Abstract:
An image display device capable of being produced with reduced manufacturing cost, and improved product performance. The image display device comprises: an LCD module, conjoint substrate, at least one driving circuit and a plurality of contacts, wherein the LCD module includes at least one liquid crystal layer and one transparent electrode, for displaying images in accompaniment with the a plurality of electrodes provided on the upper surface of the conjoint substrate, each pixel electrode being connected to a predetermined location at a lower surface of the conjoint substrate through at least one conductive route and then to driving transistors provided in the driving circuit through the contacts, so as to preserve the superior performance of active matrix displays while improving the production yield and reducing the manufacturing cost of the final products. Also disclosed are process of making and using and products comprising the image display device.

Description:
BACKGROUND OF THE PRESENT INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to an image display device, particularly to one capable of reducing manufacturing cost, and improving product performance. The image display device uses a conjoint substrate electrically connecting switching transistors of a driving circuit and a Liquid Crystal Display (LCD) or Organic Light Emitting Display (OLED) module, so as to preserve the superior performance of active matrix displays while improving the production yield and reducing the manufacturing cost of the final products.  
         [0003]     2. Brief Description of the Related Art  
         [0004]     Recently, to meet the various demands of the computer commercial market, the image display industry has invested significant amount of efforts in developing new products. Due to the high potentiality of reduced weight, and thickness profile, and power consumption, the variety of products that have been developed by the image display industry has also gained consumers&#39; great attention.  
         [0005]      FIG. 1  is a cross-sectional view illustrating the structure of a conventional TFT LCD panel, comprising: a glass substrate  10 , a plurality of thin film transistors  14  and storage capacitors  15  formed thereover; a inter-layer insulating film  11  deposited over the thin film transistors  14  and storage capacitors  15 , and a plurality of pixel electrodes  12  formed thereover, each pixel electrode  12  being electrically connected to the respective thin film transistor  14  and storage capacitor  15  through a contact hole  113 ; and a liquid crystal layer  13 , a transparent electrode  123  and a transparent substrate  17  sequentially deposited over the pixel electrode  12 .  
         [0006]     As shown by the planar schematic view of the pixel structure illustrated in  FIG. 1B , it is known that sources  143  of thin film transistors are connected to the longitudinally extending data line  16 , the gate  141  to horizontally extending gate line (scanning line)  18 , and drain  145  to the storage capacitor  15  and pixel electrode  12 . The data line  16  and gate line  18  intersects each other to form pixel areas. Except for the range covered by the thin film transistor  14 , each pixel electrode  12  substantially covers the respective pixel area in entirety for displaying images in accompaniment with the liquid crystal layer and transparent electrode.  
         [0007]     The above structure, upon incorporation of a back light module and other optical thin films, features the image display device with a wide viewing angle, high luminance and fast response time, while facilitating manufacturing of a large-scale image display device.  
         [0008]     The process for forming a matrix circuitry of thin film transistors over a glass substrate is similar to the manufacturing of semiconductor ICs, both with complicated manufacturing procedures and requiring investment in costly image display manufacturing equipment. However, the driving current and other electrical characteristics of amorphous silicon thin film transistors are not inferior to those of transistors made from semiconductor manufacturing process, monocrystalline manufacturing process, or polycrystalline manufacturing process. In addition, in accordance with the above structure, the area occupied by the thin film transistor in each pixel area is incapable of displaying thereby reducing the overall performance of the image display device.  
       SUMMARY OF THE INVENTION  
       [0009]     In view of the above, it is a primary objective of this invention to provide an image display device having an conjoint substrate electrically connecting a switching transistors of driving circuit and an LCD module, wherein the switching transistors of driving circuit and LCD module of the image display device may be independently manufactured prior to assembly so as to improve the production yield and reliability of the products significantly.  
         [0010]     It is another objective of this invention to provide an image display device, where the process of manufacturing the liquid crystal module is independent from the semiconductor manufacturing process for manufacturing the switching transistors of driving chip so as to reduce the manufacturing cost significantly.  
         [0011]     It is a further objective of this invention to provide an image display device, wherein the pixel electrode and switching transistors are discretely formed and electrically connected by conductive circuits, so as to preserve the advantages provided by active matrix displays while increasing the effective display area at the same time.  
         [0012]     It is another objective of this invention to provide an image display device, where the conjoint substrate and conductive circuits may be made of a transparent material, and the conjoint substrate is provided thereunder with a diffusive surface capable of guiding light and serving as a back light module upon incorporation with an illuminant device.  
         [0013]     It is another objective of this invention to provide an image display device, where the conjoint substrate and conductive circuits are made of a flexible material so as to obtain a flexible display panel.  
         [0014]     It is a further objective of this invention to provide an image display device, where the conductive circuits may form a patterned circuit for electrically connecting the pixel electrodes to predetermined locations of a lower surface of the conjoint substrate and then electrically connecting to the switching transistors of driving chip, to facilitate the manufacturing of large-scale panels.  
