Abstract:
A pixel module comprising a first transistor, a second transistor, and a connection line is disclosed. The first transistor is coupled to a first gate line, a source line, and a first drain line. The second transistor is coupled to a second gate line, the source line, and a second drain line. The connection line overlaps and isolates the first and the second drain lines.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The disclosure relates to a pixel module, and more particularly to a pixel module having a repairable structure. 
     2. Description of the Related Art 
     Liquid crystal displays (LCD) are a commonly used flat panel display technology possessing the advantages of low power consumption, thin profile, and low driving voltage. LCDs are used in a wide variety of applications including, personal computers (PC), word processors, navigation systems, video games, projectors, viewfinders, and portable apparatuses, such as watches, calculators and televisions. 
     The dielectric and conductive anisotropy of liquid crystal molecules allows the molecular orientation of liquid crystal molecules to be shifted by an external electrical field, thus, various optical effects are produced. Thin film transistors (TFT) serve as the active elements in LCDs as they possess the advantages of low power consumption, thin profile, and low driving voltage. 
       FIG. 1  is a schematic diagram of a conventional display panel. For clarity, the conventional display panel  10  only shows two pixel units  11  and  12 . The pixel unit  11  comprises a transistor  111  and a pixel capacitor  112 . A scan electrode provides a scan signal S 1  for turning on the transistor  111 . A data electrode provides a video signal D 1  to the transistor  111  for charging the pixel capacitor  112 . The liquid crystal molecules of the pixel unit  11  are rotated according to a voltage stored in the pixel capacitor  112  such that light passes through the pixel unit  11 . 
     The pixel unit  12  comprises a transistor  121  and a pixel capacitor  122 . A scan electrode provides a scan signal S 2  for turning on the transistor  121 . A data electrode provides a video signal D 1  to the transistor  121  for charging the pixel capacitor  122 . The liquid crystal molecules of the pixel unit  12  are rotated according to voltage stored in the pixel capacitor  122  such that light passes through the pixel unit  12 . 
     When the transistors  111  and  121  are normal, the pixel capacitors  112  and  122  are charged according to the video signal D 1 . When the transistors  111  and  121  are abnormal, the video signal D 1  is unable to charge the pixel capacitors  112  and  122  via the transistors  111  and  121 . Thus, liquid crystal components of the pixel units  11  and  12  do not rotate such that light cannot pass through the pixel units  11  and  12 . 
     BRIEF SUMMARY OF THE INVENTION 
     The pixel modules are provided. An embodiment of a pixel module comprises a first transistor, a second transistor, and a connection line. The first transistor is coupled to a first gate line, a source line, and a first drain line. The second transistor is coupled to a second gate line, the source line, and a second drain line. The connection line is overlapped and insulated from the first and the second drain lines. 
     Another embodiment of the pixel module having a repairable structure comprises a first transistor, a second transistor, and a connection line. The first transistor is coupled to a first gate line, a source line, and a first drain line to drive a first pixel. The second transistor is coupled to a second gate line, the source line, and a second drain line to drive a second pixel. The connection line is overlapped and insulated from the first and the second drain lines. When the first transistor is unable to drive the first pixel, a connection between the first drain line and the first transistor is cut off and the first drain line electrically connects to the second drain line via the connection line. 
     Display devices are also provided. An embodiment of a display device comprises a scan driver, a data driver, and a pixel module. The scan driver provides a plurality of scan signals. The data driver provides a plurality of the video signals. The pixel module comprises a first transistor, a second transistor, and a connection line. The first transistor is coupled to a first gate line for receiving the corresponding scan signal, a source line, and a first drain line for receiving the corresponding video signal. The second transistor is coupled to a second gate line for receiving the corresponding scan signal, the source line, and a second drain line for receiving the corresponding video signal. The connection line is overlapped and insulated from the first and the second drain lines. 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by referring to the following detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a schematic diagram of a conventional display panel; 
         FIG. 2  is a schematic diagram of an embodiment of a display device; 
         FIG. 3   a  is a schematic diagram of an embodiment of a pixel module; 
         FIG. 3   b  is a flowchart of an embodiment of a repair method applied in the pixel module; and 
         FIGS. 4˜9  are schematic diagrams of the other embodiments of the pixel module. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
       FIG. 2  is a schematic diagram of an embodiment of a display device. The display device  20  comprises a scan driver  21 , a data driver  22 , and a pixel module  23 . The scan driver  21  provides scan signals S 1 ˜S n . The data driver  22  provides video signals D 1 ˜D m . The pixel module  23  displays image according to the scan signals S 1 ˜S n  and the video signals D 1 ˜D m . 
