Abstract:
A liquid crystal display device (LCD), and particularly to a liquid crystal display which has reduced production cost and enhanced performance. The LCD comprises an optical module, a control module and a backlight module. The optical module is fabricated with known liquid crystal manufacturing process to provide at least a liquid crystal layer and a plurality of pixel unit electrodes, which are provided with a pixel electrode transparent area and a pixel electrode reflective area respectively. The control module is fabricated with known semiconductor manufacturing process. Further, using a plurality of conductive plugs disposed at preset positions, the backlight module is electrically connected to the pixel unit electrodes of optical module and the control circuit devices of the control module. The structure of the present invention resulting enhanced performance of the product, production yield and reliability, and reduced production cost.

Description:
BACKGROUND OF THE PRESENT INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a liquid crystal display device, and particularly to a liquid crystal display which can reduce the production cost and enhance product performance. Further, using a plurality of conductive plugs disposed at preset positions, the backlight module electrically connects the pixel unit electrodes to the optical module, which is made with known liquid crystal manufacturing process, and to the control circuit devices of control module which is made with known semiconductor manufacturing process.  
         [0003]     2. Brief Description of the Related Art  
         [0004]     The rapidly changing information industry, consumers&#39; eager expectation of new products, and the ever changing product landscape in recent years, the manufacturers are investing a great deal of endeavors in product development. In the display area, the liquid crystal display (LCD) device holds great potential due to its, lightness, thinness, and low power consumption. Further, diversification of product also attracts eyes of the consumers.  
         [0005]     The pixel unit structure of the conventional thin film transistor (TFT) liquid crystal display panel shown in  FIG. 1  mainly includes a plurality of transverse gate lines  131  and a plurality of longitudinal data lines  133  to cross over each other and to form a plurality of pixel unit areas. A thin film transistor (TFT)  139  is provided at intersections of the data lines  133  and the gate lines  131  respectively. Each of the data line  133  extends to form a source electrode  134 , each of the gate lines  131  extends to form a gate electrode  132  and the drain electrode  135  connects with the gate electrode  132  and the pixel electrode  137 . The liquid crystal particles can be controlled to rotate by way of the thin film transistor  139  controlling potential of the pixel electrode  137  associated with an electrode disposed at another side of the liquid crystal layer (not shown) such that the image can be displayed.  
         [0006]     There are two conventional types of liquid crystal display device, reflection type and transmission type. The pixel electrode  137  of reflection liquid crystal display device is made of material with excellent optical reflection property so that the image can appear by way of ambient reflection light. But, the displaying effect becomes inferior when the ambient light is weak. The pixel electrode  137  of the transmission type liquid crystal display device is made of transparent conductive material and the image can be shown by way of the transparent pixel unit electrode associated with the backlight light. The disadvantage of the transmission type liquid crystal display device is a great deal of power has to be consumed for producing the backlight. When the ambient light is stronger, the image display contrast of the backlight decreases and the display effect becomes undesirable.  
         [0007]     Further, the thin film transistors  139  occupy part of the pixel area in the conventional pixel unit structure so that the display effect is degraded.  
       SUMMARY OF THE INVENTION  
       [0008]     An object of the present invention is to provide a liquid crystal display device, which has a backlight module disposed between the optical module and the control module to enhance the display effect in case of the ambient light being not sufficient.  
         [0009]     Another object of the present invention is to provide a liquid crystal display device in which the conductive plugs formed in the backlight module connects with separately made optical module and control module to enhance the perfection rate and the reliability of the product.  
         [0010]     A further object of the present invention is to provide a liquid crystal display device in which the control transistor of the pixel unit electrode can be independently made by way of matured semiconductor technique to increase the effective area of the pixel unit.  
         [0011]     A further object of the present invention is to provide a liquid crystal display device in which the lower surface of pixel electrode reflective area on the pixel unit electrode has a cone shaped and the backlight projected over the pixel electrode reflective area can be dispersed to the pixel electrode transparent area for intensifying the quantity of the light.  
         [0012]     A further object of the present invention is to provide a liquid crystal display in which the upper surface of the pixel electrode reflective area on the pixel unit electrode has a convex shape to expand the viewable angle.  
         [0013]     A further object of the present invention is to provide a liquid crystal display in which a lens set can be provided to enhance display quality and magnify the image.  
         [0014]     A further object of the present invention is to provide a liquid crystal display in which the optical module has an arc surface structure to enhance the integral quality of the formed image.  
