Abstract:
A method of manufacturing a liquid crystal display panel, comprising the steps of: forming a plurality of pixels on a first substrate; forming a plurality of micro cell structures on the first substrate, wherein each micro cell structure surrounds at least one pixel; forming a first alignment layer on the first substrate; providing the micro cell structures with a liquid crystal by utilizing Ink Jet Printing technology; and combining the first substrate with a second substrate by forming a sealing member therebetween.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a method of manufacturing a liquid crystal display panel. In particular, the invention relates to a method of manufacture whereby the steps of forming a plurality of micro-cell structures on one substrate of the display, injecting the liquid crystal into the cells and sealing the two substrates accomplish the manufacture of the liquid crystal display. 
   2. Description of the Related Art 
     FIG. 1  shows a basic structure of the conventional liquid crystal panel. As shown in  FIG. 1 , a thin layer of liquid crystal  2  is retained between two substrates  16   a ,  16   b  by a sealing member  19 . The substrate  16   a  has transparent electrodes  17   a  formed on regions of the inner surface thereof, with an alignment layer  18   a  (i.e. for molecular alignment of the liquid crystal) formed over the electrodes and the remainder of the inner surface of the substrate. The substrate  16   b  is similarly formed with transparent electrodes  17   b  and alignment layer  18   b . Spacers  23  are disposed in the liquid crystal, for maintaining a uniform size of gap between the two opposing surfaces of the substrates. 
   In general, it is necessary to mutually laterally position the two substrates of a liquid crystal display panel to a very high degree of accuracy, i.e. to position one substrate very precisely above the other. The most popular method of manufacture for such a liquid crystal display panel is as follows. Firstly, an empty cavity is formed, i.e. consisting of the two opposed substrates  16   a ,  16   b  accurately mutually aligned, and mutually attached by the sealing member  19  between them, but without the liquid crystal  2 . The cavity is then filled with the liquid crystal  2 , utilizing a vacuum insertion method, and then sealed. However such a method has various disadvantages, such as a considerable length of time being required to complete the process of filling the cavity with the liquid crystal  2 , in the case of a large-size liquid crystal display panel. 
   For that reason, a method of manufacture has been proposed which is based upon first dropping liquid crystal onto a substrate, as described in Japanese Patent Laid-open No. 62-89025. The basic concepts of the “dropping” method are illustrated in  FIG. 2 , in which a sealing member  22  is formed in a peripheral region of one substrate  20   a , while liquid crystal  21  is dropped onto the other substrate  20   b . With the two substrates held spaced apart, the substrates are placed within a vacuum chamber of a vacuum assembly apparatus. In that condition (still under atmospheric pressure), the lateral positions of the two substrates  20   a ,  20   b  are mutually aligned, i.e. so that the substrate  20   a  becomes positioned precisely above the substrate  20   b . The air pressure within the vacuum chamber is then reduced, and under the condition of the low pressure, the two substrates are brought together so that the substrate  20   a  becomes superposed on the substrate  20   b . Thereafter, the sealing member  22  is hardened, e.g. by application of suitable radiation. 
   However, with this method, it is necessary to execute very accurate mutual lateral alignment of the two substrates while the substrates are within the vacuum chamber, with the substrates being held apart by only a few millimeters. It is therefore necessary to achieve a positioning accuracy within the range of several microns to several tens of microns, for position adjustment and position control within the vacuum chamber. Hence, the overall size, complexity and cost of a vacuum assembly apparatus that utilizes such a vacuum chamber are excessive. Moreover, this will result in an increase in the most common causes of defects in liquid crystal display panels, i.e. defects due to the presence of dust particles within the panel cavity, short-circuits between the electrodes of the upper and lower substrate, etc. 
   SUMMARY OF THE INVENTION 
   To solve the above problems, it is an object of the present invention to provide a method of manufacturing a liquid crystal display panel, comprising the steps of: forming a plurality of pixels on a first substrate; forming a plurality of micro cell structures on the first substrate, wherein each micro cell structure surrounds at least one pixel; forming a liquid crystal material within a plurality of micro cell structures by Ink Jet Printing technology; and combining the first substrate with a second substrate by sealing member. 