       FIG. 3   a  is a schematic diagram of an embodiment of a pixel module. For clarity, the pixel module shown in  FIG. 3   a  only comprises two pixel units. The pixel module  30  comprises two transistors T 1 , T 2 , and a connection line  301 . 
     The transistor T 1  is coupled to a gate line  311 , a source line  321 , and a drain line  331 . The source line  321  and the drain line  331  are parallel at a side of one pixel unit. A pixel electrode is disposed in a region  341 . When the pixel electrode overlaps a common line  351 , an auxiliary capacitor is formed between the pixel electrode and common line  351 . The transistor T 1  controls one pixel unit and a pixel capacitor of the pixel unit controlled by the transistor T 1 . 
     The transistor T 2  is coupled to a gate line  312 , a source line  321 , and a drain line  332 . The source line  321  and the drain line  332  are parallel at a side of another pixel unit. The drain lines  332  and  331  are unconnected. A pixel electrode is disposed in a region  342 . When the pixel electrode overlaps a common line  352 , an auxiliary capacitor is formed between the pixel electrode and the common line  352 . The transistor T 2  controls another pixel unit and a pixel capacitor of the pixel unit controlled by the transistor T 2 . 
     The connection line  301  is overlapped and insulated from the drain lines  331  and  332 . The connection line  301  and gate lines  311  and  312  are formed by the same metal layer. In some embodiments, connection line  301  is formed by a metal layer and gate lines  311 ,  312  are formed by another metal layer. 
     The gate line  311  receives a corresponding scan signal and the gate line  312  receives another corresponding scan signal. The source line  321  receives a corresponding video signal. The drain lines  331  and  332  respectively charge the corresponding pixels according to the video signals. 
     The efficiency of pixel module  30  is influenced by an area overlapped by the drain line  331  and the gate line  311  and another area overlapped by the drain line  332  and the gate line  312 . An RC delay is caused by a parasitic capacitor formed between a source line and a gate line or formed between a drain line and a gate line. Thus, a region overlapped by the source line and the gate line is required to be smaller. Similarly, a region overlapped by the source line and the gate line is also required to be smaller. 
     In this embodiment, the drain line  331  traverses the gate line  311  symmetrically and crookedly for maintaining an overlapping area between the drain line  331  and gate line  311 . The drain line  332  traverses the gate line  312  symmetrically and crookedly for maintaining an overlapping area between the drain line  332  and gate line  312 . Additionally, the source line  321  traverses the gate lines  311  and  312  symmetrically and crookedly. When an alignment error occurs in a vertical direction, the overlapping area between the drain line  331  and the gate line  311 , and the overlapping area between the drain line  332  and the gate line  312  are not affected. 
     When the widths of a source line and a drain line are greater, a transistor, coupled to the source and the drain lines charges faster. Additionally, if a distance between the source and the drain lines is shorter, transistor charges faster. 
       FIG. 3   b  is a flowchart of an embodiment of a repair method applied in the pixel module. With reference to  FIG. 3   a , if the transistor T 1  is abnormal, the corresponding pixel capacitor is unable to store perfect charges. Thus, a laser is utilized to cut off drain line  331  (step  31 ) such that the transistor T 1  is not able to control the corresponding pixel capacitor. In this embodiment, the drain line  331  in a region A is cut off The laser can be a YAG laser, a ruby laser, or a CO 2  laser. 
