Abstract:
A liquid crystal display panel including a first substrate, a second substrate, a liquid crystal layer, a scan line, a data line intersects the scan line, an active device, a pixel electrode, an insulating layer covering the pixel electrode, an auxiliary electrode, a shielding electrode, and a first polymer stabilized alignment (PSA) layer is provided. 
     The liquid crystal layer between the first substrate and the second substrate includes liquid crystal molecules and a monomer material. The active device includes three terminals coupled to the scan line, the data line, and the pixel electrode. The auxiliary electrode on the insulating layer is electrically connected to the pixel electrode. The shielding electrode on the insulating layer located at peripheries of the pixel electrode surrounds the auxiliary electrode. The first PSA layer between the first substrate and the liquid crystal layer is polymerized from the monomer material in the liquid crystal layer.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation application of and claims the priority benefit of U.S. application Ser. No. 12/493,253 filed on Jun. 29, 2009, now allowed, which claims the priority benefit of Taiwan application serial no. 97138938, filed Oct. 9, 2008. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a liquid crystal display (LCD) panel and a manufacturing method thereof. More particularly, the present invention relates to an LCD panel applying a polymer-stabilized alignment technology and a manufacturing method thereof. 
         [0004]    2. Description of Related Art 
         [0005]    At the current stage, LCD panel technologies that have been developed to satisfy the requirement of a wide viewing angle include: twisted nematic (TN) LCD panels equipped with wide viewing films, in-plane switching (IPS) LCD panels, fringe field switching LCD panels and multi-domain vertically alignment (MVA) LCD panels. Among these LCD panels, the MVA-LCD panels are widely used in various electronic devices. 
         [0006]    In a conventional MVA-LCD panel, an alignment structure is formed, such that liquid crystal (LC) molecules in different areas tilt in different angles and accomplish the wide viewing angle effect. However, the design of the MVA-LCD panel still has the issue regarding unfavorable display contrast. Hence, a polymer-stabilized alignment (PSA) LCD panel aiming at the establishment of a multi-domain alignment through a PSA manufacturing process has been proposed. 
         [0007]    The PSA manufacturing process includes first doping reactive monomers into a liquid crystal (LC) layer and applying a specific electrical field thereto. Next, the LC layer is irradiated by a light beam or a thermal source under the electrical field, and thereby the reactive monomers are polymerized and cured, such that a PSA layer is formed on a substrate at respective sides of the LC layer simultaneously. Here, the molecules of the PSA layer are arranged in a certain manner, which is conducive to tilting or arranging the LC molecules in different directions, so as to achieve the wide viewing angle effect. 
         [0008]    Besides, in order to enhance the alignment effect of the LC molecules, fine slits are formed on a pixel electrode or alignment protrusions are produced on a substrate in the PSA LCD panel. Nevertheless, the fine slits on the pixel electrode would result in loss of display brightness in the pixel and consequently affect display quality. On the other hand, the disposition of the alignment protrusions causes the LC molecules at peripheries of the alignment protrusions to tilt in discontinuous directions and result in light leakage. Therefore, display contrast of the LCD panel is reduced, and production of extra alignment protrusions results in burdens of the manufacturing process and affects the yield rate thereof. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is directed to a manufacturing method of an LCD panel to resolve a conventional issue regarding the structure design of the LCD panel that results in inability to enhance brightness or generation of light leakage. 
         [0010]    The present invention is further directed to an LCD panel to resolve an issue regarding loss of brightness of the LCD panel due to disposition of fine slits on a pixel electrode. 
         [0011]    The present invention is further directed to a manufacturing method of an LCD panel to complete a polymer-stabilized alignment (PSA) manufacturing process by means of scan lines and data lines providing necessary voltages for polymerization of a monomer material. 
