Abstract:
A liquid crystal (LC) cell and the liquid crystal display with the same are disclosed. The LC cell includes a first LC cell and a second LC cell arranged opposite to the first LC cell, wherein the first LC cell is a normally white cell, and the second LC cell is a normally black cell. A display brightness of the second LC cell is white when the display brightness of the first LC cell transforms from white to black. The display brightness of the first LC cell is white when the display brightness of the second LC cell transforms from black to white. By mixing the normally white cell and the normally black cell, the response time is enhanced. In addition, the tracking or blurring effects occurring for the moving objects are efficiently eliminated.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present disclosure relate to liquid crystal display (LCD) technology, and more particularly to a liquid crystal (LC) cell and the LCD with the same. 
         [0003]    2. Discussion of the Related Art 
         [0004]    Currently, LCDs have a strict requirement of response time, that is, the time the display brightness transforms from white to black or from black to white. Response time is a key factor when evaluating the display performance of the LCDs. The slow response time results in tracking effect for moving objects, such as moving ping-pong balls or fishing rods. In addition, edges of the image may be seriously blurred for the reason that the LCDs are hold-type displays. 
         [0005]    Many solutions have been conceived to overcome the above effects. For example, the structure of the LC is enhanced to obtain a better response time, increasing the refresh rate from 120 Hz to 240 Hz, over-driving or impulsive driving methods, and motion estimate and motion compensation (MEMC) technology. However, the above solutions may occupy a large amount of resources, such as memory or storage, and thus introduce side effects, such as reducing the brightness of the LCD. On the other hand, the response time is still not comparable to organic light-emitting diode (OLED) or Plasma displays. 
       SUMMARY 
       [0006]    The object of the claimed invention is to provide a mixed LC cell including a first LC cell and a second LC cell opposite to the first LCD cell. The first LC cell is the normally white cell, and the second LC cell is the normally black cell. 
         [0007]    In one aspect, a LC cell includes: a first LC cell and a second LC cell arranged opposite to the first LC cell, wherein the first LC cell is a normally white cell, and the second LC cell is a normally black cell. 
         [0008]    Wherein a display brightness of the second LC cell is white when the display brightness of the first LC cell transforms from white to black, and the display brightness of the second LC cell is black when the display brightness of the first LC cell transforms from black to white. 
         [0009]    Wherein the display brightness of the first LC cell is white when the display brightness of the second LC cell transforms from black to white, and the display brightness of the first LC cell is black when the display brightness of the second LC cell transforms from white to black. 
         [0010]    Wherein the display brightness of the first LC cell is white when the display brightness of the second LC cell transforms from black to white, and the display brightness of the first LC cell is black when the display brightness of the second LC cell transforms from white to black. 
         [0011]    Wherein the time period for the diving voltage of the first LC cell is the same with that of the second LC cell, the driving voltage of the first LC cell remains at a high level for a first high time period and remains at a low level for a first low time period, the driving voltage of the second LC cell remains at the high level for a second high time period and remains at the low level for a second low time period, when the first high time period equals the first low time period, the second high time period equals to a sum of the second low time period and a response time for which the display brightness of the second LC cell transforms from white to black. 
         [0012]    Wherein the LC cell includes a plurality of pixels arranged in a matrix form, and each of the pixels is driven by two gate lines and two data lines, a first gate line turns on a gate of a first transistor and a first data line provides data voltage to the pixels by a source of the first transistor when the display brightness of the LC cell transforms from white to black, and a second gate line turns on a gate of a second transistor and a second data line provides the data voltage to the pixel by a source of the second transistor when the display brightness of the LC cell transforms from black to white. 
         [0013]    In another aspect, a liquid crystal display includes: a liquid crystal (LC) cell and a backlight module arranged opposite to the LC cell, the backlight module supplies light to the LC cell, and the LC cell includes a first LC cell and a second LC cell arranged opposite to the first LC cell, wherein the first LC cell is a normally white cell, and the second LC cell is a normally black cell. 
         [0014]    Wherein a display brightness of the second LC cell is white when the display brightness of the first LC cell transforms from white to black, and the display brightness of the second LC cell is black when the display brightness of the first LC cell transforms from black to white. 
