Abstract:
A liquid crystal display panel is provided. The LCD panel has a first substrate having at least a conductive material layer thereon, a second substrate having at least a repair line positioned in a predetermined area, and a liquid crystal layer positioned between the first substrate and the second substrate. The predetermined area is underneath the first substrate excluding the portions having the conductive material layer, thus reducing RC delay of the repair line.

Description:
BACKGROUND OF INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a liquid crystal display (LCD) panel, and more particularly, to an LCD panel with at least a repair line structure.  
           [0003]    2. Description of the Prior Art  
           [0004]    A traditional LCD panel comprises a thin-film transistor (TFT) substrate, a color filter (CF) substrate, and a liquid crystal layer positioned between the TFT substrate and the CF substrate. The TFT substrate contains a plurality of matrix pixels, which consist of a plurality of datalines and a plurality of scan lines, and a plurality of pixel driving circuits consisting of a plurality of electric components, such as thin-film transistors and capacitors. The pixel driving circuits are positioned on the intersections of each data line and each scan line for receiving an image data signal transmitted by the data line and a switching/addressing signal transmitted by the scan line to control operation of each pixel. For avoiding disconnection of data lines or scan lines which cause the failure of signal transmission, the method according to the prior art is to set a plurality of repair lines in the area around the LCD panel. Thus external image data signals or switching/addressing signals are capable of passing through the repair lines to control operation of pixels, and this will avoid the defects of the LCD panel caused by disconnecting data lines.  
           [0005]    Please refer to FIG. 1, which is a structure of a prior-art LCD panel  10 . As shown in FIG. 1, an LCD panel  10  contains a display area  12  and a non-display area  14  surrounding the display area  12 . The display area  12  contains a plurality of matrix pixels  16 , which consist of a plurality of data lines  20  and a plurality of scan lines  30 , and a plurality of pixel driving circuits consisting of a plurality of electric components, such as thin-film transistors and capacitors. The pixel driving circuits are positioned on the intersections of each data line  20  and each scan line  30 . The non-display area  14  contains some package testing materials, such as main sealants, electric components, and repair lines.  
           [0006]    Please refer to FIG. 2, which is a section view of the prior-art LCD panel  10 . As shown in FIG. 2, the prior-art LCD panel  10  contains a lower substrate (often called a TFT substrate)  40 , an upper substrate (often called a CF substrate)  46  covering the lower substrate  40 , a liquid crystal layer (not shown in FIG. 2) positioned between the lower substrate  40  and the upper substrate  46  in the display area  12 , and a main sealant  52  positioned between the lower substrate  40  and the upper substrate  46  in the non-display area  14  for binding the two substrates. On the lower substrate  40  are a plurality of repair lines  42  in the non-display area  14  and a passivation layer  44 , such as a silicon nitride layer, covers on the display area  12  and the non-display area  14 . On the surface of the upper substrate  46  are a black matrix  48  in the non-display area  14  and a conductive material layer  50 , such as an indium tin oxide (ITO) layer, in both display area  12  and non-display area  14  for being a transparent electrode.  
           [0007]    In the structure of the prior-art LCD panel, the conductive material layer  50  completely covers the surface of the upper substrate  46 , including the display area  12  and the non-display area  14 , and therefore the conductive material layer  50  in the non-display area  14 , the repair lines  42  underneath the conductive material layer  50 , and the liquid crystal will form a capacitance. The formation of the capacitance causes an RC delay effect to the repair line, and the RC delay decreases the successful rate of using a repair line to repair a disconnecting wire. As the large size LCD panels are developed, to efficiently decrease the RC delay on the repair lines has become an important issue for increasing the yield of the production.  
         SUMMARY OF INVENTION  
         [0008]    It is therefore an objective of the present invention to provide an LCD panel that can decrease the RC delay of the repair lines and increase the successful rate of utility of the repair lines.  
           [0009]    According to the claimed invention, the LCD panel contains a first substrate having at least a conductive material layer thereon, a second substrate having at least a repair line thereon, and a liquid crystal layer positioned between the first substrate and the second substrate. The repair line is positioned in a predetermined area underneath the first substrate excluding portions having the conductive material layer, and the repair line repairs a disconnecting line on the second substrate so that an external signal, which is predetermined to transmit to the line, is capable of passing through the repair line to the line.  
           [0010]    It is an advantage of the claimed invention that the repair line of the LCD panel is positioned in the area underneath the first substrate excluding portions having the conductive material layer so that it avoids the liquid crystal to form the capacitances between the repair line and the conductive material layer, which decreases the RC delay on the repair line and further increase the successful rate of utility of the repair line and the yield of the LCD panel.  
           [0011]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and the drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0012]    [0012]FIG. 1 is a structure of a prior-art LCD panel.  
         [0013]    [0013]FIG. 2 is a section view of the prior-art LCD panel shown in FIG. 1.  
         [0014]    [0014]FIG. 3 is a section view of an LCD panel according to a first preferred embodiment of the present invention.  
         [0015]    [0015]FIG. 4 is a section view of an LCD panel according to a second preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0016]    Please refer to FIG. 3. FIG. 3 is a section view of an LCD panel according to the first preferred embodiment of the present invention. The LCD panel of the present invention contains a lower substrate (often called a TFT substrate)  60 , an upper substrate (often called a CF substrate)  66  covering the lower substrate  60 , a liquid crystal layer (not shown in FIG. 3) positioned between the lower substrate  60  and the upper substrate  66  in a display area  12 , and a main sealant  72  positioned between the lower substrate  60  and the upper substrate  66  in a non-display area  14  for binding the two substrates.  