         [0015]     A further object of the present invention is to provide a liquid crystal display in which the conductive studs and the conductive connection terminals can be disposed between different control modules to offer diversified functions 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The detail structure, the applied principle, the function and the effectiveness of the present invention can be more fully understood with reference to the following description and accompanying drawings, in which:  
         [0017]      FIG. 1  is a plan view of pixel unit structure in the conventional TFT liquid crystal display panel;  
         [0018]      FIG. 2  is a partial sectional view of a preferred embodiment according to the present invention;  
         [0019]      FIG. 3  is a sectional view of pixel unit layer shown in  FIG. 2 ;  
         [0020]      FIGS. 4A and 4B  are partial sectional views illustrating different joining types between modules in the present invention;  
         [0021]      FIGS. 5A and 5B  are partial sectional views of pixel unit electrodes in different shapes;  
         [0022]      FIG. 6  is a partial sectional view of another embodiment according to the present invention;  
         [0023]      FIG. 7  is a partial sectional of a further embodiment according to the present invention;  
         [0024]      FIGS. 8A and 8B  are partial sectional views illustrating different joining ways for the modules shown in  FIG. 7 ;  
         [0025]      FIG. 9  is a partial sectional of a further embodiment according to the present invention; and  
         [0026]      FIG. 10 a  partial sectional of a further embodiment according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     Firstly, referring to  FIGS. 2, 3 ,  4 A and  4 B, a preferred embodiment is illustrated. The embodiment is a liquid crystal display device provided with transmission and reflection effects. The optical module  25  of the liquid crystal device according to the present invention has a first transparent substrate  243  with a plurality of pixel unit electrodes  256  formed thereon. Each pixel unit electrode  256  has a pixel electrode reflective area  245  and a pixel electrode transparent area  247 . The pixel reflection area  245  can be made of metallic material or any other conductive material with excellent reflection capability and the pixel electrode transparent area  247  can be made of transparent conductive material such as Indium Tin Oxide (ITO). The pixel electrode reflection area  245  can be arranged at the center of each of the pixel unit electrodes  256  respectively and the pixel electrode transparent area  247  can be arranged to surround the pixel electrode reflection area  245  as shown in  FIG. 3 . Alternatively, the pixel electrode reflection area  245  and the pixel electrode transparent area  247  can be arranged in another ways such as, the pixel electrode transparent area  247  can be arranged at the center of each of the pixel unit electrodes  256  respectively and the pixel electrode reflection area  245  can be arranged to surround the pixel electrode transparent area  247  or being disposed pixel electrode transparent area  247  and pixel electrode reflection area  245  at a lateral side of the respective pixel unit electrode  256 .  
         [0028]     The respective pixel unit electrode  256  can be formed with a guard layer  249  for protection. The first transparent substrate  243  is provided with at least a hole (shown in  FIG. 4A ) by way of etching at the lower surface thereof corresponding to the respective pixel unit electrode  256  and a first alignment film  263  can be provided on the passivation layer  249 .  
         [0029]     The second transparent substrate  267  is provided with a transparent electrode  266  at the lower surface thereof and a second alignment film  265  is formed at the lower surface of the transparent electrode  266 . A liquid crystal layer  261  is sandwiched between the first alignment film  263  of the first transparent substrate  243  and the second alignment film  265  of the second transparent substrate  267 . Besides, the first transparent substrate  243  and the second transparent substrate  267  are provided at the upper surfaces thereof a first polarizer layer  241  and a second polarizer layer  269  respectively such that the light can be polarized thereof to comply with characteristics of the liquid crystal and generate effect of showing image.  
         [0030]     A backlight module  22  can be embodied in multiple ways. For instance,  FIG. 2  shows at least an illuminative member  221  is utilized to produce a backlight source and the light is sent to every part of the display device through a light guide layer  223 . The lower surface of the light guide light layer  223  is treated to form a diffuse reflective surface  225  and the light can be distributed evenly upward to every part of the display device. The light guide layer  223  is provided with conductive material made conductive plugs  28  corresponding to the holes  244  of the optical module  25 . In order to enhance conductive effect of the light, the conductive plugs  28  can be made of transparent conductive material such as TCO (the preceding ITO is a kind of transparent conducting oxide (TCO)), conductive high molecules and one of combined transparent conducing oxide (TCO) and conductive high molecules. Further, the backlight module  22  can provide a layer of organic electro-luminescent device (OLED) between the optical module  25  and the control module  10  and the OLED can emit light upward directly to offer backlight source. A conductive plug  28  is mounted at each of the holes  244  as medium for connecting with the control module  10  and pixel unit electrode  256 . Each of the conductive plugs  28  in the preceding embodiment can provide an insulating layer  285  at the edge of a lateral side thereof to offer protection for the conductive plugs  28  and other peripheral components of the conductive plugs  28  in addition to secure function of the circuit. Each of the substrate can be made of flexible material to provide the flexibility of display panel.  
