Abstract:
A driving method for a display including a source driver and at least one pixel is disclosed. The source driver is activated to provide a first data signal to the pixel. The first data signal includes a first pulse. The source driver is activated to provide a second data signal to the pixel. The second data signal includes a second pulse. The width of the first pulse is different from the width of the second pulse and a gray level is composed of the first and the second pulses.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority of Taiwan Patent Application No. 97148455, filed on Dec. 12, 2008, the entirety of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a driving method, and more particularly to a driving method for driving a display. 
         [0004]    2. Description of the Related Art 
         [0005]    Because cathode ray tubes (CRTs) are inexpensive and provide high definition, they are utilized extensively in televisions and computers. With technological development, new flat-panel displays are continually being developed. When a larger display panel is required, the weight of the flat-panel display does not substantially change when compared to CRT displays. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Driving methods for a display are provided. An exemplary embodiment of a driving method for an electro-wetting display (EWD) comprising a source driver and at least one pixel is described in the following. The source driver is activated to provide a first data signal to the pixel. The first data signal comprises a first pulse. The source driver is activated to provide a second data signal to the pixel. The second data signal comprises a second pulse. The width or the polarity of the first pulse is different from the width or the polarity of the second pulse. 
         [0007]    Another exemplary embodiment of a driving method for a display comprising a source driver and at least one pixel is described in the following. The source driver is activated to provide a first data signal to the pixel. The first data signal comprises a first pulse. The source driver is activated to provide a second data signal to the pixel. The second data signal comprises a second pulse. The width of the first pulse is different from the width of the second pulse and a gray level is composed of the first and the second pulses. 
         [0008]    Displays are also provided. An exemplary embodiment of an electro-wetting display (EWD) comprises at least one pixel, a gate driver, and a source driver. The gate driver provides a gate signal to the pixel. The source driver provides a first data signal and a second data signal to the pixel. The first data signal comprises a first pulse. The second data signal comprises a second pulse. The width or the polarity of the first pulse is different from the width or the polarity of the second pulse. 
         [0009]    Another exemplary embodiment of a display comprises at least one pixel, a gate driver, and a source driver. The gate driver provides a gate signal to the pixel. The source driver provides a first data signal and a second data signal to the pixel. The first data signal comprises a first pulse. The second data signal comprises a second pulse. The width of the first pulse is different from the width of the second pulse, and a gray level is composed of the first and the second pulses. 
         [0010]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention can be more fully understood by referring to the following detailed description and examples with references made to the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a schematic diagram of an exemplary embodiment of a display; 
           [0013]      FIG. 2A  shows a relationship between the data signal and the gray level; 
           [0014]      FIG. 2B  shows another relationship between the data signal and the gray level; 
           [0015]      FIGS. 3A˜3C  show other relationships between the data signal and the gray level; and 
           [0016]      FIGS. 4A and 4B  show other relationships between the data signal and the gray level. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0018]      FIG. 1  is a schematic diagram of an exemplary embodiment of a display. The display  100  may be a liquid crystal display (LCD), a plasma display panel (PDP), or an electro-wetting display (EWD). The EWD possess the favorable advantages of low power consumption, high response speed, high contrast, and high reflectivity. In this embodiment, the display  100  comprises a gate driver  110 , a source driver  120 , and pixels P 11 ˜P mn . 
         [0019]    The gate driver  110  provides scan signals SS 1 —SS n  to the pixels P 11 ˜P mn  via gate lines GL 1 ˜GL n . The source driver  120  provides data signals SD 1 ˜SD m  to the P 11 ˜P mn  via data lines DL 1 ˜DL m . The pixels P 11 ˜P mn  receive the data signals SD 1 ˜SD m  according to the scan signals SS 1 ˜SS n  and display the corresponding gray levels according to the data signals SD 1 ˜SD m . For clarity, the scan signal SS 1 , the data signal SD 1 , and the pixel P 11  are given as an example to describe the characteristic between the data signal SD 1  and the gray level displayed by the pixel P 11 . 
