Patent Publication Number: US-2013248086-A1

Title: Film substrate liquid crystal sealing method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International Application PCT/JP 2010/073462 filed on Dec. 24, 2010 and designated the U.S., the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The embodiment discussed herein is related to a film substrate liquid crystal sealing method for sealing a liquid crystal material injected between first and second substrates. 
     BACKGROUND OF THE INVENTION 
     Conventionally, a liquid crystal panel for making a display by affixing one transparent substrate on which transparent electrodes are disposed to the other transparent substrate so that the electrodes face each other, by sealing a liquid crystal material between the transparent substrates, and by applying a voltage between the electrodes to make the liquid crystal material react is known. 
     As one method for injecting a liquid crystal material, a method for injecting a liquid crystal material via an opening part arranged in a sealing frame part for affixing the first substrate and the second substrate can be cited (for example, see Patent Document 1). 
     This injection method is briefly described with reference to  FIGS. 4A to 4C  and  5 A to  5 I. 
     As illustrated in  FIGS. 4A to 4C , a first substrate  110  and a second substrate  120 , which are respectively composed of a transparent film, are affixed by a rectangular sealing frame part  130 . On one of four sides of the sealing frame part  130 , an opening part  131  for injecting a liquid crystal material is formed. The sealing frame part  130  seals a liquid crystal material to be described later between the first substrate  110  and the second substrate  120 . 
     The first substrate  110  and the second substrate  120 , which are affixed by the sealing frame part  130  as illustrated in  FIG. 5A , are accommodated by a housing not illustrated, and the inside of the housing is depressurized, for example, to a vacuum by depressurizing means (depressurized state). 
     Then, as illustrated in  FIG. 5B , the opening part  131  side illustrated in  FIGS. 4A and 4B  of the sealing frame part  130  is immersed in a liquid crystal material  140  within a liquid crystal reservoir  170  in the depressurized state unchanged. 
     When the depressurized state of the inside of the housing not illustrated is released to a normal pressure state, an outside atmospheric pressure P is applied to the liquid crystal material  140 , which is filled within the sealing frame part  130  as illustrated in  FIGS. 5C and 5D . Thereafter, the first substrate  110  and the second substrate  120  are taken out of the liquid crystal material  140  within the liquid crystal reservoir  170  as illustrated in  FIG. 5E . 
     Then, as illustrated in  FIG. 5F , the opening part  131  (see  FIGS. 4A and 4B ) side of the sealing frame part  130  of the first substrate  110  and the second substrate  120  is immersed in a sealing material  151  within a sealing material reservoir  180 . 
     Thereafter, when the first substrate  110  and the second substrate  120  are taken out of the sealing material  151  within the sealing material reservoir  180 , the sealing material  151  is adhered to the first substrate  110  and the second substrate  120  as illustrated in  FIG. 5G . 
     Next, an ultraviolet ray irradiation part  160  hardens the adhered sealing material  151  with an ultraviolet ray UV (hardened sealing material  152 ) as illustrated in  FIG. 5 . Then, a portion  152 ′ of the hardened sealing material  152  is removed along surfaces of the first substrate  110  and the second substrate  120 . 
     As another method for injecting a liquid crystal material, a method for injecting a liquid crystal material via an opening arranged on a first substrate or a second substrate can be cited (for example, see Patent Documents 2 and 3). Also with this method, a sealing material is hardened and an unneeded protrusion part is removed similarly to the method for injecting a liquid crystal material via the opening arranged in the sealing frame part as described above. 