         [0012]    The present invention provides a manufacturing method of an LCD panel. The manufacturing method includes following steps. A panel is provided, where the panel includes a first substrate, a second substrate and a liquid crystal (LC) layer. The first substrate has a plurality of scan lines and a plurality of data lines, and the scan lines intersect with the data lines respectively to define a plurality of pixel areas on the first substrate. The first substrate in every pixel area further includes an active device, a pixel electrode, an auxiliary electrode and a shielding electrode, where the active device is coupled to the corresponding scan lines and data lines. The pixel electrode is coupled to the active device. The auxiliary electrode is disposed on the pixel electrode and is coupled to the pixel electrode. The shielding electrode is disposed at peripheries of the pixel electrode and surrounds the auxiliary electrode. The second substrate has an opposite electrode. The LC layer is located between the first substrate and the second substrate, and the LC layer has a plurality of the LC molecules and a monomer material. Next, a first curing voltage is applied to the scan lines and a second curing voltage is applied to the data lines. Here, the first curing voltage is higher than an absolute value of the second curing voltage. At this time, the second curing voltage transmits to the pixel electrode and generates an electrical field in the LC layer to align the LC molecules at a pre-tilt angle. Subsequently, the monomer material in the LC layer is polymerized to form a first PSA layer between the LC layer and the first substrate and to form a second PSA layer between the LC layer and the second substrate. The electrical field is then removed. 
         [0013]    In one embodiment of the present invention, the method of polymerizing the monomer material in the LC layer includes a light irradiation of the monomer material. Practically, a power of the light irradiating the monomer material is from 50 mW to 1000 mW, for instance. Moreover, a time of light irradiation of the monomer material is from 50 seconds to 500 seconds. 
         [0014]    In one embodiment of the present invention, when the electrical field is applied to the LC layer, a voltage difference between the pixel electrode and the opposite electrode is from 5V to 40V. 
         [0015]    In one embodiment of the present invention, a voltage difference between the first curing voltage and the second curing voltage is greater than a threshold voltage of the active device. 
         [0016]    In one embodiment of the present invention, a voltage difference between the first curing voltage and the second curing voltage is greater than 7V. 
         [0017]    In one embodiment of the present invention, a potential of the opposite electrode and the shielding electrode includes a grounded potential. 
         [0018]    The present invention further provides an LCD panel which includes a first substrate, a second substrate, an LC layer, a first PSA layer and a second PSA layer. The first substrate has a plurality of scan lines and a plurality of data lines. The scan lines intersect with the data lines respectively and define a plurality of pixel areas on the first substrate. Besides, the first substrate in every pixel area includes an active device, a pixel electrode, an auxiliary pixel and a shielding electrode, where the active device is coupled to the corresponding scan line and data line. The pixel electrode is coupled to the active device. The auxiliary electrode is disposed on the pixel electrode and is coupled to the pixel electrode. The shielding electrode is disposed at peripheries of the pixel electrode and surrounds the auxiliary electrode. The second substrate has an opposite electrode. The LC layer is disposed between the first substrate and the second substrate, and the LC layer has a plurality of LC molecules. The first PSA layer is disposed between the first substrate and the LC layer. In addition, the second PSA layer is disposed between the second substrate and the LC layer. 
         [0019]    In one embodiment of the present invention, the first P SA layer and the second PSA layer are polymerized by a monomer material doped in the LC layer. Practically, the monomer material is a light reactive monomer material, for example. The monomer material is polymerized to form the first PSA layer and the second PSA layer through a light irradiation, where a power of the light irradiating the monomer material is from 50 mW to 1000 mW. Moreover, a time that the light irradiates the monomer material is from 50 seconds to 500 seconds. Before the irradiation, an electrical field is further applied to the LC layer through the opposite electrode and the pixel electrode, such that the LC molecules are arranged at a pre-tilt angle. When applying the electrical field to the LC layer, a voltage difference between the pixel electrode and the opposite electrode is from 5V to 40V. Besides, when applying the electrical field to the LC molecules, a voltage applied to the scan lines is higher than an absolute value of a voltage applied to the data lines. In addition, a voltage difference between the scan lines and the data lines is greater than a threshold voltage of the active device. When applying the electrical field to the LC molecules, a voltage difference between the scan lines and the data lines is greater than 7V, for instance. 
         [0020]    In one embodiment of the present invention, the above-mentioned first substrate further includes a plurality of color filter units respectively disposed in the pixel areas. 
         [0021]    In one embodiment of the present invention, the second substrate further includes a plurality of color filter units respectively corresponding to the pixel areas. 
