Patent Publication Number: US-2013235321-A1

Title: Method of producing film substrate

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International Application PCT/JP2010/069922 filed on Nov. 9, 2010 and designated the U.S., the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The embodiments described herein are related to a method of producing a film substrate having flexibility. 
     BACKGROUND OF THE INVENTION 
     According to conventional techniques, a liquid crystal panel has a sealing part formed for sealing a liquid crystal material between two opposite substrates, and a liquid crystal is injected into the sealing part (see, for example, Patent Documents 1 through 3). 
       FIG. 6  is a plan view showing a mother film  20  for explaining a conventional method of producing a film substrate. 
       FIG. 7  explains a conventional step of injecting a liquid crystal. 
       FIG. 8  is a sectional view along line B-B in  FIG. 7 . 
     Two first substrates  11  shown in  FIG. 7  are formed from a mother film  20  shown in  FIG. 6  by, for example, performing a cutting process along cutting lines  14 . 
     A sealing part  13  that seals a liquid crystal material  15  is formed into a rectangle (of four sides  13   a  through  13   d ) having a liquid crystal material injection port  13   e  projecting outwards on the mother film  20 . At the tip of the liquid crystal material injection port  13   e , there is an opening  13   f.    
     Each of the cutting lines  14  for cutting out the first substrate  11  from the mother film  20  is rectangular. Part of the tip of the liquid crystal material injection port  13   e  of the sealing part  13  is cut along the cutting line  14 . Note that the cutting lines  14  are virtual lines, as indicated by double-dot dash lines, and are not visible. 
     A second substrate  12  shown in  FIG. 7  is cut out from a mother film that is similar to the mother film  20 , and is adhered to the first substrate  11  in such a manner that transparent electrodes  11   a  and  12   a  are opposite to each other. The first substrate  11  and the second substrate  12  adhered to each other are decompressed until, for example, the sealing part  13  becomes a vacuum, and under that condition, the liquid crystal material injection port  13   e  is inserted into the liquid crystal material  15  of a liquid crystal holding part  16 . Thereafter, when the decompression in the sealing part  13  is cancelled, the liquid crystal material  15  is injected into the sealing part  13 . 
     Patent Document 1: Japanese Laid-open Patent Publication No. 2002-049043 
     Patent Document 2: Japanese Laid-open Patent Publication No. 2002-072915 
     Patent Document 3: Japanese Laid-open Patent Publication No. 2000-310784 
     BRIEF SUMMARY OF THE INVENTION 
     A method of producing a film substrate disclosed herein includes forming a sealing part for sealing a liquid crystal material between a first substrate and a second substrate into a shape having an outward projecting liquid crystal material injection port of the sealing part, and cutting the first substrate and the second substrate into a shape having outward projecting parts opposite to the liquid crystal material injection port, in which the forming of the sealing part forms the liquid crystal material injection port of the sealing part on a cutting line of the cutting of the first substrate and the second substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a plan view showing a mother film illustrated for explaining a sealing part forming step and a substrate cutting step according to an embodiment; 
         FIG. 2  is an enlarged view showing part A of  FIG. 1 ; 
         FIG. 3  is a plan view showing a first substrate and a second substrate before a liquid crystal is injected according to an embodiment; 
         FIG. 4  explains a liquid crystal injection step according to an embodiment; 
         FIG. 5  is a plan view showing the first substrate and the second substrate after a liquid crystal has been injected according to an embodiment; 
         FIG. 6  is a plan view showing a mother film for explaining a conventional method of producing a film substrate; 
         FIG. 7  shows a conventional liquid crystal injection step; 
       and 
         FIG. 8  is a sectional view along line B-B. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The sealing part  13  shown in  FIG. 7  is cut out together with the first substrate  11  and the second substrate  12  along the cutting line  14  in the liquid crystal material injection port  13   e  in the projecting direction by a cutter or the like. Accordingly, there is a narrow margin between the first substrate  11  (second substrate  12 ) and an injection port forming side  13   a , which is the side on which the liquid crystal material injection port  13   e  is provided among the four sides ( 13   a  through  13   d ) of the rectangle of the sealing part  13 . 
