Patent Publication Number: US-2011063281-A1

Title: Pixel array and driving method thereof and flat panel display

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 98130910, filed Sep. 14, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a flat panel display. More particularly, the present invention relates to a half source driving (HSD) panel pixel array and a driving method thereof. 
     2. Description of Related Art 
     Along with development of large-scale display panels, in various pixel array structures of current liquid crystal display (LCD) panels, there is a so-called half source driving (HSD) structure. According to the HSD structure, a number of data lines can be reduced to a half, so that a price of a source driver is accordingly reduced. In detail, in a pixel array of the HSD structure, two adjacent sub-pixels share one data line, so that the number of the data lines can be reduced to a half. 
     However, in the HSD pixel array, to maintain a same frame frequency, reduction of the source drivers can result in a fact that a charge time of each of the sub-pixels (which is 8-9 us) is less than a half of that of a conventional structure (which is, 18-19 us). Therefore, a charge rate becomes an important issue. As a resolution of the pixel array increases, the charge time of the high resolution HSD pixel array becomes shorter. Regarding a 1600×900 resolution, the charge time of each of the sub-pixels is about 6-7 us, only. 
     The larger the size of the pixel array is, the longer the lengths of the data lines (which is also referred to as source lines) and scan lines (which is also referred to as gate lines) thereof are, and the more obvious a signal delay effect is. Since the charge time of the HSD pixel array is shorter than that of the conventional structure, the signal delay effect of the data line and the scan line generally may influence gray levels of a part of the sub-pixels. For example, at a tail end of the data line, a data line delay can lead to different charge rates of odd sub-pixels and even sub-pixels, so that a display defect of bright/dark lines is generated. Moreover, at a tail end of the scan line, a scan line delay leads to a result that a gate is not disabled during a polarity conversion, so that the defect of the bright/dark lines is generated due to a charge error of the even sub-pixels. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a pixel array and a driving method thereof, and a flat panel display using the driving method, so as to mitigate a display defect of bright/dark lines. 
     The present invention provides a pixel array including a first pixel row, a second pixel row, a plurality of data lines and a gate driving circuit. The first pixel row includes a first scan line, a second scan line, a plurality of first pixels, and a plurality of second pixels. The first pixels and the second pixels are disposed between the first scan line and the second scan line in interlace. The second pixel row includes a third scan line, a fourth scan line, a plurality of third pixels, and a plurality of fourth pixels. The third pixels and the fourth pixels are disposed between the third scan line and the fourth scan line in interlace. The data lines are correspondingly coupled to the first pixels, the second pixels, the third pixels and the fourth pixels. The gate driving circuit is electrically coupled to the first scan line, the second scan line, the third scan line and the fourth scan line. Wherein, in a first frame period, the gate driving circuit sequentially provides a driving signal to the first, the second, the fourth and the third scan lines. In a second frame period, the gate driving circuit sequentially provides the driving signal to the second, the first, the third and the fourth scan lines. 
     The present invention provides a driving method for the aforementioned pixel array. The driving method includes following steps. In a first frame period, a driving signal is sequentially provided to the first, the second, the fourth and the third scan lines. In a second frame period, the driving signal is sequentially provided to the second, the first, the third and the fourth scan lines. 
     The present invention provides a flat panel display including a half source driving (HSD) panel, a gate driving circuit and a source driving circuit. The HSD panel includes a plurality of data lines, an a-th pixel row and a b-th pixel row. The a-th and the b-th pixel rows respectively include a plurality of first pixels, a plurality of second pixels, a first scan line and a second scan line, wherein the first pixels and the second pixels are disposed between the first scan line and the second scan line in interlace. The data lines are correspondingly coupled to the first pixels and the second pixels. A gate control terminal of the first pixels is coupled to the first scan line, and a gate control terminal of the second pixels is coupled to the second scan line. The gate driving circuit is electrically coupled to the a-th pixel row and the b-th pixel row. In a first frame period, the gate driving circuit drives the a-th pixel row in a sequence of “the first can line, the second scan line”, and drives the b-th pixel row in a sequence of “the second scan line, the first scan line”. In a second frame period, the gate driving circuit drives the a-th pixel row in a sequence of “the second can line, the first scan line”, and drives the b-th pixel row in a sequence of “the first scan line, the second scan line”. The source driving circuit is coupled to the data lines, wherein the source driving circuit drives the data lines according to a timing of the gate driving circuit. 