         [0015]    Wherein the display brightness of the first LC cell is white when the display brightness of the second LC cell transforms from black to white, and the display brightness of the first LC cell is black when the display brightness of the second LC cell transforms from white to black. 
         [0016]    Wherein the display brightness of the first LC cell is white when the display brightness of the second LC cell transforms from black to white, and the display brightness of the first LC cell is black when the display brightness of the second LC cell transforms from white to black. 
         [0017]    Wherein the time period for the diving voltage of the first LC cell is the same with that of the second LC cell, the driving voltage of the first LC cell remains at a high level for a first high time period and remains at a low level for a first low time period, the driving voltage of the second LC cell remains at the high level for a second high time period and remains at the low level for a second low time period, when the first high time period equals the first low time period, the second high time period equals to a sum of the second low time period and a response time for which the display brightness of the second LC cell transforms from white to black. 
         [0018]    Wherein the LC cell includes a plurality of pixels arranged in a matrix form, and each of the pixels is driven by two gate lines and two data lines, a first gate line turns on a gate of a first transistor and a first data line provides data voltage to the pixels by a source of the first transistor when the display brightness of the LC cell transforms from white to black, and a second gate line turns on a gate of a second transistor and a second data line provides the data voltage to the pixel by a source of the second transistor when the display brightness of the LC cell transforms from black to white. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1   a  is a schematic view of a normally white cell in accordance with one embodiment. 
           [0020]      FIG. 1   b  is a schematic view of a normally black cell in accordance with one embodiment. 
           [0021]      FIG. 2  is a waveform diagram of the normally white cell and the normally black cell. 
           [0022]      FIG. 3  is a schematic view of the mixed LC cell including the normally white cell and the normally black cell in accordance with one embodiment. 
           [0023]      FIG. 4  is a waveform diagram of the liquid crystal cell of  FIG. 3 . 
           [0024]      FIG. 5  is a block diagram of the pixel driving circuit of the LC cell of  FIG. 3 . 
           [0025]      FIG. 6  is a schematic view of the LCD in accordance with one embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0026]    Embodiments of the invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. 
         [0027]      FIG. 1   a  is a schematic view of a normally white cell in accordance with one embodiment.  FIG. 1   b  is a schematic view of a normally black cell in accordance with one embodiment. 
         [0028]    As shown in  FIG. 1   a , the normally white cell  10  includes an up substrate  111 , a down substrate  112 , liquid crystal (not shown) filled in the normally white cell  10 , an up polarizer  121 , and a down polarizer  122 . The up polarizer  121  and the down polarizer  122  respectively attach to an outer surface of the up substrate  111  and the down substrate  112 . The up polarizer  121  and the down polarizer  122  are for allowing only the polarized beams with a certain polarized direction to pass through. In addition, the polarized directions of the up polarizer  121  and the down polarizer  122 , as indicated by the solid and dashed arrow lines, are orthogonal to each other. When no voltage is applied, the beams radiated from a backlight module pass through such that the display brightness is white. When a voltage is applied, the beams irradiated from the backlight module are blocked such that the display brightness is black. Compared with  FIG. 1   a , the polarized directions of the up polarizer  121  and the down polarizer  122  of the normally black cell  11 , as indicated by the solid and dashed arrow lines, are parallel to each other. When no voltage is applied, the beams radiated from the backlight module are blocked such that the display brightness is black. When the voltage is applied, the beams pass through and the display brightness is white. 
         [0029]      FIG. 2  is a waveform diagram of the normally white cell and normally black cell.  FIG. 2   a  is a waveform diagram of the driving voltage  211 .  FIG. 2   b  is a waveform diagram showing the display brightness  212  of the normally white cell.  FIG. 2   c  is a waveform diagram showing the display brightness  212  of the normally black cell. In  FIG. 2 , x-axis represents the time, and y-axis represents the change of the display brightness. 
         [0030]    In order to illustrate the difference, the same driving voltage  211  is adopted to drive the normally white cell and the normally black cell. It is to be understood that other driving voltage may be adopted also. The driving voltage  211  may be a wave having a time period T, which indicates the time needed to display one frame for the normally white cell or the normally black cell. 
