Patent Publication Number: US-2013235314-A1

Title: Substrate and liquid crystal display device

Description:
TECHNICAL FIELD 
     The present invention relates to a substrate and a liquid crystal display device, and particularly to a substrate having a surface on which a thin film is formed as well as a liquid crystal display device in which the substrate is used. 
     BACKGROUND ART 
     A liquid crystal display device commonly has a structure in which a liquid crystal layer is encapsulated between a pair of substrates. Of the pair of substrates, one substrate is a TFT (Thin-Film Transistor) substrate on which components such as a plurality of gate lines, a plurality of source lines, a plurality of pixel electrodes, and a plurality of TFTs are formed. The other substrate of the pair of substrates is an opposite substrate on which a common electrode shared by a plurality of pixel electrodes is formed. The liquid crystal layer between the TFT substrate and the opposite substrate is surrounded and thereby encapsulated by a frame-like seal member. 
     In the above-described pair of substrates, a pixel region serving as a display region and a border region serving as a non-display region provided around the outer perimeter of the pixel region are formed. The border region of the TFT substrate includes a seal-member-formed region and a terminal region provided around the outer perimeter of the seal-member-formed region. In the terminal region, a plurality of terminals are formed for providing a signal to the pixel region. 
     The TFT substrate and the opposite substrate each have a surface facing the liquid crystal layer and provided with an alignment film for regulating the alignment of liquid crystal molecules in the liquid crystal layer. The alignment film is formed as a film of a resin such as polyimide for example and has its surface rubbed or photo-aligned to gain an alignment ability. 
     The alignment film is formed in the following way. Liquid polyimide is applied to the surface of the TFT substrate and the opposite substrate and thereafter baked and accordingly cured. Polyimide can be applied in accordance with, for example, the inkjet printing method. A conventional technology of using the inkjet printing method to emit droplets of an alignment film onto a substrate is disclosed, for example, in Japanese Patent Laying-Open No. 2006-320839 (PTD 1). 
     CITATION LIST 
     Patent Document 
     
         
         PTD 1: Japanese Patent Laying-Open No. 2006-320839 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     It is necessary, for a process of forming an alignment film by means of the inkjet method, to make relatively low the viscosity of an alignment film material such as polyimide, so that the alignment film material emitted toward and landing onto a substrate spreads sufficiently on the surface of the substrate. A low-viscosity alignment film material is easy to spread on a substrate surface and is therefore likely to spread into a border region where the alignment film is not intended to be formed because the alignment film is unnecessary for the border region. 
     Meanwhile, the liquid crystal display device is required to have a slim border, namely a slimmed border region around the outer perimeter of the display region. In order to achieve a slim border of the liquid crystal display device, it is necessary to reduce the distance between the seal member disposed in the border region and the pixel region. If the above-described low-viscosity alignment film material spreads into the border region to reach the seal-member-formed region, the seal member and the alignment film material overlap each other. If the seal member and the alignment film material overlap each other, the adhesion between the seal member and the substrate is weakened and accordingly the outside air enters the liquid crystal layer from the interface between the seal member and the substrate. It is therefore considered important to accurately apply the alignment film material to the substrate and prevent overlapping of the seal member and the alignment film material. 
     The present invention has been made in view of the above problem, and a chief object of the invention is to provide a substrate for which the accuracy of positioning, on a surface of a substrate, a thin-film material applied onto the substrate surface can be improved. Another object of the present invention is to provide a liquid crystal display device in which this substrate is used. 
     Solution to Problem 
     A substrate according to the present invention has a surface with a thin film to be formed on the surface, the substrate includes a depression-protrusion shape in which a plurality of island-like depressions or protrusions formed in the surface are two-dimensionally arranged, and a marking to which a thin-film material forming the thin film is fed is formed in a part of the depression-protrusion shape. 
     Regarding the substrate, preferably the depression-protrusion shape is formed by depressing a part of the surface. 
     Regarding the substrate, preferably the depression-protrusion shape is formed by protruding a part of the surface. 
     The substrate preferably has a thin-film-formed region where the thin film is to be formed on the substrate, and a positional identifier is disposed outside the thin-film-formed region. 
     Regarding the substrate, preferably a coordinate system indicating respective positions of a plurality of island-like depressions or protrusions is defined in the depression-protrusion shape. 
