Abstract:
A liquid crystal display panel includes a first substrate, at least two first printed circuit boards, and at least one repair line. Each of the first printed circuit boards is utilized to output signals to a plurality of first conducting wires in parallel arranged on the first substrate. Additionally, the repair line has a first part located on the first substrate, a second part located on each of the first printed circuit boards, and a third part located on a connecting region between the first printed circuit boards.

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 that has a repair line structure with a lower RC delay.  
           [0003]    2. Description of the Prior Art  
           [0004]    In a thin film transistor (TFT) LCD panel, a plurality of thin film transistors, which are formed in a matrix, are in combination with appropriate electric components, such as capacitors and binding pads, to drive liquid crystal pixels to produce a beautiful image. Because TFT LCD panels are small, have a light weight, consume less power, and do not produce radiation, TFT LCD panels are widely used in many portable information products, such as notebooks and PDAs, and replace the traditional CRT monitors of personal computers.  
           [0005]    An ordinary TFT LCD panels contains an upper substrate with a color filter, a lower substrate, and a liquid crystal material filled between the upper substrate and lower substrate. The lower substrate has a plurality of scan lines (also called gate lines) thereon and a plurality of data lines (also called signal lines) thereon perpendicular with the scan lines. At the intersection of each of the scan lines and data lines are set at least a thin film transistor for use as a switch device of a pixel. On the lower substrate are further formed a plurality of repair lines for serving as replacing wires to send a signal to every thin film transistor correctly when there is a disconnection on a data line.  
           [0006]    Please refer to FIG. 1, which is a schematic structure of an LCD panel  10  according to prior art. As shown in FIG. 1, an LCD panel  10  contains a substrate  12 , an X-axial printed circuit board (X-board)  14  and a Y-axial printed circuit board (Y-board)  16 , and a flexible printed circuit board (FPC)  29  for electrically connecting the X-board  14  and the Y-board  16 , wherein the X-board  14  and the Y-board  16  are used for transmitting signals to the substrate  12  to enable the LCD panel  10  to produce images. The LCD panel  10  further contains a plurality of tape carrier packages (TCPs)  18  for electrically connecting the X-board  14  and the substrate  12 , and a plurality of TCPs  20  for electrically connecting the Y-board  16  and the substrate  12 . Each TCP  18  or  20  contains an integrated circuit (IC) chip (not shown in FIG. 1).  
           [0007]    The substrate  12  has a plurality of scan lines S 1 -S m  thereon and a plurality of data lines D 1 -D n  thereon perpendicular with the scan lines S 1 -S m . The scan lines S 1 -S m  and the data lines D 1 -D n  are used for defining a plurality of pixels (not shown in FIG. 1) formed in matrix in an active region  26  on the substrate. Each of the scan lines S 1 -S m  is electrically connected to its corresponding TCP  20  through a bonding pad  24 , and similarly, each of the data lines D 1 -D n  is electrically connected to its corresponding TCP  18  through a bonding pad  22 . The substrate  12  further contains at least a repair line  28 . The repair line  28  is set on the X-board  14 , Y-board  16 , and the substrate  12  for repairing the data line D 1 -D n  on the substrate  12  when there is a disconnection on a data line D 1 -D n  . The method of repairing a data line is described below.  
           [0008]    Please refer to FIG. 2, which is a schematic diagram of a method using a repair line to repair an LCD panel  10  according to prior art. If a disconnection occurs at the point A of the data line D n , the prior art method uses a laser welding to connect the terminals point B and C of the data line D n  with the repair line  28 . Therefore a signal will pass through the path  30  to every pixel when the X-board  14  outputs a signal to the data line D n .  
           [0009]    According to the prior art, the repair line  28  transversely crosses data line D 1 -D n , so it will cause an RC delay effect on the repair line. As a result, the effect of the RC delay will be greater when the size of the LCD panel  10  becomes larger and the RC delay will cause the distortion of the image signal on the panel finally. Therefore, how to distribute and set the repair line on the X-board, Y-board, or the substrate to reduce the RC delay becomes a main issue for improving the yield of manufacturing an LCD panel with a large size.  
