Abstract:
The present invention discloses a method of driving a 3D LCD. The 3D LCD includes N data lines and 2M scan lines. The driving method includes that scanning two adjacent scan lines of 2M scan lines once a time in order in a first scanning period while outputting data correspondent to a first frame to the N data lines, and turning even number of the 2M scanning lines on in order in a second scanning period while outputting data of a second frame to the N data lines, wherein the first frame is for user&#39;s one eye, and the second frame is for user&#39;s the other eye.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a liquid crystal display (LCD) and a driving method, more particularly, to a three-dimension (3D) LCD and a driving method. 
       DESCRIPTION OF THE PRIOR ART 
       [0002]    There are some advantages for a LCD, such as lightness, slimness, low energy consuming, which are widely used in modern information devices, like computer, mobile phone and personal digital assistant. A conventional LCD are assembled by a LCD panel and a backlight module. The LCD panel mainly comprises an array substrate, a color filter substrate and a liquid crystal layer sandwiched between the two substrates. The array substrate comprises pixel area formed by pixel arrays. 
         [0003]    There is a major trend for a 3D LCD capable of displaying 3D image because people have more and more demands for image display. The principle of 3D LCD shutter glasses is to use the concept of alternate-frame sequencing. The LCD alternates a left-eye frame and a right-eye frame in every 1/60 second and controls a switch of shutters in the glasses. The glasses blocks light for appropriate eye when the converse eye&#39;s image is displayed on the LCD, so that the left eye sees the left-eye frame and the right eye sees the right-eye frame. In the end, it synthesizes a 3D image in brain due to persistence and parallax of vision. 
         [0004]    Please refer to  FIG. 1 ,  FIG. 1  demonstrates a timing diagram of three conventional 3D displays. Generally speaking, there are three kinds of 3D displays. One is a 3D display alternately outputting left-eye and right-eye frames with 120 Hz frame rate, another one is a 3D display alternately outputting two left-eye frames and two right-eye frames with 240 Hz frame rate, and the other is a 3D display using black frame between a left-eye frame and aright-eye frame with 240 Hz frame rate. 
         [0005]    As the one skilled in the art is aware, a crosstalk function is used to evaluate the display quality of the 3D display, and is defined as follow: 
         [0000]      crosstalk=[L(WB)−L(BB)]/[L(BW)−L(BB)]  (1)
 
         [0000]    where L(WB) represents a lightness of the displaying image when the left-eye frame is white and the right-eye frame is black, L(BB) represents a measured lightness of the displaying image when the left-eye frame and the right-eye frame are black, and L(BW) represents a lightness of the displaying image when the left-eye frame is black and the right-eye frame is white, all the parameters are obtained by measuring the lightness of the display through right glass. The less crosstalk indicates that it is not visible to the left-eye frame for the right eye by means of the right glass, and results in a better 3D display quality. 
         [0006]    In hence, it is necessary to develop a 3D display having less crosstalk to upgrade 3D display quality. 
       SUMMARY OF THE INVENTION 
       [0007]    The object of the present invention is to provide a 3D LCD and a driving method for effectively decreasing crosstalk to improve the 3D display quality of the 3D LCD. 
         [0008]    According to the present invention, a method of driving a 3D LCD is provided. The 3D LCD comprises N data lines and 2M scan lines. The method comprises: sequentially turning on two adjacent scan lines of 2M scan lines once a time in a first scanning period while outputting data correspondent to a first frame to the N data lines; and sequentially turning on even number of the 2M scanning lines in a second scanning period while outputting data of a second frame to the N data lines. The first frame is viewed by user&#39;s one eye, and the second frame is viewed by user&#39;s the other eye. 
         [0009]    In one aspect of the present invention, the first scanning period is equal to the second scanning period. 
         [0010]    In another aspect of the present invention, the first scanning period is 1/240 second. 
         [0011]    In another aspect of the present invention, the second scanning period is 1/240 second. 
         [0012]    In another aspect of the present invention, the second scanning period is adjacent to the first scanning period. 
         [0013]    According to the present invention, a 3D LCD comprises: N data lines and 2M scan lines; a gate driving module for sequentially turning on two adjacent scan lines of 2M scan lines once a time in a first scanning period and sequentially turning even number of the 2M scanning lines on in order in a second scanning period; and a source driving module coupled to the N data lines for outputting data of a first frame in the first scanning period and data of a second frame to the N data lines in the second scanning period. The first frame is viewed by user&#39;s one eye, and the second frame is viewed by user&#39;s the other eye. 
         [0014]    In one aspect of the present invention, the first scanning period is equal to the second scanning period. 
         [0015]    In another aspect of the present invention, the first scanning period is 1/240 second. 
         [0016]    In another aspect of the present invention, the second scanning period is 1/240 second. 
         [0017]    In another aspect of the present invention, the second scanning period is adjacent to the first scanning period. 
         [0018]    The advantage of the present invention is that the 3D display is capable of decreasing crosstalk to improve 3D image display quality. It takes only half time for scanning a whole image because the present invention scans two scan lines once a time. In hence, the present invention just spends 1/240 second scanning an image when it drives at 120 Hz frame rate. 