     A liquid crystal display device according to the present invention includes: a pair of substrates disposed opposite to each other; and a liquid crystal layer disposed between the pair of substrates. The substrates each include a display region where an image is to be displayed and a border region around an outer perimeter of the display region. The substrates each have a surface facing the liquid crystal layer and an alignment film which is a cured form of an alignment film material having flowability is formed on the surface. The surface of at least one of the pair of substrates has a depression-protrusion shape in which a plurality of island-like depressions or protrusions are two-dimensionally arranged. A marking to which the alignment film material forming the alignment film is fed is formed in a part of the depression-protrusion shape. 
     Advantageous Effects of Invention 
     With the substrate of the present invention, the accuracy of positioning the applied thin-film material on the substrate surface can be improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional view showing a general configuration of a liquid crystal display device in a first embodiment. 
         FIG. 2  is a plan view of the liquid crystal display device shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view showing, in an enlarged form, a part of a TFT substrate. 
         FIG. 4  a plan view showing, in an enlarged form, a part of the TFT substrate. 
         FIG. 5  is a cross-sectional view showing, in an enlarged form, a support structure in the TFT substrate. 
         FIG. 6  is a plan view showing, in an enlarged form, a part of an opposite substrate. 
         FIG. 7  is a cross-sectional view of the part of the opposite substrate along a line VII-VII shown in  FIG. 6 . 
         FIG. 8  is a schematic diagram of a mother glass from which the TFT substrate is formed. 
         FIG. 9  is an enlarged view of a region IX shown in  FIG. 8 . 
         FIG. 10  is a cross-sectional view of an alignment mark along a line X-X shown in  FIG. 9 . 
         FIG. 11  is a schematic diagram showing a state where a droplet of a thin-film material is being dropped onto the alignment mark shown in  FIGS. 8 to 10 . 
         FIG. 12  is a schematic diagram showing the thin-film material attaching to the alignment mark. 
         FIG. 13  is a schematic diagram of a mother glass from which the opposite substrate is formed. 
         FIG. 14  is an enlarged view of a region XIV shown in  FIG. 13 . 
         FIG. 15  is a cross-sectional view of an alignment mark along a line XV-XV shown in  FIG. 14 . 
         FIG. 16  is a schematic diagram showing a state where a droplet of a thin-film material is being dropped onto the alignment mark shown in  FIGS. 13 to 15 . 
         FIG. 17  is a schematic diagram showing the thin-film material attaching to the alignment mark. 
         FIG. 18  is a schematic diagram showing a target position in the alignment mark on which the droplet is to be dropped and a landing position therein onto which the droplet has landed. 
         FIG. 19  is a cross-sectional view showing a general configuration of a liquid crystal display device in a second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will hereinafter be described based on the drawings. In the following drawings, the same or corresponding components are denoted by the same reference numerals, and a description thereof will not be repeated. 
     First Embodiment 
       FIG. 1  is a cross-sectional view showing a general configuration of a liquid crystal display device  1  in a first embodiment.  FIG. 2  is a plan view of liquid crystal display device  1  shown in  FIG. 1 .  FIG. 1  is a cross-sectional view of liquid crystal display device  1  along a line I-I shown in  FIG. 2 . As shown in  FIGS. 1 and 2 , liquid crystal display device  1  includes a TFT substrate  11  as a first substrate, an opposite substrate  12  as a second substrate disposed opposite to TFT substrate  11 , and a liquid crystal layer  13  provided between TFT substrate  11  and opposite substrate  12 . A pair of TFT substrate  11  and opposite substrate  12  is disposed so that they are opposite to each other. Liquid crystal layer  13  is disposed between the pair of TFT substrate  11  and opposite substrate  12 . 
     Liquid crystal display device  1  also includes a seal member  14  provided between TFT substrate  11  and opposite substrate  12 . As shown in  FIG. 2 , seal member  14  is formed in the shape of a generally rectangular frame, and surrounds and thereby seals liquid crystal layer  13 . Seal member  14  is formed, for example, of a UV/thermosetting resin such as acrylic or epoxy-based resin. In seal member  14 , a plurality of spacers and electrically-conductive particles (not shown) are mixed so that they are dispersed therein. Seal member  14  has a line width, for example, of approximately 0.5 mm to 2.5 mm. 
     TFT substrate  11  and opposite substrate  12  each include a pixel region  31  as a display region where an image is to be displayed and a border region  32  as a non-display region which is a region around the outer perimeter of pixel region  31 . Border region  32  includes a seal-member-formed region  34  (region in which seal member  14  is formed) provided at a predetermined distance from pixel region  31 . In border region  32 , a plurality of leads  17  are formed. Lead  17  has a line width of approximately 10 μm. The interval between leads  17  adjacent to each other is approximately 20 μm in seal-member-formed region  34 . 