         [0031]    When the driving voltage  211  transforms from a low voltage to a high voltage along a rising edge, the display brightness  212  of the normally white cell transforms from the white to black. As the capacity of the liquid crystal and storage capacitor is huge, it takes time to accumulate the electrical charge. The above mentioned “time” is generally referred to as the “response time.” In  FIG. 2 , t 1  refers to the response time of the normally white cell. When the driving voltage  211  transforms from the high voltage to the low voltage along the falling edge, the display brightness  212  of the normally white cell transforms from black to white. Similarly, the discharging process also needs the same “response time” for transforming the black to white, which is indicated by t 2  in  FIG. 2 . It can be understood that the response time t 1  is smaller than the response time t 2  for the normally white cell. Thus, it takes longer for the normally white cell to transform from white to black than to transform from black to white. 
         [0032]    When the driving voltage  211  transforms from the low voltage to the high voltage along the rising edge, the display brightness  213  of the normally black cell transforms from the black to white. For the display brightness  213  of the normally black cell, the process of transforming from black to white needs the response time t 3 . When the driving voltage  211  transforms from the high voltage to the low voltage along the falling edge, the display brightness  213  of the normally black cell transforms from white to black. Similarly, the process of transforming from white to black needs the response time t 4 . It can be understood that the response time t 3  is smaller than the response time t 4  for the normally white cell. That is, it takes longer for the normally black cell to transform from white to black than to transform from black to white. 
         [0033]    In one embodiment, a mixed LC cell includes the normally white cell and the normally black cell. The white-to-black transformation is controlled by the normally white cell, and the black-to-white transformation is controlled by the normally black cell. It is to be noted that the response time of the mixed LC cell is shorter than the normally white cell or the normally black cell. 
         [0034]      FIG. 3  is a schematic view of the mixed LC cell. As shown, the mixed LC cell  30  includes a first LC cell  31  and a second LC cell  32  arranged opposite to the first LC cell  31 . The first LC cell  31  is the normally white cell of  FIG. 1   a , and the second LC cell  32  is the normally black cell of  FIG. 1   b . During the displaying process, the display brightness of the first LC cell  31  transforms from white to black, and that of the second LC cell  32  transforms from black to white. 
         [0035]    It is to be noted that the first LC cell  31  may be the normally black cell of  FIG. 1   b , and the second LC cell  32  may be the normally white cell of  FIG. 1   a.    
         [0036]      FIG. 4  is a waveform diagram of the liquid crystal cell of  FIG. 3 .  FIGS. 4   a  and  4   c  are waveform diagrams of the driving voltage  311 ,  321  respectively for the first LC cell  31  and the second LC cell  32 . In  FIG. 4 , x-axis represents the time, and y-axis represents the change of the voltage.  FIGS. 4   b  and  4   d  are waveform diagrams respectively showing the display brightness  312 ,  322  of the first LC cell  31  and the second LC cell  32 .  FIG. 4   e  is a waveform diagram showing the display brightness  301  of the mixed LC cell  30 . In  FIGS. 4   b ,  4   d  and  4   e , x-axis represents the time, and y-axis represents the change of the display brightness. 
         [0037]    As shown in  FIG. 4 , the driving voltage  311 ,  321  are waves having a time period T. The changes of the display brightness  301  of the LC cell  30  during one time period T will be described. When the driving voltage  311  transforms from the low voltage to the high voltage along the rising edge, the display brightness  312  of the first LC cell  31  transforms from white to black with the response time t 1 . At this moment, the driving voltage  321  is high, and the display brightness  322  of the second LC cell  32  is white. The transformation of the display brightness  301  of the mixed LC cell  30  is the same with that of the display brightness  312  of the first LC cell  31 , that is, the white-to-black transformation. And the response time is t 1 . When the driving voltage  321  transforms from the low voltage to the high voltage along the rising edge, the display brightness  322  of the second LC cell  32  transforms from black to white with the response time t 3 . At this moment, the driving voltage  321  is low, and the display brightness  312  of the first LC cell  31  is white. The transformation of the display brightness  301  of the mixed LC cell  30  is the same with that of the display brightness  322  of the second LC cell  32 , that is, the black-to-white transformation. And the response time is t 3 . 