     According to the pixel array, the driving method thereof, and the flat panel display using the driving method, in a same frame period, the uneven bright/dark pixels are arranged in interlace in space, so as to mitigate a display defect of vertical bright/dark lines. Regarding a same pixel, the uneven bright/dark pixel is alternately presented on timing, so as to avoid presenting fixed bright/dark points on an image. Therefore, according to the present invention, the display defect of the bright/dark lines occurred when the HSD pixel array is driven by the conventional technique can be mitigated. 
     In order to make the aforementioned and other features and advantages of the present invention comprehensible, several exemplary embodiments accompanied with figures are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
         FIG. 1  is a system block schematic diagram of a flat panel display according to an embodiment of the present invention. 
         FIG. 2  is a system block schematic diagram of a gate driving circuit of  FIG. 1  according to an embodiment of the present invention. 
         FIG. 3  is a timing diagram of signal waveforms of  FIG. 1  according to a first embodiment of the present invention. 
         FIG. 4  is a timing diagram of signal waveforms of  FIG. 1  according to a second embodiment of the present invention. 
         FIG. 5  is a timing diagram of signal waveforms of  FIG. 1  according to a fourth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  is a system block schematic diagram of a flat panel display  100  according to an embodiment of the present invention. Referring to  FIG. 1 , the flat panel display  100  includes a timing controller  110 , a source driving circuit  120 , a gate driving circuit  130  and a half source driving (HSD) panel  140 . In the present embodiment, the HSD panel  140  is a liquid crystal display (LCD) panel. According to a design requirement and a fabrication demand, the source driving circuit  120  and/or the gate driving circuit  130  can be disposed on a printed circuit board, a flexible circuit board, a glass substrate of the HSD panel  140 . For example, the gate driving circuit  130  of the present embodiment is disposed on the glass substrate of the HSD panel  140  to form a pixel array module. 
     The HSD panel  140  includes a plurality of pixel rows (four pixel rows are illustrated in  FIG. 1 , though the present invention is not limited thereto), a plurality of data lines (two data lines S 1  and S 2  are illustrated in  FIG. 1 , though the present invention is not limited thereto). The data lines S 1  and S 2  are coupled to the source driving circuit  120 . Base on a control of the timing controller  110 , the source driving circuit  120  correspondingly drives the data lines S 1  and S 2  according to the timing of the gate driving circuit  130 . 
     Each of the pixel rows includes two scan lines, a plurality of first pixels Pix 1 , and a plurality of second pixels Pix 2 . The first pixels Pix 1  and the second pixels Pix 2  are connected between the first scan line and the second scan line of the corresponding pixel row in interlace. The data lines S 1  and S 2  are coupled to the corresponding first pixels Pix 1  and the second pixels Pix 2 . Gate control terminals of the first pixel Pix 1  and the second pixels Pix 2  are respectively coupled to the first scan line and the second scan line of the corresponding pixel row. Taking a first pixel row as an example, input terminals of the first pixels Pix 1  and the second pixels Pix 2  connected between the first scan line G 1  and the second scan line G 2  in interlace are coupled to the corresponding data lines S 1  and S 2 . The first pixels Pix 1  belonged to the first pixel row are coupled to the first scan line G 1 , and the gate control terminals of the second pixels Pix 2  are coupled to the second scan line G 2 . Structures of the other pixel rows are substantially the same to the structure of the first pixel row. The pixels Pix 1  and Pix 2  are arranged on the HSD panel  140  in a matrix. 
     The gate driving circuit  130  is electrically connected to each of the pixel rows on the HSD panel  140 . In a first frame period, according to a control signal YSW output by the timing controller  110 , the gate driving circuit  130  drives one of or a plurality of the pixel rows (which is referred to as an a-th pixel row hereinafter) in a sequence of “the first scan line, the second scan line”, and drives another one of or a plurality of the pixel rows (which is referred to as a b-th pixel row hereinafter) in a sequence of “the second scan line, the first scan line”. Taking a third pixel row and a fourth pixel as an example, the gate driving circuit  130  drives the third pixel row in a sequence of “a scan line G 5 , a scan line G 6 ”, and drives the fourth pixel row in a sequence of “a scan line G 8 , a scan line G 7 ”. 