         [0022]    The present invention provides another manufacturing method of an LCD panel. The method includes following steps. A panel is provided. The panel includes a first substrate, a second substrate and an LC layer. Here, the first substrate has a scan line and a data line. The scan line intersects with the data line respectively. The first substrate also includes an active device and a pixel electrode, where the active device is coupled to the scan line and the data line, and the pixel electrode is coupled to the active device. The second substrate has an opposite electrode. The LC layer is located between the first substrate and the second substrate, and the LC layer has a plurality of LC molecules and a monomer material. Then, a first curing voltage is applied to the scan line, and a second curing voltage is applied to the data line. Here, the first curing voltage is higher than an absolute value of the second curing voltage. The second curing voltage flows into the pixel electrode and generates an electrical field in the LC layer to align the LC molecules at a pre-tilt angle. Subsequently, the monomer material in the LC layer is polymerized to form a first PSA layer between the first substrate and the LC layer and to form a second PSA layer between the second substrate and the LC layer. The electrical field is then removed. 
         [0023]    The present invention applies the PSA technology in the LCD panel having the design of the auxiliary electrode and the shielding electrode. Therefore, the LCD panel of the present invention utilizes the PSA layer to provide an appropriate anchor force in cooperation with the structural design of the auxiliary electrode, so as to render the LC molecules in a multi-domain arrangement. In other words, the LCD panel of the present invention does not require disposition of the fine slits in the pixel electrode or disposition of the alignment protrusions on the substrate, which conduces in the enhancement of the display brightness of the LCD panel and increases light transmittance. 
         [0024]    To make the above and other features and advantages of the present invention more comprehensible, several embodiments accompanied with figures are detailed as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0026]      FIG. 1  is a schematic top view of an LCD panel of one embodiment of the present invention. 
           [0027]      FIG. 2A and 2B  show a manufacturing method of the LCD panel taken along cross-sectional lines A-A′, B-B′, and C-C′ in  FIG. 1 . 
           [0028]      FIGS. 3A and 3B  respectively show a schematic top view and a schematic cross-sectional view of the first substrate of the LCD panel in another embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0029]      FIG. 1  is a schematic top view of a liquid crystal display (LCD) panel in an embodiment of the present invention.  FIG. 2A and 2B  show a manufacturing method of the LCD panel taken along cross-sectional lines A-A′, B-B′, and C-C′ in  FIG. 1 . Referring to  FIG. 1  and  FIG. 2A , the manufacturing method of an LCD panel  100  in the present invention includes providing a panel  100 ′ at first. The panel  100 ′ includes a first substrate  110 , a second substrate  130 , and a liquid crystal (LC) layer  150 . The first substrate  110  has an active device array  110 ′. The second substrate  130  has an opposite electrode  132 . The LC layer  150  is disposed between the first substrate  110  and the second substrate  130 , and the LC layer  150  has a plurality of liquid crystal (LC) molecules  152  and a monomer material  154  that is able to be polymerized. 
         [0030]    More specifically, the first substrate  110  includes a plurality of scan lines  112  and a plurality of data lines  114 . In  FIG. 1 , only one scan line  112  and two data lines  114  are shown to provide a clear indication of each element. The scan lines  112  intersect with the data lines  114 , respectively, so as to define a plurality of pixel areas P arranged in matrix on the first substrate  110 . The first substrate  110  in each of the pixel areas further includes an active device  116 , a pixel electrode  118 , an auxiliary electrode  120 , and a shielding electrode  122 . The active device  116  is coupled to the corresponding scan line  112  and the corresponding data line  114 , and the pixel electrode  118  is coupled to the active device  116 . The auxiliary electrode  120  is disposed on the pixel electrode  118  and is coupled to the pixel electrode  118 . The shielding electrode  122  is located at peripheries of the pixel electrode  118  and is surrounding the auxiliary electrode  120 . Notably, the shielding electrode  122  can be used as a capacitor electrode in the LCD panel  100 . The shielding electrode  122  and the pixel electrode  118  form a storage capacitor to maintain a display voltage of the pixel electrode  118 . 
         [0031]    Then, referring to both  FIG. 1  and  FIG. 2B , a first curing voltage Vcur 1 , i.e., a scan line curing voltage, is applied to the scan lines  112 , and a second curing voltage Vcur 2 , i.e., a data line curing voltage, is applied to the data lines  114 . Moreover, an opposite potential of the opposite electrode  132  and the shielding electrode  122  includes a grounded potential or a fixed potential. Under such circumstances, the second curing voltage Vcur 2  transmits to the pixel electrode  118 , and an electrical field E is generated in the LC layer  150 . The LC molecules  152  are then aligned at a pre-tilt angle. 
