Patent Abstract:
A liquid crystal display panel includes a repair line for substituting open-circuited signal lines. Signal lines are disposed over a first side of a first substrate of the liquid crystal display panel for data transmission. Repair lines are disposed over a first side of a second substrate of the liquid crystal display panel for substituting open-circuited signal lines. The first side of the first substrate faces the first side of the second substrate. A liquid crystal layer is disposed between the first and second substrates of the liquid crystal panel.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/626,384, filed Jan. 24, 2007 and incorporated herein in their entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display panel, and more particularly, to a liquid crystal display (LCD) panel having a plurality of repair lines and signal lines disposed at different substrates. 
     2. Description of the Prior Art 
     Liquid crystal displays (LCDs) have advantages over certain other displays, including advantages of portability, low power consumption, and low radiation emissions. The LCDs have been widely used in various portable information products, such as notebooks, personal digital assistants (PDAs), video cameras, and other similar devices. Furthermore, CRT monitors are being replaced by the LCD. 
     A general architecture of the LCD panel includes a thin-film transistor (TFT) substrate, a color filter (CF) substrate, and a liquid crystal layer between the two substrates. The TFT substrate includes a pixel matrix composed by a plurality of data lines and a plurality of scan lines. The pixel matrix of the TFT substrate, formed by the plurality of data lines and the plurality of scan lines, includes a pixel driver IC formed by electrical components such as a TFT and a capacitor installed at each intersection of each data line and each scan line. The pixel driver IC can receive a video data signal transmitted from the data line and a switch/address signal transmitted from the scan line to control operation of the corresponding pixel. In order to prevent an open circuit in the signal transmission of the data line or the scan line, in manufacturing the LCD panel, a plurality of repair lines is usually disposed in a peripheral area of the panel so that when an open circuit occurs in the transmission of external video data signals or the switch/address signal, the signals can still be transmitted to the LCD panel via the repair line for controlling the pixel operation such that poor display quality of the LCD panel due to the open circuit of the data line or scan line can be prevented. 
       FIG. 1  illustrates a top view diagram of a TFT substrate of a conventional LCD panel  10 . The TFT substrate of the LCD panel  10  includes a plurality of parallel data lines D 1 -Dm and a plurality of parallel scan lines S 1 -Sn disposed in a display area  20 . The data lines D 1 -Dm and the scan lines S 1 -Sn are intersecting and form a pixel matrix  12 . Each pixel and corresponding pixel driver IC formed by electrical components such as TFTs and capacitors is represented as a dot in  FIG. 1 . A source driver IC and a gate driver IC are packaged in a tape carrier package (TCP) manner and are represented as TCPs  24  and  26  of  FIG. 1 . The data lines D 1 -Dm can be coupled to a printed wiring board (PWB)  14  through the TCP  24  and can receive signals transmitted from the source driver IC, and the scan lines S 1 -Sn can be coupled to a PWB  16  through the TCP  26  and can receive signals transmitted from the gate driver IC. Repair lines T 1 -Ts of the LCD panel  10  can be disposed in an area outside of the display area  20  of the TFT substrate as a backup route for transmitting signals when an open circuit occurs in the data lines D 1 -Dm. Under normal circumstances, the repair lines T 1 -Ts and the data lines D 1 -Dm are not electrically connected. 
       FIG. 2  illustrates a resolution for a conventional LCD panel  10  when an open circuit occurs in a data line. If the open circuit occurs at a point A of the data line Dm (the open circuit is illustrated as “x” in  FIG. 1 ), the conventional method utilizes a laser welding method to connect a point B and a point C of the data line Dm to two ends of the repair line T 1 . The connecting point of the data line Dm and the repair line T 1  after the laser welding is illustrated as ▴ in  FIG. 2 , and the arrows in  FIG. 2  represent the signal transmission route at this moment. The normal signal transmission route starts from point B and continues to point C of the data line Dm, however, if an open circuit occurs in the data line Dm, the signal will be transmitted from point B to point C of the data line through the repair line T 1 . In other words, the signal has to pass through the topside, left side, and bottom side of the display area  20  before transmission is completed. The resulting resistance value will be too high because the transmission route is too long. More specifically, a resistance: RC delay effect is easily generated with the liquid crystal layer, hence the success rate of repairing the open circuited line is reduced. Furthermore, this technique increases the power consumption of the LCD panel  10 . 