         SUMMARY OF INVENTION  
         [0010]    It is therefore a primary objective of the claimed invention to provide an LCD panel that has a repair line with a lower RC delay to solve the above-mentioned problem.  
           [0011]    According to the claimed invention, the LCD panel contains a first substrate, at least two first printed circuit boards, and at least a repair line. The first substrate has a plurality of first conductive wires thereon, and the first conductive wires are arranged in parallel with each other along a first direction. Each of the first printed circuit boards is electrically connected to the first substrate respectively for outputting signals to the first conductive wires. In addition, the repair line contains a first portion positioned on the first substrate, a second portion positioned on each of the printed circuit boards, and a third portion positioned on a connective region located between each of the first printed circuit boards.  
           [0012]    It is an advantage of the claimed invention that the LCD panel contains a connective region so that the repair line on each of the first printed circuit boards is capable of being connected in the connective region, wherein the connective region is set on the substrate, a flexible printed circuit (FPC), which electrically connects each of the first printed circuit boards, or a control board. If the connective region is set on the substrate of the LCD panel, the amount of the connectors for connecting two adjacent first printed circuit boards and the effect of the RC delay on the repair line will both be reduced. If the connective region is set on the FPC or a control board, the advantage is that the manufacturing process can be simplified.  
           [0013]    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 drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0014]    [0014]FIG. 1 is a schematic structure of an LCD panel according to prior art.  
         [0015]    [0015]FIG. 2 is a schematic diagram of a method using a repair line to repair an LCD panel according to prior art.  
         [0016]    [0016]FIG. 3 is a schematic structure of an LCD panel according to a first embodiment of the present invention.  
         [0017]    [0017]FIGS. 4A and 4B are cross-sectional views along line  4 - 4 ″ of the LCD panel shown in FIG. 3.  
         [0018]    [0018]FIGS. 5A and 5B are schematic diagrams of a method using a repair lines to repair an LCD panel according to the present invention.  
         [0019]    [0019]FIG. 6 is a schematic structure of an LCD panel according to a second embodiment of the present invention.  
         [0020]    [0020]FIG. 7 is a schematic structure of an LCD panel according to a third embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0021]    Please refer to FIG. 3, which is a schematic structure of an LCD panel  40  according to a first embodiment of the present invention. As shown in FIG. 3, the LCD panel  40  contains a substrate  42 , two X-axial printed circuit boards (X-boards)  44   a  and  44   b , a Y-axial printed circuit board (Y-board)  46 , and a flexible printed circuit (FPC)  51  for electrically connecting the X-board  44   b  and the Y-board  46 , wherein the use of the X-boards  44   a ,  44   b , and the Y-board  46  is to output signals to the substrate  42  for enabling the LCD panel  40  to produce images. In addition, the LCD panel  40  further contains a plurality of Tape Carrier Packages (TCPs)  48  and  50 , wherein each TCP  18  or  20  contains an ICchip (not shown in FIG. 3). The TCPs  48  are used for electrically connecting the X-boards  44   a ,  44   b , and the substrate  42 , and the TCPs  50  are used for electrically connecting the Y-board  46  and the substrate  42 .  
         [0022]    On the substrate  42  are set a plurality of scan lines S 1 -S m  and a plurality of data lines D 1 -D n  perpendicular with the scan lines S 1 -S m  for defining a plurality of pixels formed in matrix on an active region  52  of the substrate  42 . The substrate  42  further contains an outer lead bonding region  54  and a plurality of bonding pads (not shown in FIG. 3) set on the outer lead bonding region  54 . Every scan line S 1 -S m  is electrically connected to its corresponding TCP  50  through a corresponding bonding pad, similarly, every data line D 1 -D n  is electrically connected to its corresponding TCP  48  through a bonding pad.  