         [0015]     It is another objective of this invention to provide an image display device, where the image display device may be implemented in Organic Light Emitting Display (OLED) devices so as to simplify the manufacturing process and improve the production yield of the products. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     These and other modifications and advantages will become apparent from the following detailed description of a preferred embodiment of the invention and from the drawings in which:  
         [0017]      FIG. 1A  illustrate a partial cross-sectional view of conventional TFT LCD panel;  
         [0018]      FIG. 1B  is a planar schematic view illustrating a pixel of a conventional TFT LCD panel;  
         [0019]      FIG. 2  is a partial cross-sectional view of a preferred embodiment of this invention;  
         [0020]      FIG. 3  is a partial cross-sectional view of a conjoint substrate of this invention;  
         [0021]      FIG. 4  is a partial cross-sectional view of the switching transistors of driving chip illustrated in the embodiment of  FIG. 2 ;  
         [0022]      FIG. 5  is a partial cross-sectional view of an alternative embodiment of the conjoint substrate of this invention;  
         [0023]      FIG. 6  is a partial cross-sectional view of another preferred embodiment of this invention; and  
         [0024]      FIGS. 7A and 7B  are schematic views illustrating different circuits embodied in the embodiment of  FIG. 6 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     FIGS.  2  to  4  illustrate the partial cross-sectional views of a preferred embodiment, a conjoint substrate and a switching transistors of driving chip according to this invention. As shown, this invention includes: an LCD module  24 , a conjoint substrate  20  and a switching transistors of driving circuit  30 , wherein the conjoint substrate  20  is provided on an upper surface thereof with a plurality of pixel electrodes  201 . The pixel electrodes  201  are sequentially deposited thereover with a passivation layer  246 , a first alignment film  243 , a liquid crystal layer  241 , a second alignment film  245 , a transparent electrode  247 , a transparent substrate  249  and a polarizer layer  248 , thereby constructing an LCD module  24 . The conjoint substrate  20  is provided therein with a plurality of conductive circuits  203  for electrically connecting the pixel electrode  201  to the predetermined location of a lower surface of a conjoint substrate. The conjoint substrate  20  may be made by a semiconductor manufacturing process, by forming the conductive circuits  203  within the substrate, thereby the terminals exposing out of a lower surface  207  of the conjoint substrate thereby serving as the conductive terminals  205 .  
         [0026]     The switching transistors of driving circuit may be integrated into a driving chip  30  by using the semiconductor manufacturing process. First, a plurality of switching transistors  34  and storage capacitors  36  is formed on silicon substrate  32  and then deposited thereover with an insulating layer  38 . The insulating layer  38  is provided with conductive wires made of a conductive material (such as metal) in the form of metal lines  383  and  385 . Each metal line is respectively connected to the drain  341 , source  345  and storage capacitor  36  of the driving transistor  34  through an individual contact hole  381 . The metal lines may be deposited thereover with an insulating layer  387 , such that an opening is predetermined over the metal line for allowing electrical connection with the conductive terminals  205 . The metal lines  383  connecting to the drain  341  are in fact data lines, and gates  343  are connected to the respective gate lines (not shown). In the above driving circuit, the switching transistors  34  may be provided to drive the pixel electrodes  201  without the predesigned storage capacitors, which is an alternative embodiment of the LCD device.  
         [0027]     Each set of switching transistor  34  and storage capacitor  36  is electrically connected to the respective pixel electrode  201  through the metal lines  385 , conductive terminals  205  and conductive circuits  203 , thereby constructing an active matrix switching pixel electrode array. By incorporating the LCD module  24  and the driving circuit of the data lines and gate lines with other optical modules (such as a back light module or other optical thin film), this invention ensures superior display performance with a wide viewing angle, high luminance and fast response time.  
         [0028]     In the above structure, a high performance reflective LCD device is obtained by using a light reflective material (such as a metal) to form the pixel electrodes  201 . Furthermore, a transmissive LCD device is obtained, by using a transparent conductive material for forming the pixel electrodes  201  and conductive circuits, and using a transparent material for forming the conjoint substrate  20 , and the lower surface  207  of the conjoint substrate predesigned into a diffusive surface matching with illuminant as through a light guide, using optical films or metal sputtering or other surface treatment techniques.  
         [0029]      FIG. 5  illustrates a partial cross-sectional view of another embodiment of the conjoint substrate of this invention. As shown, an opening hole is formed on the predetermined positions of each pixel electrode  201  within a conjoint substrate  30 . The opening hole is then filled with a conductive material to become conductive circuits  403 , thereby a patterned circuit  409  is formed at a lower surface  407  of the conjoint substrate. The conductive circuits  403  are electrically connected to predetermined locations of the lower surface  407  of the conjoint substrate and then electrically connecting with the respective conductive terminals  205 . In addition, a passivation layer  408  may be provided to cover the patterned circuit  409  serving as a protective shield.  