         [0031]     The control module  10  is fabricated by way of conventional manufacturing process for semiconductor to integrate the circuits and device components into at least a chip. First of all, device components of control circuit such as transistors and capacitors are fabricated with semiconductor manufacturing process steps on a semiconductor substrate  11 . The transistor includes a drain electrode  113  and a source electrode  115  and a gate electrode  117  is provided on a gate dielectric layer  119 . An isolation layer  111  is disposed between circuit device components as a partition. The capacitor component is provided with a bottom electrode  121 , a dielectric layer  123  a top electrode  125  sequentially on the isolation layer  111 . Once the circuit components have been manufactured on the semiconductor substrate  11 , an insulating layer  12  is formed on the substrate to protect the components in addition to providing insulation and isolation.  
         [0032]     After forming the insulating layer  12 , the contacts are formed at the position of the drain electrode  113 , the source electrode  115  and the top electrode  125  by etching process and the contacts are filled with conductive material such as titanium, titanium nitride, tungsten and aluminum to connect with the drain electrode  113 , the source electrode  115  and the top electrode  125  respectively to form conductive contacts (via)  161 ,  163  and  165 . The surface of the insulating layer  12  has a conductive circuit layout formed with metal. The metal line  141  connects with the drain electrode  113  through the conductive contact  161  and the metal line  143  connects with the source electrode  115  and the top electrode  125  through the conductive contacts  163  and  165 .  
         [0033]     The surface of the insulating layer  12  provides preset positions for the conductive circuit layout and each of the preset positions has a conductive connection terminal  203  respectively and forms an insulating layer  14  covering each metal line. A reflective layer  201  is formed on the insulating layer  14 , and another silicon dioxide insulating layer  147  covering the reflective layer thereon. The reflecting layer  201  can enhance reflection effect of the diffuse reflective surface  225  in the light guide layer  223 .  
         [0034]     After each of the modules having been fabricated completely, the modules are combined and the arrangement can be the configuration as shown in  FIGS. 4A and 4B . It can be seen that the backlight module  22  has the conductive plugs  28  extending upward and downward beyond the upper and lower surfaces thereof to form top studs  281  and bottom studs  283 . The top studs  281  are inserted into the holes  244  of the first transparent substrate  243  to connect pixel unit electrode  256  during assembling. The bottom studs  283  connect with conductive connection terminals  203  of the control module  10  or connect with the preset positions of the conductive circuit layout in the control module  10 . In this way, the pixel unit electrode  256  is electrically connected to the control circuit of the control module  10  as shown in  FIG. 4A .  
         [0035]     Further, a conductive stud  287  made of conductive material can be provided in the hole  244  of the first transparent substrate  243  with an insulating layer  289  between the conductive stud  287  and the first transparent substrate  243 . The conductive connection terminal  205  of the control module  10  can extend outward from the upper surface of the control module  10 , by way of the conductive stud  287  and the conductive connection terminal  205  electrically connecting with the conductive plug  28  of the backlight module  22  such that the control circuit of control module  10  and the pixel unit electrode  256  can be electrically connected. Furthermore, the conductive plug  28  of the backlight module can be ignored by extending the conductive stud  287  and the conductive connection terminal  205 , such that the control circuit of control module  10  and the pixel unit electrode  256  can be electrically connected.  
         [0036]     Referring to  FIGS. 5A and 5B , it can be seen from the partial sectional views of different arrangements for the pixel unit electrodes that the pixel electrode reflective area  245  of the pixel unit electrode can improve the display effect by way of the minor design change. The lower surface  246  of the pixel electrode reflective area  245  can be made to have a cone shaped outward surface so that the light from the backlight module illuminating the lower surface  246  of the pixel electrode reflective area  245  can be reflected to other areas and finally penetrates the pixel electrode transparent area  247  as shown in  FIG. 5A  so as to reduce energy loss and enhance the luminance of the backlight.  
         [0037]     The upper surface  248  of the pixel electrode reflective area  245  can be made as a convex surface, which provides function of diffusion such that it is possible to make up the deficiency of the pixel electrode transparent area having insufficient luminance during creating image in case of the ambient light being stronger and it is capable of eliminating the visional space between pixel units in the conventional liquid crystal display. Furthermore, partial convex design of the pixel unit electrode  256  can result in a minor pretilt angle during part of the liquid crystal molecules being arranged to increase visual range of the display device.  