     In the architecture of the conventional LCD panel  10 , the data lines D 1 -Dm, the scan lines S 1 -Sn, and the repair lines T 1 -Ts are disposed on the TFT substrate. In order to avoid affecting the operation of the pixel, the repair lines T 1 -Ts must be disposed outside the display area  20 , such that the lengths of the repair lines T 1 -Ts are longer than those of the data lines D 1 -Dm, making the transmission route provided by the repair lines T 1 -Ts too long, the resistance value too high, and the RC delay effect too easily generated with the liquid crystal layer, hence the success rate of repairing the open circuited line is lowered and the power consumption of the LCD panel  10  is increased. Furthermore, after the components, such as the data lines, the scan lines, and the driver ICs, are disposed on the TFT substrate, there is limited space left to dispose the repair lines. Therefore, the conventional LCD panel  10  can only provide a limited amount of space for repair lines and the repair capability is insufficient. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a display panel having a plurality of repair lines and a plurality of signal lines formed at different substrates. The display panel comprises: a first substrate, a plurality of signal lines being formed over a first side of the first substrate for data transmission; a second substrate, a plurality of repair lines being formed over a first side of the second substrate, and the first side of the second substrate faces the first side of the first substrate; a plurality of first connecting wires formed over the first substrate, intersects with a first end of the corresponding signal lines, and coupled to a first end of the corresponding repair lines through an electrical conductive material; and a plurality of second connecting wires formed over the first substrate, intersects with a second end of the corresponding signal lines, and coupled to a second end of the repair lines through the electrical conductive material. 
     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 THE DRAWINGS 
         FIG. 1  illustrates a top view diagram of a TFT substrate according to a conventional LCD panel. 
         FIG. 2  illustrates a resolution for a conventional LCD panel when an open circuit occurs in a data line. 
         FIG. 3  illustrates a top view diagram of a TFT substrate of an LCD panel according to an embodiment of the present invention. 
         FIG. 4  illustrates a top view diagram of a color filter substrate of an LCD panel according to an embodiment of the present invention. 
         FIG. 5  illustrates a cross-sectional diagram of a color filter substrate of an LCD panel along a sectional  5 - 5 ′ direction, according to the present invention. 
         FIG. 6  illustrates a cross-sectional diagram of the LCD panel along direction of the repair line R 1 , according to an embodiment of the present invention. 
         FIG. 7  illustrates a resolution for an LCD panel when an open circuit occurs in a data line, according to an embodiment of the present invention. 
         FIG. 8  illustrates a cross-sectional diagram of the color filter substrate of the LCD panel along the sectional  8 - 8 ′ direction, according to an embodiment of the present invention. 
         FIG. 9  illustrates a cross-sectional diagram of the color filter substrate of the LCD panel along the sectional  9 - 9 ′ direction, according to an embodiment of the present invention. 
         FIG. 10  illustrates a cross-sectional diagram of the color filter substrate of the LCD panel along the sectional  10 - 10 ′ direction, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In one embodiment of the present invention, a signal line of an LCD panel is disposed on a TFT substrate, and a repair line of the LCD panel is disposed on a color filter substrate.  FIG. 3  illustrates a top view diagram of a TFT substrate  30  of an LCD panel  50  according to the present invention.  FIG. 4  illustrates a top view diagram of a color filter substrate  40  of an LCD panel  50  according to the present invention. 