     Accordingly, when the liquid crystal material  15  is injected into the sealing part  13 , it is not only injected into the sealing part  13  through the liquid crystal material injection port  13   e  (a liquid crystal material  15 - 1 ), but part of it flows to the peripheries of the first substrate  11  and the second substrate  12  (a liquid crystal material  15 - 2 ). 
     As described above, the liquid crystal material  15 - 2  that has flowed to the peripheries of the first substrate  11  and the second substrate  12  deteriorates as shown in  FIG. 8  ( 15 - 2 ′), and corrodes, for example, the transparent electrode  12   a  of the second substrate  12  ( 12   a ′). 
     As described above, when a liquid crystal material has flowed to peripheries of a sealing part for sealing a liquid crystal material, electrodes are corroded. Thus, a step of washing a panel is necessary for eliminating a liquid crystal material that has flowed to peripheries of a sealing part. Further, a liquid crystal material that has flowed to peripheries of a sealing part cannot be utilized, giving rise to the need for more liquid crystal material than is actually injected into a sealing part. 
     Hereinafter, explanations will be given for a method of producing a film substrate according to an embodiment by referring to the drawings. 
       FIG. 1  is a plan view showing a mother film  10  illustrated for explaining a sealing part forming step and a substrate cutting step according to an embodiment. 
     First, explanations will be given for the sealing part forming step and the substrate cutting step. 
     In the sealing part forming step, a sealing part  3  for sealing a liquid crystal material  5  between a first substrate  1  and a second substrate  2  shown in  FIG. 3  is formed into a rectangle (such as a square, an oblong, or the like) having a liquid crystal material injection port  3   e  projecting outwards. This step will be explained later in more detail. 
     In the substrate cutting step, the first substrate  1  and the second substrate  2  are cut out so that they become rectangles respectively having outward projecting parts  1   c  and  2   c  that are opposite to the liquid crystal material injection port  3   e.    
     Note that a rectangle as a shape of the sealing part  3 , the first substrate  1 , and the second substrate  2  is only an example, and thus they can employ other shapes. 
     The mother film  10  shown in  FIG. 1  is, for example, a flexible transparent film made of plastic. Two (an example of at least one) of the first substrates  1  shown in  FIG. 3  are formed by cutting the mother film  10  by performing a die-cut process or the like along a cutting line. 
     Each of the cutting lines  4 , which indicate the shape for die cutting to be performed on the first substrate  1  and second substrate  2 , depicts a rectangle having an outward projecting part  4   a  that is opposite to the liquid crystal material injection port  3   e  of the sealing part  3 . The cutting lines  4  are virtual lines, as depicted by double-dot dash lines, and do not have to be visible lines. 
     When the sealing part  3  is to be formed, the sealing part  3  is formed so that it is a rectangle having the liquid crystal material injection port  3   e  projecting outwards (sealing part forming step). At the projecting tip of the liquid crystal material injection port  3   e , an opening  3   f  is provided. 
     In the sealing part forming step, the liquid crystal material injection port  3   e  of the liquid crystal material injection port  3   e  and an injection port forming side  3   a , which is one side of four sides  3   a  through  3   d  of the sealing part  3 , are formed along the cutting line  4 . Accordingly, part of the liquid crystal material injection port  3   e  and the injection port forming side  3   a  in the width direction are cut out in the substrate cutting step. 
     Note that it is also possible to employ a configuration in which the injection port forming side  3   a  is not formed entirely on the cutting line  4 , but a portion (for example, an area of 2 mm in length or longer) extending at least to liquid crystal material injection port  3   e  on both sides of the liquid crystal material injection port  3   e  is formed on the cutting line  4 . 
     The liquid crystal material injection port  3   e  alone may also be formed on the cutting line  4 . 
     As shown in  FIG. 2 , which is an enlarged view showing part A in  FIG. 1 , in the sealing part forming step, sealing width W 1  of the liquid crystal material injection port  3   e  and the injection port forming side  3   a  located on the cutting line  4  is greater than sealing width W 2  of the three sides  3   b  through  3   d , i.e., the sides other than the injection port forming side  3   a.    
