Abstract:
A liquid crystal display device includes first and second substrates facing each other and attached to each other with a cell-gap therebetween, gate lines and data lines arranged horizontally and vertically on the first substrate, first lines formed on the first substrate, connected to the gate lines or the data lines, and each having a link bending point and bent at an angle, a TCP electrically attached to the first substrate, and second lines formed on the TCP and electrically connected to the first lines respectively. At least one link bending point is positioned at a region of the TCP.

Description:
[0001]     The present invention claims the benefit of Korean Patent Application No. P2003-57609 filed in Korea on Aug. 20, 2003, which is hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a flat and light LCD device.  
         [0004]     2. Description of the Related Art  
         [0005]     In general, a LCD device includes a LCD panel for displaying an image, and a driving unit for driving the LCD panel. The LCD panel is fabricated by attaching a thin film transistor array substrate to a color filter substrate with a cell-gap therebetween, and filling the cell-gap with a liquid crystal material to form a liquid crystal layer. The driving unit includes a gate driving unit, a data driving unit and a printed circuit board (PCB). The gate driving unit includes a plurality of driving integrated circuits (D-IC), and supplies a scan signal to the gate lines sequentially to activate the pixels. The data driving unit also includes a plurality of D-ICs, and supplies an image signal to the pixels through the data lines.  
         [0006]     The printed circuit board (PCB) supplies control signals and an image signal to the gate driving unit and the data driving unit. Various devices are mounted on the PCB. The PCB processes and converts externally supplied data into control signals for driving a LCD device. Then, the PCB distributes the control signals to the gate driving unit and the data driving unit.  
         [0007]     Several methods can be used for electrically connecting the D-ICs constituting the data driving unit and the gate driving unit to the LCD panel, examples of which are tape-automated bonding (TAB) method and chip-on-glass (COG) method. In the TAB method, the D-ICs are connected to the LCD panel by electrically connecting a TCP (tape carrier package) at the location where the D-ICs are mounted to the LCD panel. An edge of the thin film transistor array substrate is exposed when the two substrates are attached because an area of the thin film transistor array substrate is larger than that of the color filter substrate. Moreover, the TCP is attached to the exposed area along the edge. One D-IC is mounted on each TCP.  
         [0008]     In the COG method for electrically connecting the D-ICs to the LCD panel, the D-ICs are directly mounted on the LCD panel. The COG method has several advantages. For example, in the COG method, the LCD panel can be made compact because the D-ICs are directly mounted on a glass substrate of the LCD panel. However, the COG method may cause damages to the glass substrate due to the high temperature required for directly mounting the D-ICs on the glass substrate. For this reason, the TAB method, which involves simpler processes, is mainly used.  
         [0009]      FIG. 1A  is a view of a related art LCD device employing a TAB method. As shown in  FIG. 1A , the LCD device includes a thin film transistor array substrate G 1  and a color filter substrate G 2  which are attached to each other. A plurality of TCPs  10  are electrically connected to the thin film transistor array substrate G 1 . A D-IC  9  is mounted on each TCP  10 . A PCB  5  is connected to the TCP  10  to provide an image signal and a control signal to the thin film transistor array substrate G 1  through the TCP  10 . One side of the TCP  10  is connected to an edge of the thin film transistor array substrate G 1 . Another side of the TCP  10  is connected to the PCB  5 .  
         [0010]     Although not shown in  FIG. 1A , gate lines and data lines are arranged horizontally and vertically on an LCD panel. The gate lines and the data lines are attached to the thin film transistor array substrate G 1  and the color filter substrate G 2 , and cross each other. The crossing of the gate lines and the data lines define pixel regions in a matrix arrangement. The pixel is a minimum unit for displaying an image. The arrangement of the pixels form an active area  13  where an image is actually displayed.  