         [0019]    These and other features, aspects and advantages of the present disclosure will become understood with reference to the following description, appended claims and accompanying figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  demonstrates a timing diagram of three conventional 3D displays. 
           [0021]      FIG. 2  illustrates a LCD panel. 
           [0022]      FIG. 3  shows a relation between transmittances of each of the region, the region and the region and time when the LCD panel scans at 120 Hz frame rate. 
           [0023]      FIG. 4  illustrates a crosstalk curve diagram of the LCD panel in the vertical direction. 
           [0024]      FIG. 5  illustrates another LCD panel. 
           [0025]      FIG. 6  shows a relation between liquid crystal transmittance of each of the region, the region and the region and time when the LCD panel scans at 240 Hz frame rate. 
           [0026]      FIG. 7  illustrates a crosstalk curve of the LCD panel in the vertical direction. 
           [0027]      FIG. 8  shows a diagram of a 3D LCD according to an embodiment of the present invention. 
           [0028]      FIG. 9  is a timing diagram of driving the 3D LCD. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    For better understanding embodiments of the present invention, the following detailed description taken in conjunction with the accompanying drawings is provided. Apparently, the accompanying drawings are merely for some of the embodiments of the present invention. Any ordinarily skilled person in the technical field of the present invention could still obtain other accompanying drawings without use laborious invention based on the present accompanying drawings. 
         [0030]    Referring to  FIG. 2 ,  FIG. 2  illustrates a LCD panel  200 . The LCD panel  200  scans at 120 Hz frame rate, in which a region  210 , a region  220  and a region  230  respectively stand for upper, middle and lower region of the LCD panel  200 . The direction of arrow in  FIG. 2  means the scanning direction of the LCD panel  200 . The LCD panel  200  generally scans from top to bottom. 
         [0031]    Referring to  FIG. 3  showing a relation between transmittances of each of the region  210 , the region  220  and the region  230  and time when the LCD panel  200  scans at 120 Hz frame rate, a line segment  211  means transmittance of the region  210 , a line segment  221  means transmittance of the region  220  and a line segment  231  means transmittance of the region  230 . The liquid crystal transmittance of the upper region  210 , the middle region  220  and the lower region  230  in the LCD panel  200  is much different from each other at the same time because it takes longer to scan from top to bottom when the LCD panel  200  scans at 120 Hz frame rate. Take a backlight of two regions for instance. On the one hand, the upper part (the region  210 ) is brighter and the lower part (the region  230 ) is darker in a white image because the transmittance of the upper part (the region  210 ) of the LCD panel  200  is higher than that of the lower part(the region  230 ) as it turns the backlight of the upper part on. On the contrary, the upper part(the region  210 ) is darker and the lower part (the region  230 ) is brighter because the transmittance of the upper part (the region  210 ) of the LCD panel  200  is lower than that of the lower part(the region  230 ) as it turns the backlight of the lower part on. On the other hand, the upper part(the region  210 ) is darker and the lower part (the region  230 ) is brighter in a black image because the transmittance of the upper part (the region  210 ) of the LCD panel  200  is lower than that of the lower part(the region  230 ) as it turns the backlight of the upper part on and vice versa. 
         [0032]    Referring to  FIG. 4 ,  FIG. 4  illustrates a crosstalk curve diagram of the LCD panel  200  in the vertical direction. The crosstalk of the LCD panel  200  in the vertical direction is lowest in the middle of the panel (correspondent to the region  220 ) and is relatively higher on top and bottom sides (correspondent to the region  210  and the region  230 ). 
         [0033]    Referring to  FIG. 5 ,  FIG. 5  illustrates another LCD panel  500 . The LCD panel  500  scans at 240 Hz frame rate, wherein a region  510 , a region  520  and a region  530  respectively stand for upper, middle and lower region of the LCD panel  500 . The direction of arrow in  FIG. 5  means the scanning direction of the LCD panel  500 . The LCD panel  500  generally scans from top to bottom. 
         [0034]    Referring to  FIG. 6  showing a relation between liquid crystal transmittance of each of the region  510 , the region  520  and the region  530  and time when the LCD panel  500  scans at 240 Hz frame rate, a line segment  511  means transmittance of the region  510 , a line segment  521  means transmittance of the region  520  and a line segment  531  means transmittance of the region  530 . Please pay attention that difference of the liquid crystal transmittance of the upper region  510 , the middle region  520  and the lower region  530  in the LCD panel  500  is not quite large at the same time because it takes shorter to scan from top to bottom when the LCD panel  500  scans at 240 Hz frame rate. Take a backlight of two regions for instance. On the one hand, the difference of brightness between the upper part (the region  210 ) and the lower part (the region  230 ) is not quite large in a white image because the transmittance of the lower part (the region  530 ) of the LCD panel  500  is lower than that of the upper part (the region  510 ), and the difference of the LCD panel  500  is smaller than that of the LCD panel  200  at 120 Hz as it turns the backlight of the upper part on. On the contrary, brightness between the upper part and the lower part is similar as it turns the backlight of the lower part on. 