     In  FIG. 3 , a plurality of parallel data lines D 1 -Dm and a plurality of parallel scan lines S 1 -Sn are disposed in a display area  35  of the TFT substrate  30 . The data lines D 1 -Dm and the scan lines S 1 -Sn are intersecting and form a pixel matrix  32 . Each pixel and corresponding pixel driver IC formed by electrical components such as TFTs and capacitors is represented as a dot in  FIG. 3 . A source driver IC and a gate driver IC of the LCD panel  50  are packaged in a tape carrier package (TCP) manner and are represented as TCPs  44  and  46  of  FIG. 3 . The data lines D 1 -Dm can be coupled to a printed wiring board (PWB)  34  through the TCP  44  and can receive signals transmitted from the source driver IC, and the scan lines S 1 -Sn can be coupled to a PWB  36  through the TCP  46  and can receive signals transmitted from the gate driver IC. Connecting wires CU 1 -CUs and CL 1 -CLs are respectively disposed at two ends of the display area  35  and are respectively intersecting at two ends of the corresponding data line. An end of the connecting wires CU 1 -CUs respectively includes pads U 1 ′-Us′, and an end of the connecting wires CL 1 -CLs respectively includes pads L 1 ′-Ls′. Under normal circumstances, the connecting wires CU 1 -CUs and CL 1 -CLs and the data lines D 1 -Dm are not electrically connected. 
     In  FIG. 4 , repair lines R 1 -Rs of the LCD panel  50  are disposed on the color filter substrate  40 . As the surface of the TFT substrate  30  is disposed opposite to the surface of the color filter substrate  40 , an area  45  of the color filter substrate  40  corresponds to the display area  35  of the TFT substrate  30 . Two ends of the repair lines R 1 -Rs include pads U 1 -Us and L 1 -Ls, respectively. The pads U 1 -Us and L 1 -Ls are respectively disposed at locations corresponding to the pads U 1 ′-Us′ and L 1 ′-Ls′. 
     A black matrix, a plurality of color filters (CFs), and a counter electrode of a transparent electrically conductive layer are also disposed on the color filter substrate  40 .  FIG. 5  illustrates a cross-sectional diagram of a color filter substrate  40  of the LCD panel  50  along a sectional  5 - 5 ′. The color filter substrate  40  shown in  FIG. 5  includes color filters  51 - 54 , a black matrix  77 , a flat layer  55 , a transparent electrically conductive layer  56 , and repair lines R 1 -R 2 , and the TFT substrate  30  includes data lines D 1 -D 3 . A liquid crystal layer  59  is interposed between the TFT substrate  30  and the color filter substrate  40 . As the surface of the TFT substrate  30  is opposite to the surface of the color filter substrate  40 , the order sequence of each layer of color filter substrate  40  as illustrated in  FIG. 5  is opposite to the forming sequence of each layer of color filter substrate  40 , as this is presented in a different manner, the black matrix  77  in the figure can be located either on the top or the bottom of the color filter substrate. While only the top side is used for explanation herein, this is not a limitation of the present invention. 
     In the embodiment of  FIG. 5 , the color filters  51 - 54  can be red, green, or blue color filters disposed over the top of the color filter substrate  40  corresponding to a position between the data lines D 1 , D 2 , and D 3 . The black matrix  77  is installed between each color filter for blocking interference between different color lights such as red, green, and blue, and also for preventing any light leakage when the user views at an angle. The flat layer  55  is formed over the color filters  51 - 54  and the black matrix  77  to provide a flat surface for subsequent processes. The transparent electrically conductive layer  56  is utilized as a counter electrode of the LCD panel  50  which can be made of indium zinc oxide (IZO) or indium tin oxide (ITO). The repair lines R 1  and R 2  each include a conductive layer  57  and an insulating layer  58  disposed at a position corresponding to the black matrix  77 . 
     Next, in the following, a connecting method of the connecting wires CU 1 -CUs and CL 1 -CLs with the repair lines R 1 -Rs is explained.  FIG. 6  illustrates a cross-sectional diagram of the LCD panel  50  along direction of the repair line R 1 . The pads U 1  and L 1  at two ends of the repair line R 1  are respectively coupled to the pads U 1  and L 1  of the TFT substrate  30  through a electrically conductive material  60  (such as a silver glue) such that the repair line R 1  and the connecting wires CU 1  and CL 1  can be electrically connected. 