         [0023]    In addition, the LCD panel  40  further contains a plurality of repair lines  58 . For easily explaining the repair line  58 , FIG. 3 only illustrates one repair line  58 . The repair line  58 , as shown in FIG. 3, comprises a first portion  58   a  positioned on the substrate  42 , two second portions  58   b  positioned on the X-board  44   a  and  44   b  respectively, and a third portion  58   c  positioned on a connective region  60 , and a fourth portion  58   d  positioned on the Y-board  46 , wherein the first portion  58   a  is connected to the fourth portion  58   d  by way of a conductive wire  61   a  on the TCP  50 , the second portion  58   b  is connected to the substrate  42  by way of a connective wire  61   d  on the TCP  48 , and the third portion  58   c  is connected to each second portion  58   b  by way of the connective wires  61   b  and  61   c  on the TCPs  48 . According to this embodiment, the connective region  60  is located on an outer lead bonding region  54  that is positioned between two adjacent data lines D x  and D x-1 , therefore the third portion  58   c  in the connective region will not transversely cross the data lines D 1 -D n  and thereby avoid an RC delay.  
         [0024]    Please refer to FIG. 4A and 4B. FIG. 4A and 4B are cross-sectional views along line  4 - 4 ″ of the LCD panel  40  shown in FIG. 3. The third portion  58   c  of the repair line  58  is a metal layer, which is capable of being formed with the scan lines S 1 -S m  or the data lines D 1 -D n  simultaneously. In addition, the third portion  58   c  of the repair line  58  can be formed with more than two metal layers electrically connected in parallel to reduce the resistance. For example, as shown in FIG. 4B, the third portion  58   c  of the repair line  58  is formed with a metal layer  59   a  and a metal layer  59   c , which is electrically connected in parallel with the metal layer  59   a . An insulating layer  59   d  is formed between the metal layer  59   a  and the metal later  59   c , and the metal layer  59   a  is electrically connected to the metal layer  59   c  by a transparent electrode  59   b , wherein the transparent electrode  59   b  is formed by a transparent indium tin oxide (ITO). And between the transparent electrode  59   b  and the metal layer  59   a  is set a passivation layer  59   e . Furthermore, the metal layer  59   a  and the scan line S 1 -S m  are formed simultaneously, and the metal layer  59   c  and the data lines D 1 -D n  are formed simultaneously.  
         [0025]    Please refer to FIG. 5A and 5B, which are schematic diagrams of a method using a repair lines to repair an LCD panel  40  according to the present invention. If there is a disconnection at point A of data line D n-1 , the terminals point B and C of the data line D n-1  will be connected to the repair line  58  by using laser welding. Therefore when a signal is outputted from the X-board  44   a  or  44   b  to the data line D n-1 , the signal will be transmitted to every pixel by passing through a path  62 , shown in FIG. 5B, to enable every pixel corresponding to the data line D n-1  to work correctly.  
         [0026]    In this embodiment, the repair line  58  is divided into a first portion  58   a , two second portions  58   b , and a third portion  58   c  to connect the X-board  44   a  and  44   b . The second portions  58   b  on the X-board  44   a  and  44   b  are connected without any connectors, therefore the total amount of the connectors used in the LCD panel  40  can be reduced. In addition, due to the third portion  58   c  of the repair line  58  being set on the substrate  42  directly, this shortens the length of the repair line  58 , reduces the resistance of the repair line  58 , avoids the repair line  58  transversely crossing the conductive wires on the X-board  44   a  and  44   b , and furthermore reduces the RC delay of the repair line  58 .  
         [0027]    Please refer to FIG. 6. FIG. 6 is a schematic structure of an LCD panel  70  according to a second embodiment of the present invention. The LCD panel  70  contains a substrate  72 , two X-boards  74   a  and  74   b , a Y-board  76 , and a FPC  81  for connecting the X-board  74   b  and the Y-board  76 , wherein the X-board  74   a  can be connected to the X-board  74   b  by a FPC  75 , and the FPC  75  can be replaced by a flexible flat cable (FFC). The LCD panel  70  further contains a plurality of TCPs  78  for electrically connecting the X-boards  74   a ,  74   b  and the substrate  72 , and a plurality of TCPs  80  for electrically connecting the Y-board  76  and the substrate  72 .  