     In the present embodiment, sealing width W 1  of the liquid crystal material injection port  3   e  and the injection port forming side  3   a  is 2.5 mm, while sealing width W 2  of the three sides other than the injection port forming side  3   a  ( 3   b  through  3   d ) is 1.5 mm. The width of the part inside of the cutting line  4  in the liquid crystal material injection port  3   e  and the injection port forming side  3   a  is 1.5 mm, and accordingly, even if part of the sealing width of the liquid crystal material injection port  3   e  and the injection port forming side  3   a  is cut along the cutting line  4  (a liquid crystal material injection port  3   e ′ and an injection port forming side  3   a ′ shown in  FIG. 3 ), a sealing width that is the same or substantially the same as that of the three sides  3   b  through  3   d  is secured. 
     Also, the width (1.0 mm) of the part outside of the cutting line  4  in the liquid crystal material injection port  3   e  and the injection port forming side  3   a  is smaller than the width (1.5 mm) of the inner part, reducing the amount of materials to be used as the sealing part  3 . 
     It is also possible for the entire sealing part  3  to have a sealing width that is large enough to secure a sufficient sealing width even if the liquid crystal material injection port  3   e  and the injection port forming side  3   a  are cut (for example, 2.5 mm). However, this would lead to a large increase in the amount of materials to be used as the sealing part  3 . 
     The sealing part  3  formed as above seals the liquid crystal material  5  shown in  FIG. 4  between the first substrate  1  and the second substrate  2  shown in  FIG. 3 . In the present embodiment, the sealing part  3  is also used as an adhesive for fixing the connection between the first substrate  1  and the second substrate  2 . 
     Next, when the first substrate  1  and the second substrate  2  are cut out into the shapes shown in  FIG. 3 , the first substrate  1  and the second substrate  2  are adhered to each other by using, for example, the above sealing part  3  in such a manner that transparent electrodes  1   a  and  2   a  are opposite to each other. Note that the second substrate  2  as well may be formed from, for example, a flexible transparent mother film made of plastic similarly to the mother film  10 . 
     Thereafter, by using, for example, a Thomson die, die cutting is performed so as to form the first substrate  1  and the second substrate  2  into large rectangles (along the cutting line  4  having a projection part  4   a  as shown in  FIG. 1 ) including an extending part  1   b  extending to the upper direction in  FIG. 3  and an extending part  2   b  extending to the left in  FIG. 3 , respectively. 
     Thereby, the first substrate  1  and the second substrate  2  are cut out into rectangles having the outward projecting parts  1   c  and  2   c , which are opposite to the liquid crystal material injection port  3   e  (substrate cutting step). Also, the sealing part  3  is formed by performing die cutting on part of the liquid crystal material injection port  3   e  and the injection port forming side  3   a  in the width direction along the cutting line  4 . 
     It is also possible to cut out only the liquid crystal material injection port  3   e  by performing a die cutting process along the cutting line  4 . 
     Thereafter, the left edge of the first substrate  1  in  FIG. 3  is cut, and the upper edge of the second substrate  2  shown in  FIG. 3  is also cut. Thereby, the first substrate  1  and the second substrate  2  are cut out into different-sized rectangles having the extending parts  1   b  and  2   b  extending in different directions. The extending parts  1   b  and  2   b  can be formed by making grooves along the cutting line by, for example, laser irradiation, and eliminating unnecessary parts. 
     Next, explanations will be given for the “liquid crystal injection step”, in which the liquid crystal material  5  is injected into the sealing part  3 . 
     The first substrate  1  and the second substrate  2  adhered as shown in  FIG. 3  are decompressed by a decompression unit (not shown) until the sealing part  3  becomes a vacuum, and the projection parts  1   c  and  2   c  are inserted into the liquid crystal material  5  of a liquid holding part  6  as shown in  FIG. 4 , and thereafter the decompression is cancelled. Thereby, the liquid crystal material  5  is injected into the sealing part  3  (liquid crystal injection step). 