     SUMMARY OF THE INVENTION 
     A film substrate liquid crystal sealing method disclosed in this specification includes injecting a liquid crystal material between a first substrate and a second substrate via an opening part formed on the first substrate, the second substrate or combination thereof, injecting a sealing material for sealing the liquid crystal material injected in the injecting of the liquid crystal material via the opening part, and hardening the sealing material in a pressed state by pressing down a portion that protrudes from the opening part of the sealing material injected in the injecting of the sealing material toward an inside of the opening part with a pressing member. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a disassembly view of a film substrate for explaining a liquid crystal sealing method according to an embodiment; 
         FIG. 1B  is a plan view of the film substrate for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 1C  is a cross-sectional view taken along a line A-A of  FIG. 1B ; 
         FIG. 2A  is a cross-sectional view (No. 1) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 2B  is a cross-sectional view (No. 2) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 2C  is a cross-sectional view (No. 3) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 2D  is a cross-sectional view (No. 4) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 2E  is a cross-sectional view (No. 5) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 2F  is a cross-sectional view (No. 6) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 2G  is a cross-sectional view (No. 7) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 2H  is a cross-sectional view (No. 8) for explaining the liquid crystal sealing method according to the embodiment; 
         FIG. 3A  is a cross-sectional view for explaining a shape of an opening part of a substrate in the embodiment; 
         FIG. 3B  is a cross-sectional view for explaining a shape of an opening part of a substrate in a first modification example of the embodiment; 
         FIG. 3C  is a cross-sectional view for explaining a shape of an opening part of a substrate in a second modification example of the embodiment; 
         FIG. 3D  is a cross-sectional view for explaining a shape of an opening part of a substrate in a third modification example of the embodiment; 
         FIG. 3E  is a cross-sectional view for explaining a shape of an opening part of a substrate in a fourth modification example of the embodiment; 
         FIG. 4A  is a disassembly view of a film substrate for explaining a related liquid crystal injection method; 
         FIG. 4B  is a plan view of the film substrate for explaining the related liquid crystal injection method; 
         FIG. 4C  is a cross-sectional view taken along a line B-B of  FIG. 4B ; 
         FIG. 5A  is a cross-sectional view (No. 1) for explaining the related liquid crystal injection method; 
         FIG. 5B  is a cross-sectional view (No. 2) for explaining the related liquid crystal injection method; 
         FIG. 5C  is a cross-sectional view (No. 3) for explaining the related liquid crystal injection method; 
         FIG. 5D  is a cross-sectional view (No. 4) for explaining the related liquid crystal injection method; 
         FIG. 5E  is a cross-sectional view (No. 5) for explaining the related liquid crystal injection method; 
         FIG. 5F  is a cross-sectional view (No. 6) for explaining the related liquid crystal injection method; 
         FIG. 5G  is a cross-sectional view (No. 7) for explaining the related liquid crystal injection method; 
         FIG. 5H  is a cross-sectional view (No. 8) for explaining the related liquid crystal injection method; and 
         FIG. 5I  is a cross-sectional view (No. 9) for explaining the related liquid crystal injection method; 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     With the method for injecting a liquid crystal material via the opening part  131  arranged in the sealing frame part  130  as described above with reference to  FIGS. 4A to 4C  and  5 A to  5 I, the liquid crystal material  140  having an amount that is equal to or larger than that injected into the sealing frame part  130  is needed within the liquid crystal reservoir  170 . Normally, there is a problem that the liquid crystal material  140  cannot be used due to a contamination (absorption of water content or the like) if the liquid crystal material  140  is exposed to the air for a longer time period. 
     Additionally, a step of removing the hardened sealing material  152  is needed, posing a problem that longer time is needed or a problem that the sealing material can be possibly peeled off or the vicinity of the opening part can be broken. The problems associated with the removal of the hardened sealing material can similarly occur also in the method for injecting a liquid crystal material via the opening arranged on the first or the second substrate. 
     A film substrate liquid crystal sealing method according to an embodiment is described below with reference to the drawings. 
       FIGS. 1A and 1B  are a disassembly view and a plan view of a film substrate for explaining the liquid crystal sealing method according to the embodiment.  FIG. 1C  is a cross-sectional view taken along a line A-A of  FIG. 1B . 
     As illustrated in  FIGS. 1A to 1C , a first substrate  10  and a second substrate  20 , which are respectively made of flexible plastic, are affixed by a rectangular sealing frame part  30  so that transparent electrodes, not illustrated, of the substrates face each other nearly orthogonally. Either of the first substrate  10  and the second substrate  20  does not need to be transparent. 
     The first substrate  10  is provided with, for example, an opening part  11  having a circular cross-section. The opening part  11  is formed, for example, at one of four corners in a portion as opposed to a region enclosed by the sealing frame part  30 . The opening part  11  may be formed not on the first substrate  10  but on the second substrate  20 , or on both of the first substrate  10  and the second substrate  20 . Moreover, the number of opening parts formed, a shape of the opening part  11  are not particularly limited as long as a liquid crystal material and a sealing material, which will be described later, can be injected. 
     As illustrated in  FIG. 3A , a cross-sectional area of an opening area A 1  on an external side of the opening part  11  is smaller than an opening area A 2  on an internal side (A 1 &lt;A 2 ), and a cross-sectional area decreases gradually from an edge of the internal side (opening area A 2 ) toward an edge of the external side (opening area A 1 ) as will be described later. 
     The sealing frame part  30  in this embodiment seals the liquid crystal material to be described later between the first substrate  10  and the second substrate  20 , and affixes the first substrate  10  and the second substrate  20  as described above. 
       FIGS. 2A to 2H  are cross-sectional views for explaining the liquid crystal sealing method according to the embodiment. 
