Abstract:
The present invention provides an array substrate. The array substrate includes a base substrate, a first metal layer, an insulating layer, and a second metal layer subsequently formed on the base substrate. The first metal layer is scan lines or charge sharing lines of the array substrate. The second metal layer is one of a source electrode and drain electrode of a charge sharing thin film transistor of the array substrate. The first metal layer, the second metal layer, and the insulating layer between them stack together to forma charge sharing capacitor of the array substrate. The present invention further provides the liquid crystal display panel and the liquid crystal display device with the above-mentioned array substrate. By means of array substrate, the present invention can increase the pixel aperture ratio.

Description:
FIELD 
       [0001]    The present invention relates to liquid crystal display technology, more particularly to an array substrate, a liquid crystal display panel, and its liquid crystal display device. 
       BACKGROUND 
       [0002]    In order to improve color shift phenomenon of the liquid crystal display (LCD) at large viewing angle, the prior art technology applies charge sharing pixel design. That is, one pixel is divided to a main pixel region and a sub pixel region. During displaying, the scanning line is charged and the charge sharing line is turned off, and the main pixel region and the sub pixel region are charged to the same electric potential. Then, the scanning line is turned off and the charge sharing line is turned on. Due to the effect of the charge sharing capacitor, the sub pixel region has a lower electric potential than the main pixel region. Different electric potentials make the liquid crystal molecules in these two regions to have different orientation, thus improving color shift at large viewing angle. However, one metal layer forming the charge sharing capacitor is the common electrode signal line in the display region. The shielding metal layer will occupy area of the display region, thus decreasing pixel aperture ratio. 
       SUMMARY 
       [0003]    In view of the above problem, the present invention provides an array substrate, a liquid crystal display panel, and a liquid crystal display device, in order to increase pixel aperture ratio. 
         [0004]    According to embodiments of the present invention, the array substrate includes a base substrate, a first metal layer, an insulating layer, and a second metal layer subsequently formed on the base substrate. The first metal layer is scan lines or charge sharing lines of the array substrate. The second metal layer is one of a source electrode and drain electrode of a charge sharing thin film transistor of the array substrate. The first metal layer, the second metal layer, and the insulating layer between them are stacked together to form a charge sharing capacitor of the array substrate. 
         [0005]    The array substrate is divided to a plurality of pixel units. Each of the pixel units includes a main pixel region, a sub pixel region, and a trace region between the two pixel regions. Each of the pixel units is connected to one of the scanning lines and one of the charge sharing lines. One of the scanning lines and one of the charge sharing lines are disposed side by side in the trace region. The first metal forming the charge sharing capacitor is the charge sharing line of the array substrate. 
         [0006]    The array substrate includes a plurality of the scanning lines along a row direction, and a plurality of the charge sharing lines. The pixel unit of the nth row is electrically connected to the scanning line of the nth row, and the second metal layer of the pixel unit of the nth row is insulated from and overlapped with the charge sharing line of the nth row, wherein n is a positive integer. 
         [0007]    The pixel unit of the array substrate is a Tri-gate structure, and the first metal forming the charge sharing capacitor is the scanning line. 
         [0008]    The array substrate includes a plurality of the scanning lines along row direction. The pixel unit of the mth row is electrically connected to the scanning line of the mth row, and the second metal layer of the pixel unit of the mth row is insulated from and overlapped with the scanning line of the (m+1)th row, wherein m is a positive integer. 
         [0009]    The array substrate further includes a plurality of data lines along a column direction, a first thin film transistor, a first storage capacitor, and a second thin film transistor and a second storage capacitor electrically connected to each other. In the first thin film transistor, a gate electrode is electrically connected to the scanning lines, a source electrode is electrically connected to the data lines, and a drain electrode is electrically connected to one end of the first storage capacitor. The other end of the first storage capacitor is electrically connected to a common electrode. In the second thin film transistor, a gate electrode is electrically connected to the scanning lines, a source electrode is electrically connected to the data lines, and a drain electrode is electrically connected to one end of the second storage capacitor. The other end of the second storage capacitor is electrically connected to the common electrode. In the charge sharing thin film transistor, a gate electrode is electrically connected to the charge sharing line, the other one of a source electrode and a drain electrode is electrically connected to the drain electrode of the second thin film transistor. 
         [0010]    The second metal layer forming the charge sharing capacitor is connected to the common electrode through a via hole. 
         [0011]    According to embodiments of the present invention, the liquid crystal display panel includes an array substrate, a color filter substrate opposite to the array substrate, and liquid crystal disposed between the array substrate and the color filter substrate. The array substrate includes a base substrate, a first metal layer, an insulating layer, and a second metal layer subsequently formed on the substrate. The first metal layer is scan lines or charge sharing lines of the array substrate. The second metal layer is one of a source electrode and drain electrode of a charge sharing thin film transistor of the array substrate. The first metal layer, the second metal layer, and the insulating layer between them are stacked together to form a charge sharing capacitor of the array substrate. 