         [0011]      FIG. 1B  is an enlarged view of a portion ‘A’ of the related art LCD device depicted in  FIG. 1A . As shown in  FIG. 1B , a width (W T ) of the TCP  10  attached to the LCD panel is smaller than a width (W L ) of a region within the active area  13  where data/gate lines  20  for connection to the TCP  10  are formed. A plurality of link lines  22  are formed at the LCD panel. The plurality of link lines  22  are connected to data/gate lines  20 . Because the intervals between link lines  22  are narrower than the intervals between the data/gate lines  20 , the link lines  22  are spread out, like the ribs of a fan, from the TCP  10  to the active region  13  for connection to the data/gate lines  20 .  
         [0012]      FIG. 1C  is an enlarged view of a portion ‘B’ of the related art LCD device depicted in  FIG. 1B , showing a connection between a TCP output line and a link line. As shown in  FIG. 1C , a link line  22  connected to a TCP output line  21  is bent at an angle for connection to the data and gate lines. The point at which a link line is bent is defined as a link bending point  25 . The link lines  22  and the TCP output lines  21  are disposed at regular intervals.  
         [0013]     To prevent the link lines  22  from short-circuiting each other, link bending points  25  are obliquely arranged between each side of the TCP  10 , and a central region thereof. Accordingly, a distance of the link bending points  25  from the TCP  10  increases as the link bending points get closer to the central region of the TCP  10 . Moreover, as the link bending points get closer to the central region of the TCP  10 , each corresponding link line  22  is extended from one side of the TCP  10  by an extension length (L P ). Thus, the link bending points  25  are formed outside, not within the TCP  10  region.  
         [0014]     The extension of the link lines  22  allows an interval to be maintained between the link lines  22  to prevent the link lines from short-circuiting each other. Such a short-circuit could generate an interference between the link lines  22 . An area in which link lines  22  are formed is referred to as a panel link region. A width of the panel link region is referred to as a panel link length (W A ). In order to connect the data lines and the gate lines to the TCP  10  like the ribs of a fan as described above, each link line  22  has to be extended by an appropriate extension length (L P ). Thus, a panel link region having an appropriate panel link length (W A ) is required.  
         [0015]     When fabricating a high-resolution LCD device, because of a corresponding increase in the number of gate lines, data lines, TCP output lines, and link lines, the extension lengths of link lines have to be correspondingly increased to maintain the intervals between link lines. Accordingly, the panel link length increases correspondingly in high-resolution applications. Moreover, various lines are formed within the panel link region to supply various control signals or image signals to an active area. Thus, if a panel link length increases, the LCD device correspondingly increases in weight and size of a LCD.  
       SUMMARY OF THE INVENTION  
       [0016]     Accordingly, the present invention is directed to a liquid crystal display device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.  
         [0017]     An object of the present invention is to provide a flat and light liquid crystal display device.  
         [0018]     Another object of the present invention is to provide a liquid display device with a reduced panel area.  
         [0019]     Another object of the present invention is to provide a liquid display device with an improved image display quality.  
         [0020]     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. These and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0021]     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the liquid crystal display device includes first and second substrates facing each other and attached to each other with a cell-gap therebetween, gate lines and data lines arranged horizontally and vertically on the first substrate. First lines are formed on the first substrate, connected to the gate lines or the data lines, and each having a link bending point and bent at an angle. A TCP is electrically attached to the first substrate. Second lines are formed on the TCP and electrically connected to the first lines respectively. At least one link bending point is positioned at a region of the TCP.  
         [0022]     In another aspect, the liquid crystal display device includes first and second substrates facing each other and attached to each other with a cell-gap therebetween, a plurality of first lines formed on the first substrate and each having a link bending point at which the first line is bent at an angle, and a plurality of second lines electrically connected to the first lines respectively. The TCP has a slanted portion at an edge thereof. At least one link bending point is positioned on the slanted portion of the TCP.  