       FIG. 7  illustrates a resolution for the LCD panel  50  when an open circuit occurs in a data line. If the open circuit occurs at point A of the data line D 1  (the open circuit is illustrated as “x” in  FIG. 7 ), the method can utilize a laser welding method to respectively connect point B and point C of the data line D 1  to the conducting wires CU 1  and CL 1 . The connecting point of the data line D 1  and the conducting wires CU 1  and CL 1  is represented as “▴” in  FIG. 7 . At this time, signals are being transmitted from an end of the data line D 1  to the repair line R 1  through the pad U 1 ′ , the electrically conductive material  60  and the pad U 1 , and then the signals are transmitted to the other end of the data line D 1  through the pad L 1 ′, the electrically conductive material  60  and the pad L 1 . The arrows of  FIG. 6  represent the signal transmission route at the moment of time. Since the repair lines R 1 -Rs of the present invention are disposed over the color filter substrate  40  instead of over the TFT substrate  30  like the data lines D 1 -Dm, it is not required to dispose the repair lines R 1 -Rs in order to avoid the data lines D 1 -Dm and other components as in the conventional method. Thus, the length of the repair lines R 1 -Rs are identical to that of the data lines D 1 -Dm. When there is an open circuit in the data line, a low resistance value transmission route can be provided to effectively lower the RC delay effect and power consumption of the LCD panel  50 . 
       FIG. 8  illustrates a diagram of an embodiment of the present invention.  FIG. 8  can also illustrate a cross-sectional diagram of the color filter substrate  40  of the LCD panel  50  along the sectional  8 - 8 ′ direction. In  FIG. 8 , color filters  81 - 84  can be red, green, or blue color filters disposed over corresponding positions between data lines D 1 , D 2 , and D 3 . A black matrix  99  is formed between each color filter for blocking interference between different color lights, such as red, green, and blue, and also for preventing any light leakage when the user views at an angle. A flat layer  85  is formed over the color filters  81 - 84  and the black matrix  99  to provide a flat surface for subsequent processes. A transparent electrically conductive layer  86  is utilized as a counter electrode of the LCD panel  50  which can be made of indium zinc oxide (IZO) or indium tin oxide (ITO). In the embodiment of  FIG. 5 , the repair lines R 1  and R 2  are further formed on the transparent electrically conductive layer  56 . In the embodiment of  FIG. 8 , the repair lines R 1  and R 2  are manufactured in an etching process and can be defined by directly corresponding to a position of the black matrix layer  99  on the transparent electrically conductive layer  86 . 
     In the above-mentioned embodiment, the repair lines are formed on the transparent electrically conductive layer  56  and correspond to position of the black matrix layer  77 , or the repair lines can be defined by directly corresponding to the position of the black matrix layer  99 . As the black matrix layers  77  and  99  are utilized for blocking light, therefore installation of the repair lines of the present invention will not affect an opening rate of the LCD panel  50 . However, the present invention is not limited to the structure formed by disposing the repair lines corresponding to the position of the black matrix, as long as the repair lines are disposed on the color filter substrate to substitute the open circuited data line of the TFT substrate of the LCD panel, which falls within the metes and bounds of the present invention. 
     In the embodiment of  FIG. 5  and  FIG. 8 , in each set of data lines (such as data lines D 1 -D 3 ) only two repair lines are provided, however the present invention can also provide more sets of repair lines. In order to avoid affecting the opening rate as mentioned, a repair line can be disposed on the transparent electrically conductive layer  56  to correspond to a position of the black matrix layer  77 , such as the repair lines R 1 , R 1 ′, and R 2  illustrated in  FIG. 9  (cross-section  9 - 9 ′ of  FIG. 4 ). Alternately, each repair line can be defined directly corresponding to the position of the black matrix layer  99  on the transparent electrically conductive layer  86 , such as the repair lines R 1 , R 2 , and R 2 ′ shown in  FIG. 10  (cross-section  10 - 10 ′ of  FIG. 4 ). 
     According to another embodiment of the present invention, the repair lines are disposed on the TFT substrate, and the data lines are disposed over a different substrate. Therefore, it is not necessary to avoid the data lines and other components when disposing the repairing lines as in the conventional method. Thus, the length of the repair line, according to one embodiment of the present invention, is identical to the length of the data line. When there is an open circuit in the data line, a low resistance transmission route can be provided to effectively lower the RC delay effect and power consumption of the LCD panel. Furthermore, with more available space on the TFT substrate, more repair lines can be provided to increase the repair ability without lowering the opening rate. In comparison to the prior art, the present invention provides an LCD panel with a low RC effect, low power consumption, and high repair ability. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method 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.

Technology Classification (CPC): 6