   A feature of the invention is to form the micro cell structures, of photoresist layer or protective layer, on the substrate with thin-film transistors to replace the spacer, wherein each micro cell structure surrounds at least one pixel. 
   Another feature of the invention is to form the micro cell structures, of photoresist layer or protective layer, on the substrate with color filter to replace the spacer, wherein each micro cell structure surrounds at least one pixel. 
   Another feature of the invention is to provide the liquid crystal material within each micro cell structure by utilizing Ink Jet Printing technology, including thermal bubble type and micro piezoelectric type Ink Jet Printing technologies. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This and other objects and features of the invention will become clear from the following description, taken in conjunction with the preferred embodiments with reference to the drawings, in which: 
       FIG. 1  schematically shows a general structure of a conventional liquid crystal display panel; 
       FIG. 2  is a diagram for use in describing a prior art method of manufacture of a liquid crystal display panel; 
       FIG. 3A  to  3 F are diagrams illustrating a manufacturing method of the first embodiment of the invention; 
       FIG. 4A  to  4 F are diagrams illustrating a manufacturing method of the second embodiment of the invention; 
       FIGS. 5A and 5D  schematically shows a trench formed between the sealing member and the micro cell structure; 
       FIG. 6A  to  6 C are diagrams showing the micro cell structure surrounding at least one pixel; 
       FIG. 7A  to  7 N are diagrams illustrating the micro cell structures connected by a passage; 
       FIG. 8A  to  8 D schematically show different geometric shapes of the micro cell structures according with the geometric patterns of the pixels; 
       FIG. 9  is a cross-section of the micro cell structure; 
       FIG. 10A  schematically shows an In-plane Switching mode of the liquid crystal display panel; 
       FIG. 10B  schematically shows a Vertical Alignment mode of the liquid crystal display panel. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   First Embodiment 
   As shown in  FIG. 3A , a plurality of pixels  110  are formed on a transparent substrate  100 ; wherein each pixel is surrounded by the gate lines  120  and the data lines  130 , and a thin film transistor  125  is connected with the gate line  120 . Next, as shown in  FIG. 3B , a photoresist layer  140  is formed on the transparent substrate  100  to cover the thin film transistor  125  and a transparent electrode  17   a . Next, a micro cell structure  150  surrounding at least one pixel is formed by photolithography; wherein the side wall of the micro cell structure  150  is formed over the gate line and data line and has a height of 3 to 5 μm. Next, as shown in  FIG. 3C , the micro cell structures  150  surrounding each pixel have the same height by the planarization for the photoresist. Next, as shown in  FIG. 3D , a first alignment layer  160  is formed on the transparent electrode  17   a  on the substrate  100  by Printing. 
   Next, as shown in  FIG. 3E , the liquid crystal is provided within the micro cell structure by Ink Jet Printing technology. The Ink Jet Printing technology includes the thermal bubble type and micro piezoelectric type of Ink Jet Printing technology. In this embodiment, the liquid crystal material  170  can be injected into the micro cell structures  150  under the condition of normal, or low air pressure, or vacuum. 
   Next, as shown in  FIG. 3F , another substrate  200  with a color filter  190  and second alignment layer  165  is combined with the substrate  100 . In the embodiment, a sealing member  180  is formed on the edge of the substrate  100  and surrounds the micro cell structure before injecting the liquid crystal  170  into the micro cell structures, and then the substrate  100  with the sealing member  180  is combined with another substrate  200  under the condition of normal, low air pressure or vacuum. As well, a sealing member  180  can be formed on the edge of the substrate  100  and surrounds the micro cell structure after injecting the liquid crystal  170  into the micro cell structures, and then the substrate  100  with the sealing member  180  is combined with another substrate  200  under the condition of normal or low air pressure. Moreover, forming the sealing member  180  on the substrate  100  and providing the liquid crystal  170  within the micro cell structure can be accomplished at the same time, and then the two substrates  100 ,  200  are sealed together under the condition of normal or low air pressure. 