     In a second frame period, the gate driving circuit  130  drives the a-th pixel row in a sequence of “the second scan line, the first scan line”, and drives the b-th pixel row in a sequence of “the first scan line, the second scan line” according to the control signal YSW. Again, taking the third pixel row and the fourth pixel as an example, in the second frame period, the gate driving circuit  130  drives the third pixel row in a sequence of “the scan line G 6 , the scan line G 5 ”, and drives the fourth pixel row in a sequence of “the scan line G 7 , the scan line G 8 ”. 
     Regarding a certain pixel row (for example, the third pixel row of  FIG. 1 ), since the first scan line (for example, the scan line G 5 ) is first driven, and then the second scan line (for example, the scan line G 6 ) is driven, the pixels on the firstly driven scan line G 5  are probably insufficiently charged, and the pixels on the secondly driven scan line G 6  are sufficiently charged, so that the even pixels (for example, the pixels Pix 2 ) are relatively dark, and the odd pixels (for example, the pixels Pix 1 ) are relatively bright. Conversely, in the pixel row (for example, the fourth pixel row in  FIG. 1 ) adjacent to the above pixel row, since the second scan line (for example, the scan line G 8 ) is first driven, and then the first scan line (for example, the scan line G 7 ) is driven, the pixels on the scan line G 8  are probably insufficiently charged, so that the odd pixels (for example, the pixels Pix 1 ) are relatively dark, and the even pixels (for example, the pixels Pix 2 ) are relatively bright. Therefore, the uneven bright/dark pixels can be arranged in interlace in space, so as to avoid a situation that the bright pixels are all located at the odd (or even) columns, and accordingly a display defect of vertical bright/dark lines can be mitigated. 
     Regarding a certain pixel row (for example, the first pixel row in  FIG. 1 ), in the first frame period, since the first scan line (for example, the scan line G 1 ) is first driven, and then the second scan line (for example, the scan lien G 2 ) is driven, the pixels on the scan line G 1  are probably insufficiently charged, and the pixels on the scan line G 2  are sufficiently charged, so that the even pixels (for example, the pixels Pix 2 ) are relatively dark, and the odd pixels (for example, the pixels Pix 1 ) are relatively bright. Thereafter, in the second frame period, since the scan line G 2  is first driven, and then the scan line G 1  is driven, the pixels on the scan line G 2  are probably insufficiently charged, and the pixels on the scan line G 1  are sufficiently charged, so that the odd pixels Pix 1  are relatively dark, and the even pixels Pix 2  are relatively bright. Therefore, regarding a same pixel, the uneven bright/dark pixel is alternately presented on timing, so as to avoid presenting fixed bright/dark points on an image. Therefore, the display defect of the bright/dark lines occurred when the HSD pixel array is driven by the conventional technique can be mitigated. 
       FIG. 2  is a system block schematic diagram of the gate driving circuit  130  of  FIG. 1  according to an embodiment of the present invention. Referring to  FIG. 2 , the gate driving circuit  130  includes a plurality of shift registers  131 , a plurality of AND gates  132 , a plurality of buffers  133 , and a plurality of switches (only five switches are illustrated in  FIG. 1 , and four of which are marked as SW 1 -SW 4 , though the present invention is not limited thereto). The switches SW 1 -SW 4  respectively have a first, a second, a third and a fourth connecting terminals. According to a control of the control signal YSW, the first and the second connecting terminals are respectively connected to the third and the fourth connecting terminals, or the first and the second connecting terminals are respectively connected to the fourth and the third connecting terminals. The timing controller  110  provides a gate clock YCLK and a gate start pulse YDIO to the shift registers  131 . A plurality of output terminals of the shift register  131  outputs gate pulses according to a trigger timing of the gate clock YCLK. The gate pulses respectively pass through the gates  132 , the buffers  133  and the switches (for example, the switches SW 1 -SW 4 ), and are transmitted to the corresponding scan lines (for example, the scan lines G 1 -G 8 ) on the HSD panel  140 . The gates  132  can modify widths of the gate pulses according to an enable signal YOE output by the timing controller  110 . 