     As illustrated in  FIG. 2A , the first substrate  10  and the second substrate  20 , which are affixed by the sealing frame part  30 , are depressurized by depressurizing means, not illustrated, so that the inside of the sealing frame part  30  enters, for example, in a vacuum state. 
     Then, as illustrated in  FIG. 2B , the liquid crystal material  40  is injected between the first substrate  10  and the second substrate  20  via the opening part  11 , for example, by being dripped while the first substrate  10  and the second substrate  20  are in the depressurized state (liquid crystal material injection step). 
     As illustrated in  FIG. 2C , the depressurized state is released to a normal pressure state, and also a protrusion part  41  of the liquid crystal material  40 , which does not fit within the opening part  11 , is filled within the sealing frame part  30  by an outside atmospheric pressure P. Then, the liquid crystal material  40  is filled within the entire sealing frame part  30  as illustrated in  FIG. 2D . 
     Next, as illustrated in  FIG. 2E , the sealing material  51  that seals the liquid crystal material  40  is coated (injected), for example, by being dripped from the opening part  11  (sealing material injection step). 
     A protrusion part  51   a  that is injected in this way and protrudes from the opening part  11  of the sealing material  51  as illustrated in  FIG. 2F  is flattened by a pressing member  60  toward the inside of the opening part  11 . When the protrusion part  51   a  is flattened, the sealing material  51  is flattened (pressed down) to be clipped so that the pressing member  60  makes contact with the edge (the opening area A 1  in  FIG. 3A ) of the external side of the opening part  11 , and an unneeded sealing material  51  is made to go out of the pressing member  60 . 
     Additionally, a hardening mechanism (hardening means) is embedded in the pressing member  60 . Only the sealing material  51  at the opening part  11  is hardened in the state where the sealing member  51  is being pressed down, whereby the unneeded sealing material  51  can be easily removed in an unhardened state. 
     Note that the pressing member  60  has, at its bottom, a flat surface part  60   a  that is larger than the opening area A 1 , illustrated in  FIG. 3A , of the edge on the external side of the opening part  11 . If a diameter of the opening area A 1  is 2 mm, it is preferable to make the diameter of the plane part  60   a , for example, but not particularly limited to, larger than 2 mm and equal to or smaller than 10 mm. The pressing member  60  includes, for example, a cylinder tube  61 , and a light guiding part  62  such as an optical fiber within the tube  61 . A pressing surface of the pressing unit  60  is a flat surface. 
     As illustrated in  FIG. 2G , only the portion injected via the opening part  11  of the sealing material  51  is hardened in the flattened state unchanged by being irradiated with an ultraviolet ray UV that is guided by the light guiding part  62  (sealing material hardening step). 
     Note that the pressing member  60  does not always need to irradiate the sealing material  51  portion with light. For example, a light irradiation part different from the pressing member  60  may irradiate the sealing material  51  portion with light, for example, from a side as opposed to the substrate without hardening the sealing material  51   b  that protrudes externally to the pressing member  60 , for example, in a state where the transparent pressing member  60  flattens the protrusion part  51   a  of the sealing material  51 . Moreover, the sealing material  51  may be hardened with light other than an ultraviolet ray, a chemical reaction, heat, or the like. Especially, if the sealing material  51  is hardened with heat, it is preferable to take measures such as heat insulation so as to prevent heat from being transferred to the other members such as the sealing material  51 ′ external to the opening part  11 , the first substrate  10  and the like. 
     As illustrated in  FIG. 2H , after the sealing material  51  injected via the opening part  11  is hardened with the ultraviolet ray (hardened sealing material  52 ), an unhardened sealing material  51 ′ external to the opening part  11  is removed, for example, by being wiped. As a result, the sealing of the liquid crystal material  40  on the film substrate (liquid crystal panel) is complete. 
     First to fourth modification examples of this embodiment are described next. 
       FIGS. 3A to 3E  are cross-sectional views for explaining shapes of the opening part  11  in this embodiment and the first to the fourth modification examples of this embodiment. 
     In the above described opening part  11  illustrated in  FIG. 3A , the opening area A 1  on the external side is smaller than the opening area A 2  on the internal side (A 1 &lt;A 2 ), and a cross-sectional area decreases gradually from the edge (opening area A 2 ) of the internal side toward the edge of the external side (opening area A 1 ) at a certain ratio. 
     Similarly to the opening part  11  illustrated in  FIG. 3A , an opening area All on an external side on an opening part  11 - 1  of a first substrate  10 - 1  illustrated in  FIG. 3B  (first modification example) is smaller than an opening area A 12  on an internal side (A 11 &lt;A 12 ), and a cross-sectional area decreases gradually from an edge (opening area A 12 ) of the internal side toward an edge of the external side. However, since the opening part  11 - 1  takes the shape of a bowl, the ratio at which the cross-sectional area decreases grows by degrees. 
