Abstract:
The exemplary examples of the present invention provide a transmission interface and method thereof for reducing power consumption and electromagnetic interference. The transmission interface is used in the Liquid Crystal Display (LCD), and the LCD has x source drivers. The i th  source driver processes k i  transmission signals, wherein k i  is a natural number larger than 1, x is a natural number, and i is an integer from 1 to x. The transmission interface includes an encoding device. The encoding device receives 
     
       
         
           
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     transmission signal, and sets the differential value between the 
     
       
         
           
             
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     transmission signal, wherein j is an integer from 1 to x, and y j  is an integer from 2 to k j .

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority benefit of Taiwan application serial no. 97120791, filed on Jun. 4, 2008. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an internal transmission interface of a liquid crystal display (LCD) and method thereof and more particularly, to a transmission device for reducing power consumption and electromagnetic interference (EMI) and method thereof. 
         [0004]    2. Description of Related Art 
         [0005]    With the advancement in the fabrication technologies, thin LCDs have been widely used everywhere in daily life. Generally, there are a plurality of source drivers in an LCD, each of which is used to process a plurality of transmission signals (i.e. each source driver comprises a plurality of channels). Then, each source driver transmits the processed transmission signals to the LCD panel, thereby generating images. 
         [0006]    Referring to  FIG. 1 ,  FIG. 1  is an internal circuit diagram of a conventional LCD device  10 . The LCD device  10  comprises a timing controller  110 , an LCD panel  120 , a plurality of source drivers  130 , and a plurality of gate drivers  140 . The LCD panel  120  is coupled to the plurality of source drivers  130  and the plurality of gate drivers  140 . The timing controller  110  is coupled to the plurality of source drivers  130  and the plurality of gate drivers  140 . 
         [0007]    The timing controller  110  receives a plurality of image signals and generates a plurality of control signals for the plurality of source drivers  130  and the plurality of gate drivers  140 . The source drivers  130  receive the plurality of transmission signals transmitted from the timing controller  110 , wherein the plurality of transmission signals are equal to the plurality of image signals. Then, the gate drivers  140  and the source drivers  130  enable the LCD units inside the LCD panel  120  to emit light according to the plurality of control signals so as to generate images corresponding to the transmission signals. As described above, the LCD device  10  uses a conventional transmission interface in which the timing controller  110  simply transmits the image signals directly to each source driver  130 . Thus, if the image signal values stay the same consecutively, problems such as EMI and high power consumption may occur. 
         [0008]    Referring to  FIG. 2 ,  FIG. 2  is a schematic view of a gradient horizontal line  201  and values of a plurality of image signals  200  thereof. Suppose the resolution of the LCD panel  120  is 1024×768 pixels and each pixel is represented by 8 bits. Then, a gradient horizontal line  201  of gray scale values 0˜255 is as what is shown in  FIG. 2  and values of the plurality of image signals  200  are also as shown in  FIG. 2 . Each gray scale value is represented by four consecutive image signals. In the conventional transmission interface, the plurality of image signals  200  are simply transmitted directly to each source driver as a plurality of transmission signals. 
         [0009]    Suppose there are 8 source drivers, and each of which processes 128 image signals  200 . Then, the j th  source driver processes the image signal  200  of gray scale values [32·(j−1)]˜(32·j−1), wherein j is an integer between 1 and 8. After the image signals  200  of an entire gradient horizontal line have been transmitted to the source driver  130 , being incorporated with the control of the gate driver  140 , an entire gradient horizontal line may be displayed on the LCD. A whole image picture may be displayed with 768 repetitions of such an operation. 
         [0010]    In summary, when a conventional LCD transmits an image picture, the image signals at various points are directly set as transmission signals for transmission regardless of the transmission interface. Even if the image consists of continuous and identical image signals, each image signal is required to be completely re-transmitted. As a result, the conventional transmission interface may easily lead to serious EMI, resulting in transmission error. In addition, re-transmission of identical image signals results in excessive power consumption, which fails to follow the current trend in electronic products of low power consumption. 
       SUMMARY OF THE INVENTION 