         [0032]    In the present embodiment, the first curing voltage Vur 1  is substantially higher than an absolute value of the second curing voltage Vcur 2 . Specifically, when the electrical field E is applied to the LC layer  150 , a voltage difference between the pixel electrode  118  and the opposite electrode  132  is from 5V to 40V. Besides, in the manufacturing method, a voltage difference between the first curing voltage Vcur 1  and the second curing voltage Vcur 2  is greater than a threshold voltage of the active device  116 , for instance. Practically, the voltage difference between the first curing voltage Vcur 1  and the second curing voltage Vcur 2  is greater than 7V, for instance, which allows the second curing voltage Vcur 2  to be transmitted to the pixel electrode  118  successfully. 
         [0033]    In detail, referring to  FIG. 2A and 2B , the method of polymerizing the monomer material  154  in the LC layer  150  includes irradiating the monomer material  154  by using an ultraviolet (UV) light, for example. A power of the UV light irradiating the monomer material  154  is from 50 mW to 1000 mW, for instance. Furthermore, a time that the UV light irradiating the monomer material  154  can be from 50 seconds to 500 seconds. Practically, in the steps of irradiation of the monomer material  154 , the power and the time of irradiation of the monomer material  154  can be complemented by modification, so as to satisfy different manufacturing requirements. The present invention is not limited to the power and the time of irradiating the monomer material  154  mentioned above. Additionally, the present embodiment is elaborated by taking a light reactive monomer material  154  as an example. When the monomer material  154  is a thermal reactive monomer material or any other material, alternative methods should be utilized for the polymerization of the monomer material  154 . 
         [0034]    The manufacturing method of the present embodiment utilizes the irradiating method for polymerizing the monomer material  154  in the LC layer  150 , so as to form a polymer layer on inner surfaces of the first substrate  110  and the second substrate  130 . Consequently, a first polymer stabilized alignment (PSA) layer  162  is formed between the first substrate  110  and the LC layer  150 , and a second PSA layer  164  is formed between the second substrate  130  and the LC layer  150 . Here,  FIG. 2B  is illustrated schematically. The electrical field E is then removed to complete the fabrication of the LCD panel  100 . 
         [0035]    In the first substrate  110  of the present embodiment, each of the pixel electrodes  118  and the auxiliary electrode  120  disposed above each of the pixel electrodes  118  belong to different film layers and are disposed on different planes. Thus, when the pixel electrode  118  is applied with the second curing voltage Vcur 2 , a fringe field effect (FFE) would be generated at the edge of the auxiliary electrode  120 . Moreover, the shielding electrode  122  surrounding the auxiliary electrode  120  would also generate the FFE at the edge of the pixel electrode  118 . Therefore, the electrical field E is not evenly distributed in each of the pixel areas P. 
         [0036]    Under the FFE provided by the auxiliary electrode  120  and the shielding electrode  122 , the LC molecules  152  are aligned in a specific arrangement, such as the condition shown in  FIG. 2B . In other words, under the structural design of the first substrate  100 , when the second curing voltage Vcur 2  transmits to the pixel electrode  118 , the LC molecules  152  at different locations would be arranged at different pre-tilt angles. At this time, the alignment manner of the LC molecule  152  affects the polymerization process of the monomer material  154 . Thus, the alignment manner of the polymers in the first PSA layer  162  and the second PSA layer  164  has specific structural characteristics. In the present invention, the second curing voltage Vcur 2  is directly applied to the pixel electrode  118 , where the second curing voltage Vcur 2  provides a more stable and more accurate liquid crystal alignment effect than the curing voltage of a common electrode coupled to the pixel electrode  118 . 
         [0037]    After the electrical field E is removed, the specific structural characteristics of the first PSA layer  162  and the second PSA layer  164  provide a certain alignment anchor force and conduce in enhancement of a response rate of the LC molecules  152 . In other words, the present embodiment does not require the design of fine slits or fine protrusions for performing the PSA manufacturing process to form the MVA-LCD panel  100 , and a relatively stable alignment effect can still be achieved. Therefore, in the LCD panel  100  produced by the manufacturing process described above, the LC molecules  152  have an efficient response rate. Moreover, the display quality of the LCD panel  100  is not affected by the fine slits or the alignment protrusions, and is further elevated. 