     Next, the laser is again utilized for electrically connecting the drain lines  331  and  332  by the connection line  301  (step  32 ). Since the connection line  301  overlaps the drain lines of adjacent transistors, when the transistor T 1  is abnormal, the corresponding pixel capacitor is controlled by the transistor T 2 . Since the drain line  331  electrically connects the drain line  332 , the pixel capacitors of two pixel units stores the same charges. 
       FIGS. 4˜9  are schematic diagrams of the other embodiments of the pixel module. Pixel electrodes are well known to those skilled in the art, thus, for brevity,  FIGS. 4˜9  do not show pixel electrodes. As shown in  FIG. 4 , a source  421  traverses the gate lines  411  and  412  straight. A drain line  431  traverses the gate line  411  straight for maintaining an overlapping area between the drain line  431  and gate line  411 . The Drain line  432  traverses gate line  412  straight for maintaining an overlapping area between the drain line  432  and gate line  412 . A distance between the source line  421  and the drain line  431 , and a distance between the source line  421  and the drain line  432  are fixed. A common line  451  overlaps a portion of the drain line  431 . Common line  452  overlaps a portion of the drain line  432 . 
     As shown in  FIG. 5 , the source line  521  traverses gate lines  511  and  512  slantwise. A drain line  531  traverses a gate line  511  slantwise. A drain line  532  traverses a gate line  512  slantwise. A distance between source line  521  and drain line  531 , and a distance between source line  521  and drain line  532  are fixed. Common line  551  overlaps drain line  531 . A common line  552  overlaps drain line  532 . 
     As shown in  FIG. 6 , a source line  621  traverses gate lines  611  and  612  non-symmetrically and crookedly. A drain line  631  traverses the gate line  611  non-symmetrically and crookedly for maintaining an overlapping area between the drain line  631  and gate line  611 . A drain line  632  traverses the gate line  612  non-symmetrically and crookedly for maintaining an overlapping area between the drain line  632  and gate line  612 . A distance between source line  621  and drain line  631 , and a distance between source line  621  and drain line  632  are fixed. A common line  651  overlaps a portion of the drain line  631 . A common line  652  overlaps a portion of the drain line  632 . 
     As shown in  FIG. 7 , a source line  721  traverses gate lines  711  and  712  slantwise. A drain line  731  traverses the gate line  711  slantwise. A drain line  732  traverses the gate line  712  slantwise. In this embodiment, two source lines are collocated with one drain line disposed between two source lines such that the channel width of a transistor coupled to the source lines and the drain line is increased. When the locations of gate lines  711 ˜ 714  and common lines  741  and  742  change, the color contrast of the pixel module is increased. In this embodiment, gate lines  711 ˜ 714  and common lines  741  and  742  are parallel. Gate lines  712  and  714  are disposed at the top of a pixel unit and common lines  741  and  742  are disposed at the bottom of the pixel unit. Additionally, common lines  741  and  742  are disposed at the top of another pixel unit and gate lines  711  and  713  are disposed at the bottom of another pixel unit. A connection line is disposed between two adjacent common lines for repairing adjacent pixel units. 
     As shown in  FIG. 8 , a source line  821  traverses gate lines  811  and  812  crookedly. A drain line  831  traverses gate line  811  crookedly for maintaining an overlapping area between the drain line  831  and gate line  811 . Drain line  832  traverses gate line  812  crookedly for maintaining an overlapping area between the drain line  832  and gate line  812 . A distance between source line  821  and drain line  831 , and a distance between source line  821  and drain line  832  are fixed. As shown in  FIG. 9 , source line  921  traverses gate lines  911  and  912  slantwise. A drain line  931  traverses gate line  911  slantwise for maintaining an overlapping area between the drain line  931  and gate line  911 . A drain line  932  traverses gate line  912  slantwise for maintaining an overlapping area between the drain line  932  and gate line  912 . 
     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.