Abstract:
A passive matrix display and manufacture method, which makes a various microstructure on the general substrate or flexible substrate, coat or inkjet a conductive layer between the microstructures, fill a plurality of display media in the gaps. The microstructure provides stronger strength for the cell gap. The device and method avoid the increased driving voltage arising from the residual layer in the embossing process.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a passive matrix display and manufacture method, which makes a passive matrix display microstructures on an upper substrate, a lower substrate, coating a conductive layer on the residual layer, and assembling the upper and lower substrates to produce a passive matrix display.  
         [0003]     2. Description of Related Art  
         [0004]     In general, the structure of a display device adopting an embossing technology usually is disposed with a conductive layer before performing the embossing process, and the residual layer produced by the embossing process will increase the drive voltage of the display device.  
         [0005]     U.S. Pat. No. 6,751,008, entitled “Electrophretic display and novel process for its manufacture”, issued to Sipix Imaging Inc., successfully adopts a roll-to-roll process and an embossing technology to produce an architecture that has microcups without filling in aligned display media.  
         [0006]     U.S. Pat. No. 5,956,112, entitled “Liquid crystal display and method for manufacturing the same”, issued to Sharp Company, produces a stripe structure on a side of a substrate along a certain specific direction, and then utilizes a phase separation method to grow a polymer stripe structure perpendicular to the stripe structure and define a sealed structure and adhere the upper and lower substrates.  
         [0007]     An excessively large pressure applied to a flexible substrate during the embossing process may easily result in a crack of the conductive layer, and the LCD produced by the phase separation method has poor contrast. These prior arts thus have certain limitations on their applications.  
       SUMMARY OF THE INVENTION  
       [0008]     To overcome the shortcomings of the prior art LCD manufacturing processes, the inventor of the present invention proposes a passive matrix display and manufacture method.  
         [0009]     Therefore, it is a primary objective of the present invention to provide a manufacture method of a passive matrix display, which makes a various microstructure on the general substrate or flexible substrate, and then coat or inkjet a conductive layer between the microstructures, and combines the substrates. Such a microstructure acts as the alignment layer or as a bank for color filter. Since the microstructures are not sealed and it provides strength for a cell gap when the upper and lower substrates are combined, display media can flow therein as they are filled.  
         [0010]     To achieve the foregoing objective, the present invention proposes a passive matrix display and manufacture method comprising the steps of preparing an upper substrate and a lower substrate; producing a plurality of microstructures on the upper substrate, the lower substrate or both; forming a conductive layer between the microstructures on a residual layer; disposing an alignment layer on the conductive layer for alignment treatment; combining the upper substrate and the lower substrate, such that a gap is formed between the microstructures of the upper substrate and the microstructures of the lower substrate; and filling a plurality of display media in the gaps. Or the filling step is to fill a plurality of display media in the gap between the microstructures before the upper substrate and the lower substrate are assembled.  
         [0011]     To achieve the foregoing objective, the present invention also proposes a passive matrix display comprising an upper substrate and a lower substrate; a plurality of microstructures produced on the upper substrate, the lower substrate or both; a color filter formed on the microstructures; a conductive layer formed between the microstructures; an alignment layer disposed on the conductive layer; a cell gap formed between the upper substrate and the lower substrate and a plurality of display media filled in the cell gap between the upper substrate and the lower substrate. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The foregoing aspects and many of the attendant advantages of this invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0013]      FIGS. 1A  to  1 G show the process of manufacturing a passive matrix display of the present invention;  
         [0014]      FIGS. 2A and 2B  are side views of microstructures of different heights of the present invention;  
         [0015]      FIGS. 3A  to  3 C are top views of non-continuous microstructures of upper and lower substrates of the present invention;  
         [0016]      FIGS. 4A  to  4 C are top views of non-continuous microstructures of upper and lower substrates of the present invention;  
         [0017]      FIGS. 5A  to  5 C are top views of non-continuous microstructures and continuous microstructures of upper and lower substrates of the present invention;  
         [0018]      FIG. 6  is a top view of non-continuous microstructures and continuous microstructures of another form of upper and lower substrates after combining with each other in accordance with the present invention; and  
         [0019]      FIG. 7  is a top view of a sealed structure formed by combining the structures as depicted in FIGS.  1  to  6  by polymerization in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     To make it easier for our examiner to understand the objective of the invention, its structure, innovative features, and performance, we use a preferred embodiment together with the attached drawings for the detailed description of the invention. However, the drawings are provided for examples only and not intended to limit the present invention.  