         [0035]    On the other hand, brightness of the upper part (the region  510 ) and the lower part (the region  530 ) is not quite different from each other in a black image because the transmittance of the upper part and the lower part of the LCD panel  200  is low as it turns the backlight of the upper part on. On the contrary, brightness of the upper part (the region  510 ) and the lower part (the region  530 ) is not quite different from each other because the transmittance of the upper part and the lower part of the LCD panel  200  is low as it turns the backlight of the lower part on. 
         [0036]    Referring to  FIG. 7 ,  FIG. 7  illustrates a crosstalk curve of the LCD panel  500  in the vertical direction. The crosstalk distribution of the LCD panel  500  in the vertical direction is similar with that of the LCD panel  200 . The crosstalk is lowest in the middle of the panel (correspondent to the region  520 ) and is relatively higher on top and bottom sides (correspondent to the region  510  and the region  530 ). But please take a notice that comparing with  FIG. 4  and  FIG. 7 , the crosstalk of the LCD panel  500  is not only relatively lower than that of the LCD panel  200  but also the difference of the crosstalk between the top, bottom sides and the middle part is relatively smaller. 
         [0037]    That is the character the present invention uses to decrease crosstalk of a LCD panel. 
         [0038]    Please referring to  FIG. 8 ,  FIG. 8  shows a diagram of a 3D LCD  800  according to an embodiment of the present invention. The 3D LCD  800  comprises a gate driving module  810 , a data driving module  820  and a LCD panel  830 . The LCD panel  830  comprises the N number of data lines (D 1 ˜D N ) overlapped mutually and the 2M number of scan lines (G 1 ˜G 2M ). The gate driving module  810  is coupled to the scan lines G 1 ˜G M  and used for driving the scan lines in the LCD panel  830 . The data driving module  820  is coupled to the scan lines D 1 ˜D N  and used for outputting the data about being displayed to the data lines D 1 ˜D N . 
         [0039]    Please go on to refer to  FIG. 9 .  FIG. 9  is a timing diagram of driving the 3D LCD  800 . As  FIG. 9  shows, there are two periods of scanning period in the present invention, the first scanning period T 1  and the second scanning period T 2 . Please take a notice that the second scanning period T 2  is next to the first scanning period T 1 , and both correspond to 1/240 second in the embodiment. 
         [0040]    As the 3D LCD  800  has to mutually display left-eye frames and right-eye frames, it displays one of the images (like the left-eye frame) in the first scanning period T 1  and displays the other (like the right-eye frame) in the second scanning period T 2 . 
         [0041]    The operation in the present invention is: 
         [0042]    The gate driving module  810  scans two adjacent scan lines of the LCD panel  830  once a time in the first scanning period T 1  while the data driving module  820  is outputting the data correspondent to one image (such as the mentioned left-eye frame) to the data lines D 1 ˜D N . The driving method of the gate driving module  810  in the embodiment demonstrates in  FIG. 9  that it drives the scan lines G 1  and G 2  first, the scan lines G 3  and G 4  next and scans all the scan lines G 1 ˜G 2M  in the order of two adjacent scan lines as an unit. In the meantime, the data driving module  820  is outputting the data correspondent to one image (such as the mentioned left-eye frame) to the data lines D 1 ˜D N  to display the data of the whole image (such as the mentioned left-eye frame) in the LCD panel  830 . 
         [0043]    And then, the gate driving module  810  scans the even number of the scan lines (G 2 , G 4 , G 6  . . . G 2M ) of the LCD panel  830  once a time in the second scanning period T 2  while the data driving module  820  is outputting the data correspondent to one image (such as the mentioned right-eye frame) to the data lines D 1 ˜D N . The driving method of the gate driving module  810  in the embodiment demonstrates in  FIG. 9  that it drives the scan line G 2  first and the scan line G 4  next, and scans all even number of the scan lines G 2 , G 4 , G 6  . . . G 2M  in order. In the meantime, the data driving module  820  is outputting the data correspondent to one image (such as the mentioned right-eye frame) to the data lines D 1 ˜D N  to display the data of the whole image (such as the mentioned right-eye frame) in the LCD panel  830 . 
         [0044]    It is noted that the 3D LCD  800  just spends half of the time on scanning because the 3D LCD  800  scans two scan lines a time or half of the all scan lines. The driving method for the 3D LCD  800  that spends 1/240 second on scanning the first frame (the left-eye frame) or the second frame (the right-eye frame) in the embodiment is similar to that for the mentioned 240 Hz panel. Therefore, the transmittances of areas in the LCD panel  830  are more convergent, and the crosstalk of the LCD panel  830  is less than that of a LCD panel using 120 Hz frame rate, such that the uniformity of the LCD panel  830  is better than that of LCD panel using 120 Hz frame rate. 
         [0045]    It is not limited by the order in the present invention that the LCD  800  outputs the left-eye frame first and then the right-eye frame. In practical, the LCD  800  outputting the right-eye frame first and then the left-eye frame is also in the scope of the present invention. 
         [0046]    Compared with the prior art, the LCD  800  of the present invention has less crosstalk and better uniformity to upgrade 3D image quality. 
         [0047]    Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.