     An opening area A 21  on an external side of an opening part  11 - 2  of a first substrate  10 - 2  illustrated in  FIG. 3C  (second modification example) is smaller than an opening area A 22  on an internal side (A 21 &lt;A 22 ). The opening part  11 - 2  has a small-diameter part (small cross-sectional area part)  11   a  on the external side, a large-diameter part (larger cross-sectional area part)  11   b  on the internal side, and a level difference part (portion where the cross-sectional area decreases from the internal side to the external side) between the small-diameter part  11   a  and the large-diameter part  11   b.    
     Although an opening area A 31  on an external side of an opening part  11 - 3  of a first substrate  10 - 3  illustrated in  FIG. 3D  (third modification example) is the same as an opening area A 32  on an internal side, a cross-sectional area increases halfway from the internal side (maximum cross-sectional area A 33 ), and decreases gradually toward the external side. As described above, the portion from the maximum cross-sectional area A 33  up to the opening part (opening area A 31 ) on the external side is the portion where the cross-sectional area decreases gradually from the internal side toward the external side. 
     Similarly to the opening part  11 - 3  illustrated in  FIG. 3D , also an opening area A 41  on an external side of an opening part  11 - 4  of a first substrate  10 - 4  illustrated in  FIG. 3E  (fourth modification example) is the same as an opening area A 42  on an internal side. However, a cross-sectional area of the opening part  11 - 4  decreases halfway from the internal side (minimum cross-sectional area A 43 ), and thereafter increases toward the external side. As described above, the portion from the internal side (opening area A 42 ) to the minimum cross-sectional area A 43  is the portion where the cross-sectional area decreases gradually from the internal side to the external side. 
     In the above described embodiment, a film substrate manufacturing method includes a sealing material hardening step of pressing down the portion (protrusion part  51   a ) that protrudes from the opening part  11  of the sealing material  51  toward the inside of the opening part  11  with the pressing member  60 , and of hardening the sealing material  51  in the pressed state. 
     Accordingly, the liquid crystal reservoir  170  and the sealing material reservoir  180 , which are intended to inject a liquid crystal or coat a sealing material, can be omitted. Moreover, since the sealing material  51  is hardened by being flattened toward the inside of the opening  11  with the pressing member  60 , a labor of removing a hardened sealing material can be saved. 
     Additionally, according to this embodiment, the quantity of the liquid crystal material  40  used can be reduced, and the operation of removing the sealing material  51  can be easily performed. 
     Furthermore, in this embodiment, the opening parts  11  illustrated in  FIGS. 3A to 3E  have the portion where the cross-section area decreases gradually from the internal side toward the external side. Accordingly, retention force for retaining the sealing material  51  hardened at the opening part  11  so as to prevent the sealing material  51  from going out of the opening part  11  can be strengthened. 
     Still further, in this embodiment, the opening area A 1 , A 11 , or A 21  on the external side of the opening part  11  illustrated in  FIGS. 3A and 3C  is smaller than the opening area A 2 , A 12  or A 22  on the internal side. Therefore, retention force for retaining the sealing material  51  hardened at the opening part  11  so as to prevent the sealing material  51  from going out of the opening part  11  can be further strengthened. 
     Still further, in this embodiment, the cross-sectional area of the opening part  11  illustrated in  FIGS. 3A and 3B  decreases gradually from the edge of the internal side (opening area A 2 , A 12 ) toward the edge of the external side (opening area A 1 , A 11 ). Accordingly, retention force for retaining the sealing material  51  hardened at the opening part  11  so as to prevent the sealing material  51  from going out of the opening part  11  can be further strengthened. 
     Still further, in this embodiment, only the portion of the sealing member  51 , which is injected via the opening part  11 , is hardened by being irradiated with light in the sealing material hardening step. Therefore, the sealing material  51 ′ external to the opening part  11  is unhardened, whereby the operation of removing the sealing material  51 ′ external to the opening part  11  can be more easily performed. 
     Still further, in this embodiment, the portion (protrusion part  51   a ) that protrudes from the opening part  11  of the sealing material  51  is flattened toward the inside of the opening part  11  with the pressing member  60  having the flat surface part  60   a  that is larger than the opening area (A 1  or the like) on the external side of the opening part  11  in the sealing material hardening step. Accordingly, the protrusion part  51   a  of the sealing material  51  can be securely flattened with the flat surface part. Moreover, since the hardened surface of the sealing material is the same as the film substrate and the overflowing sealing material  51  is unhardened, the operation of removing the sealing material  51  can be more easily performed. 
     Note that the type of hatching does not impose limitations on a material although the cross-sections are hatched in the drawings.