     As described above, the injection port forming side  3   a  and the liquid crystal material injection port  3   e  of the sealing part  3  are located on peripheries of the first substrate  1  and the second substrate  2  because they are formed on the cutting line  4  and a portion of them is cut in the width direction. This prevents the liquid crystal material  5  from flowing from the liquid crystal material injection port  3   e  of the sealing part  3  to along the peripheries of the first substrate  1  and the second substrate  2 . 
     After the liquid crystal material  5  has been injected into the sealing part  3 , an appropriate process such as sealing the liquid crystal material  5  within the sealing part  3  is performed, in which a washing step of removing the liquid crystal material  5  that has flowed from the liquid crystal material injection port  3   e  of the sealing part  3  can be omitted because the liquid crystal material  5  has been prevented from flowing from the liquid crystal material injection port  3   e  of the sealing part  3 . As described above, a film substrate that can be used as a liquid crystal panel made of a film can be produced. 
     The sealing part forming step in the above explained present embodiment forms the liquid crystal material injection port  3   e  of the sealing part  3  on the cutting line  4  in the substrate cutting step. 
     Accordingly, the liquid crystal material injection port  3   e  is located on peripheries of the first substrate  1  and the second substrate  2 , reducing a space into which the liquid crystal material  5  flows after flowing along peripheries of the first substrate  1  and the second substrate  2 . 
     Accordingly, the present embodiment can prevent the liquid crystal material  5  from flowing to portions around the sealing part  3  for sealing the liquid crystal material  5 . Further, because the liquid crystal material  5  is prevented from flowing to such portions, it is possible to reduce the amount of material to be used as the liquid crystal material  5 , to reduce the panel washing step, and to prevent corrosion and the like of the transparent electrodes  1   a  and  2   a  that would be caused by the flowing of the liquid crystal material  5  to such portions. 
     Also, according to the present embodiment, in the sealing part forming step, the liquid crystal material injection port  3   e  of the sealing part  3  and the injection port forming side  3   a  including the liquid crystal material injection port  3   e  (at least a portion extending to the liquid crystal material injection port  3   e ) are formed on the cutting line  4  of the substrate cutting step. Accordingly, the liquid crystal material injection port  3   e  and the injection port forming side  3   a  are located on peripheries of the first substrate  1  and the second substrate  2 , making it possible to prevent the liquid crystal material  5  from flowing to portions around the sealing part  3  for sealing the liquid crystal material  5  more securely. 
     Also, in the present embodiment, sealing width W 1  of the liquid crystal material injection port  3   e  is greater than sealing width W 2  of the sides  3   b  through  3   d , which are all the sides except for the injection port forming side  3   a  in the sealing part forming step. This makes it possible to secure the sealing width so as to prevent the unnecessary flowing of the liquid crystal material  5  even if part of the liquid crystal material injection port  3   e  in the width direction is cut in the substrate cutting step. 
     Also, according to the present embodiment, in the sealing part forming step, sealing width W 1  of the injection port forming side  3   a  on the cutting line  4  is greater than sealing width W 2  of the other sides, making it possible to prevent the unnecessary flowing of the liquid crystal material  5  more securely even if part of the injection port forming side  3   a  in the width direction is cut in the substrate cutting step. 
     Also, according to the present embodiment, the liquid crystal material injection port  3   e  of the sealing part  3  is cut out by die cutting along the cutting line  4  in the substrate cutting step. This makes it possible to cut out part of the liquid crystal material injection port  3   e  in the width direction along the cutting line  4  accurately, and thus to prevent an uneven sealing width of the liquid crystal material injection port  3   e.    
     Also, according to the present embodiment, the liquid crystal material injection port  3   e  and the injection port forming side  3   a  (at least a portion extending to the liquid crystal material injection port  3   e ) of the sealing part  3  are cut out by die cutting along the cutting line  4 . This makes it possible to cut out part of the liquid crystal material injection port  3   e  and the injection port forming side  3   a  in the width direction along the cutting line  4  accurately, and thus to prevent an uneven sealing width of the liquid crystal material injection port  3   e.    
     Also, according to the present embodiment, the liquid crystal material injection port  3   e  is formed into a shape projecting outwards (a rectangle), making it possible to enhance the durability against variations in pressure occurring (during a heating process or the like) in the liquid crystal panel of a flexible film substrate.