       FIG. 3  is a cross-sectional view showing, in an enlarged form, a part of TFT substrate  11 .  FIG. 4  a plan view showing, in an enlarged form, a part of TFT substrate  11 . In  FIG. 4 , an alignment film  23  and a depression  48 , which will be described later herein, are not shown. 
     Border region  32  of TFT substrate  11  has, as shown in  FIG. 4 , a terminal region  33  which is a region opposite to pixel region  31  with respect to seal-member-formed region  34 . Terminal region  33  is formed, as shown in  FIG. 2 , in a lateral side region of TFT substrate  11 . In terminal region  33 , a plurality of terminals  28  are formed for providing a signal to pixel region  31 . 
     In seal-member-formed region  34  of TFT substrate  11  as shown in  FIG. 4 , a pad  20  is formed as a stacked electrode made up of a conductive film and a transparent conductive film such as ITO (Indium Tin Oxide). A plurality of pads  20  are formed on a surface of a planarization film  43  shown in  FIG. 3 . Pad  20  is formed so that its ITO having a thickness of approximately 100 nm is connected, via a through hole made in an underlying insulating layer, to a line of an underlying layer. Pads  20  are arranged at predetermined intervals along seal member  14 . Pad  20  is used for electrically connecting to a common electrode  26  of opposite substrate  12  via electrically conductive particles of seal member  14 . 
     In pixel region  31  of TFT substrate  11 , a plurality of pixels  5  are arranged in the form of a matrix. At pixels  5 , pixel electrodes  15  each formed of a transparent conductive film such as ITO are formed, respectively. At pixels  5 , TFTs (not shown) connected to pixel electrodes  15  and serving as switching elements are also formed, respectively. Further, in TFT substrate  11 , lines such as gate lines and source lines (not shown) connected to the TFTs are formed. 
     TFT substrate  11  as shown in  FIG. 3  has a glass substrate  21  which is a support substrate. This glass substrate  21  has a surface  21   a  on the liquid crystal layer  13  side, and a gate insulating film  41  covering the gate lines (not shown) is formed on surface  21   a . Gate insulating film  41  is formed for example of SiN or an oxide film such as SiO 2  with a thickness of approximately 0.4 μm. A plurality of leads  17  are made of the same material as the gate lines, and terminals  28  are provided at respective ends of leads  17 . The source lines are connected to leads  17 . 
     Gate insulating film  41  has a surface on which a passivation film  42  serving as a protective film is formed. Passivation film  42  is formed for example of an inorganic film such as SiN with a thickness of approximately 0.25 μm. Passivation film  42  has a surface on which planarization film  43  is formed that is an insulating film covering passivation film  42 . Planarization film  43  is made for example of a photo-setting acrylic resin and formed to have a thickness of approximately 2.5 μm. 
     In pixel region  31 , a plurality of above-described pixel electrodes  15  are formed on the surface of planarization film  43 . In seal-member-formed region  34 , seal member  14  is formed on the surface of planarization film  43 . A part of planarization film  43  forms a support structure  50  which supports alignment film  23  and an alignment film material  24 . 
     On the liquid crystal layer  13  side of TFT substrate  11 , alignment film material  24  having flowability is cured to form alignment film  23  which is formed to spread from pixel region  31  toward the region where seal member  14  is formed. In other words, surface  11   a  (see  FIG. 1 ), on the liquid crystal layer  13  side, of TFT substrate  11  is directly covered with alignment film  23 . 
     Alignment film  23  is made of a resin material such as polyimide for regulating the initial alignment of liquid crystal molecules in liquid crystal layer  13 . Alignment film material  24  has its viscosity lowered by a solvent added to polyimide for example. As alignment film material  24 , a vertical alignment film material with a viscosity of 6.5 mPa·s manufactured by JSR Corporation, for example, can be applied. 
       FIG. 5  is a cross-sectional view showing, in an enlarged form, support structure  50  in TFT substrate  11 . Support structure  50  has a side  51  that is formed as shown in  FIG. 5  in such a manner that a tangent plane  53  which meets the surface of side  51  inclines toward glass substrate  21  and to the outside of support structure  50  (namely toward seal-member-formed region  34 , which is located on the left side in  FIG. 5 ). Side  51  of support structure  50  is located between pixel region  31  and a plurality of terminals  28  (particularly between pixel region  31  and seal-member-formed region  34  in the present embodiment) and supports an edge  25  of alignment film  23  and alignment film material  24 . 