         [0028]    The substrate  72  has a plurality of scan lines S 1 -S m  thereon and a plurality of data lines D 1 -D n  thereon, wherein the scan lines S 1 -S m  are perpendicular with the data lines D 1 -D n  for defining pixels (not shown in FIG. 6) formed in a matrix in an active region  82  of the substrate  72 . The substrate  72  further contains an outer lead bonding region  84  and a plurality of bonding pads (not shown) set in the outer lead bonding region  84 . Each of the scan lines S 1 -S m  is electrically connected to its corresponding TCPs  80  through a corresponding bonding pad, and similarly each of the data lines D 1 -D n  is electrically connected to its corresponding TCPs  78  through a bonding pad.  
         [0029]    The LCD panel  70  further contains at least a repair line  88 . The repair line  88  is divided into a first portion  88   a  positioned on the substrate  72 , two second portions  88   b  positioned on the X-board  74   a  and  74   b , a third portion  88   c  for connecting every second portions  88   b , and a fourth portion  88   d  positioned on the Y-board  76 . The third portion  88   c  is set on a connective region  90 , which is positioned on the FPC  75  between the X-boards  74   a  and  74   b . It is an advantage that the conductive wire on the FPC  75  can serve as the third portion  88   c  of the repair line  88  so that the manufacturing process is capable of being simplified.  
         [0030]    Please refer to FIG. 7, which is a schematic structure of an LCD panel  100  according to a third embodiment of the present invention. The LCD panel  100  contains a substrate  102 , two X-boards  104   a  and  104   b , a Y-board  106 , and a control board  105  for outputting a signal to the X-boards  104   a  and  104   b  to control the operation of the LCD panel  100 . The control board  105  is connected to the X-boards  104   a  and  104   b  by a plurality of FPCs  105   a . The LCD panel  100  further contains a plurality of TCPs  108  and  110 , wherein the TCPs  108  is utilized for electrically connecting the X-boards  104   a ,  104   b , and the substrate  102 , and the TCPs  110  are utilized for electrically connecting the Y-board  106  and the substrate  102 .  
         [0031]    The substrate  102  has a plurality of scan lines S 1 -S m  thereon and a plurality of data lines D 1 -D n  thereon, wherein the scan lines S 1 -S m  are perpendicular with the data lines D 1 -D n  for defining pixels (not shown in FIG. 7) formed in matrix in an active region  102  of the substrate  102 . The substrate  72  further contains an outer lead bonding region  114  and a plurality of bonding pads (not shown) set in the outer lead bonding region  114 . Each of the scan lines S 1 -S m  is electrically connected to its corresponding TCPs  110  through a corresponding bonding pad, and similarly each of the data lines D 1 -D n  is electrically connected to its corresponding TCPs  108  through a bonding pads.  
         [0032]    The LCD panel  100  further contains at least a repair line  118 . The repair line  118  is divided into a first portion  118   a  positioned on the substrate  102 , two second portions  118   b  positioned on the X-boards  104   a  and  104   b , a third portion  118   c  for connecting every second portions  118   b , and a fourth portion  118   d  positioned on the Y-board  106 . The third portion  118   c  is set on a connective region  120  positioned on the control board  105 , and the conductive wire on the control board  105  can serve as the third portion  118   c  directly so as to simplify the manufacturing process.  
         [0033]    For avoiding the distortion of the image signal because of the long transmitting path, one can add output amplifiers on the repair line path of the X-board or the Y-board.  
         [0034]    In contrast to the prior art, the present invention LCD panel contains a connective region so that the repair line on each of the X-boards can be connected in the connective region. The connective region can be set on the substrate, on the FPC, which electrically connects each of the X-boards, or on a control board. If the connective region is set on the substrate of the LCD panel, the amount of the connectors for connecting two adjacent X-boards can be reduced. It will also shorten the length of the repair line so that the resistance of the repair line and the situation of the repair line transversely crossing conductive wires of the X-boards will both be reduced, and that will reduce the effect of the RC delay. If the connective region is set on the FPC or on a control board, the conductive wires on the FPC or the control board can be used to connect the repair line so that the manufacturing process can be simplified.  
         [0035]    Those skilled in the art will readily observe that numerous modification 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 metes and bounds of the appended claims.