       [0011]    The exemplary examples of the present invention provide a transmission interface and method thereof which is applicable in an LCD and reduces power consumption and EMI. The transmission interface and method thereof take advantage of the continuity of the picture data and transmits the differential values of image signals between neighboring points instead of transmitting the image signals at each point, thereby reducing power consumption and EMI effects during transmission. 
         [0012]    The exemplary example of the present invention provides a transmission interface which is applicable in an LCD and reduces power consumption and EMI. The LCD comprises x source drivers. The i th  source driver processes k i  transmission signals, wherein k i  is a natural number larger than 1, x is a natural number, and i is an integer from 1 to x. The transmission interface comprises an encoding device which receives 
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         [0000]    image signals. Then, the encoding device sets the 
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         [0000]    image signal as the 
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         [0000]    transmission signal, and sets the differential value between the 
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         [0000]    and the 
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         [0000]    image signals as the 
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         [0000]    transmission signal, wherein j is an integer from 1 to x, and y j  is an integer from 2 to k j . 
         [0013]    According to the exemplary example of the present invention, the abovementioned transmission interface further comprises a decoding device which is coupled to the encoding device. The decoding device is used to decode the 
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         [0000]    transmission signals output from the encoding device and to transmit the 
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         [0000]    transmission signals after decoding to the j th  source driver. The value of the 
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         [0000]    transmission signal after decoding remains unchanged and the decoded value of the 
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         [0000]    transmission signal becomes the sum of the 
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         [0000]    to the 
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         [0000]    transmission signals. 
         [0014]    According to the exemplary example of the present invention, the abovementioned transmission interface further comprises x decoding devices which are coupled to the encoding device. The j th  decoding device is used to decode the 
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         [0000]    transmission signals and to transmit the 
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         [0000]    transmission signals after decoding to the j th  source driver. The value of the 
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         [0000]    transmission signal after decoding remains unchanged and the decoded value of the 
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         [0000]    transmission signal becomes the sum of the 
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         [0000]    to the 
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         [0000]    transmission signals. 
         [0015]    According to the exemplary example of the present invention, the number of bits of the abovementioned transmission signals and the number of bits of the image signals are the same. When the differential value between the 
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         [0000]    image signal is a negative value, the 
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         [0000]    transmission signal uses a 2&#39;s complement of the differential value to represent each bit thereof. 
         [0016]    The exemplary example of the present invention provides a transmission method which is applicable in an LCD and reduces power consumption as well as EMI. The LCD comprises x source drivers. The i th  source driver processes k i  transmission signals, wherein k i  is a natural number larger than 1, x is a natural number, and i is an integer from 1 to x. The transmission method comprises the following steps: (a) receiving 
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         [0000]    image signal as the 
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         [0000]    transmission signal, wherein j is an integer from 1 to x; (c) setting the differential value between the 
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         [0000]    image signal and the 
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         [0000]    image signal as the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal, wherein y j  is an integer from 2 to k j . 
         [0017]    According to the exemplary example of the present invention, the above transmission method further comprises the following step: (d) decoding the 
         [0000]    
       