     The angle formed between the surface of glass substrate  21  and tangent plane  53  which meets side  51  at edge  25  of alignment film  23 /alignment film material  24  is represented by θ 1 , and the angle formed between tangent plane  53  and a tangent plane  54  which meets, at edge  25  of alignment film  23 /alignment film material  24 , the surface of edge  25  is represented by θ 2 . 
     Since tangent plane  53  of side  51  inclines at angle θ 1 , alignment film material  24  flowing from the direction of pixel region  31  can be stopped at angle θ 2  at side  51 . Consequently, alignment film  23  and alignment film material  24  bulge toward liquid crystal layer  13  in the vicinity of side  51  of support structure  50 . 
       FIG. 6  is a plan view showing, in an enlarged form, a part of opposite substrate  12 .  FIG. 7  is a cross-sectional view of the part of opposite substrate  12  along a line VII-VII shown in  FIG. 6 . As shown in  FIGS. 6 and 7 , opposite substrate  12  has a glass substrate  22  which is a support substrate. Glass substrate  22  has a surface  22   a  on the liquid crystal layer  13  side. On this surface  22   a , a plurality of coloring layers  37  and a black matrix  38  which is a light shielding film are formed to constitute a color filter  36 . Black matrix  38  has a thickness of approximately 1.5 μm. On surface  22   a , common electrode  26  formed of a transparent conductive film such as ITO is also formed with a thickness of approximately 100 nm. 
     Coloring layers  37  are each a filter transmitting R (red), G (green), or B (blue) light, and arranged in the form of a matrix in pixel region  31  of opposite substrate  12 . Black matrix  38  is formed to prevent light from penetrating between coloring layers  37  adjacent to each other and also prevent light from penetrating through border region  32 . Seal member  14  is the same as the one formed on TFT substrate  11 , and disposed in seal-member-formed region  34  of border region  32 . 
     On the liquid crystal layer  13  side of opposite substrate  12  as well, alignment film material  24 , which is the same as the one formed on TFT substrate  11 , is cured to form alignment film  23  which is formed to spread from pixel region  31  toward seal-member-formed region  34 . A surface  12   a  (see  FIG. 1 ), on the liquid crystal layer  13  side, of opposite substrate  12  is directly covered with alignment film  23 . 
     Opposite substrate  12  includes, similarly to TFT substrate  11 , a support structure  50  formed therein. Support structure  50  is provided in the vicinity of seal-member-formed region  34  and formed of a protrusion  56  extending in the form of a rib along seal member  14 . 
     Protrusion  56  has a base portion  57  made of the same material as, for example, blue coloring layer  37 , and a cover portion  58  covering base portion  57 . Cover portion  58  is made of a photosensitive acrylic resin which is the same material as a rib (not shown) or photospacer (not shown) formed in opposite substrate  12  for controlling liquid crystal molecules so that they are vertically aligned. 
     Support structure  50  of opposite substrate  12  also has a side  51  similar to that of support structure  50  of TFT substrate  11 . Side  51  of support structure  50  in opposite substrate  12  is also located between pixel region  31  and seal-member-formed region  34 . Alignment film  23  and alignment film material  24  also have an edge  25  supported similarly by side  51 . 
       FIG. 8  is a schematic diagram of a mother glass  60  from which TFT substrate  11  is formed. When TFT substrate  11  is to be manufactured, commonly a large glass plate called mother glass  60  is cut to thereby form a plurality of glass substrates  21 .  FIG. 8  shows an example where six TFT substrates  11  are formed from one mother glass  60 . In  FIG. 8 , regions of mother glass  60  that correspond to glass substrates  21  are each identified as a thin-film-formed region  62 . Mother glass  60  serves as an inkjet printing substrate having its surface  61  (see  FIG. 10  described later herein) on which a thin film is printed by means of the inkjet method. A thin film, which is typically gate insulating film  41 , passivation film  42 , planarization film  43 , alignment film  23 , or the like, is formed within thin-film-formed region  62 , and accordingly a plurality of TFT substrates  11  are fabricated. 
     As shown in  FIG. 8 , thin-film-formed region  62  is formed so that its two-dimensional shape is the shape of a rectangle. In the vicinity of an apex of the rectangle, an alignment mark  70  is disposed outside thin-film-formed region  62 . Alignment mark  70  serves as a position identifier for identifying a position, in surface  61  of mother glass  60 , on which a droplet of a thin-film material forming a thin film (for example, a droplet  24   a  of alignment film material  24  forming alignment film  23  shown in  FIG. 11 ) is to be dropped. 