         [0021]     Reference is made to  FIG. 1F  for a passive matrix display in accordance with the present invention. And reference is made to  FIGS. 1A  to  1 F for the manufacturing procedure of a passive matrix LCD in accordance with the present invention, and the procedure is described below.  
         [0022]      FIG. 1F  shows the structure of a passive matrix display, comprising an upper substrate  10  and a lower substrate  20 . The upper  10  and lower substrates  20  are glass substrates or flexible substrates. Pluralities of microstructures  12 ,  22  are produced on the upper  10  and lower substrates  12  or both. The microstructures  12 ,  22  are formed by photo (or heat) polymerization, printing or embossing. The microstructures  12 ,  22  act as spacers for the gap cell, alignment layer, and/or microwalls. The microstructures  12 ,  22  are, for example, a plurality of non-continuous microstructures or a plurality of continuous microstructures. The non-continuous microstructures are circular, rectangular, or other geometric shapes.  
         [0023]     A conductive layer  14  is formed on the microstructures  12  of the upper substrate  10 , and a conductive layer  24  is formed on the microstructures  22  of the lower substrate  20 . A color filter  26  is formed on the microstructures  22  of the lower substrate  20 . An alignment layer  28  is coated on the conductive layer  24  for alignment. A plurality of fluid media is filled into a gap between the microstructures  12  of the upper substrate  10  or the microstructures  22  of the lower substrate  20  by filling, ODF, or coating. A sealed structure (not shown) is formed by a plurality of polymers which is added a plurality of initiators and going through a polymerization process.  
         [0024]     Reference is made to  FIGS. 1A  to  1 F for the manufacturing procedure of a passive matrix LCD in accordance with the present invention.  
         [0025]      FIGS. 1A and 1B  show the manufacture method of an upper substrate. In  FIG. 1A , an upper substrate  10  made of a glass substrate or a flexible substrate is provided, and a plurality of microstructures  12  is produced on the upper substrate  10 . The microstructures  12  are formed by photo (or heat) polymerization, printing or embossing. The microstructures  12  are, for example, a plurality of non-continuous microstructures or a plurality of continuous microstructures. The non-continuous microstructures are circular, rectangular, or other geometric shapes. The height of the microstructures is equal to or smaller than the cell gap, and the microstructures act as spacers for the gap cell, alignment layer, and/or microwalls. The microstructures on a substrate are all arranged in the same direction with linearly arrangement between the conductive layers, and thus electrodes in row can be produced. If a rubbing method is adopted for the alignment, the rubbing direction is parallel to the direction of the microstructures to avoid the occurrence of defects.  
         [0026]     In  FIG. 1B , a conductive layer  14  is formed on the microstructures, where the conductive layer  14  is produced by a sputtering or an inkjet process, and the conductive layer acts as a passive matrix electrode.  
         [0027]      FIGS. 1C  to  1 E show the manufacture method of a lower substrate. In  FIG. 1C , a lower substrate made of a glass substrate or a flexible substrate is provided, and a plurality of microstructures  22  is produced on the lower substrate  20 . The microstructures  22  are produced by photo or heat polymerization, printing, or embossing process. The microstructures  22  are, for example, a plurality of non-continuous microstructures or a plurality of continuous microstructures. The non-continuous microstructures are circular, rectangular, or other geometric shapes. The height of the microstructures  22  is equal to or smaller than the cell gap, and the microstructures  22  act as spacers for gap cell, alignment layer, and/or microwalls. The microstructures  22  on a substrate are all arranged in the same direction with linearly arrangement between the conductive layers, and electrodes in row can be produced. If a rubbing method is adopted for the alignment, the rubbing direction is parallel to the direction of the microstructures to avoid the occurrence of defects.  
