Abstract:
A liquid crystal display panel is provided. The liquid crystal display panel includes a first substrate, a second substrate disposed parallel to the first substrate, a liquid crystal layer interposed therebetween, and a plurality of hybrid spacers disposed between the first substrate and second substrate, wherein the hybrid spacers comprise a soft material and a rigid material.

Description:
BACKGROUND  
       [0001]     The invention relates to a liquid crystal display panel and in particular to a liquid crystal display panel having a specific spacer and fabrication method thereof.  
         [0002]     Liquid crystal display panels are among the most popular type of displays.  FIG. 1  is a cross section of a liquid crystal display panel. The liquid crystal display panel comprises a first substrate  12  and a second substrate  14 . The first substrate  12  and the second substrate  14  may be glass substrate, color filter (CF) substrate or thin film transistor (TFT) substrate. A plurality of spacers  18  are disposed between the first substrate  12  and the second substrate  14  for filling liquid crystal  16  therebetween.  
         [0003]     One drop fill (ODF) shown in  FIG. 2A ˜ 2 C is one of the most important technologies for liquid crystal display panel fabrications. In  FIG. 2A , gel  13  is coated on the first substrate  12 . Liquid crystal  16  is dropped on the first substrate  12 , and then second substrate  14  is assembled with first substrate  12  in vacuum as shown in  FIG. 2B . After back to atmosphere pressure, the two substrates  12  and  14  are assembled to form a liquid crystal display panel, as shown in  FIG. 2C . Spacers  18  as shown in  FIG. 1  can be disposed on first substrate  12  or second substrate  14 . The amount of the liquid crystal  16  is based on the volume of spacer  18 .  
         [0004]     However, bubbles form as the liquid crystal or the spacers shift. Bubbles formation deteriorates the performance of the liquid crystal display panel.  
         [0005]     One way to address the bubble problem is to use softer spacers to improve the liquid crystal margin (LC margin), but the compressive resistance of the liquid crystal display panel decreases.  
       SUMMARY  
       [0006]     Accordingly, embodiments of the invention provide a liquid crystal display panel and a fabrication method thereof.  
         [0007]     In an embodiment of the invention, a liquid crystal display panel comprises a first substrate, a second substrate disposed parallel to the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate and a plurality of hybrid spacers disposed between the first substrate and second substrate, wherein the hybrid spacers comprise a soft material and a rigid material.  
         [0008]     In another embodiment, a fabrication method for a liquid crystal display panel is provided. This method comprises providing a first substrate and forming a plurality of hybrid spacers on the first substrate. The hybrid spacers comprise a soft material and a rigid material. Liquid crystal is applied to the first substrate. A second substrate is assembled with the first substrate. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0009]     The embodiments can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
         [0010]      FIG. 1  is a cross section illustrating a conventional liquid crystal display panel structure.  
         [0011]      FIGS. 2A  to  2 C are cross sections illustrating a fabrication process of a conventional liquid crystal display panel.  
         [0012]      FIGS. 3A  to  3 C are cross sections illustrating a fabrication process of a liquid crystal display panel of an embodiment.  
         [0013]      FIGS. 4A  to  4 C are cross sections illustrating hybrid spacer structures of embodiments of the invention.  
     
    
     DETAILED DESCRIPTION  
       [0014]     Embodiments of liquid crystal display panels are described with  FIG. 3A  to  3 C and  FIG. 4A  to  4 C.  
         [0015]     In  FIG. 3A , a plurality of hybrid spacers  120  are formed on first substrate  110 . The first substrate  110  may be thin film transistor (TFT) substrate or color filter (CF) substrate, comprising a glass or indium tin oxide (ITO) substrate. The hybrid spacers  120  may be formed by photoresist or acrylic resin. The hybrid spacers  120  comprise a soft material  124  and a rigid material  122 . The soft material  124  has pencil hardness of less than about  3 H, and the rigid material  122  has pencil hardness more of than about  3 H. The soft material  124  and the rigid material  122  are distributed uniformly contained in hybrid spacer  120  as shown in  FIG. 4A , or are layered distributed as shown in  FIGS. 4B and 4C . The ratio of soft material  124  and the rigid material  122  can be altered depending on different needs. Note that the terms “soft” and “rigid” merely represent relative hardness, not necessarily limited to pencil hardness. Furthermore, those skilled in the art will understand that more than two materials of different hardness may be used to form the hybrid spacer of the invention.  
         [0016]     A method for forming hybrid spacers  120  as shown in  FIG. 4A  is described in the following. A hybrid spacer  120  including soft material  124  and rigid material  122  is coated on the first substrate  110 . The hybrid mixture of hybrid spacer  120  can be prepared by mixing the soft material  124  and the rigid material  122  or by using a hybrid photoresist comprising soft material  124  and rigid material  122 . The hybrid layer may be patterned by lithography and etching to form a plurality of hybrid spacers  120 .  
         [0017]     A method for forming hybrid spacers  120  as shown in  FIGS. 4B and 4C  is described in the following. A hybrid mixture including soft material  124  and rigid material  122  is coated on the first substrate  110  to form a hybrid layer. The characteristics of soft material  124  and rigid material  122 , such as density difference, hydrophilic, hydrophobic, surface tension, soft material  124  and rigid material  122  in the hybrid mixture enable natural layer distribution. After patterning the hybrid layer, the hybrid spacer  120  is formed shown as  FIG. 4B  or  FIG. 4C .  
         [0018]     Another method for forming hybrid spacers  120  as shown in  FIGS. 4B and 4C  is described in the following. A first layer A and a second layer B are formed on the first substrate  110  sequentially. After patterning the first layer A and the second layer B, the hybrid spacer  120  is formed shown as  FIG. 4B  or  FIG. 4C . The hybrid spacer  120  comprising the first layer A including the rigid material  122  and the second layer B including the soft material  124  is shown as  FIG. 4B . The hybrid spacer  120  comprising the first layer A including the soft material  124  and the second layer B including the rigid material  122  is shown as  FIG. 4C .  
         [0019]     The thickness of hybrid spacer  120  depends on the predetermined space between the first substrate  110  and the subsequent assembles of second substrate  140 . The thickness of the hybrid spacer  120  is about 1 to 10 μm. The hybrid spacer  120  is pillar-shaped or ball-shaped.  
         [0020]     In  FIG. 3B , liquid crystal is dropped onto the first substrate  110  by the one drop fill (ODF) method or into the space between the first substrate  110  and the second substrate  140  after assembling.  
         [0021]     In  FIG. 3C , the second substrate  140  is assembled with the first substrate  110 . The second substrate  140  may be a thin film transistor (TFT) substrate or a color filter (CF) substrate comprising a glass substrate or indium tin oxide (ITO) substrate.  
         [0022]     The liquid crystal display panel of the present invention comprises a hybrid spacer. During the one drop fill process, the soft material of the hybrid spacer decreases compressive resistance between the substrates, thus bubbles decrease. After the one drop fill process, the rigid material of the hybrid spacer increases compressive resistance between the substrates, thus durability of the liquid crystal display panel improves.  
         [0023]     While the invention has been described by way of Example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation to encompass all such modifications and similar arrangements.