       FIG. 9  is an enlarged view of a region IX shown in  FIG. 8 .  FIG. 10  is a cross-sectional view of alignment mark  70  along a line X-X shown in  FIG. 9 . As clearly shown in  FIG. 10 , alignment mark  70  includes a depression-protrusion shape  72  into which a part of surface  61  of mother glass  60  is processed to be formed. More specifically, in depression-protrusion shape  72 , a plurality of island-like depressions  73  formed by depressing a part of surface  61  are two-dimensionally planarly arranged. Depression-protrusion shape  72  is made up of a plurality of depressions  73  formed by removing a part of surface  61  of mother glass  60  and a ridge-like portion  74  provided between depressions  73  adjacent to each other and raised relative to depressions  73 . “Island-like” herein means that a plurality of depressions  73  are not connected to each other but arranged discontinuously. Since depressions  73  are formed like islands, ridge-like portion  74  is formed to surround the perimeter of depression  73 . 
     As shown in  FIG. 9 , depressions  73  are each formed to have a square two-dimensional shape. A plurality of depressions  73  are formed so that they are aligned along one direction (the left-right direction in  FIG. 9 ). The plurality of depressions  73  are arranged linearly so that they extend along this one direction. Groups of linearly-arranged depressions  73  are arranged in order along the other direction (the top-bottom direction in  FIG. 9 ) which is orthogonal to the above-referenced one direction. In this way, two-dimensionally extending alignment mark  70  shown in  FIG. 9  is formed. 
     Ridge-like portion  74  extends linearly along the above-referenced one direction over the whole of alignment mark  70 , and separates from each other the groups of depressions  73  that are aligned along the other direction. Ridge-like portion  74  extending along the other direction is separated into small sections each having a length corresponding to the length of one depression  73  along the other direction. Referring to  FIG. 9 , regarding the groups of depressions  73  arranged along the other direction, ridge-like portions  74  formed in the groups of depressions  73  in every other row are located at the same position with respect to the above-referenced one direction. Regarding depressions  73  in two rows arranged along the other direction, ridge-like portion  74  formed between depressions  73  in one of the rows is located at a central position, with respect to the above-referenced one direction, between respective positions where two ridge-like portions  74  are located that are formed between depressions  73  in the other row and arranged along the above-referenced one direction. 
     The square formed by depression  73  may have a length of its one side of 100 μm. Ridge-like portion  74  has its line width which is smaller than the length of one side of depression  73  and may for example be 30 μm. 
       FIG. 11  is a schematic diagram showing a state where droplet  24   a  of a thin-film material is being dropped onto alignment mark  70  shown in  FIGS. 8 to 10 .  FIG. 12  is a schematic diagram showing the thin-film material attaching to alignment mark  70 . Droplet  24   a  of the thin-film material having flowability with which an application device  80  is charged is to be dropped onto the position on surface  61  of mother glass  60  where alignment mark  70  is formed as shown in  FIG. 11 . In  FIG. 12 , there is shown a state where this droplet  24   a  lands in depression  73 . Since the thin-film material (alignment film material  24  in the example shown in  FIG. 12 ) has low viscosity and high flowability, alignment film material  24  partially overflows from depression  73  in which droplet  24   a  has landed and flows onto the top of ridge-like portion  74  as shown in  FIG. 12 . 
     Alignment film material  24  tends to further flow from ridge-like portion  74  into adjacent depression  73 . However, as described above with reference to  FIG. 5 , alignment film material  24  is supported by ridge-like portion  74  and thereby stopped by ridge-like portion  74  to accordingly bulge from surface  61  of mother glass  60 . Depression  73  and ridge-like portion  74  of alignment mark  70  serve as a blocking portion  71  blocking the flow, along surface  61 , of droplet  24   a  of alignment film material  24  having been dropped on surface  61  of mother glass  60 . Blocking portion  71  includes depression-protrusion shape  72  formed in a part of surface  61  to thereby suppress spread of the thin-film material along surface  61 . Consequently, a marking  78 , to which alignment film material  24  forming alignment film  23  has been fed, is formed in a part of depression-protrusion shape  72  of alignment mark  70 . 
       FIG. 13  is a schematic diagram of a mother glass  60  from which opposite substrate  12  is formed. Like mother glass  60  from which TFT substrate  11  is formed as described above, mother glass  60  from which opposite substrate  12  is formed as shown in  FIG. 13  serves as an inkjet printing substrate having its surface  61  (see  FIG. 15  described later herein) on which a thin film is printed by means of the inkjet method. Six opposite substrates  12  are formed from one mother glass  60 . Regions of mother glass  60  that correspond to glass substrates  22  are each identified as a thin-film-formed region  62 . 
