to R+K horizontal lines of F(2R−1) as positive polarity, and setting each of first pixels on every K lines thereafter as alternate negative and positive polarities; in step (c), repeating the step (b) while substituting R from 1 to K with interval of 1; and in step (d), displaying the frames F(2R−2) and F(2R−1) by sequence of comparing values of 2R−2 and 2R−1 substituted with different R. Further, via a frame initial position setting step (may be implemented as a frame initial position setting module), the frame initial position mark “n” is brought into frames F(2R−2) and F(2R−1) and represented as F(n+(2R−2)) and F(n+(2R−1)), for identifying initial positions of the frames. Furthermore, if the renew frequency of a TFT-LCD is setting as M (M&gt;K) frames per second, then the method further comprises a frame recurring step, to display the frames reiteratively for satisfying the renew frequency. The method may further comprise a horizontal line pixel distribution step (may be implemented by a horizontal line pixel distribution module), for setting the polarities of other pixels according to the first pixels of each of horizontal lines. For example, the polarity of the second pixel is opposite to the first pixel, the polarity of the third pixel is opposite to the second pixel, and so on. A distribution with alternate positive and negative polarities is generated. However, in other embodiments of the present invention, all the pixels on one horizontal line can be alternatively with the same polarity as omitting the above step. 
     In the embodiments of the present invention, a relative smaller K brings relative more times of polarity inversions, and the electric power consumption becomes higher. Therefore, in preferred embodiments of the present invention, a relative larger K, such as K≧50, is chosen for reducing the inversion times, for lowering the electric power consumption and the heat generated. However, it should be noted that in conditions of choosing relative larger K, the positions except for the polarity inversion positions (referring to continuous portions of the polarity inversion signal curve) may exhibit the behavior similar to those in line inversion approach. For preventing the green color shift problem under the checker board testing signals, in other embodiments of the present invention, the source drivers in an improved TFT-LCD are implemented as combinations of power of line (POL) and power of line reverse (POLR) polarity control signals. For example, the plurality of source drivers can be classified as odd source drivers and even source drivers, and the odd source drivers and the even source drivers may be provided with polar driving signals and reverse polar driving signals (may be implemented by coupling a NOT gate to part of the ends of the timing controller, for providing polar source drivers and reverse polar source drivers), respectively.  FIGS. 6A and 6B  show the displaying frames with “1×1” checker board testing signals according to the embodiments of the present invention, wherein the “R”, “G”, “B”, and “K” represent red, green, blue, and black, respectively.  FIG. 6A  illustrates the pixels driven by polar source driver. In the first and second rows illustrated in  FIG. 6A , the increased 4V from the pixel  6111  to the pixel  6121  is balanced with the decreased 4V from the pixel  6112  to the pixel  6122 . The increased 4V from the pixel  6114  to the pixel  6124  is balanced with the decreased 4V from the pixel  6115  to the pixel  6125  as well. One of the improvements of the embodiment is that the voltage increases from the pixel  6113  to the pixel  6123  and from the pixel  6116  to the pixel  6126  will not cause the green color shift problem. It is credited to the existence of voltage decreases from the pixel  6213  to the pixel  6223  and from the pixel  6216  to the pixel  6226  shown in  FIG. 6B  (driven by reverse polar driving signals), while the voltage changes among other pixels  6211 ,  6221 ,  6212 ,  6222 ,  6214 ,  6224 ,  6215 , and  6225  are balanced. Further, when the second row and the third row are considered, for example, the voltage changes of pixels  6121 ,  6131 ,  6122 , and  6132  are balanced, and the voltage changes of pixels  6124 ,  6134 ,  6125 , and  6135  are balanced as well. The left voltage decreases from pixels  6123  to  6133  and from pixels  6126  to  6136  can be balanced with the voltage increases from pixels  6223  to  6233  and from pixels  6226  to  6236 , as shown in  FIG. 6B . Therefore, the problem of green color shift is not happened. The above-mentioned solution can be implemented by a polarity distribution setting step, for setting the plurality of odd source drivers and even source drivers as opposite polarity distribution. 
     In other embodiments of the present invention, the undercharging problem at the first lines, marked as “1” in the RGB data  313 ,  323 ,  333 ,  343 ,  353 , and  363 , are solved by coupling two horizontal storage units, such as memories, to the timing controller, while the undercharging problem at other lines can be solved by the dynamically polarity inversion method mentioned above. Taking “1+K” polarity mode and the frame F(n+0) as example, the exemplary timing diagrams for improving the undercharging problem are shown in  FIGS. 7A and 7B . In  FIG. 7A , in addition to information of STV  701 , CLKV  702 , RGB data  703 , and “1+K” polarity distribution signal  704 , the diagram further comprises data enable (DE) signal (or data initiating signal)  750  which may be implemented by a signal generating module coupled to the timing controller. When the DE signal  750  is high (from position  705   a ), the polarity data of the first horizontal line (first horizontal data, for brevity) of the frame is stored within the first horizontal memory. The polarity data of the next horizontal line is then set to be the same with the original first horizontal data, and the first horizontal data to be transmitted to source driver is substituted with “V-Blanking” signal to delay a unit time “1H” for the STV  701 . At the second horizontal line position after the DE signal  750  is high, the original second horizontal data is stored within the second horizontal memory. Then, the STV  701  is enabled, for transmitting the data stored within the first horizontal memory to the source drivers, and then the data stored within the second horizontal memory is transmitted to the source drivers consequently. The processes of the third horizontal line and the horizontal lines thereafter follow the same way, for solving the undercharging problem at the first line of the panel by delaying the enable time. In other words, the horizontal lines  706   a  and  707   a , illustrated around the polarity inversing position  705   a , are originally distributed with opposite polarities, but the polarities of horizontal lines  706   b  and  707   b  are identical after the above-mentioned processes. Therefore, it is achieved for preventing inversing polarity at the position  705   b , and the undercharging problem is thus solved. 
     From the above description, it should be appreciated that the embodiments of the present invention implement a driving method by a driving device, for solving problems existed in driving circuit of the conventional LCD panel. For example, the brightness unbalance of lines, the green color shift problem with checker board testing signals, and the undercharging problem at the first horizontal lines can be solved. In addition, according to the embodiments of the present invention, the driving device does not cause apparently additional electric power consumption. Taking a 37″ TFT-LCD with resolution of “1920×1080” for example, if the total impedance of wiring of the source drivers is about 8.5 kohm, the total capacitance is about 200 nF, the number of source driver channels is about 720, and the driving voltage is room temperature (about 25° C.), the electric power consumption comparisons of the embodiment of the present invention to the conventional approaches are listed in TAB. 1. 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                 60 Hz 
                 120 Hz 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Power consumption  
                 Dot inversion 
                 419 
                 702 
               