         
           
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         [0000]    transmission signals and transmitting the 
         [0000]    
       
         
           
             
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         [0000]    to the 
         [0000]    
       
         
           
             
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         [0000]    transmission signals after decoding to the j th  source driver, wherein the value of the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal remains unchanged after decoding and the value of the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal after decoding becomes the sum of the 
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         [0000]    to the 
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         [0000]    transmission signals. 
         [0018]    According to the exemplary example of the present invention, the number of bits of the abovementioned transmission signals and the number of bits of the image signals are the same. When the differential value between the 
         [0000]    
       
         
           
             
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         [0000]    image signal and the 
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         [0000]    image signal is a negative value, the 
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                   k 
                   j 
                 
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             th 
           
         
       
     
         [0000]    transmission signal uses a 2&#39;s complement of the differential value to represent each bit thereof. 
         [0019]    The exemplary example of the present invention further provides another transmission interface applicable in an LCD. The LCD comprises at least a source driver and the transmission interface comprises an encoding device. The source driver is used to process x transmission signals, wherein x is an integer larger than 1. The encoding device receives x image signals, encodes the first image signal of the x image signals as the first transmission signal, and encodes the differential value between the y th  image signal and the (y−1) th  image signal of the x image signals as the y th  transmission signal, so as to generate x transmission signals, wherein y is an integer from 2 to x. 
         [0020]    According to the exemplary example of the present invention, the abovementioned transmission interface further comprises a decoding device. The decoding device is coupled to the encoding device for decoding the x transmission signals received from the encoding device and transmitting the x transmission signals to the source driver. 
         [0021]    According to the exemplary example of the present invention, the number of bits of the abovementioned transmission signals and the number of bits of the image signals are the same. When the differential value between the y th  image signal and the (y−1) th  image signal is a negative value, the y th  transmission signal uses a 2&#39;s complement of the differential value to represent each bit thereof. 
         [0022]    The exemplary example of the present invention further provides another transmission method applicable in an LCD. The LCD comprises at least a source driver used to process x transmission signals, wherein x is an integer larger than 1. The transmission method comprises the following steps: (1) receiving x image signals; (2) encoding the first image signal of the x image signals as the first transmission signal; (3) encoding the differential value between the y th  image signal and the (y−1) th  image signal of the x image signals as the y th  transmission signal, wherein y is an integer from 2 to x. 
         [0023]    According to the exemplary example of the present invention, the above transmission method further comprises the following step: (4) decoding the x transmission signals and transmitting the x transmission signals to the source driver after decoding. 
         [0024]    According to the exemplary example of the present invention, the number of bits of the abovementioned transmission signals and the number of bits of the image signals are the same. When the differential value between the y th  image signal and the (y−1) th  image signal is a negative value, the y th  transmission signal uses a 2&#39;s complement of the differential value to represent each bit thereof. 
         [0025]    The exemplary example of the present invention further provides another transmission method applicable in an LCD. The LCD comprises at least one source driver, processing at least two transmission signals, and the transmission interface. First, at least two image signals are received. The first image signal of the two image signals is encoded as the first transmission signal of the two transmission signals. Then, the differential value between the first image signal and the second image signal of the two image signals is encoded as the second transmission signal of the two transmission signals. 