         [0038]    In the present embodiment, the pixel electrode  118  is entirely disposed in the pixel area P. Hence, the LC molecules in the entire pixel area P would proceed to display when the LCD panel  100  displays an image. In comparison with the conventional design in which the LC molecules above the fine slits cannot proceed to display, the LCD panel  100  has favorable display brightness. In addition, in order for the LCD panel  100  to accomplish a multi-color display effect, the first substrate  110  or the second substrate  130  further includes a plurality of color filter units, each located in the corresponding pixel area P. That is, the second substrate  130  can be a color filter substrate, or the first substrate  110  can have a design of a color filter on array (COA) or an array on color filter (AOC). 
         [0039]    Notably, the manufacturing method of the present embodiment is not limited to the application of the LCD panel  100  as shown in  FIG. 1 . In other embodiments of the present invention, the above-mentioned manufacturing method can also be applied to LCD panels that do not include the auxiliary electrodes  120  and the shielding electrodes  122 . Besides, in the sequence of stacking metal films in the LCD panel  100  as shown in  FIG. 2B , the data line  114  is manufactured by the first metal layer directly disposed on the substrate while the scan line  112  is manufactured by the second metal layer disposed on an insulating layer. Meanwhile, the auxiliary electrode  120  and the shielding electrode  122  are manufactured by the third metal layer. Nevertheless, the present invention should not be construed as limited to the embodiments set forth herein. In another embodiment of the present invention, the data line  114  and the scan line  112  can also be manufactured respectively by the second metal layer and the first metal layer. 
         [0040]      FIGS. 3A and 3B  respectively show a schematic top view and a schematic cross-sectional view of the first substrate of the LCD panel in another embodiment of the present invention. Here,  FIG. 3B  shows cross-sectional lines D-D′, and E-E′ depicted in  FIG. 3A . Referring to  FIGS. 3A and 3B , a first substrate  300  has a plurality of scan lines  310  and a plurality of data lines  320 . Here, as an example,  FIG. 3A  shows two lines each. The scan lines  310  intersect with the data lines  320  respectively and define a plurality of pixel areas P on the first substrate  300 . The first substrate  300  in each of the pixel areas P further includes an active device  330 , a pixel electrode  340 , two auxiliary electrodes  350 , and a shielding electrode  360 . The electrical connection relationship between the aforesaid devices is identical to the electrical connection relationship between the devices in the first substrate  110  described in the previous embodiment of the present invention. Moreover, the two auxiliary electrodes  350  are surrounded by the shielding electrode  360 . 
         [0041]    In the first substrate  300 , the application of the two auxiliary electrodes  350  in an LCD panel allows the LC molecules in the LCD panel to be aligned in more multiple domains. 
         [0042]    In other words, the design of the first substrate  300  further enhances the wide viewing angle display effect of the LCD panel. Furthermore, because the two auxiliary electrodes  350  are disposed in the present embodiment, the shielding electrode  360  of the present invention is presented as the configuration of “θ”. 
         [0043]    Specifically, the cross-sectional view of  FIG. 3B  shows that the scan line  310  in the present embodiment is manufactured by the first metal layer, the data line  320  is manufactured by the second metal layer, and the auxiliary electrode  350  and the shielding electrode  360  are both manufactured by the third metal layer. In other words, the manufacturing sequence of the first substrate  300  is different from the manufacturing sequence of the first substrate  110 . 
         [0044]    Additionally, in the first substrate  300 , the auxiliary electrode  350  and the pixel electrode  340  belong to different films and are disposed on different planes. Therefore, when a voltage is applied to the pixel electrode  340 , the FFE is generated between the auxiliary electrode  350  and the pixel electrode  340 . Similarly, a corresponding FFE is generated between the shielding electrode  360  and the pixel electrode  340 . Thus, when the first substrate  300  applies the manufacturing method of the LCD panel described in the previous embodiment, the LC layer of the LCD panel can have the multi-domain alignment. In other words, the application of the first substrate  300  in the above-mentioned manufacturing method gives rise to the increase in the response rate of the LC molecules in the LCD panel and the elevation in display quality of the LCD panel. 
         [0045]    In light of the foregoing, different curing voltages are applied respectively to the scan lines and the data lines for directly supplying the curing voltages to the pixel electrode according to the present invention. Thereby, the PSA manufacturing process can be performed on the LCD panel without the dispositions of the fine slits and the alignment protrusions. As such, the LCD panel of the present invention has good display brightness, and the response rate of the LC molecules in the LCD panel remains satisfactory. In general, the manufacturing method of the LCD panel of the present invention improves the quality of the LCD panel. 
         [0046]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.