         [0020]    During a first period, the gate driver  110  activates the pixel P 11  via the scan signal SS 1 . Thus, the pixel P 11  displays a corresponding gray level according to the data signal SD 1 . At this time, the data signal SD 1  comprises a first pulse. During a second period, the gate driver  110  activates the pixel P 11  via the scan signal SS 1  again. Thus, the pixel P 11  displays another corresponding gray level according to the data signal SD 1  again. At this time, the data signal SD 1  comprises a second pulse. 
         [0021]    In one embodiment, if the display  100  is a EWD, the width or the polarity of the first pulse is different from the width or the polarity of the second pulse. For example, when the width of the first pulse is different from the width of the second pulse, the polarity of the first pulse is the same as the polarity of the second pulse. In this case, the first pulse corresponds to a first gray level and the second pulse corresponds to a second gray level. When the polarity of the first pulse is different from the polarity of the second pulse and the width of the first pulse is the same as the width of the second pulse, a gray level is composed of the first and the second pulses. 
         [0022]    In another embodiment, the width of the first pulse is different from the width of the second pulse and a gray level is composed of the first and the second pulses. The invention does not limit the width of the second pulse. The width of the second pulse may be longer than or shorter than the width of the first pulse. 
         [0023]      FIG. 2A  shows a relationship between the data signal and the gray level. The pulse width of the data signal is controlled to adjust the gray level. In this embodiment, the amount of the gray levels is 5. When a pixel receives a data signal and the data signal does not comprise a pulse, the pixel displays the gray level G 0 . When a pixel receives a data signal and the pulse of the data signal comprises a width W 1 , the pixel displays the gray level G 1 . When a pixel receives a data signal and the pulse of the data signal comprises a width W 2 , the pixel displays the gray level G 2 . When a pixel receives a data signal and the pulse of the data signal comprises a width W 3 , the pixel displays the gray level G 3 . When a pixel receives a data signal and the pulse of the data signal comprises a width W 4 , the pixel displays the gray level G 4 . In this embodiment, the relationship among the widths W 1 ˜W 4  is W 1 &lt;W 2 &lt;W 3 &lt;W 4 . In an embodiment, a multiple relationship exists among the widths W 1 ˜W 4 , but the disclosure is not limited thereto. 
         [0024]      FIG. 2B  shows another relationship between the data signal and the gray level. In this embodiment, when a pixel is required to display a gray level, a data signal received by the pixel is composed of positive pulses and negative pulses. The positive pulses and negative pulse are alternately arranged to increase the life of the pixel. For example, if the pixel P 11  is required to display the gray level G 1 , a data signal received by the pixel P 11  comprises the pulses  211  and  212 . The pulse  211  is a positive pulse and the pulse  212  is a negative pulse. The pulses  211  and  212  are alternately provided to the pixel P 11 . 
         [0025]    To define the polarity of the data signal, a common voltage is served as an offset. When a pulse is higher than the offset, the pulse is referred to as a positive pulse. In other words, the polarity of the pulse is positive. Oppositely, if a pulse is less than the offset, the pulse is referred to as a negative pulse. In other words, the polarity of the pulse is negative. In this embodiment, the common voltage comprises a direct current (DC) format. In some embodiments, the common voltage comprises an alternating current (AC) format. As shown in  FIG. 2B , the polarities of the pulses  211 ,  221 ,  231 , and  241  are positive and the polarities of the pulses  212 ,  222 ,  232 , and  242  are negative. 
         [0026]    Referring to  FIG. 2B , for the same gray level, a symmetrical relationship arises between the width of the positive pulse and the width of the negative pulse. For example, the width of the pulse  211  is the same as the width of the pulse  212 . The width of the pulse  221  is the same as the width of the pulse  222 . The width of the pulse  231  is the same as the width of the pulse  232 . The width of the pulse  241  is the same as the width of the pulse  242 . In other embodiments, an asymmetric relationship may arise between the width of the positive pulse and the width of the negative pulse. 
         [0027]    In this embodiment, the total width of the pulses  211  and  212  represents the gray level G 1 . The total width of the pulses  221  and  222  represents the gray level G 2 . The total width of the pulses  231  and  232  represents the gray level G 3 . The total width of the pulses  241  and  242  represents the gray level G 4 . 
         [0028]      FIG. 3A  shows another relationship between the data signal and the gray level. When the width of the pulse is controlled, the number of the gray levels can be increased. In this embodiment, a portion of the widths of the positive pulses are different from the corresponding widths of the negative pulse and another portion of the widths of the positive pulses are the same as the corresponding widths of the negative pulse. 