     In the vicinity of an apex of thin-film-formed region  62  having a rectangular two-dimensional shape, an alignment mark  70  is disposed outside thin-film-formed region  62 . Alignment mark  70  serves as a position identifier for identifying a position in surface  61  of mother glass  60  on which a droplet of a thin-film material forming a thin film (for example, a droplet  24   a  of alignment film material  24  forming alignment film  23  shown in  FIG. 16 ) is to be dropped. 
       FIG. 14  is an enlarged view of a region XIV shown in  FIG. 13 .  FIG. 15  is a cross-sectional view of alignment mark  70  along a line XV-XV shown in  FIG. 14 . As clearly shown in  FIG. 15 , alignment mark  70  includes a depression-protrusion shape  72  into which a part of surface  61  of mother glass  60  is processed to be formed. More specifically, in depression-protrusion shape  72 , a plurality of island-like protrusions  75  formed by protruding a part of surface  61  are two-dimensionally planarly arranged. Depression-protrusion shape  72  is made up of a plurality of protrusions  75  formed by protruding a part of surface  61  of mother glass  60  and a groove-like portion  76  provided between protrusions  75  adjacent to each other and recessed relative to protrusions  75 . Since protrusions  75  are formed like islands, grove-like portion  76  is formed to surround the perimeter of protrusion  75 . 
     Alignment mark  70  formed in opposite substrate  12  has the recessed portions and the protruded portions that are contrary to those of alignment mark  70  in TFT substrate  11  described above. Alignment mark  70  of opposite substrate  12  shown in  FIG. 14  has its shape in a plan view similar to that of alignment mark  70  of TFT substrate  11  described above with reference to  FIG. 9 . Protrusions  75  are each formed in the shape of a square in a plan view. The square formed by protrusion  75  may have each side of 100 μm in length. The line width of groove-like portion  76  is smaller than the length of each side of protrusion  75  and may, for example, be 30 μm. 
       FIG. 16  is a schematic diagram showing a state where a droplet  24   a  of a thin-film material is being dropped onto alignment mark  70  shown in  FIGS. 13 to 15 .  FIG. 17  is a schematic diagram showing the thin-film material attaching to alignment mark  70 . Droplet  24   a  of the thin-film material having flowability with which an application device  80  is charged is to be dropped onto the position on surface  61  of mother glass  60  where alignment mark  70  is formed as shown in  FIG. 16 . In  FIG. 17 , there is shown a state where this droplet  24   a  lands on the top surface of protrusion  75 . 
     Since the thin-film material (alignment film material  24  in the example shown in  FIG. 17 ) has low viscosity and high flowability, the material is likely to flow from protrusion  75  on which droplet  24   a  has landed, toward groove-like portion  76  surrounding, in the form of a frame, the perimeter of protrusion  75 , as shown in  FIG. 12 . However, as described above with reference to  FIG. 5 , alignment film material  24  is supported by the side of protrusion  75  and thereby stopped. Protrusion  75  and groove-like portion  76  of alignment mark  70  serve as a blocking portion  71  blocking the flow, along surface  61 , of droplet  24   a  of alignment film material  24  having been dropped on surface  61  of mother glass  60 . Blocking portion  71  includes depression-protrusion shape  72  formed in a part of surface  61  to thereby suppress spread of the thin-film material along surface  61 . Consequently, a marking  78 , to which alignment film material  24  forming alignment film  23  has been fed, is formed in a part of depression-protrusion shape  72  of alignment mark  70 . 
       FIG. 18  is a schematic diagram showing a target position  91  on which droplet  24   a  is to be dropped in alignment mark  70  and a landing position  92  onto which droplet  24   a  has landed.  FIG. 18  shows, by way of example, alignment mark  70  formed in opposite substrate  12 . The point of intersection of an X axis and a Y axis which are two axes orthogonal to each other as shown in  FIG. 18  represents a target center position onto which droplet  24   a  of alignment film material  24  is to be landed, and this position is referred to as target position  91 . Meanwhile, the position where droplet  24   a  has actually been dropped on surface  61  of mother glass  60  is referred to as landing position  92 . In depression-protrusion shape  72  of alignment mark  70 , a coordinate system indicating respective positions of a plurality of island-like protrusions  75  is defined. In the example shown in  FIG. 18 , the coordinates of target position  91  are (0, 0), and the coordinates of landing position  92  are (−2, −2). This coordinate system can be formed by black matrix  38  in the case of opposite substrate  12 . In the case of TFT substrate  11 , the coordinate system can be formed by gate lines, source lines, or a silicon layer. 