     Namely, under a control of the control signal YSW, the switch selectively couples an (a+1)-th output terminal and an (a+2)-th output terminal of the shift register  131  to the first and the second scan lines of the a-th pixel row on the HSD panel  140 , respectively, or selectively couples the (a+1)-th output terminal and the (a+2)-th output terminal to the second and the first scan lines of the a-th pixel row, respectively. Taking the first pixel row of the HSD panel  140  as an example, the first switch SW 1  respectively couples a first and a second output terminals of the shift register  131  to the scan lines G 1  and G 2 , or respectively couples the first and the second output terminals of the shift register  131  to the scan lines G 2  and G 1  according to the control signal YSW. Taking the second pixel row of the HSD panel  140  as an example, the second switch SW 2  respectively couples a third and a fourth output terminals of the shift register  131  to the scan lines G 3  and G 4 , or respectively couples the third and the fourth output terminals of the shift register  131  to the scan lines G 4  and G 3  according to the control signal YSW. Operations of the switches SW 3  and SW 4  can be deduced according to the operations of the switches SW 1  and SW 2 . 
     The aforementioned a-th pixel row and b-th pixel row can be respectively an odd pixel row and an even pixel row of the HSD panel  140 . According to a design requirement, any of the pixel rows on the HSD panel  140  can be regarded as the aforementioned a-th pixel row (or the b-th pixel row). Moreover, the aforementioned first frame period and the second frame period can be respectively an odd frame or an even frame. According to a design requirement, one or a plurality of frames can be regarded as the aforementioned first frame period (or the second frame period). Embodiments are provided below for further descriptions. 
     First Embodiment 
     In the present embodiment, a (2n+1)-th frame is regarded as the aforementioned first frame period, and a (2n+2)-th frame is regarded as the aforementioned second frame period, wherein n is an integer. Moreover, in the present embodiment, a (2 m+1)-th pixel row on the HSD panel  140  is regarded as the aforementioned a-th pixel row, and a (2 m+2)-th pixel row is regarded as the aforementioned b-th pixel row, wherein m is an integer. 
       FIG. 3  is a timing diagram of signal waveforms of  FIG. 1  according to an embodiment of the present invention. Referring to  FIG. 1  and  FIG. 3 , in the (2n+1)-th frame (for example, a frame Frame 1  or a frame Frame 3  in  FIG. 3 ), the gate driving circuit  130  provides a gate driving signal to the scan lines on the HSD panel  140  in a sequence of “the first scan line G 1 , the second scan line G 2 , the fourth scan line G 4 , the third scan line G 3 , . . . ”. Namely, the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(4m+1), G(4m+2), G(4m+4), G(4m+3)”. In the (2n+2)-th frame (for example, a frame Frame 2  or a frame Frame 4  in  FIG. 3 ), the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(4m+2), G(4m+1), G(4m+3), G(4m+4)”. 
     Second Embodiment 
     Similar to the first embodiment, the (2n+1)-th frame is regarded as the aforementioned first frame period, and the (2n+2)-th frame is regarded as the aforementioned second frame period. A difference between the present embodiment and the first embodiment is that a (4 m+1)-th pixel row on the HSD panel  140  is regarded as the aforementioned a-th pixel row, and a (4 m+3)-th pixel row is regarded as the aforementioned b-th pixel row. In the (2n+1)-th frame period, the (4 m+1)-th pixel row and the (4 m+2)-th pixel row on the HSD panel  140  are driven in a sequence of “the first scan line, the second scan line”, and the (4 m+3)-th pixel row and the (4 m+4)-th pixel row on the HSD panel  140  are driven in a sequence of “the second scan line, the first scan line”. In the (2n+2)-th frame period, the gate driving circuit  130  drives the (4 m+1)-th pixel row and the (4 m+2)-th pixel row in a sequence of “the second scan line, the first scan line”, and drives the (4 m+3)-th pixel row and the (4 m+4)-th pixel row in a sequence of “the first scan line, the second scan line”. Namely, in the present embodiment, eight scan lines are taken as a cycle. 
       FIG. 4  is a timing diagram of signal waveforms of  FIG. 1  according to an embodiment of the present invention. Referring to  FIG. 1  and  FIG. 4 , in the (2n+1)-th frame (for example, a frame Frame 1  or a frame Frame 3  in  FIG. 4 ), the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G 1 , G 2 , G 3 , G 4 , G 6 , G 5 , G 8 , G 7 , . . . ”. Namely, the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(8m+1), G(8m+2), G(8m+3), G(8m+4), G(8m+6), G(8m+5), G(8m+8), G(8m+7)”. In the (2n+2)-th frame (for example, Frame 2  or Frame 4  in  FIG. 4 ), the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(8m+2), G(8m+1), G(8m+4), G(8m+3), G(8m+5), G(8m+6), G(8m+7), G(8m+8)”. 