               
                   
                 (mW) 
                 Conventional 
                 303 
                 470 
               
               
                   
                   
                 “1 + 2” line 
                   
                   
               
               
                   
                   
                 inversion 
                   
                   
               
               
                   
                   
                 Embodiment of the 
                 192 
                 247 
               
               
                   
                   
                 present invention  
                   
                   
               
               
                   
                   
                 (K = 50) 
                   
                   
               
               
                   
                 Temperature when  
                 Dot inversion 
                 95 
                 145 
               
               
                   
                 operating 
                 Conventional 
                 73 
                 101 
               
               
                   
                 (° C.) 
                 “1 + 2” line 
                   
                   
               
               
                   
                   
                 inversion 
                   
                   
               
               
                   
                   
                 Embodiment of the 
                 55 
                 64 
               
               
                   
                   
                 present invention 
                   
                   
               
               
                   
                   
                 (K = 50) 
               
               
                   
                   
               
             
          
         
       
     
     In some embodiments, a storage medium readable by a timing controller is provided. The storage medium stores a program of instructions executable by the timing controller to perform a method for driving a panel of a liquid crystal display, for sending polarity control signals to a plurality of source drivers in the panel. The method comprises the steps mentioned above. 
     The description above provides the preferred embodiments of the present invention. The present should be thoroughly understood by ordinary skill in the art via the teachings. However, it should be noted that the description above and the accompanying figures may not illustrate all the details, such as the detailed conventional components. However, it should be appreciated that the driving device for implementing the driving method should comprise but not limit to a control chip, an assembly of touch panel, a housing, and/or other related components. Relative software, hardware, and/or firmware should also be included. Some of them are not described in detail for purpose of being easier to be understood of the embodiments of the present invention. Furthermore, the scope of the present invention is intended to be defined by the following claims and the equivalents.