     As shown in  FIG. 18 , with respect to target position  91  on which the thin-film material is intended to be dropped, landing position  92  deviates in both the X axis direction and the Y axis direction. The coordinate system shown in  FIG. 18  can be provided on alignment mark  70  to thereby confirm immediately whether or not landing position  92  is deviated from target position  91 . The amount of deviation of landing position  92  from target position  91  can be detected and corrected to thereby enable the thin-film material to be applied accurately on the substrate surface by means of the ink jet method. In this way, a thin film such as alignment film  23  can be formed more accurately in two-dimensional respect. Since the accuracy of positioning alignment film material  24  to be supplied to the substrate surface by means of the ink jet method can be improved, alignment film material  24  can accurately be applied to glass substrate  21 ,  22  so that seal member  14  and alignment film material  24  do not overlap each other even if the interval between seal member  14  and pixel region  31  is shortened. Accordingly, the slim border of liquid crystal display device  1  can be achieved. 
     Since alignment mark  70 , which is used for detecting the deviation of landing position  92  from target position  91  of alignment film material  24 , is disposed outside thin-film-formed region  62 , alignment mark  70  will not hinder attachment of a terminal or wire when liquid crystal display device  1  is being formed. A preferred structure is as follows. Specifically, rectangular thin-film-formed region  62  is formed to have its corners of 90° at respective apexes and, on an imaginary line drown to divide the corner of 90° into two equal halves of 45° each, alignment marks  70  are formed so that alignment marks  70  are point symmetry with respect to thin-film-formed region  62 . This structure is preferred since the thin-film material can be applied with still higher precision. 
     In the following, a method for manufacturing above-described liquid crystal display device  1  will be described. Liquid crystal display device  1  is manufactured in the following way. Frame-like seal member  14  is formed on TFT substrate  11  or opposite substrate  12 , a liquid crystal is dropped inside this seal member  14 , and thereafter TFT substrate  11  and opposite substrate  12  are attached to each other. Two mother glasses  60 ,  60  shown in  FIGS. 8 and 13  are attached together so that respective positions of respective thin-film-formed regions  62  match each other, and the laminate of mother glasses  60  is cut into and thus fabricate liquid crystal display devices  1 . 
     TFT substrate  11  is manufactured in the following way. First, on a surface of glass substrate  21  which is a transparent substrate, gate lines (not shown), gate insulating film  41 , a silicon film (not shown), source lines  16 , passivation film  42 , and planarization film  43  are formed. After this, the photolithography method and etching are used to form a plurality of depressions  48  extending through planarization film  43 , passivation film  42 , and gate insulating film  41 . In depression  48 , glass substrate  21  is exposed if there is no underlying metal layer. Thus, support structure  50  is formed as a part of planarization film  43 . 
     Simultaneously with this step of forming depressions  48 , depressions  73  are formed. Accordingly, alignment mark  70  with which the range of extension of alignment film material  24  can be controlled is formed. Since depressions  73  can be formed simultaneously with formation of depressions  48 , no additional step for forming depressions  73  is necessary, and the productivity of TFT substrate  11  can be prevented from deteriorating. 
     Next, on the surface of planarization film  43 , an ITO layer is formed and is patterned by means of photolithography and etching to thereby form a plurality of pixel electrodes  15 . 
     Subsequently, target position  91  is set on alignment mark  70  before alignment film material  24  is applied to pixel region  31 , and then droplet  24   a  of alignment film material  24  is dropped toward target position  91 , which is a position where droplet  24   a  should be dropped on alignment mark  70 . Landing position  92  onto which the dropped droplet  24   a  has actually landed is detected, and a positional deviation of landing position  92  from target position  91  is detected. Then, setting of application device  80  for alignment film material  24  is changed so that the positional deviation is reduced (typically the amount of positional deviation is reduced to zero). After this, alignment film material  24  having flowability such as polyimide is applied by means of the inkjet method so that the material covers components such as pixel electrode  15  as described above. Each time alignment film material  24  is patterned on glass substrate  21 , alignment mark  70  is monitored. Thus, the process can be monitored to see whether or not application device  80  is positionally displaced. 