         [0026]    The transmission interface and method thereof take advantage of the continuity of the picture data and transmit the differential values of image signals between neighboring points instead of transmitting the image signals at each point, thereby reducing power consumption and EMI effects during transmission. Therefore, compared with the conventional transmission interface and method, the exemplary examples of the present invention provide a transmission interface and method with advantages such as low power consumption and low EMI. 
         [0027]    In order to make the aforementioned and other features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0029]      FIG. 1  is an internal circuit diagram of a conventional LCD device  10 . 
           [0030]      FIG. 2  is a schematic view of a gradient horizontal line  201  and values of a plurality of image signals  200  thereof. 
           [0031]      FIG. 3A  is a schematic view of a plurality of transmission signals when a conventional transmission interface is used to transmit a gradient horizontal line. 
           [0032]      FIG. 3B  is a schematic view of a plurality of transmission signals when a transmission interface provided in the exemplary example of the present invention is used to transmit a gradient horizontal line. 
           [0033]      FIG. 3C  is a concept schematic diagram of the calculation of a plurality of red transmission signals  310  in the exemplary example shown in  FIG. 3B . 
           [0034]      FIG. 4A  is a schematic view of a gray scale gradient horizontal line  400 . 
           [0035]      FIG. 4B  is a schematic view of a plurality of image signals of the gray scale gradient horizontal line  400 . 
           [0036]      FIG. 4C  is a schematic diagram of a plurality of red transmission signals  420  of the transmission interface according to the exemplary example of the present invention. 
           [0037]      FIG. 5A  is a block diagram of a transmission interface  560  provided in the exemplary example of the present invention and applied in an LCD device  50 . 
           [0038]      FIG. 5B  is a block diagram of a transmission interface  565  provided by another exemplary example of the present invention and applied in an LCD device  52 . 
           [0039]      FIG. 5C  is a block diagram of a transmission interface  570  provided by another exemplary example of the present invention and applied in an LCD device  51 . 
           [0040]      FIG. 6  is a flow chart of the steps of a transmission method provided in the exemplary example of the present invention. 
           [0041]      FIG. 7A  is a waveform diagram of image signals of an LCD device adopting a multi-point low differential signal interface. 
           [0042]      FIG. 7B  is a waveform diagram of transmission signals when a conventional transmission interface is used to transmit the image signals of  FIG. 7A . 
           [0043]      FIG. 7C  is a waveform diagram of transmission signals when a transmission interface provided in the exemplary example of the present invention is used to transmit the image signals of  FIG. 7A . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0044]    Referring to  FIG. 3A˜3C ,  FIG. 3A  is a schematic view of a plurality of transmission signals when a conventional transmission interface is used to transmit a gradient horizontal line.  FIG. 3B  is a schematic view of a plurality of transmission signals when a transmission interface provided in the exemplary example of the present invention is used to transmit a gradient horizontal line.  FIG. 3C  is a concept schematic diagram of the calculation of a plurality of red transmission signals  310  in the exemplary example shown in  FIG. 3B .  FIGS. 3A and 3B  are the situations under the assumption that a source driver may process 1024 transmission signals (i.e. a source driver has 1024*3 channels). The gray scale values of the gradient horizontal line are 0 to 255. The image signal at each point includes a red image signal, a green image signal, and a blue image signal. Thus, the values of the red image signal, green image signal, and blue image signal are a sequence of {0,0,0,0,1,1,1,1, . . . ,255,255,255,255}. In addition, the transmission signal at each point includes a red transmission signal, a green transmission signal, and a blue transmission signal. 
