Patent Publication Number: US-2006007383-A1

Title: Liquid crystal display panel with perforated transmission lines

Description:
FIELD OF THE INVENTION  
      The present invention relates to a liquid crystal display (LCD) panel, and especially to an LCD panel manufactured by a one-drop-fill (ODF) method.  
     BACKGROUND  
      An LCD panel generally includes two glass substrates, a peripheral sealant, and a plurality of liquid crystal molecules disposed between the substrates. The sealant is printed on one of the glass substrates, and then adhered to the other glass substrate. The substrates and the sealant cooperatively form a space therebetween, with the liquid crystal molecules being filled in the space.  
      There are generally two methods used for filling the liquid crystal molecules into the space. The first method is to fill the liquid crystal molecules through filling ports. This method includes the following steps: firstly, coating a sealant on a first glass substrate, the sealant being rectangular and having one or more gaps that function as filling ports; secondly, attaching a second glass substrate to the first glass substrate and curing the sealant, with a space being enclosed by the sealant and the two glass substrates; thirdly, immersing the filling ports in a liquid crystal in a vacuum chamber; and finally, introducing gas into the vacuum chamber to make the liquid crystal molecules fill up the space.  
      The second method is the so-called one-drop-fill (ODF) method. This method comprises the following steps: firstly, printing a sealant on a first glass substrate, wherein the sealant is rectangular and continuous, and a space is enclosed by the sealant and the first glass substrate; secondly, putting liquid crystal molecules into the space drop by drop using a dispenser; and finally, combining a second glass substrate with the first glass substrate and curing the sealant.  
      Referring to  FIG. 8 , a conventional LCD panel  100  includes a first substrate  101  and a second substrate  102  disposed opposite to each other and spaced apart a predetermined distance, and a liquid crystal layer (not shown) containing a plurality of liquid crystal molecules disposed between the first and second substrates  101  and  102 .  
      A sealant  116  surrounds the liquid crystal layer. The sealant  116  is arranged between the first and second substrates  101  and  102 , and supports the first and second substrates  101  and  102  so that the space therebetween is maintained. A plurality of gate lines  108  and data lines  109  are cross-formed on the first substrate  101 , thereby defining a plurality of pixel regions. Each of the pixel regions includes a thin film transistor (TFT), the TFT functioning as a driver element. First and second conductive pads  114  and  115  are arranged on the first substrate  101  outside of the sealant  116 . Ends of the gate lines  108  and data lines  109  are respectively electrically connected to the first and second conductive pads  114  and  115 . The first conductive pads  114  are electrically connected to a gate driver IC (not shown), and convey scanning signals to the gate lines  108 . The second conductive pads  115  are electrically connected to a data driver IC (not shown), and convey data signals to the data lines  109 .  
      A color filter (not shown) and a black matrix  103  are arranged on the second substrate  102 . The black matrix  103  is made of opaque metal, such as Cr. The black matrix  103  shelters the gate lines  108 , data lines  109 , sealant  116  and TFT from irradiation by an external light source.  
      The LCD panel  100  is manufactured by the one-drop-fill (ODF) method, with the sealant  116  being made of an ultraviolet curing adhesive. An ultraviolet light source is provided outside of the first substrate  101 , in order to cure the sealant  116 .  
      Referring to  FIG. 9 , on the LCD panel  100 , the sealant  116  partly covers the gate line  108  and the data line  109 . Since the gate line  108  and the data line  109  are made of opaque metal, when the ultraviolet light source cures the sealant  116 , some of the ultraviolet light is blocked by the gate line  108  and the data line  109 . Accordingly, portions of the sealant  116  covered by the gate line  108  and the data line  109  may not be completely cured. This may reduce the strength and reliability of the LCD panel  100 . In addition, the sealant  116  is liable to mix with and contaminate adjacent liquid crystal molecules. Both these problems can adversely affect the display image generated by the liquid crystal layer.  
      What is needed, therefore, is an LCD panel with a high quality, reliable display effect.  
     SUMMARY  
      In an exemplary embodiment of the present invention, an LCD panel includes a first substrate and a second substrate opposite to each other, a liquid crystal layer interposeed between the first and second substrates, a sealant disposed between the first and second substrates and surrounding the liquid crystal layer, a plurality of gate lines and data lines perpendicularly formed on the first substrate. Each gate line and each data line define a plurality of overlapping areas overlapped by the sealant. Each overlapping area has at least an opening.  
      Each gate lines and data lines would include a discontinuous region, the discontinuous region has at least an opening.  
      In the LCD panel, each gate lines and data lines have a plurality of openings on the overlapping areas. Thus, ultraviolet light irradiate the sealant on the overlapping areas through the openings, and would completely cure the sealant, the sealant is not liable to pollute the liquid crystal molecules. That is, the LCD panel has a high quality display effect.  
      Other novel features and advantages will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an abbreviated, cut-away top plan view of part of an LCD panel according to a first embodiment of the present invention.  
       FIG. 2  is an enlarged, isometric view of part of the LCD panel shown in  FIG. 1 , showing a sealant overlying a plurality of gate lines on a substrate.  
       FIG. 3 - FIG. 5  are various simplified views of sequential stages in a process for forming openings in the gate lines of the LCD panel in accordance with the first embodiment.  
       FIG. 6  is an enlarged, top cross-sectional view of a pattern of openings in a gate line of an LCD panel according to a second embodiment of the present invention.  
       FIG. 7  is an enlarged, top cross-sectional view of a pattern of openings in a gate line of an LCD panel according to a third embodiment of the present invention.  
       FIG. 8  is an abbreviated, cut-away top plan view of part of a conventional LCD panel.  