         [0023]     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a unit of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:  
         [0025]      FIG. 1A  is a view of a related art LCD device employing a TAB method;  
         [0026]      FIG. 1B  is an enlarged view of a portion ‘A’ of the related art LCD device depicted in  FIG. 1A ;  
         [0027]      FIG. 1C  is an enlarged view of a portion ‘B’ of the related art LCD device depicted in  FIG. 1B , showing a connection between a TCP output line and a link line;  
         [0028]      FIG. 2A  is an enlarged view of an exemplary LCD device in accordance with a first embodiment of the present invention, showing a connection portion of a TCP output line and a link line;  
         [0029]      FIG. 2B  is an exemplary sectional view taken along line I-II of  FIG. 2A  in accordance with a second embodiment of the present invention;  
         [0030]      FIG. 3A  depict a connection of a TCP to an exemplary LCD device in accordance with a third embodiment of the present invention; and  
         [0031]      FIG. 3B  is an enlarged view of a portion ‘C’ of  FIG. 3A  depicting a connection portion of a TCP output line and a link line. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
         [0033]      FIG. 2A  is an enlarged view of an exemplary LCD device in accordance with a first embodiment of the present invention, showing a connection portion of a TCP output line and a link line. As shown in  FIG. 2A , TCP output lines  121  are formed on a TCP  110 . Link lines  122  are formed on an LCD panel. The TCP output lines  121  and the link lines  122  are electrically connected.  
         [0034]     Referring to  FIG. 2A , corresponding TCP output lines  121  and link lines  122  overlap one another within a first region of the TCP, and are connected to each other. In embodiments of the present invention, some of the link lines  122  are bent within a second region of the TCP  110  such that the bent link lines  122  are overlapped with the TCP output lines  121  in the second region of the TCP  110 . The points at which each of the links  122  bend are link bending points  125 . Specifically, some of the bending points  125  of the link lines  122  are overlapped by the TCP output lines  121  in the second region. Accordingly, some of the link bending points  125  are covered because of their overlap by the TCP output lines  121  in the second region of the TCP  110 , which are attached to a thin film transistor array substrate.  
         [0035]     In accordance with the first embodiment of the present invention, an extension length (L P ′) of each link line  122  is shorter in comparison to the related art. Moreover, a plurality of the link lines  122  do not require an extension length (L P ′) because they are bent at link bending points  125  in the second region of the TCP  110  where the link lines  122  are overlapped with the TCP output lines  121 . Accordingly, a panel link length can be reduced.  
         [0036]     However, when the TCP output lines  121  overlap the link bending points  125  in the second region of the TCP  110  as set forth above, a connection may occur between a bent link line  122  having a bending point  125  within the second region of the TCP  110 , and an adjacent TCP output line  121  other than the corresponding TCP output line  121 . Such a connection between a bent link line  122  and an adjacent TCP output line  121  will cause a short-circuit. Such a short-circuit will impair the transmission of an accurate signal through the affected lines, thereby degrading the quality of a displayed image.  
         [0037]      FIG. 2B  is an exemplary sectional view taken along line I-II of  FIG. 2A  in accordance with a second embodiment of the present invention. In the second embodiment of the invention, an insulation film is formed on the link line  122  to prevent the short-circuit discussed above. As shown in  FIG. 2B , the link line  122  is formed on the thin film transistor array substrate G 1 ′. An insulation film  130  is formed on the link line  122 . The insulation film  130  is formed on the entire panel link region. Thus, the insulation film  130  covers the link lines  122  and an exposed portion of the substrate. A contact hole  140  is formed through the insulation film  130  to expose a portion of the link line  122 . The contact hole  140  is filled with a conductive material. The conductive material may be a transparent conductive material, for example ITO (Indium Tin Oxide).  
         [0038]     The TCP output line  121  is formed on the TCP  110 . When the TCP  110  is attached to the thin film transistor array substrate G 1 ′, each TCP output line  121  is electrically connected only to a corresponding link line  122  through the contact hole  140  filled with the conductive material, for example ITO. Thus, a short-circuit is prevented because each corresponding link line  122  is only connected to the corresponding TCP output line  121  through the contact hole.  
         [0039]     In the process of insulating the link line  122 , an insulation film may be formed only within the second region where the link lines  122  bend at the link bending points  125  are overlapped with the neighboring TCP output lines  121 .  