         [0045]    If a conventional transmission interface is used to transmit the abovementioned image signals of the gradient horizontal line, the transmission signals transmitted to the source driver are as shown in  FIG. 3A . The values of the red, green, and blue transmission signals  300 - 302  will be the same as those of the original red, green, and blue image signals, respectively. That is, they all are a sequence of {0,0,0,0,1,1,1,1, . . . ,255,255,255,255}. Therefore, when transmitting continuous image signals using the conventional interface, problems mentioned in the Description of Related Art may occur. 
         [0046]    If the transmission interface provided in the exemplary example of the present invention is used, the transmission signals transmitted to the source driver are as shown in  FIG. 3B  and  FIG. 3C . Because the image signals are continuous, the value of the first red transmission signal  310  is 0 and the value of the subsequent k th  red transmission signal  310  is the differential value between the k th  red image signal  320  and the (k−1) th  red image signal  320 . In addition, the values of the green transmission signals  311  and the blue transmission signals  312  may be deduced in the same manner. In this exemplary example, the values of the red, green, and blue transmission signals  310 ˜ 312  area sequence of {0,0,0,0,1,0,0,0,1, . . . ,1,0,0,0}. 
         [0047]    However, an LCD may include a plurality of source drivers. For example, an LCD may include 8 source drivers which can process 384 channels. Each source driver may process 128 transmission signals, each of which includes a red, green, and blue transmission signal. 
         [0048]    Referring to  FIGS. 4A˜4C ,  FIG. 4A  is a schematic view of a gray scale gradient horizontal line  400 .  FIG. 4B  is a schematic view of a plurality of image signals of the gray scale gradient horizontal line  400 .  FIG. 4C  is a schematic diagram of a plurality of red transmission signals  420  of a transmission interface provided in the exemplary example of the present invention. The gradient horizontal line  400  is a gray scale gradient horizontal line  400  of values 0˜255, of which the values of the plurality of image signals are shown in  FIG. 4B . The values of the plurality of red image signals  410 , the plurality of green image signals  411 , and the plurality of blue image signals  412  are all sequences of {0,0,0,0,1,1,1,1, . . . ,255,255,255,255}. 
         [0049]    Suppose the transmission interface provided by the present example is used in an LCD having eight source drivers and each source driver is capable of processing 128 transmission signals (i.e. having 384 channels). In other words, the p th  source driver receives the [128·(p−1)+1] th  to the (128·p) th  transmission signals, wherein p is an integer from 1 to 8. 
         [0050]    According to the above assumption, the transmission signals used in the transmission interface provided in the exemplary example of the present invention are as shown in  FIG. 4C . It should be noted that the transmission signals of the present invention are transmitted as the differential values of the image signals. Thus, for each source driver, the first signal received by each source driver has to be an initial value so that the following signals may be represented by the differential values. 
         [0051]    Therefore, the [128·(p−1)+1] th  red transmission signal  420  and the [128·(p−1)+1] th  red image signal  410  are the same and the [128·(p−1)+y] th  red transmission signal  420  is the differential value between the [128·(p−1)+y] th  red image signal  410  and the [128·(p−1)+y−1] th  red image signal  410 , wherein y is an integer from 2 to 128. 
         [0052]    For example, continuously referring to  FIG. 4C , according to the above equation, the 129 th  red transmission signal  420  and the 129 th  red image signal  410  are the same. This is because each source driver processes only 128 transmission signals. The 129 th  red transmission signal  420  is processed by a second source driver. In addition, the values of the green transmission signals and the blue transmission signals may be deduced in the same manner, which will not be further described herein. 
         [0053]    Next, referring to  FIG. 5A ,  FIG. 5A  is a block diagram of a transmission interface  560  provided by the exemplary example of the present invention and applied in an LCD device  50 . The transmission interface  560  comprises an encoding device  562  and a decoding device  561 . The encoding device  562  is between a timing controller  510  and a plurality of source drivers  530 . The decoding device  561  is between the plurality of source drivers  530  and the timing controller  510 . In the present exemplary example, the encoding device  562  is included in the timing controller  510 . 
         [0054]    The LCD device  50  comprises x source drivers  530 , wherein the i th  source driver processes k i  transmission signals, k i  is a natural number larger than 1, x is a natural number, and i is an integer from 1 to x. The encoding device  562  receives 
         [0000]    
       