         [0012]    The array substrate is divided to a plurality of pixel units. Each of the pixel units includes a main pixel region, a sub pixel region, and a trace region between the two pixel regions. Each of the pixel units is connected to one of the scanning lines and one of the charge sharing lines. One of the scanning lines and one of the charge sharing lines are disposed side by side in the trace region. The first metal forming the charge sharing capacitor is the charge sharing line of the array substrate. 
         [0013]    The array substrate includes a plurality of the scanning lines along a row direction, and a plurality of the charge sharing lines. The pixel unit of the nth row is electrically connected to the scanning line of the nth row, and the second metal layer of the pixel unit of the nth row is insulated from and overlapped with the charge sharing line of the nth row, wherein n is a positive integer. 
         [0014]    The pixel unit of the array substrate is a Tri-gate structure, and the first metal forming the charge sharing capacitor is the scanning line. 
         [0015]    The array substrate includes a plurality of the scanning lines along row direction. The pixel unit of the mth row is electrically connected to the scanning line of the mth row, and the second metal layer of the pixel unit of the mth row is insulated from and overlapped with the scanning line of the (m+1)th row, wherein m is a positive integer. 
         [0016]    The array substrate further includes a plurality of data lines along a column direction, a first thin film transistor, a first storage capacitor, and a second thin film transistor and a second storage capacitor electrically connected to each other. In the first thin film transistor, a gate electrode is electrically connected to the scanning lines, a source electrode is electrically connected to the data lines, and a drain electrode is electrically connected to one end of the first storage capacitor. The other end of the first storage capacitor is electrically connected to a common electrode. In the second thin film transistor, a gate electrode is electrically connected to the scanning lines, a source electrode is electrically connected to the data lines, and a drain electrode is electrically connected to one end of the second storage capacitor. The other end of the second storage capacitor is electrically connected to the common electrode. In the charge sharing thin film transistor, a gate electrode is electrically connected to the charge sharing line, the other one of a source electrode and a drain electrode is electrically connected to the drain electrode of the second thin film transistor. 
         [0017]    The second metal layer forming the charge sharing capacitor is connected to the common electrode through a via hole. 
         [0018]    According to embodiments of the present invention, the liquid crystal display device includes a liquid crystal display panel and a light source module providing light to the liquid crystal display panel. The liquid crystal display panel includes an array substrate, a color filter substrate opposite to the array substrate, and liquid crystal disposed between the array substrate and the color filter substrate. The array substrate includes a base substrate, a first metal layer, an insulating layer, and a second metal layer subsequently formed on the substrate. The first metal layer is scan lines or charge sharing lines of the array substrate. The second metal layer is one of a source electrode and drain electrode of a charge sharing thin film transistor of the array substrate. The first metal layer, the second metal layer, and the insulating layer between them are stacked together to form a charge sharing capacitor of the array substrate. 
         [0019]    The array substrate is divided to a plurality of pixel units. Each of the pixel units includes a main pixel region, a sub pixel region, and a trace region between the two pixel regions. Each of the pixel units is connected to one of the scanning lines and one of the charge sharing lines. One of the scanning lines and one of the charge sharing lines are disposed side by side in the trace region. The first metal forming the charge sharing capacitor is the charge sharing line of the array substrate. 
         [0020]    The array substrate includes a plurality of the scanning lines along a row direction, and a plurality of the charge sharing lines. The pixel unit of the nth row is electrically connected to the scanning line of the nth row, and the second metal layer of the pixel unit of the nth row is insulated from and overlapped with the charge sharing line of the nth row, wherein n is a positive integer. 
         [0021]    The pixel unit of the array substrate is a Tri-gate structure, and the first metal forming the charge sharing capacitor is the scanning line. 
         [0022]    The array substrate includes a plurality of the scanning lines along row direction, the pixel unit of the mth row is electrically connected to the scanning line of the mth row, and the second metal layer of the pixel unit of the mth row is insulated from and overlapped with the scanning line of the (m+1)th row, wherein m is a positive integer. 
         [0023]    The array substrate further includes a plurality of data lines along a column direction, a first thin film transistor, a first storage capacitor, and a second thin film transistor and a second storage capacitor electrically connected to each other. In the first thin film transistor, a gate electrode is electrically connected to the scanning lines, a source electrode is electrically connected to the data lines, and a drain electrode is electrically connected to one end of the first storage capacitor. The other end of the first storage capacitor is electrically connected to a common electrode. In the second thin film transistor, a gate electrode is electrically connected to the scanning lines, a source electrode is electrically connected to the data lines, and a drain electrode is electrically connected to one end of the second storage capacitor. The other end of the second storage capacitor is electrically connected to the common electrode. In the charge sharing thin film transistor, a gate electrode is electrically connected to the charge sharing line, the other one of a source electrode and a drain electrode is electrically connected to the drain electrode of the second thin film transistor. The second metal layer forming the charge sharing capacitor is connected to the common electrode through a via hole. 