         [0028]     In the manufacturing procedure of the plurality of microstructures  12 ,  22 , a sealed structure is produced by a phase separation method, and a plurality of initiators and polymer monomers are added to mix with the display fluid media and dropped, coated, or filled onto the microstructures. The sealed structure can be formed by a mask or other patterns to control an illuminating position for the phase separation.  
         [0029]     In  FIG. 1D , a color filter  26  is formed on the microstructures  22  of the lower substrate  20 . The color filter  26  is produced by an inkjet process. In  FIG. 1E , a conductive layer  24  is formed on the color filter  26 . The conductive layer  24  is produced by a sputtering or an inkjet process, and the conductive layer acts as a passive matrix electrode.  
         [0030]      FIG. 1F , an alignment layer  28  is coated on the conductive layer  24  for alignment.  
         [0031]      FIG. 1G , shows the manufacturing procedure for assembling the upper substrate  10  and the lower substrate  20 , such that a gap  30  is formed between the microstructures  12  of the upper substrate  10  and the microstructures  22  of the lower substrate  20  after the upper and lower substrates  10 ,  20  are assembled, and this combining procedure adopts a traditional adhesion method. A plurality of display fluid media is then filled into the gap. The filling is achieved by a vacuum filling process, and the display fluid medium is a liquid crystal. The microstructures are not sealed when the upper and the lower substrates are combined, and the display fluid media can flow therein.  
         [0032]     In view of the description above, the manufacturing procedure of a passive matrix display in accordance with the present invention primarily utilizes the vacuum filling process. If an ODF or a coating method is adopted, the plurality of display fluid media is filled between the microstructures of one of the substrates (the upper substrate or the lower substrate) before combining the upper and lower substrates as shown in  FIG. 1F , and the display fluid medium is a liquid crystal.  
         [0033]     Reference is made to  FIGS. 2A and 2B  for side views of the microstructures with different heights. The height of the embossed structures is equal to the cell gap when the upper  10  and lower  20  substrates are compressed and combined as shown in  FIG. 2A . By then, the structure can support the cell gap and act as a spacer.  FIG. 2B  shows a side view of the embossed structures having a height smaller than or equal to the cell gap. By then, the structure can act as a wide-view-angle protrusion and spacer.  
         [0034]     Reference is made to  FIGS. 3A  to  3 C for top views of the non-continuous microstructures of the upper and lower substrates.  FIG. 3A  shows a top view of the non-continuous microstructures of the lower substrate. The non-continuous microstructures  12  are in the shape of a rectangular bar, and a conductive layer  14  is formed between the non-continuous microstructures by a sputtering or an inkjet method.  FIG. 3B  shows a top view of the non-continuous microstructures of the upper substrate. The non-continuous microstructures  22  are in the shape of a rectangular bar, and a conductive layer  24  is formed between the non-continuous microstructures by a sputtering or an inkjet method.  FIG. 3C  shows a top view of the non-continuous microstructures of the upper and lower substrates after the upper and lower substrates are combined. The non-continuous microstructures  22  of the upper substrate and the microstructures  12  of the lower substrate are in the shape of a rectangular bar.  
         [0035]     Reference is made to  FIGS. 4A  to  4 C for top views of non-continuous microstructures of the upper and lower substrates.  FIG. 4A  shows a top view of the non-continuous microstructure of the upper substrate. The non-continuous microstructure  12  is circular, and a conductive layer  14  is formed between the non-continuous microstructures by a sputtering or an inkjet method.  FIG. 4B  shows a top view of the non-continuous microstructure of the lower substrate. The non-continuous microstructure  22  is circular, and a conductive layer  24  is formed between the non-continuous microstructures by a sputtering or an inkjet method.  FIG. 4C  shows a top view of the non-continuous microstructure of the combined upper and lower substrates. The non-continuous microstructure  12  of the upper substrate and the non-continuous microstructure  22  of the lower substrate are in a rectangular bar shape.  
