Abstract:
An array structure of a liquid crystal display is provided, comprising a substrate having a first and a second pixel region thereon. Each of the pixel regions has a transistor, a pixel electrode electrically connected to a drain of the transistor, and a common electrode forming a capacitance with the pixel electrode, wherein the common electrodes of the first and second pixel regions are electrically isolated from each other.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid crystal display, particularly to an array structure of a liquid crystal display having two common electrodes. 
     2. Description of the Prior Art 
     FIG. 1 is a diagram showing a conventional array structure of a liquid crystal display. There are four pixel regions on a substrate  10 . Each scan line  102  is electrically connected to gates of transistors  101  in one line of pixel regions through via holes (not shown). Each data line  103  is electrically connected to sources of the transistors  101  in one row of pixel regions through via holes. Each pixel electrode  201  has a connector  2011  electrically connected to drains of the transistors  101  and extended portions  2012  extending from the connector  2011 . A common electrode  104  has connectors  1041  along with the lines of the pixel regions and extended portions  1042  extending from the connectors  1041 . The transistors  101  are positioned where the extended portions  1042  extend from the connectors  1041  of the common electrode  104 . Capacitances are formed between the extended portions  2012  and  1042  respectively of the pixel electrodes  201  and the common electrode  104 . 
     FIG. 2 is a diagram showing an equivalent circuit of the conventional transistor array of the liquid crystal display. The same symbols are used in FIG.  1  and FIG.  2 . The circuit comprises the transistors  101 , the scan lines  102  connected to the gates of lines of the transistors  101 , the data lines connected to the sources of rows of the transistors  101 , the common electrode  104  and the capacitances  105  formed between the drains of the transistors  101  and the common electrodes  104 . 
     However, all the pixel regions of the conventional transistor array structure have the same common electrode voltage since they have the same common electrode. It is impossible to apply two different common electrode voltages to the pixel regions. Thus, any driving method using two different common electrode voltages cannot be implemented by a conventional circuit. 
     SUMMARY OF THE INVENTION 
     Therefore, the object of the present invention is to provide an array structure of a liquid crystal display having two common electrodes isolated from each other. 
     The other object of the present invention is to provide two different driving voltages to drive the two isolated common electrode in the array structure. The two different driving voltages comprise a positive and negative voltage. 
     The present invention provides an array structure of a liquid crystal display. The circuit comprises a substrate having a first and a second pixel region thereon. Each of the pixel regions has a transistor, a pixel electrode electrically connected to a drain of the transistor and a common electrode forming a capacitance with the pixel electrode, wherein the common electrodes of the first and second pixel regions are electrically isolated from each other. 
     The present invention further provides an array structure of a liquid crystal display comprising a substrate having a first and a second pixel region thereon. Each of the pixel regions has a transistor, a pixel electrode electrically connected to a drain of the transistor, and a common electrode having an extended portion forming a capacitance with the pixel electrode and a connector which the extended portion extends from, wherein the common electrodes of the first and second pixel regions are isolated from each other, and the transistors are positioned where the extended portions extending from the connectors. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following detailed description, given by way of example and not intended to limit the invention solely to the embodiments described herein, will best be understood in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a diagram showing a conventional array structure of a liquid crystal display, 
     FIG. 2 is a diagram showing an equivalent circuit of the conventional transistor array of the liquid crystal display, 
     FIG. 3 is a diagram showing an array structure of a liquid crystal display according to a first embodiment of the invention, 
     FIG. 4 is a diagram showing an equivalent circuit of the transistor array of the liquid crystal display according to the first embodiment of the invention, 
     FIG. 5 is a diagram showing an array structure of a liquid crystal display according to a second embodiment of the invention, and 
     FIG. 6 is a diagram showing an equivalent circuit of the transistor array of the liquid crystal display according to the second embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 3 is a diagram showing an array structure of a liquid crystal display according to a first embodiment of the invention. 