     Third Embodiment 
     Similar to the first embodiment, the (2n+1)-th frame is regarded as the aforementioned first frame period, and the (2n+2)-th frame is regarded as the aforementioned second frame period. A difference between the present embodiment and the first embodiment is that six pixel rows (i.e. 12 scan lines) are taken as a cycle. In the first frame period, the gate driving circuit  130  drives a (6 m+1)-th pixel row, a (6 m+2)-th pixel row and a (6m+5)-th pixel row on the HSD panel  140  in a sequence of “the first scan line, the second scan line”, and drives a (6m+3)-th pixel row, a (6m+4)-th pixel row and a (6m+6)-th pixel row on the HSD panel  140  in a sequence of “the second scan line, the first scan line”. In the (2n+2)-th frame period, the gate driving circuit  130  drives the (6m+1)-th pixel row, the (6m+2)-th pixel row and the (6m+5)-th pixel row in a sequence of “the second scan line, the first scan line”, and drives the (6m+3)-th pixel row, the (6m+4)-th pixel row and the (6m+6)-th pixel row in a sequence of “the first scan line, the second scan line”. 
     Namely, in the (2n+1)-th frame, the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G 1 , G 2 , G 3 , G 4 , G 6 , G 5 , G 8 , G 7 , G 9 , G 10 , G 12 , G 11 , . . . ”. Namely, the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(12m+1), G(12m+2), G(12m+3), G(12m+4), G(12m+6), G(12m+5), G(12m+8), G(12m+7), G(12m+9), G(12m+10), G(12m+12), G(12m+11)”. In the (2n+2)-th frame, the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(12m+2), G(12m+1), G(12m+3), G(12m+4), G(12m+5), G(12m+6), G(12m+7), G(12m+8), G(12m+10), G(12m+9), G(12m+11), G(12m+12)”. 
     Fourth Embodiment 
     Similar to the first embodiment, a (2m+1)-th pixel row on the HSD panel  140  is regarded as the aforementioned a-th pixel row, and a (2m+2)-th pixel row is regarded as the aforementioned b-th pixel row. A difference between the present embodiment and the first embodiment is that a (4n+1)-th frame and a (4n+2)-th frame are regarded as the aforementioned first frame period, and a (4n+3)-th frame and a (4n+4)-th frame are regarded as the aforementioned second frame period. Namely, in the present embodiment, 4 frames are taken as a cycle. 
       FIG. 5  is a timing diagram of signal waveforms of  FIG. 1  according to an embodiment of the present invention. Referring to  FIG. 1  and  FIG. 5 , in the (4n+1)-th frame and the (4n+2)-th frame (for example, the frame Frame 1  and the frame Frame 2  in  FIG. 5 ), the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G 1 , G 2 , G 4 , G 3 , G 5 , G 6 , G 8 , G 7 , . . . ”. Namely, the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(4m+1), G(4m+2), G(4m+4), G(4m+3)”. In the (4n+3)-th frame and the (4n+4)-th frame (for example, the frame Frame 3  and the frame Frame 4  in  FIG. 5 ), the gate driving circuit  130  provides the gate driving signal to the scan lines on the HSD panel  140  in a sequence of “G(4m+2), G(4m+1), G(4m+3), G(4m+4)”. 
     Implementations of the present invention are not limited to the above embodiments, and those with ordinary skill in the art can deduce other implementations according to the above disclosure. According to the above embodiments, the uneven bright/dark pixels can be arranged in interlace in space, so as to avoid a situation that the bright pixels are all located at the odd (or even) columns, and accordingly a display defect of vertical bright/dark lines can be mitigated. Regarding a same pixel, the uneven bright/dark pixel is alternately presented on timing, so as to avoid presenting fixed bright/dark points on an image. Therefore, the display defect of the bright/dark lines occurred when the HSD pixel array is driven by the conventional technique can be mitigated. According to the driving method disclosed by the aforementioned embodiments, regarding the high resolution HSD panel, a width of the gate driving signal (i.e. a gate pulse width) can be suitably increased without preserving too much margin for data line delay or scan line delay. Comparatively, in the conventional technique, to preserve enough margin for the data line delay or the scan line delay, the gate pulse width has to be excessively reduced, which may cause insufficient pixel charging, so that an image contrast is insufficient. 
     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.