         [0036]     Reference is made to  FIGS. 5A  to  5 C for a top view of microstructures with different shapes of the upper and lower substrates.  FIG. 5A  shows a top view of continuous microstructure of the lower substrate. The non-continuous microstructures  12  is in the shape of a continuous long bar, and a conductive layer  14  is formed between the non-continuous microstructures by a sputtering or an inkjet method.  FIG. 5B  is a top view of non-continuous microstructure of an upper substrate. The non-continuous microstructure  22  is in the shape of a continuous long bar, the non-continuous microstructure is in the shape of a continuous long bar, and a conductive layer  24  is formed between the non-continuous microstructures by a sputtering or an inkjet method.  FIG. 5C  is a top view of non-continuous microstructure with different shapes of the combined upper and lower substrates. The non-continuous microstructure  22  of the upper substrate and the non-continuous microstructure  12  of the lower substrate are in the shape of a continuous long bar.  
         [0037]     Reference is made to  FIG. 6  for a top view of the continuous microstructures  12  and the non-continuous microstructures  22  of the combined upper and lower substrates according to another form. The non-continuous microstructure is circular.  
         [0038]     The arrangements of the continuous and non-continuous microstructures are not limited to those depicted in FIGS.  1  to  6 . The arrangement of the microstructures allows the upper and lower substrates to be installed in opposite directions.  
         [0039]     Reference is made to  FIG. 7  for a top view of a sealed structure produced by the combining procedures as shown in FIGS.  1  to  6  and then by the phase separation method. The sealed structure is formed a polarity of polymer by a phase separation method.  
         [0040]     If the microstructures in the display are produced by an embossing process, the embossing process is performed generally after a conductive layer is disposed. The residual layer in the embossing process will increase the driving voltage and an excessively large pressure applied to a flexible substrate during the embossing process may cause the conductive layer to crack easily. Therefore, the present invention produces various microstructures on a general substrate or a flexible substrate, and then disposes a conductive layer between the embossed structures by sputtering or inkjet, so as to prevent an increase of driving voltage caused by the residual layer in the embossing process.  
         [0041]     In the meantime, the present invention also can utilize a phase separation method to combine an upper substrate and a lower substrate and give a stronger support to the cell gap. The microstructures on the same substrate are arranged in the same direction, and thus electrodes in rows can be produced. If a rubbing method is used for the alignment, then the rubbing direction is parallel to the direction of the arrangement of microstructures to avoid the occurrence of defects. Such a structure acts as the alignment layer or as a bank for color filter. Since the embossed microstructures are not sealed when the upper and lower substrates are combined, display media can flow therein as the they are filled.  
         [0042]     A regular LCD substrate or a flexible display substrate requires certain microstructures to act as spacers, alignment layer, or banks for a color filter. Embossing is a good method for producing microstructures, which does not require many complicated steps as in photolithography process. The manufacturing process is thus quick and can reduce the manufacturing time and cost. If the structure of the upper and lower substrates goes with the phase separation method, the upper and lower substrates can be adhered closely with each other and a stronger support between the cell gaps is achieved.  
         [0043]     Display manufacturers hope to produce the next-generation flexible display by a low-temperature, low-vacuum (or vacuum free), printable process and use a roll-to-roll method for the manufacture, and thus the embossing technology is a good choice. It is expected that the third generation display (flexible display) will use a flexible substrate to substitute the fragile glass substrate. Therefore, the flexible display product will be lighter and thinner, and its flexibility makes the product more portable. In the meantime, the product is easy to manufacture and cut into different shapes to provide diversified appearances and freedoms for the design. Such product not only substitutes the second generation flat panels, but also offers a good opportunity for the developing market.  
         [0044]     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.