         [0038]    When the driving voltage  311  transforms from the high voltage to the low voltage along the falling edge, the display brightness  312  of the first LC cell  31  transforms from black to white transformation with the response time t 2 . At this moment, the driving voltage  321  is low, and the display brightness  322  of the second LC cell  32  is black. The display brightness  301  of the mixed LC cell  30  is black. 
         [0039]    When the driving voltage  321  transforms from the high voltage to the low voltage along the falling edge, the display brightness  322  of the second LC cell  32  transforms from white to black with the response time t 4 . At this moment, the driving voltage  311  is high, and the display brightness  312  of the first LC cell  31  is black. The display brightness  301  of the mixed LC cell  30  is black. That is to say, when the driving voltage  311  is high or the driving voltage  321  is low, the display brightness  301  of the mixed LC cell  30  is black. On the other hand, when the driving voltage  311  is low or the driving voltage  321  is high, the display brightness  301  of the mixed LC cell  30  is white. 
         [0040]    The mixed LC cell  30  displays one frame within one time period T by adopting the above driving process. Comparing to the first LC cell  31  and the second LC cell  32 , the response time of the display brightness  301  of the mixed LC cell  30  is shortened. In addition, one black frame is inserted between two consecutive white frames when the mixed LC cell  30  displays. In this way, the impulsive driving method is accomplished and the display burin-in and blur effects are eliminated in an efficiency way. 
         [0041]    In the embodiment, the driving voltage  311  of the first LC cell remains at a high level for a first high time period t 11  and remains at a low level for a first low time period t 12 . The first high time period t 11  equals to the first low time period t 12 . The driving voltage  322  of the second LC cell remains at the high level for a second high time period t 21  and remains at the low level for a second low time period t 22 . The second high time period t 21  has to be shorter than the second low time period t 22 . Specifically, the second high time period t 21  equals to the second low time period t 22  and to the response time t 4  for which the display brightness  312  of the second LC cell  32  transforms from white to black. 
         [0042]    It is to be noted that the driving voltage  311  and the driving voltage  321  are independent. That is to say, the first LC cell  31  and the second LC cell  32  are independently controlled. As such, the time period of the driving voltage  311  and the driving voltage  321  may be different. In addition, the first high time period, the first low time period, the second high time period, and the second low time period of the driving voltage  311  and the driving voltage  321  may be adjusted. 
         [0043]      FIG. 5  is a block diagram of the pixel driving circuit of the LC cell of  FIG. 3 . As the same pixel driving circuit is adopted by the first LC cell  31  and the second LC cell  32 , only one driving circuit for one pixel (P) is taken as the illustrative example. In one embodiment, the first LC cell  31  and the second LC cell  32  includes a plurality of pixels (as shown in  FIG. 5 ) arranged in the matrix form. 
         [0044]    Referring to  FIGS. 5 and 3 , in order to efficiently charge the voltage to the plurality of pixels (P) in the first LC cell  31  and the second LC cell  32 , preferably, each of the pixel (P) is driven by two gate lines (G 1 , G 2 ) and two data lines (D 1 , D 2 ). A first gate line (G 1 ) turns on a gate of a first transistor (T 1 ) and a first data line (D 1 ) provides data voltage to the pixels (P) by a source of the first transistor (T 1 ) when the display brightness of the mixed LC cell  30  transforms from white to black. A second gate line (G 2 ) turns on a gate of a second transistor (T 2 ) and a second data line (D 2 ) provides the data voltage to the pixel (P) by a source of the second transistor (T 2 ) when the display brightness of the mixed LC cell  30  transforms from black to white. The response time of the pixel driving circuit matches the response time of the LC such that the mixed LC cell  30  obtains a quicker response. 
         [0045]      FIG. 6  is a schematic view of the LCD in accordance with one embodiment. 
         [0046]    Referring to  FIGS. 6 and 3 , a liquid crystal display  600  includes a mixed LC cell  30  and a backlight module  610  arranged opposite to the mixed LC cell  30 . The backlight module  610  supplies light to the mixed LC cell  30  such that the mixed LC cell  30  can display images. 
         [0047]    It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.