Abstract:
A method of fabricating a transflective display. The method includes providing a first substrate; forming a first electrode thereon; providing a second substrate having a reflective area and a transmissive area opposite to the first substrate; forming a second electrode having a plurality of slits on the second substrate opposite to the first electrode; disposing a liquid crystal layer including a plurality of liquid crystal molecules and monomers between the first electrode and the second electrode, wherein the monomers have a weight ratio of about 0.1-20%; and polymerizing the monomers to form a plurality of non-liquid crystal polymers adjacent to the first electrode and the second electrode.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Divisional of U.S. patent application Ser. No. 11/942,747, filed Nov. 20, 2007 and entitled “method of fabricating transflective displays”, which claims priority of Taiwan Patent Application No. 96106098, filed on Feb. 16, 2007, the entireties of which are incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a method of fabricating a liquid crystal display, and in particular to a method of fabricating a transflective display. 
         [0004]    2. Description of the Related Art 
         [0005]    Liquid crystal display (LCD) is widely used in various electronic products such as portable personal computers, digital cameras, or projectors due to slimness and low power consumption. 
         [0006]    Unlike conventional cathode ray tube (CRT) and electroluminescent (EL) displays, liquid crystal display panels are unilluminated. Currently, transmissive liquid crystal displays are popular. The backlight source of the display controls light transmission. However, the backlight source accounts for 50% or more of total power consumption, a problem where power conservation is important. Additionally, in brighter environments, the viewability of the transmissive liquid crystal display becomes limited. 
         [0007]    Reflective liquid crystal displays suitable for use outdoors and in portable conditions utilize reflection of environmental light rather than a backlight source. Generally, the reflective liquid crystal display comprises twisted nematic (TN) and super twisted nematic (STN) modes. 
         [0008]    However, when the environment is dark, viewability of the reflective liquid crystal display is limited. 
         [0009]    To improve the display quality in bright environments, increased light intensity of a backlight source is required. Power consumption, however, is increased. Further, the display quality is reduced when directly exposed under sunlight or other light sources, or when the liquid crystal display screen receives sunlight or a light source, surrounding images are reflected. 
         [0010]    To improve the problem, the transmissive and reflective liquid crystal displays are combined in a transflective liquid crystal display. 
         [0011]    In liquid crystal alignment, the multi-domain vertical alignment (MVA) is used in conventional transflective liquid crystal display. The protrusions disposed on reflective area control the pretilt angles of the liquid crystal molecules. However, such technique is complex, affecting transmissive contrast, aspect ratio, and response speed. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The invention provides a method of fabricating a transflective display, in which a first substrate is provided. A first electrode is formed on the first substrate. A second substrate having a reflective area and a transmissive area is provided, opposite to the first substrate. A second electrode having a plurality of slits is formed on the second substrate, opposite to the first electrode. A liquid crystal layer comprising a plurality of liquid crystal molecules and monomers is disposed between the first electrode and the second electrode, wherein the monomers have a weight ratio of about 0.1-20%. The monomers are polymerized to form a plurality of non-liquid crystal polymers adjacent to the first electrode and the second electrode. 
         [0013]    The transflective display with polymer stabilized alignment (PSA) and multi-domain vertical alignment (MVA) improves transmissive contrast, aspect ratio, and response speed. 
         [0014]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawing, wherein: 
           [0016]      FIG. 1  shows a transflective display comprising polymers in an embodiment of the invention. 
           [0017]      FIG. 2  shows an electrode structure of a transflective display in an embodiment of the invention. 
           [0018]      FIG. 3  shows a color filter structure of a transflective display in an embodiment of the invention. 
           [0019]      FIG. 4  shows a transflective display comprising polymers in an embodiment of the invention. 
           [0020]      FIG. 5  shows an electrode structure of a transflective display in an embodiment of the invention. 
           [0021]      FIG. 6  shows a transflective display comprising monomers in an embodiment of the invention. 