         [0024]    According to embodiments of the present invention, in the array substrate, the liquid crystal display panel and the liquid crystal display device, the second metal layer forming the charge sharing capacitor is insulated from and overlapped with the charge sharing line or the scanning line. Since the charge sharing line or the scanning line is originally located in the non-display region, the second metal line with shielding will not occupy area of the display region, thus increasing the pixel aperture ratio. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a cross-sectional view of the liquid crystal display panel according to an embodiment of the present invention; 
           [0026]      FIG. 2  is a schematic diagram showing the pixel structure of the liquid crystal display panel of  FIG. 1  according to an embodiment; 
           [0027]      FIG. 3  is a schematic diagram showing one pixel unit of  FIG. 2 ; 
           [0028]      FIG. 4  is an equivalent circuit diagram of the pixel structure of  FIG. 3 ; 
           [0029]      FIG. 5  is a structural cross-sectional view of the array substrate of  FIG. 1 , taken along line A-A of  FIG. 3 ; 
           [0030]      FIG. 6  is a schematic diagram showing one pixel unit with Tri-gate structure according to the present invention; 
           [0031]      FIG. 7  is a structural cross-sectional view taken along line B-B of  FIG. 6 ; and 
           [0032]      FIG. 8  is a schematic diagram showing the liquid crystal display device according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    In the following, the technology in the embodiments of the present invention will be described in detail by incorporating the appended figures and embodiments. 
         [0034]      FIG. 1  is a cross-sectional view showing a liquid crystal display panel according to an embodiment of the present invention.  FIG. 2  is a schematic diagram showing a pixel structure of the liquid crystal display panel of  FIG. 1 . Referring to  FIG. 1  and  FIG. 2 , the liquid crystal display panel  10  includes a color filter substrate (CF substrate)  11 , an array substrate (a thin film transistor substrate; TFT substrate)  12  disposed opposite to the CF substrate, and a liquid crystal layer  13  filled between the two substrates. The array substrate  12  includes a plurality of data lines D along a column direction, a plurality of scanning lines G along a row direction, and a plurality of pixel units P defined by the plurality of scanning lines G and the plurality of data lines D. Each pixel unit P is connected to a corresponding data line and a corresponding scanning line G. Each scanning line G is connected to a gate driver  21  to provide scanning voltage to each pixel unit P. Each data line D is connected to a source driver  22  to provide gray level voltage to each pixel unit P. 
         [0035]    The pixel units P are disposed in an array arrangement and have the same structure. Therefore, in the following, one pixel unit  30 , as shown in  FIG. 3 , located on the nth row is taken for an example for explanation, wherein n is a positive integer. 
         [0036]    Referring to  FIG. 3 , the pixel unit  30  includes a main pixel region  31 , a sub pixel region  32 , and a trace region  33  located between the main pixel  31  and the sub pixel  32 . The pixel unit  30  is electrically connected to the scanning line Gn on the nth row and the charge sharing line Ln on the nth row respectively. The scanning line Gn and the charge sharing line Ln are arranged parallel in the trace region  33 . 
         [0037]      FIG. 4  is an equivalent circuit diagram of the pixel structure of  FIG. 3 . Referring to  FIG. 4 , the array substrate  12  includes a charge sharing thin film transistor Tcs, a charge sharing capacitor Cst 3 , a first thin film transistor Tmain, a storage capacitor Cst 1 , a first liquid crystal capacitor Clc 1 , a second thin film transistor Tsub, a second storage capacitor Cst 2 , and a second liquid crystal capacitor Clc 2 , wherein: 
         [0038]    the first liquid crystal capacitor Clc 1  is formed by a pixel electrode located in the main pixel region  31 , a common electrode of the liquid crystal display panel  10 , and the liquid crystal layer  13  between them; 
         [0039]    the second liquid crystal capacitor Clc 2  is formed by a pixel electrode located in the sub pixel region  32 , the common electrode of the liquid crystal display panel  10 , and the liquid crystal layer  13  between them; 
         [0040]    the first storage capacitor Cst 1  is formed by a source electrode or drain electrode of the charge sharing thin film transistor Tcs of the thin film transistor substrate  12 , the common electrode of the liquid crystal display panel  10  of the main pixel region  31 , and an insulating layer between them; 
         [0041]    the second storage capacitor Cst 2  is formed by a source electrode or drain electrode of the charge sharing thin film transistor Tcs of the thin film transistor substrate  12 , the common electrode of the liquid crystal display panel  10  of the sub pixel region  32 , and an insulating layer between them; 
         [0042]    the gate electrode of the first thin film transistor Tmain is electrically connected to the scanning line Gn, the source electrode is electrically connected to the data line D, the drain electrode is electrically connected to an end of the first storage capacitor Cst 1 , the other end of the first storage capacitor Cst 1  is electrically connected to the common electrode of the liquid crystal display panel  10 ; 
         [0043]    the gate electrode of the second thin film transistor Tsub is electrically connected to the scanning line Gn, the source electrode is electrically connected to the data line D, the drain electrode is electrically connected to an end of the second storage capacitor Cst 2 , the other end of the second storage capacitor Cst 2  is electrically connected to the common electrode of the liquid crystal display panel  10 ; 
         [0044]    the gate electrode of the charge sharing thin film transistor Tcs is electrically connected to the charge share line Ln, one of the source electrode and the drain electrode is electrically connected to the drain electrode of the second thin film transistor Tsub, the other of the source electrode and the drain electrode is electrically connected to one end of the charge sharing capacitor Cst 3 , the other end of the charge sharing capacitor Cst 3  is electrically connected to the common electrode of the liquid crystal display panel  10 . 