         [0038]     The pixel electrode transparent area  247  and the pixel electrode reflective area  245  of the pixel unit electrode  256  can be coated with different optical films on the surfaces thereof to adjust different optical path required for transmission display and reflection display, or the pixel electrode transparent area  247  and the pixel electrode reflective area  245  can be provided with a thickness different from each other to achieve adjustment of optical path during manufacturing the passivation layer.  
         [0039]     In addition, a light sensor  32  can be mounted in the preceding embodiment to connect the backlight module  22  and the control module  10  respectively to turn on the backlight, turn off the backlight and adjust the intensity of backlight based on sensed ambient luminance so as to maintain optimum display quality and save power consumption.  
         [0040]     Referring to  FIG. 6 , another embodiment is illustrated. The structure of the present embodiment is similar to that shown in  FIG. 2  and the difference of the present embodiment from the first embodiment is to use a transmission type liquid crystal display device. Hence, the control module  10  and the backlight module  22  of the present embodiment are not different from those in the first embodiment. The pixel unit electrode  256  in the optical module  25  is made of transparent conductive material such as ITO.  
         [0041]     Referring to  FIGS. 7, 8A  and  8 B, a further embodiment is illustrated. The present embodiment is to apply the art disclosed in the present invention to a reflection type liquid crystal display device. The present embodiment basically includes an optical module  25  and a control module  10  and both the modules are almost the same as those shown in  FIG. 2 .  
         [0042]     The pixel unit electrode  256  of the optical module  25  and a light mask layer  207  of the control module  10  can be matched and changed to different shapes. In case of the pixel unit electrode  256  being made of conductive material with excellent reflection capability such as metallic material, the substrate  242  can be made of opaque material and the light mask layer  207  can be made of excellent light absorption material to block or absorb diffusion light so as to prevent the diffusion light from interfering the circuit components. When the pixel unit electrode  256  is made of transparent conductive material such as ITO, the transparent material should be chosen for the substrate  242  and material with excellent reflection capability should be chosen for the light mask layer  207  so as to enhance the effect of light reflection.  
         [0043]     Referring to  FIGS. 8A and 8B , assembly of the control module  10  and the optical module  25  is illustrated. Each of the conductive connection terminals  205  extends outward from the upper surface of the control module  10  to insert into corresponding holes  244  in the substrate  242  for connecting with the pixel unit electrode  256  as shown in  FIG. 8A . Besides, a conductive plug  28  made of conductive material is inserted into each of the holes  244  and a lateral side of the conductive plug  28  can provide an insulating layer  289  at the edge thereof. An end of the conductive plug  28  extends downward from the lower surface of the substrate  242  to form a conductive stud  287  and the pixel unit electrode  256  can be electrically connected with the control circuit by way of the conductive studs  287  electrically connecting with the conductive connection terminal  203  of the control module  10 .  
         [0044]     Referring to  FIG. 9 , a further embodiment of the present invention is illustrated. It can be seen that the liquid crystal display device of the present invention can add a lens module  30  to the optical module  25 . The liquid crystal display device is driven and controlled with the control module  10  and the image can be displayed with the optical module  25 . The quality of the display image can be improved or magnified with the lens module  30  to enhance the capability of the display device. Further, the upper surface  251  of the optical module  25  can be made as an arc surface to present more perfect image display therein matching with the lens module  30 .  
         [0045]     Finally, referring to  FIG. 10 , a further embodiment of the present invention illustrated and it can be seen from the sectional view in the figure that the embodiment can further include at least a second control module  101  fabricated by way of manufacturing process for semiconductor. The control modules  10  can form a plurality of conductive studs  103  at the lower surfaces thereof with the same principle and the second control module  101  has a conductive connection terminals  105  thereof corresponding to the conductive studs  103 . By using the conductive studs  103  being electrically connected to the conductive connection terminals  105 , the control modules in different function features can be associated with each other such that the liquid crystal display device can provide more powerful and diversified functions.  
         [0046]     Due to the technique of manufacturing process for semiconductor and technique for making a liquid crystal display panel being very mature, the technique provided in the present invention makes the optical module, the backlight module and the control module possible to be fabricated independently before being joined together with innovative structure design involving in utilization of the existing art. Hence, the present invention can not only increase the production yield but also simplify the manufacturing process and reduce the cost.  
         [0047]     It is appreciated that the liquid crystal display device has at the backlight module thereof a plurality of preset positions being provided with a conductive plug respectively to connect the optical module made by way of matured liquid crystal manufacturing process and to connect the control module made by way of matured semiconductor manufacturing process so as to increase the production yield and lower production cost.  
         [0048]     While the invention has been described with referencing to the preferred embodiments thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention, which is defined by the appended claims.