         
           
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         [0000]    image signals from the timing controller  510 . Then, the encoding device  562  sets the 
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         [0000]    image signal as the 
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         [0000]    transmission signal and sets the differential value between the 
         [0000]    
       
         
           
             
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         [0000]    and the 
         [0000]    
       
         
           
             
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         [0000]    image signals as the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal, wherein j is an integer from 1 to x, and y j  is an integer from 2 to k j . 
         [0055]    The decoding device  561  is used to decode the 
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         [0000]    transmission signals output from the encoding device  562  and to transmit the 
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         [0000]    to 
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         [0000]    transmission signals after decoding to the j th  source driver. The value of the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal after decoding remains unchanged and the decoded value of the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal becomes the sum of the 
         [0000]    
       
         
           
             
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         [0000]    to the 
         [0000]    
       
         
           
             
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         [0000]    transmission signals. 
         [0056]    Generally, each source driver  530  processes the same number of transmission signals. In other words, k i  is equal to k i′+1  and i′ is an integer from 1 to (x−1). However, the transmission interface  560  provided in the exemplary example of the present invention is not limited to the case in which each source driver processes the same number of transmission signals. 
         [0057]    Furthermore, as described above, each image signal includes red, green, and blue image signals and each transmission signal includes red, green, and blue image signals. 
         [0058]    The case in which each source driver  530  processes the same number of transmission signals has been shown in  FIG. 4A˜4C . Another exemplary example in which two source drivers  530  process different number of transmission signals is illustrated below. Suppose the LCD device  50  has two source drivers and a plurality of image signals of a horizontal line are to be transmitted. The plurality of red image signals of the image signals are a sequence of {1,2,2,2,3,3,3,3}, the plurality of green image signals are a sequence of {0,0,0,2,2,2,2,2}, and the plurality of blue image signals are a sequence of {5,7,7,7,7,7,8,8}. 
         [0059]    If the first source driver  530  may process 5 transmission signals and the second source driver  530  may process 3 transmission signals. 
         [0060]    The first red transmission signal to the fifth red transmission signal are a sequence of {1,1,0,0,1} and the sixth red transmission signal to the eighth red transmission signal are a sequence of {3,0,0}. The first red transmission signal to the fifth red transmission signal are processed by the first source driver  530  and the sixth red transmission signal to the eighth red transmission signal are processed by the second source driver  530 . 
         [0061]    The first green transmission signal to the fifth green transmission signal are a sequence of {0,0,0,2,0} and the sixth green transmission signal to the eighth green transmission signal are a sequence of {2,0,0}. The first green transmission signal to the fifth green transmission signal are processed by the first source driver  530  and the sixth green transmission signal to the eighth green transmission signal are processed by the second source driver  530 . 
         [0062]    The first blue transmission signal to the fifth blue transmission signal are a sequence of {5,2,0,0,0} and the sixth blue transmission signal to the eighth blue transmission signal are a sequence of {7,1,0}. The first blue transmission signal to the fifth blue transmission signal are processed by the first source driver  530  and the sixth blue transmission signal to the eighth blue transmission signal are processed by the second source driver  530 . 
         [0063]    In the above exemplary example, the first red transmission signal to the fifth red transmission signal are a sequence of {1,1,0,0,1}. When decoding, except for that the first red image signal is equal to the first red transmission signal, the rest of the red image signals are the accumulated values of their preceding red transmission signals. Thus, the first red transmission signal to the fifth red transmission signal become a sequence of {1,2,2,2,3} after decoding and the first red transmission signal to the fifth red transmission signal after decoding are the same as the first red image signal to the fifth red image signal. 
         [0064]    The sixth red transmission signal to the eighth red transmission signal are a sequence of {3,0,0}. Therefore, when decoding, except for that the sixth red image signal is equal to the sixth red transmission signal, the rest of the red image signals are the accumulated values of their preceding red transmission signals. Thus, the sixth red transmission signal to the eighth red transmission signal become a sequence of {3,0,0} after decoding and the sixth red transmission signal to the eighth red transmission signal after decoding are the same as the sixth red image signal to the eighth red image signal. In addition, the same manners are applicable for the green transmission signals and the blue transmission signals, which will not be further described herein. 
         [0065]    It should be noted that the number of bits of the transmission signals and the number of bits of the image signals are the same. When the differential value between the 
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         [0000]    image signal and the 
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         [0000]    image signal is a negative value, the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal uses a 2&#39;s complement of the differential value to represent each bit thereof. 
         [0066]    Two neighboring image signals may be from high gray scale to low gray scale or from low gray scale to high gray scale so the variation range is from −255 to 255. Suppose image signals of 8 bits are used for transmission. The values of the image signals are 0˜255 so the differential values may be directly transmitted from low gray scale to high gray scale. However, from high gray scale to low gray scale, in order to accurately transmit the transmission signals without increasing the number of bits, 2&#39;s complements of the negative differential values are adopted to solve this problem. 
         [0067]    For example, if the differential value between two image signals is −127, then the value 129 is transmitted. Represented with a binary number, 127 is {0111 1111} and its 2&#39;s complement is {1000 0001}, i.e. 129. The decoding device  561  adds the values 127 and 129, takes the lowest 8 bits, discards the bits in excess of 8, and obtains the image signal with value 0. Represented with a binary number, the result of adding {0111 1111} and {1000 0001} is {1 0000 0000}. Take the 8 least significant bits and the result is 0. Therefore, if the differential value between signals is negative, a correct image signal may be decoded by transmitting a 2&#39;s complement value. 
         [0068]    Next, referring to  FIG. 5B ,  FIG. 5B  is a block diagram of a transmission interface  565  provided by another exemplary example of the present invention and applied in an LCD device  52 . In this exemplary example, the encoding device  566  is still included in the timing controller  510  and the decoding device  567  is included in the source driver  530 . The j th  decoding device  567  is used to decode the 
         [0000]    
       