         [0030]     In addition, the conjoint substrate of this invention can be manufactured with a flexible material, while the conductive circuits can be manufactured with a conductive polymer, a transparent conductive material (such as ITO) or a metal, to facilitate the manufacturing of flexible display panels. In each embodiment, the conductive terminals  205  are formed by exposing the terminals of the conductive circuits from the predetermined locations of the lower surface of the conjoint substrate, or by forming a stud of metal lines  205 , therein extruding from the top surface of driving chip, for electrically connecting the sources electrode  345  of the switching transistors  34  and storage capacitors  36 .  
         [0031]     In the driving circuit  30  of this invention, other than the switching transistors  34  of driving circuit and storage capacitors  36 , the circuit may also include a scanning circuit for driving the gate lines, a data driving circuit for driving the data lines, a digital signal processor, a microprocessor, a memory, and other control circuits (not shown) that are integrated into a single chip so as to improve the display performance and reduce the manufacturing cost. Using the conductive circuits as an electrical connection interface, the switching transistors of driving circuits and storage capacitors of a driving chip of a relatively smaller size can be electrically connected to the pixel electrodes of a lage-scale conjoint substrate, thereby facilitating the manufacturing of large scale display panels.  
         [0032]     With reference to  FIGS. 6, 7A  and  7 B, where  FIG. 6  is a partial cross-sectional view of another preferred embodiment of this invention; and  FIGS. 7A and 7B  are schematic views illustrating different circuits embodied in the embodiment of  FIG. 6 . Accordingly, the structure of this invention may also be implemented in the manufacturing of organic light emitting diode (OLED) image display devices. As shown, the device includes: an organic light emitting module  50 , a conjoint substrate  20  and a switching transistors of driving circuit, wherein the organic light emitting module  50  is provided with organic pixels formed on the respective pixel electrodes  201  and having an electron transport layer, a light-emitting layer and a hole transport layer. The organic pixels  54  are isolated from each other by means of an insulator  541 . The image display device is further provided with a transparent electrode  543  connecting to an upper surface of each organic pixel  54  and covered by a passivation layer  545 . The top most layer of the image display device is a transparent substrate  56 . The conjoint substrate can be e.g., the structure as shown in  FIG. 3  or  FIG. 5 . The driving circuit can be integrated into a driving chip  52  by using the conventional semiconductor manufacturing process. The driving chip is provided with a plurality of switching transistors  521 , thereby electrically connected to an upper surface of each of the driving chip  52  by a conductive material (metals, not shown), and then electrically connected to pixel electrodes  201  through the respective conductive terminals  205  and conductive circuits  203 .  
         [0033]     Similarly, the conjoint substrate of this invention can be formed from a flexible material, and the conductive circuits can be formed from a conductive polymer, a transparent conductive material (such as ITO), or a metal material, to facilitate the manufacturing of flexible display panels. The conductive terminals  205  are formed by exposing the terminals of the conductive circuits from the predetermined locations of the lower surface of the conjoint substrate  20 , or by forming a stud of a metal lines, therein extruding from the top surface of driving chip  52 , for electrically connecting with the sources electrode of the switching transistors  34 .  
         [0034]     In the driving circuit  52  of this invention, other than the switching transistors  521 , each of the switching transistors can also be connected to at least one transistor  523  and one capacitor  525  to serve as different driving means of the organic pixels  54 , to provide gate voltage stored in the switching transistors, to stabilize current passing through the organic pixels  54 , to enhance the image, and to reduce the response time, so as to improve the display performance of the organic light emitting diode (OLED) image display devices.  
         [0035]     In addition, the driving chip  52  may also include a scanning circuit for driving the gate lines  58 , a data driving circuit for driving the data lines  57 , a digital signal processor, a microprocessor, a memory, and other control circuits (not shown) that are integrated into a single chip so as to improve the display performance and reduce the manufacturing cost. Using the conductive circuits as an electrical connection interface, therein the switching transistors of driving circuits and storage capacitors of a driving chip, compared smaller size than the conjoint substrate, are electrically connected to the pixel electrodes of the lage-scale conjoint substrate to facilitate the manufacturing of large scale display panels.  
         [0036]     According to the disclosure of this invention, the pixel electrodes and switching transistors of driving circuits are designed to be manufactured independently so as to maximize the overall area of the pixel electrodes, to increase the effective light-emitting area, and to improve the display performance, while the independent switching transistors of driving circuit can be manufactured by mature semiconductor process procedures, monocrystalline process procedures or polycrystalline process procedures, so as to preserve the superior performance of active matrix image displays device while improving the production yield and reducing the manufacturing cost of the products.  
         [0037]     In summary, this invention relates to an image display device capable of reducing manufacturing cost, and improving product performance. This invention employs a conjoint substrate electrically connecting a switching transistor of driving circuit and an LCD module or OLED module, so as to preserve the superior performance of active matrix displays while improving the production yield and reducing the manufacturing cost of the final products.  
         [0038]     This invention is related to a novel creation that makes a breakthrough in the art. Aforementioned explanations, however, are directed to the description of preferred embodiments according to this invention. Since this invention is not limited to the specific details described in connection with the preferred embodiments, changes and implementations to certain features of the preferred embodiments without altering the overall basic function of the invention are contemplated within the scope of the appended claims.