         [0029]    To clarify, the gray levels G 1 ˜G 3  are provided as an example. The total width of the pulses  311 A and  312 A represents the gray level G 1 . The total width of the pulses  321 A and  322 A represents the gray level G 2 . The total width of the pulses  331 A and  332 A represents the gray level G 3 . As shown in  FIG. 3A , the width of the pulse  311 A is the same as the width of the pulse  312 A. The width of the pulse  321 A is different from the width of the pulse  322 A. The width of the pulse  331 A is the same as the width of the pulse  332 A. 
         [0030]    In another embodiment, the width of the pulse  321 A may be the same as the width of the pulse  322 A and the width of the pulse  331 A may be different from the width of the pulse  332 A. In some embodiments, the width of each positive pulse may be different from the width of the corresponding negative pulse. 
         [0031]    Furthermore, for the gray levels G 1  and G 2 , the width of the pulse  311 A is the same as the width of the pulse  312 A and the width of the pulse  322 A is longer than the width of the pulse  312 A. For the gray levels G 2  and G 3 , the width of the pulse  331 A is longer than the width of the pulse  321 A and the width of the pulse  332 A is the same as the width of the pulse  322 A. The described width relationship between the positive pulse and the negative pulse is not limited thereto. Those skilled in the field can utilize other width relationships to replace the above width relationships. 
         [0032]      FIG. 3B  shows another relationship between the data signal and the gray level. In this embodiment, the width of the pulse  321 B is different from the width of the pulse  311 B and the width of the pulse  321 B is longer than the width of the pulse  322 B. Additionally, the width of the pulse  331 B is the same as the width of the pulse  321 B and the width of the pulse  331 B is different from the width of the pulse  322 B. 
         [0033]    In this embodiment, for the gray levels G 1  and G 2 , the width of the pulse  321 B is longer than the width of the pulse  311 B and the width of the pulse  322 B is the same as the width of the pulse  312 B. For the gray levels G 2  and G 3 , the width of the pulse  331 B is the same as the width of the pulse  321 B and the width of the pulse  332 B is longer than the width of the pulse  322 B. Similarly, those skilled in the field can utilize other width relationships to replace the width relationship as shown in  FIG. 3B . 
         [0034]      FIG. 3C  shows another relationship between the data signal and the gray level. In this embodiment, for the gray levels G 1  and G 2 , the width of the pulse  311 C is the same as the width of the pulse  321 C and the width of the pulse  322 C is longer than the width of the pulse  312 C. For the gray levels G 2  and G 3 , the width of the pulse  331 C is longer than the width of the pulse  321 C and the width of the pulse  332 C is the same as the width of the pulse  322 C. For the gray levels G 3  and G 4 , the width of the pulse  341 C is longer than the width of the pulse  331 C and the width of the pulse  342 C is the same as the width of the pulse  322 C. 
         [0035]    Referring to  FIGS. 2A˜3C , the pulses comprise the same amplitude, but the disclosure is not limited thereto. In other embodiment, the amount of the gray levels can be increased by adjusting the width or the amplitude of the pulse.  FIG. 4A  shows another relationship between the data signal and the gray level. The amplitudes of the positive and the negative pulses, which correspond to the gray levels G 1 , G 3 , and G 5 , are the same as the amplitudes of the positive and the negative pulses as shown in  FIG. 2B . 
         [0036]    Referring to  FIG. 4A , the width of the pulse  421 A is the same as the width of the pulse  411 A and the amplitude of the pulse  421 A is higher than the amplitude of the pulse  411 A. In some embodiments, the width of the pulse  421 A may be different from the width of the pulse  411 A and the amplitude of the pulse  421 A may be the same as the amplitude of the pulse  411 A. In this embodiment, the width of the pulse  422 A is the same as the width of the pulse  412 A and the amplitude of the pulse  422 A is higher than the amplitude of the pulse  412 A. 
         [0037]      FIG. 4B  shows another relationship between the data signal and the gray level. The relationship between the positive pulse and the corresponding negative pulse is shown in  FIG. 4B . Thus, the description is omitted. 
         [0038]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.