         [0040]     In  FIG. 2B , the insulation film  130  is formed on the thin film transistor array substrate G 1 ′, and the contact hole  140  is formed through the insulating film  130 . However, the insulation film  130  may be formed on the TCP  110 , thereby insulating the TCP output line  121  and the link line  122 . Then, the contact hole  140  should be formed by removing the insulation film in a region corresponding to the TCP output line  121 .  
         [0041]     By the above-mentioned insulation methods, a TCP structure which can prevent a short-circuit between the link lines  122  and the neighboring TCP output lines  121  can be formed, thereby decreasing the panel link length.  
         [0042]     In a second embodiment of the present invention, a short-circuit between the TCP output line  121  and the link line  122  is prevented by forming the insulation film within the second region, where the neighboring TCP output line  121  and the link line  122  are overlapped, or over an entire panel link region. However, if the insulation film is destroyed or damaged due to high pressure or heat applied in TCP bonding, while attaching the TCP  110  to the thin film transistor array substrate G 1 ′, the TCP output line  121  and the link line  122  may electrically come in contact with each other through the damaged part of the insulation film, thereby causing a short-circuit.  
         [0043]     To address the potential short-circuit due to destruction or damage of the insulation film, and ensure the reliability of the insulating film between the TCP output line  121  and the link line  122 , an improved TCP structure is disclosed in accordance with a third embodiment of the present invention.  
         [0044]      FIG. 3A  depicts a connection of a TCP to an exemplary LCD device in accordance with a third embodiment of the present invention. As shown therein, a structure of a third embodiment is similar to the TCP structure of the first embodiment except for a change in the position of a link bending point, at which a link line  122  is bent.  
         [0045]     Referring to  FIG. 3A , both ends of a TCP  110 , which is attached to an edge G 1 ′ of a thin film transistor array substrate of an LCD panel, are removed obliquely. Herein, both ends of the TCP  110  are processed obliquely to remove the extension of the TCP output lines beyond the link bending points. Accordingly, when link bending points are formed on the TCP  110 , spurious connections between the link lines  122  and adjacent TCP output lines  121  are prevented, thus avoiding the potential short-circuit described in reference to the first embodiment.  
         [0046]      FIG. 3B  is an enlarged view of a portion ‘C’ of  FIG. 3A  depicting a connection portion of a TCP output line and a link line. As shown in  FIG. 3B , when both edges of the TCP  110  are removed obliquely, the second region depicted in  FIG. 2 , where a plurality of the TCP output lines  121  overlap some of the link lines  122 , is removed. The link bending points of the link lines  122  formed at the oblique area are positioned on one side of the TCP  110 . Accordingly, a short-circuit between the TCP output lines  121  and the link lines  122  is prevented.  
         [0047]     As shown in  FIG. 3A , when both ends of the TCP  110  have been removed at an oblique angle. A width (Wc) of a central region of the TCP  110  is different than a width (We) at its edge. The oblique angle depends on a position of a link bending point on the TCP  110 , an interval between the link lines  122 , and an angle between the TCP output line  121  and the link line  122 . Thus, even if the number of link lines  122  is larger than in the related art, the link lines  122  can be arranged at regular intervals within panel line region of the same size because the link bending points are formed along the slanted edge. The bending points of the link lines  122  formed within a central region of the TCP  110  are formed after the link lines  122  have been extended from a side of the TCP  110  by lengths similar to the first embodiment. Specifically, the link bending points formed within the central region of the TCP  110  are formed outside the TCP  110  region.  
         [0048]     In the third embodiment of the present invention, the occurrence of a short-circuit between the link lines  122  and adjacent TCP output lines  121  can be prevented without using a special insulating film. Thus, the issue of reliability of the insulation film of the first embodiment can be resolved. In addition, because the link lines are bent on the end portions of the slanted sides made by removing both ends of the TCP obliquely, even if the number of link lines  122  increases, they can be arranged at regular intervals to fit even within a small panel line region. Moreover, a panel link length can be reduced. Accordingly, the size of the LCD device can be reduced.  
         [0049]     It will be apparent to those skilled in the art that various modifications and variations can be made in the liquid crystal display device of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.