   Second Embodiment 
   As shown in  FIG. 4A , a plurality of pixels  310  are formed on a transparent substrate  300 ; wherein each pixel  310  has a transparent electrode  17   b , a color filter  320  and a black matrix  330 . The color filter  320  may be a red color filter, green color filter, or a blue color filter. Next, as shown in  FIG. 4B , a transparent electrode  17   b  and photoresist layer  340  are sequentially formed on the transparent substrate  300 . Next, as shown in  FIG. 4C , a micro cell structure  350  surrounding the black matrix  330  of the pixel  310  is formed by photolithography on the photoresist layer  340 . The side wall of the micro cell structure  350  is formed over black matrix  330  and has a height of 3 to 5 μm. The micro cell structure can be transparent or non-transparent material, and thus the micro cell structure can also be treated as part of the black matrix. Next, the micro cell structures  350  surrounding each pixel  310  have the same height by the planarization. Next, as shown in  FIG. 3D , a first alignment layer  360  is formed on the substrate  300  by Printing. 
   Next, as shown in  FIG. 4E , the liquid crystal  370  is provided within the micro cell structure  350  by Ink Jet Printing technology, including thermal bubble type and micro piezoelectric type Ink Jet Printing technology. In this embodiment, the liquid crystal material  370  can be injected into the micro cell structures  350  under the condition of normal, low air pressure or vacuum. 
   Next, as shown in  FIG. 4F , another substrate  400  with a thin film transistor  380  and a second alignment layer  365  is combined with the substrate  300 . In the embodiment, a sealing member  390  is formed on the edge of the substrate  300  and surrounds the micro cell structures before injecting the liquid crystal  370  into the micro cell structures, and then the substrate  300  with the sealing member  390  is combined with another substrate  400  under the condition of normal, low air pressure or vacuum. As well, a sealing member  390  can be formed on the edge of the substrate  300  and surrounds the micro cell structures after injecting the liquid crystal  370  into the micro cell structures, and then the substrate  300  with the sealing member  390  is combined with another substrate  400  under the condition of normal or low air pressure. Moreover, forming the sealing member  390  on the substrate  300  and providing the liquid crystal  370  within the micro cell structure can be accomplished at the same time, and then the two substrates  300 ,  400  are sealed together under the condition of normal or low air pressure. 
   As shown in  FIG. 5A  to  5 D, in the invention, a trench  500  is formed between the sealing member  510  and the micro cell structure  520 . The trench can exist at one side, two sides, three sides, or four sides, and contains the surplus liquid crystal overflowing the micro cell structure. Thus, the trench can prevent the surplus liquid crystal from squeezing. 
   As show in  FIG. 6A  to  6 C, in the invention, the micro cell structure further surrounds several pixels. The micro cell structure  610  surrounds at least one pixel (refer to dotted line)  620 . Thus, as the area of the pixel becomes smaller, the liquid crystal material can be also provided within the micro cell structure. 
   As shown in  FIG. 7A  to  7 N, in the invention, the adjacent micro cell structures are connected by a passage  630 . When the liquid crystal is provided within one micro cell structure, the liquid crystal can uniformly fill other micro cell structure by the passages. 
   As shown in  FIG. 8A  to  8 D, in the invention, the geometric shape of the micro cell structure is formed by the accordance of the geometric pattern of the pixel. For example, the geometric shape of the micro cell structure may be rectangular, V-shaped, or other profiles. 
   As shown in  FIG. 9 , in the invention, the cross-sectional diagram of the micro cell structure may be rectangular, semicircular, triangular, trapezoid, or other profiles. 
   In the invention, the micro cell structure can apply to the liquid crystal display panel of Twisted Nematic mode (refer to TN mode), In-plane Switching mode (refer to IPS mode) shown in  FIG. 10A , or Vertical Alignment mode (refer to VA mode) shown in FIG.  10 B. 
   While the preferred embodiment of the present invention has been described, it is to be understood that modifications will be apparent to those skilled in the art without departing from the spirit of the invention. The scope of the invention, therefore, is to be determined solely by the following claims.