       FIG. 9  is an enlarged, isometric view of part of the LCD panel shown in  FIG. 8 , showing a sealant overlying a plurality of gate lines on a substrate. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      Referring to  FIG. 1 , an LCD panel  200  according to a first embodiment of the present invention includes a first substrate  201  and a second substrate  202  disposed opposite to each other and spaced apart a predetermined distance, and a liquid crystal layer (not shown) containing a plurality of liquid crystal molecules is disposed between the first and second substrates  201  and  202 .  
      A sealant  216  is disposed between the first and second substrates  201  and  202 , such that the sealant  216  surrounds the liquid crystal layer. A plurality of gate lines  208  and data lines  209  are crosswisedly formed on the first substrate  201 , thereby defining a plurality of pixel regions. Each of the pixel regions includes a thin film transistor (TFT), the TFT functioning as a driver element. A plurality of first and second conductive pads  214  and  215  are arranged on the first substrate  201  outside of the sealant  216 . Ends of the gate lines  208  and the data lines  209  are respectively electrically connected to the first and second conductive pads  214  and  215 . The first conductive pads  214  are electrically connected to a gate driver IC (not shown), and convey scanning signals to the gate lines  208 . The second conductive pads  215  are electrically connected to data driver IC (not shown), and convey data signals to the data lines  209 .  
      A color filter (not shown) and a black matrix  203  are arranged on the second substrate  202 . The black matrix  203  is made of opaque metal, such as Cr, and shelters the gate lines  208 , data lines  209 , sealant  216  and TFTs from irradiation by ambient light. The sealant  216  is a rectangular, continuous body made of an ultraviolet curing adhesive. An ultraviolet light source outside of the first substrate  201  is used to cure the sealant  216 .  
      Also referring to  FIG. 2 , this is an enlarged view of the sealant  216  overlying a plurality of the gate lines  208 . Each gate line  208  is partially overlapped by the sealant  216 , thereby defining a plurality of overlapping areas  218  of the gate line  208 . Each overlapping area  218  has a plurality of openings  204 . Each opening  204  is circular. A diameter of the opening  204  is in the range from 1 to 5 microns, and a distance separating each two adjacent openings  204  is in the range from 1 to 5 microns. In this exemplary embodiment of the present invention, the diameter of each opening  204  is 3 microns. Each data line  209  is also partially overlapped by the sealant  216 , thereby defining a further plurality of overlapping areas  218  of the data line  209 .  
      When an ultraviolet light source is used at the outside of the first substrate  201  to cure the sealant  216 , some of the ultraviolet light directly irradiates parts of the sealant  216  behind the overlapping areas  218  via the openings  204 . On the other hand, a total area of the openings  204  in each overlapping area  216  is less than 90% of the total area of the overlapping area  216 . This configuration helps ensure that the sealant  216  behind the overlapping areas  218  can be effectively cured, while also helping to ensure that scanning and data signals can be effectively transmitted through the gate and data lines  208 ,  209 .  
      In summary of the LCD panel  200 , each of the gate lines  208  and data lines  209  has a plurality of openings  204  in the overlapping areas  218  thereof. Ultraviolet light irradiates the sealant  216  behind the overlapping areas  218  through the openings  204 , and thus can completely cure the sealant  216  thereat. As a result, the sealant  216  is prevented from contaminating the liquid crystal molecules. That is, the LCD panel  200  can provide a high quality display effect.  
      The openings  204  are formed by a photo mask and etching process. Referring to  FIG. 3 , this shows a schematic, abbreviated top view of a photo mask  3 . The photo mask  3  includes an opening pattern  31 . The opening pattern  31  includes a plurality of circular openings  311 . The opening pattern  31  is located corresponding to one of the overlapping areas  218  of the LCD panel  200 .  
      Referring to  FIG. 4  and  FIG. 5 , the gate lines  208  are formed on the first substrate  201 . A photo resist layer  4  is uniformly coated on the gate lines  208  and the first substrate  201 . The photo mask  3  is positioned above the photo resist layer  4 . Light beams irradiate the photo resist layer  4  through the openings  311 , and form a photo resist pattern on the gate lines  208 . Then the gate lines  208  are etched, thereby forming the openings  208  on an area of the gate lines  208  corresponding to openings  311 . A corresponding procedure is performed for the data lines  209 .  
      Referring to  FIG. 6 , this shows a schematic, top view of a second embodiment of the opening pattern of the gate lines  208 . The opening pattern includes a plurality of rectangular openings  304 . The openings  304  are parallel to each other. A length L of the openings  304  is less than a breadth D of the date lines  208 . A distance S separating each two adjacent openings  304  is less than a breadth W of the openings  304 . In the illustrated embodiment, the distance S is less than 50 microns. A total area of the openings  304  in each overlapping area  318  is less than 90% of a total area of the overlapping area  318 . In this embodiment, the length L of the openings  304  is equal to the breadth D of the date lines  208 .  
      Referring to  FIG. 7 , this shows a schematic, top view of a third embodiment of the opening pattern of the gate line  208 . The opening pattern includes a plurality of square openings  404 , the openings  404  cooperatively forming matrix array. A total area of the openings  404  in each overlapping area  418  is less than 90% of a total area of the overlapping area  418 .  
      In the LCD panel, the openings of the data lines have the same configuration as the openings of the gate lines. The openings of the gate lines and the data lines can alternatively be elliptical, triangular, or polygonal. The sealant can alternatively be made of a mixture of an ultraviolet curing adhesive and a heat curing adhesive.  
      In the LCD panel, each gate lines and data lines have a plurality of openings on the overlapping areas, ultraviolet light irradiate the sealant on the overlapping areas through the openings, and would completely cure the sealant, the sealant is not liable to pollute the liquid crystal molecules. That is, the LCD panel has a high quality display effect.  
      It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.