     There are at least four pixel regions as a unit on a substrate  30 . There are two electrically connected scan lines  502  for each line of pixel regions, which are also electrically connected to gates of transistors  501  in the line through via holes (not shown). Each data line  503  is electrically connected to sources of the transistors  501  in one row of pixel regions through via holes. Each pixel electrode  507  has a connector  5071  electrically connected to drains of the transistors  501  and extended portions  5072  extending from the connector  5071 . Two common electrodes  504   a  and  504   b,  isolated from each other, are provided, and have connectors  5041   a  and  5041   b  along with the lines of the pixel regions and extended portions  5042   a  and  5042   b  extending from the connectors  5041   a  and  5041   b,  respectively. The transistors  501  are positioned where the extended portions  5042   a  and  5042   b  extend from the connectors  5041   a  and  5041   b  of the common electrodes  504   a  and  504   b.  Capacitances are formed between the extended portions  5072 ,  5042   a  and  5042   b,  respectively of the pixel electrodes  507  and the common electrodes  504   a  and  504   b.    
     FIG. 4 is a diagram showing an equivalent circuit of the transistor array of the liquid crystal display according to the first embodiment of the invention. The same symbols are used in FIG.  3  and FIG.  4 . 
     The circuit comprises the transistors  501 , the scan lines  502  connected to the gates of lines of the transistors  501 , the data lines  503  connected to the sources of rows of the transistors  501 , the common electrode  504   a  and  504   b,  and the capacitances  505  formed between the drains of the transistors  501  and the common electrodes  504   a  and  504   b.  The common electrodes  504   a  and  504   b  provide two different driving voltages. The two adjacent pixel regions have the common electrodes  504   a  and  504   b  and are driven by the two different voltages, respectively. 
     FIG. 5 is a diagram showing an array structure of a liquid crystal display according to a second embodiment of the invention. 
     There are at least four pixel regions as a unit on a substrate  60 . Each scan line  602  for two adjacent lines of pixel regions is electrically connected to gates of transistors  601  near the scan line  602  through via holes (not shown). Each data line  603  is electrically connected to sources of the transistors  601  in one row of pixel regions through via holes. Each pixel electrode  607  has a connector  6071  electrically connected to drains of the transistors  601  and extended portions  6072  extending from the connector  6071 . Two common electrodes  604   a  and  604   b  isolated from each other are provided, and have connectors  6041   a  and  6041   b,  along with the lines of the pixel regions and extended portions  6042   a  and  6042   b  extending from the connectors  6041   a  and  6041   b,  respectively. The transistors  601  are positioned where the extended portions  6042   a  and  6042   b  extend from the connectors  6041   a  and  6041   b  of the common electrodes  604   a  and  604   b.  Capacitances are formed between the extended portions  6072 ,  6042   a  and  6042   b  respectively, of the pixel electrodes  607  and the common electrodes  604   a  and  604   b.    
     FIG. 6 is a diagram showing an equivalent circuit of the transistor array of the liquid crystal display according to the second embodiment of the invention. The same symbols are used in FIG.  5  and FIG.  6 . 
     The circuit comprises the transistors  601 , the scan lines  602  between two adjacent lines of transistors  601 , which is alternatively connected to the gates of the transistors  601  in the two adjacent lines, the data lines  603  connected to the sources of rows of the transistors  601 , the common electrode  604   a  and  604   b,  and the capacitances  605  formed between the drains of the transistors  601  and the common electrodes  604   a  and  604   b.  The common electrodes  504   a  and  504   b  provide two different driving voltages. The two adjacent pixel regions have the common electrodes  604   a  and  604   b  and are driven by the two different voltages, respectively. 
     In the second embodiment, the connection of the scan lines to the transistor gates is different from that of a conventional liquid crystal display circuit so that the order of the scanned pixel regions is changed. An ordinary person skilled in the art can easily provide a new driving method for an LCD circuit configured in accordance with the second embodiment. 
     In conclusion, the present invention changes the structure of the common electrode to provide two common electrodes isolated from each other. Thus, it is possible for the pixel regions to have two different common electrode voltages having two different polarities. 
     While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. On 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.