           [0022]      FIG. 7  shows a transflective display comprising monomers in an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0024]    In an embodiment, a transflective display is shown in  FIG. 1 . The transflective display  10  comprises a first substrate  16 , a first electrode  18 , a second substrate  12 , a second electrode  14 , and a liquid crystal layer  20  comprising a plurality of liquid crystal molecules  22  and non-liquid crystal polymers  24 . 
         [0025]    The second substrate  12  has a reflective area  26  and a transmissive area  28 . The second electrode  14  is formed on the second substrate  12 . The first substrate  16  is opposite to the second substrate  12 . The first electrode  18  is formed on the first substrate  16 , opposite to the second electrode  14 . The liquid crystal layer  20  is disposed between the first electrode  18  and the second electrode  14 . 
         [0026]    The second electrode  14  or the first electrode  18  may have a plurality of slits  30  (as shown in  FIG. 2 ) to align the liquid crystal molecules  22 . The transflective display  10  further comprises a reflective layer  32  disposed on the reflective area  26  of the second substrate  12 . The reflective layer  32  may be any material with high reflectivity such as aluminum. The transflective display  10  further comprises an insulation layer  34  formed between the reflective layer  32  and the second electrode  14 . 
         [0027]    The transflective display  10  further comprises a color filter  36  formed between the first substrate  16  and the first electrode  18 . Generally, the color filter  36  corresponding to the reflective area  26  may have a hole  38  (as shown in  FIG. 3 ) to increase light transmission. The transflective display  10  further comprises a dielectric layer  40  formed between the color filter  36  and the first electrode  18  corresponding to the reflective area  26 . 
         [0028]    Most of the non-liquid crystal polymers  24  formed in the liquid crystal layer  20  are adjacent to the first electrode  18  and the second electrode  14  to effectively control the pretilt angles of the liquid crystal molecules  22 . Additionally, the liquid crystal layer  20  has different heights, for example, the liquid crystal layer  20  corresponding to the reflective area  26  has a first height  42  and the liquid crystal layer  20  corresponding to the transmissive area  28  has a second height  44 . The second height  44  may be 1.5 to 2.5 times the first height  42 . 
         [0029]    In another embodiment, a transflective display is shown in  FIG. 4 . The transflective display  10  comprises a first substrate  16 , a first electrode  18 , a second substrate  12 , a second electrode  14 , and a liquid crystal layer  20  comprising a plurality of liquid crystal molecules  22  and non-liquid crystal polymers  24 . 
         [0030]    The second substrate  12  has a reflective area  26  and a transmissive area  28 . The second electrode  14  is formed on the second substrate  12 . The first substrate  16  is opposite to the second substrate  12 . The first electrode  18  is formed on the first substrate  16 , opposite to the second electrode  14 . The liquid crystal layer  20  is disposed between the first electrode  18  and the second electrode  14 . 
         [0031]    The second electrode  14  or the first electrode  18  may have a plurality of slits  30  (as shown in  FIG. 5 ) to align the liquid crystal molecules  22 . A protrusion  46  disposed on the first electrode  18  corresponding to the reflective area  26  is also used to align the liquid crystal molecules  22  (as shown in  FIG. 5 ). The transflective display  10  further comprises a reflective electrode  32 ′ disposed on the reflective area  26  of the second substrate  12 . The reflective electrode  32 ′ may be any material with a high reflectivity such as aluminum. 
         [0032]    The transflective display  10  further comprises a color filter  36  formed between the first substrate  16  and the first electrode  18 . Generally, the color filter  36  corresponding to the reflective area  26  may have a hole  38  to increase light transmission. The transflective display  10  further comprises a dielectric layer  40  formed between the color filter  36  and the first electrode  18  corresponding to the reflective area  26 . 