         [0045]    In the normal displaying, after receiving the scanning voltage of the gate driver  21 , the scanning line Gn is turned on, and the charge sharing scanning line Ln is turned off simultaneously. The main pixel region  31  and the sub pixel region  32  are charged to the same electric potential. Afterwards, the gate driver  21  stops to provide scanning voltage, so as to turn off the scanning line Gn and turn on the charge sharing line Ln simultaneously. Due to the effect of the charge sharing capacitor Cst 3 , the electric potential of the sub pixel region  32  is lower than the electric potential of the main pixel region  31 . Different electric potential causes the liquid crystal molecules in the two display regions to have different orientation, thus improving color shift at large viewing angle. 
         [0046]      FIG. 5  is a structural cross-sectional view of the array substrate  12  of  FIG. 1 , taken along line A-A of  FIG. 3 . Referring to  FIG. 5 , in the array substrate  12  applying the charge sharing technology, the charge sharing capacitor Cst 3  is formed by stacking a first metal layer M 1 , a second metal layer M 2 , and an insulating layer  123  between them. The first metal layer M 1 , the insulating layer  123 , and the second metal layer M 2  is subsequently formed on a base substrate  121 . The first metal layer M 1  is the charge sharing line Ln of the array substrate  12  shown in  FIG. 4 , the second metal layer M 2  is the source electrode or drain electrode of the charge sharing thin film transistor Tcs of the array substrate  12  in  FIG. 4 . The second metal layer M 2  forming the charge sharing capacitor Cst 3  is connected to the common electrode of the liquid crystal display panel  10  through the via hole. 
         [0047]    Referring to  FIG. 3  again, according to the embodiment, the second metal layer M 2  forming the charge sharing capacitor Cst 3  is overlapped with the charge sharing line Ln or the scanning line Gn. Since the charge sharing line Ln or the scanning line Gn is originally located in the non-display region, the second metal layer M 2  with shielding will not occupy area of the display region. Moreover, each pixel unit P includes the first metal layer M 1 , the insulating layer  123 , and the second metal layer M 2 , thus increasing pixel aperture ratio. 
         [0048]    Regarding the pixel unit of the array substrate  12  is of Tri-gate structure, the pixel unit  60  on the mth row in  FIG. 6  is a representative embodiment, wherein m is a positive integer. 
         [0049]    Referring to  FIG. 6  in combination to the cross-sectional view of  FIG. 7 , the pixel unit  60  is electrically connected to the scanning line Gm on the mth row. This embodiment is based on the above embodiments, but differs in that the charge sharing capacitor Cst 3  of the array substrate  12  is formed by the second metal layer M 2  in the pixel unit  60  on the mth row insulated from and overlapped with the scanning line Gm+1 on the (m+1)th row. That is, the first metal layer M 1  forming the charge sharing capacitor Cst 3  is the scanning line Gm+1, but not the charge sharing line. 
         [0050]    According to an embodiment of the present invention, a liquid crystal display device  80  as shown in  FIG. 8  is provided. The liquid crystal display device  80  includes the above-mentioned liquid crystal display panel  10  and a light source module  81  providing light to the liquid crystal display panel  10 . Since the liquid crystal display device  80  also includes the array substrate  12  with the above design, it also has the same effect. 
         [0051]    The scope of the present invention is not limited by the above-mentioned embodiments. Changes on the equivalent structure or equivalent process based on the specification and appended figures of the present invention are within the scope of the present invention, for example, combination between technology of various embodiments, or direct or indirect utilization to other related technology.