         
           
             
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         [0000]    to the 
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         [0000]    transmission signals output from the encoding device  562  and to transmit the 
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         [0000]    to 
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         [0000]    transmission signals after decoding to the j th  source driver. The value of the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal after decoding remains unchanged and the decoded value of the 
         [0000]    
       
         
           
             
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         [0000]    transmission signal becomes the sum of the 
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         [0000]    to the 
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             th 
           
         
       
     
         [0000]    transmission signals. 
         [0069]    Next, referring to  FIG. 5C ,  FIG. 5C  is a block diagram of a transmission interface  570  provided by another exemplary example of the present invention and applied in an LCD device  51 . The difference between  FIG. 5C  and  FIG. 5B  lies in that the encoding device  577  is placed before the timing controller  510  while the encoding device  566  is placed at the back end of the timing controller  510 . Although the positions of the two encoding devices  577  and  566  are different, the principles are the same and will not be further described herein. In addition, the encoding device  577  may also be placed at the front end of the timing controller  510 . Simply speaking, those of ordinary skill in the art may apply the transmission interface provided in the exemplary example of the present invention in an LCD device and the position of the elements of the interface may vary according to design requirement. 
         [0070]    Next, referring to  FIG. 6 ,  FIG. 6  is a flow chart of the steps of a transmission method provided in the exemplary example of the present invention. The transmission method is used in an LCD which comprises x source drivers. The i th  source driver processes k i  transmission signals, wherein k i  is a natural number larger than 1, x is a natural number, and i is an integer from 1 to x. The transmission method comprises the following steps: (S 610 ) receiving 
         [0000]    
       
         
           
             ( 
             
               
                 ∑ 
                 
                   i 
                   = 
                   1 
                 
                 x 
               
                
               
                 k 
                 i 
               
             
             ) 
           
         
       
     
         [0000]    image signals; (S 620 ) setting the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 1 
               
               ] 
             
             th 
           
         
       
     
         [0000]    image signal as the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 1 
               
               ] 
             
             th 
           
         
       
     
         [0000]    transmission signal, wherein j is an integer from 1 to x; (S 630 ) setting the differential value between the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
               
               ] 
             
             th 
           
         
       
     
         [0000]    image signal and the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
                 - 
                 1 
               
               ] 
             
             th 
           
         
       
     
         [0000]    image signal as the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
               
               ] 
             
             th 
           
         
       
     
         [0000]    transmission signal, wherein y j  is an integer from 2 to k j ; (S 640 ) decoding the 
         [0000]    
       
         
           
             ( 
             
               
                 ∑ 
                 
                   i 
                   = 
                   1 
                 
                 x 
               
                
               
                 k 
                 i 
               
             
             ) 
           
         
       
     
         [0000]    transmission signals and transmitting the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 1 
               
               ] 
             
             th 
           
         
       
     
         [0000]    to the 
         [0000]    
       
         
           
             
               ( 
               
                 
                   ∑ 
                   
                     i 
                     = 
                     1 
                   
                   j 
                 
                  
                 
                   k 
                   i 
                 
               
               ) 
             
             th 
           
         
       
     
         [0000]    transmission signals after decoding to the j th  source driver, wherein the value of the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 1 
               
               ] 
             
             th 
           
         
       
     
         [0000]    transmission signal remains unchanged after decoding and the value of the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
               
               ] 
             
             th 
           
         
       
     
         [0000]    transmission signal after decoding becomes the sum of the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                         
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 1 
               
               ] 
             
             th 
           
         
       
     
         [0000]    to the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
               
               ] 
             
             th 
           
         
       
     
         [0000]    transmission signals. 
         [0071]    Certainly, the number of bits of the transmission signals and the number of bits of the image signals are the same. When the differential value between the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
               
               ] 
             
             th 
           
         
       