         [0033]    Most of the non-liquid crystal polymers  24  formed in the liquid crystal layer  20  are adjacent to the first electrode  18  and the second electrode  14  to effectively control the pretilt angles of the liquid crystal molecules  22 . Additionally, the liquid crystal layer  20  has different heights, for example, the liquid crystal layer  20  corresponding to the reflective area  26  has a first height  42  and the liquid crystal layer  20  corresponding to the transmissive area  28  has a second height  44 . The second height  44  may be 1.5 to 2.5 times the first height  42 . 
         [0034]    An embodiment of a method of fabricating a transflective display is shown in  FIG. 6 . A first substrate  16  and a second substrate  12  having a reflective area  26  and a transmissive area  28  are provided. The first substrate  16  is opposite to the second substrate  12 . A color filter  36  is then formed on the first substrate  16 . Next, a dielectric layer  40  is formed on the color filter  36  corresponding to the reflective area  26  of the second substrate  12 . A first electrode  18  is then formed on the dielectric layer  40  and the color filter  36 . 
         [0035]    A reflective layer  32  is formed on the reflective area  26  of the second substrate  12 . An insulation layer  34  is then formed on the reflective layer  32  and the second substrate  12 . Next, a second electrode  14  is formed on the insulation layer  34 . The second electrode  14  is opposite to the first electrode  18 . The first and second electrodes may have a plurality of slits  30  (as shown in  FIG. 2 ). 
         [0036]    A liquid crystal layer  20  comprising a plurality of liquid crystal molecules  22  and monomers  48  is disposed between the first electrode  18  and the second electrode  14 . The monomers  48  have a weight ratio of about 0.1 to 20%, also 0.1 to 5%. 
         [0037]    Next, the monomers  48  are polymerized by irradiation such as ultraviolet or heating to form a plurality of non-liquid crystal polymers  24  (as shown in  FIG. 1 ). The non-liquid crystal polymers  24  are adjacent to the first electrode  18  and the second electrode  14 . 
         [0038]    A hole  38  (as shown in  FIG. 3 ) may be created in the color filter  36  corresponding to the reflective area  26  to increase light transmission, facilitating the polymerization of the monomers  48  corresponding to the reflective area  26  during ultraviolet irradiation. 
         [0039]    Another embodiment of a method of fabricating a transflective display is shown in  FIG. 7 . A first substrate  16  and a second substrate  12  having a reflective area  26  and a transmissive area  28  are provided. The first substrate  16  is opposite to the second substrate  12 . A color filter  36  is then formed on the first substrate  16 . Next, a dielectric layer  40  is formed on the color filter  36  corresponding to the reflective area  26  of the second substrate  12 . A first electrode  18  is then formed on the dielectric layer  40  and the color filter  36 . 
         [0040]    A reflective electrode  32 ′ is formed on the reflective area  26  of the second substrate  12 . Next, a second electrode  14  is formed on the second substrate  12 . The second electrode  14  is opposite to the first electrode  18 . The first and second electrodes may have a plurality of slits  30  (as shown in  FIG. 2 ). 
         [0041]    A liquid crystal layer  20  comprising a plurality of liquid crystal molecules  22  and monomers  48  is disposed between the first electrode  18  and the second electrode  14 . The monomers  48  have a weight ratio of about 0.1 to 20%, also 0.1 to 5%. 
         [0042]    A protrusion  46  is further formed on the first electrode  18  corresponding to the reflective area  26  to align the liquid crystal molecules  22 . 
         [0043]    Next, the monomers  48  are polymerized by irradiation such as ultraviolet or heating to form a plurality of non-liquid crystal polymers  24  (as shown in  FIG. 4 ). The non-liquid crystal polymers  24  are adjacent to the first electrode  18  and the second electrode  14 . 
         [0044]    A hole  38  (as shown in  FIG. 3 ) may be created in the color filter  36  corresponding to the reflective area  26  to increase light transmission, facilitating the polymerization of the monomers  48  corresponding to the reflective area  26  during ultraviolet irradiation. 
         [0045]    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 so as to encompass all such modifications and similar arrangements.