         [0017]    On the lower substrate  60  are formed a plurality of matrix pixels, which consist of a plurality of data lines and a plurality of scan lines, in the display area  12 , and a plurality of pixel driving circuits positioned on the intersections of each data line and each scan line for controlling the operation of pixels of the LCD panel. The pixel driving circuits consist of a plurality of electric components, such as thin-film transistors and capacitances. In addition, the lower substrate  60  further comprises a plurality of repair lines  62  in the non-display area  14 , and the repair lines  62  enclose the TFT pixels in the display area  12  for repairing a disconnecting line, such as a data line, on the lower substrate  60  to transmit an external signal passing through the repair lines  62  to the corresponding pixels. A passivation layer  64 , such as a silicon nitride layer, covers the pixel driving circuits and repair lines  62 .  
         [0018]    The surface of the upper substrate  66  has a black matrix  68  in the non-display area  14  and a conductive material layer  70  covering the display area  12  and portions of the non-display area  14 . The black matrix  68  is an opaque layer made by an insulating material. The conductive material layer  70  serves as a transparent electrode, which is formed by a transparent conductive material, such as ITO. It should be noted that the conductive material layer  70  should not be positioned in an area over portions of the lower substrate  60  where the repair lines  62  are. For the reason of avoiding liquid crystal capacitances, as well as the RC delay, formed by the conductive material layer  70  and the repair lines  62 , one can use a shadow mask or a photolithography process to define at least a pattern of the conductive material in the area on the surface of the upper substrate  66  excluding portions right over the repair lines  62 . A main sealant  72  is positioned outside of the repair lines  62  or covers some repair lines  62 .  
         [0019]    Please refer to FIG. 4, which is a section view of an LCD panel according to the second preferred embodiment of the present invention. As shown in FIG. 4, the LCD panel of the present invention contains a lower substrate (often called a TFT substrate)  80 , an upper substrate (often called a CF substrate)  86  covering the lower substrate  80 , a liquid crystal layer (not shown in FIG. 4) positioned in a display area  12  between the lower substrate  80  and the upper substrate  86 , and a main sealant  92  positioned in a non-display area  14  between the lower substrate  80  and the upper substrate  86  for binding the two substrates.  
         [0020]    On the lower substrate  80  are formed matrix pixels, which consist of a plurality of data lines and a plurality of scan lines, in the display area  12  and a plurality of pixel drivers positioned on the intersections of each data line and each scan line for controlling operation of pixels of the LCD panel, wherein the pixel drivers consist of a plurality of electric components, such as thin-film transistors and capacitances. In addition, the lower substrate  80  further comprises a plurality of repair lines  82  in the non-display area  14 , and the repair lines  82  surround the TFT pixels in the display area  12  for repairing a disconnecting line, such as a data line, on the lower substrate  80  to transmit an external signal passing through the repair lines  82  to corresponding pixels. A passivation layer  84 , such as a silicon nitride layer, covers the pixel driving circuits and repair lines  82 .  
         [0021]    The surface of the upper substrate  86  has a black matrix  88  in the non-display area  14  and a conductive material layer  90  covering the display area  12  and portions of the non-display area  14 . The black matrix  88  is an opaque layer and made by an insulating material or a conductive material, such as chromium, Cr 2 O 3 , or CrN. The conductive material layer  90  serves as a transparent electrode and made by transparent conductive materials, for example by ITO. The conductive material layer  90  should not be positioned in an area over portions of the lower substrate  80  where the repair lines  82  are. For the reason of avoiding the formation of the liquid crystal capacitances, formed by the black matrix  88 , the conductive material layer  90 , and the repair lines  82 , and of the RC delay on the repair lines, one can use a shadow mask or a photolithography process to define at least a pattern of the conductive material in the area on the surface of the upper substrate  86  excluding portions right over the repair lines  82 . A main sealant  92  is positioned in the non-display area  14 , for example outside of the black matrix  88 , and covers the surface of the lower substrate  80  outside of the repair lines  82  or covers some repair lines  82 .  
         [0022]    For saving the lead time of injecting liquid crystal when fabricating large size LCD panels, currently the liquid crystal layer is filled between the upper substrate and lower substrate by the way of One Drop Filling (ODF), and a main sealant UV exposure area is set on the edge of the upper and lower substrate in advance. Then ultraviolet light is used to solidify the main sealant, which is positioned in the main sealant UV exposure area, for binding and fixing the two substrates. In the second preferred embodiment of the present invention, the black matrix  88  avoids the area right over the repair line  82  so that the main sealant  92  and repair lines  82  are set in a transparent area. More specifically, the fabrication of the LCD panel of the present invention is capable of applying to ODF method, setting the black matrix and the transparent electrode on the surface of the upper substrate outside of the main sealant transparent area, and positioning repair lines on the lower substrate in the main sealant transparent area. As a result, the conductive materials, such as the black matrix and the transparent electrode, are not positioned above the repair lines so that the RC delay caused by the formation of liquid crystal capacitances, formed between the conductive materials and repair lines, can be avoided effectively.  
         [0023]    In contrast to the prior art, the present invention LCD panel provides a pattern of the conductive materials, such as the black matrix and the transparent electrode, on the surface of the upper substrate avoiding portions right over repair lines. Thus the liquid crystal capacitances between the repair lines and the conductive material patterns will be avoided, and it will avoid the RC delay interfering with the signals transmitted by repair lines. Furthermore, the present invention improves the successful rate of the utility of repair lines and the yield of the LCD panel.  
         [0024]    Those skilled in the art will readily observe that numerous medications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the mate and bounds of the appended claims.