     
         [0000]    image signal and the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
                 - 
                 1 
               
               ] 
             
             th 
           
         
       
     
         [0000]    image signal is a negative value, the 
         [0000]    
       
         
           
             
               [ 
               
                 
                   ( 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         1 
                       
                       j 
                     
                      
                     
                       k 
                       i 
                     
                   
                   ) 
                 
                 - 
                 
                   k 
                   j 
                 
                 + 
                 
                   y 
                   j 
                 
               
               ] 
             
             th 
           
         
       
     
         [0000]    transmission signal uses a 2&#39;s complement of the differential value to represent each bit thereof. 
         [0072]    In addition, the number of transmission signals processed by each source driver may be the same or different. Each image signal includes red, green, and blue image signals and each transmission signal includes red, green, and blue image signals. 
         [0073]    Next, referring to  FIGS. 7A˜7C ,  FIG. 7A  is a waveform diagram of image signals of an LCD adopting a multiple low voltage differential signaling (MLVDS) interface.  FIG. 7B  is a waveform diagram of transmission signals when a conventional transmission interface is used to transmit image signals of  FIG. 7A .  FIG. 7C  is a waveform diagram of transmission signals when a transmission interface provided in the exemplary example of the present invention is used to transmit image signals of  FIG. 7A . 
         [0074]      FIG. 7A  illustrates the case when 6 transmission lines, each of 6 bits, are used for transmission. A signal CLK represents a clock signal. A transmission line LV 0  transmits the 6 bits  0 R 0 ˜ 0 R 5  of the first red image signal and the 6 bits  2 R 0 ˜ 2 R 5  of the third red image signal. A transmission line LV 1  transmits the 6 bits  0 G 0 ˜ 0 G 5  of the first green image signal and the 6 bits  2 G 0 ˜ 2 G 5  of the third green image signal. A transmission line LV 2  transmits the 6 bits  0 B 0 ˜ 0 B 5  of the first blue image signal and the 6 bits  2 B 0 ˜ 2 B 5  of the third blue image signal. 
         [0075]    A transmission line LV 3  transmits the 6 bits  1 R 0 ˜ 1 R 5  of the second red image signal and the 6 bits  3 R 0 ˜ 3 R 5  of the fourth red image signal. A transmission line LV 4  transmits the 6 bits  1 G 0 ˜ 1 G 5  of the second green image signal and the 6 bits  3 G 0 ˜ 3 G 5  of the fourth green image signal. A transmission line LV 5  transmits the 6 bits  1 B 0 ˜ 1 B 5  of the second blue image signal and the 6 bits  3 B 0 ˜ 3 B 5  of the fourth blue image signal. 
         [0076]    Suppose each of the red, green, and blue image signals is 1. When a conventional transmission interface is used, the waveform diagram of the transmission signals in the transmission lines LV 0 ˜LV 5  are as shown in  FIG. 7B . Each of the transmission lines LV 0 ˜LV 5  has to be toggled twice. Therefore, the transmission signals in the transmission lines LV 0 ˜LV 5  are toggled for a total of 12 times. 
         [0077]    When the transmission interface of the exemplification of the present invention is used, the waveform diagram of the transmission signals in the transmission lines LV 0 ˜LV 5  are as shown in  FIG. 7C . The transmission signals in the transmission lines LV 0 ˜LV 5  are toggled for a total of 3 times. Except for the first red, green, and blue transmission signals which are 1, the rest of the red, green, and blue transmission signals are 0. Hence, from the above exemplary example, the transmission interface provided in the one of the exemplary examples of the present invention has fewer toggles among the transmission signals and may reduce power consumption and EMI effects. 
         [0078]    In summary, the transmission interface and method provided in the exemplary examples of the present invention take the advantage of the continuity commonly found in image signals. Except for certain pixels for which complete image signals need to be transmitted, for the rest of the pixels, the differential values between neighboring pixels are transmitted. As such, variations of the transmission signals on the data bus may be reduced and thus save power consumption and decrease EMI effects during transmission. 
         [0079]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.