     Alignment film material  24  flows from pixel region  31  into border region  32  to reach side  51  of support structure  50 . At this time, edge  25  of alignment film material  24  is supported by this side  51 . As a result, as shown in  FIG. 3 , alignment film material  24  bulges toward liquid crystal layer  13  and thus stopped in the vicinity of side  51  of support structure  50 . After this, alignment film material  24  is baked to form alignment film  23 . 
     Opposite substrate  12  is manufactured in the following way. On the surface of glass substrate  22  which is a transparent substrate, common electrode  26  and color filter  36  are formed. Here, simultaneously with formation of coloring layers  37  of color filter  36 , base portion  57  is formed of the same material as coloring layers  37 , on the surface of black matrix  38  in border region  32 . Simultaneously, protrusions  75  are formed. Accordingly, alignment mark  70  with which the range of extension of alignment film material  24  can be controlled is formed. Since protrusions  75  can be formed simultaneously with formation of coloring layers  37 , no additional step for forming protrusions  75  is necessary, and the productivity of opposite substrate  12  can be prevented from deteriorating. 
     Next, a photosensitive acrylic resin for example is deposited to cover base portion  57  and color filter  36 , and thereafter subjected to photolithography and then developed. Thus, cover portion  58  which covers base portion  57  and a photospacer (not shown) or a rib for controlling liquid crystal molecules so that they are vertically aligned are formed simultaneously. 
     Subsequently, target position  91  is set on alignment mark  70  before alignment film material  24  is applied to pixel region  31 , and then droplet  24   a  of alignment film material  24  is dropped toward target position  91 , which is a position where droplet  24   a  should be dropped on alignment mark  70 . Landing position  92  onto which the dropped droplet  24   a  has actually landed is detected, and a positional deviation of landing position  92  from target position  91  is calculated. Then, setting of application device  80  for alignment film material  24  is changed so that the positional deviation is reduced (typically the amount of positional deviation is reduced to zero). After this, alignment film material  24  having flowability such as polyimide is applied by means of the inkjet method so that the material covers components such as color filter  36  as described above. 
     Alignment film material  24  flows from pixel region  31  into border region  32  to reach side  51  of support structure  50 . At this time, edge  25  of alignment film material  24  is supported by this side  51 . As a result, as shown in  FIG. 7 , alignment film material  24  bulges toward liquid crystal layer  13  and thus stopped in the vicinity of side  51  of support structure  50 . After this, alignment film material  24  is baked to form alignment film  23 . 
     As seen from the foregoing description, prior to inkjet application of alignment film material  24  which has high flowability, droplet  24   a  of alignment film material  24  is dropped on alignment mark  70  and a positional deviation of landing position  92  from target position  91  is adjusted. Accordingly, highly precise inkjet application of alignment film material  24  can be achieved. When liquid crystal display device  1  of the slim border type having a narrowed interval between pixel region  31  and seal member  14  is to be manufactured, alignment film  23  can be disposed with high accuracy in two-dimensional respect, and therefore, seal member  14  and alignment film material  24  can be prevented from overlapping each other and the adhesion of seal member  14  can be ensured. 
     Alignment mark  70  formed in mother glass  60  of TFT substrate  11  may be formed through formation of the gate lines, silicon layer or source lines, or formation of a contact hole in a photosensitive acrylic resin which is an interlayer insulating film. Alignment mark  70  formed in mother glass  60  of opposite substrate  12  may be formed through formation of the coloring layer such as black matrix, or the rib or photospacer provided for controlling liquid crystal alignment. 
     Second Embodiment 
       FIG. 19  is a cross-sectional view showing a general configuration of a liquid crystal display device in a second embodiment. The liquid crystal display device of the second embodiment has a similar configuration to that of above-described liquid crystal display device  1 . The second embodiment, however, differs from the first embodiment in that alignment mark  70 , which serves as a positional identifier for identifying a position where droplet  24   a  of alignment film material  24  is to be dropped, is formed in border regions  32  of TFT substrate  11  and opposite substrate  12 , and in that alignment mark  70  has a blocking portion  71  which blocks flow, along the surface, of droplet  24   a  having been dropped on surface  11   a  of TFT substrate  11  and surface  12   a  of opposite substrate  12 . 
     In the first embodiment, alignment mark  70  is formed outside thin-film-formed region  62  of mother glass  60  and thus alignment mark  70  does not appear on liquid crystal display device  1  in the form of a completed product. In contrast, the liquid crystal display device of the second embodiment includes alignment mark  70  in border regions  32  of TFT substrate  11  and opposite substrate  12  as shown in  FIG. 19 . This configuration of the second embodiment still enables improvement of the accuracy of positioning alignment film material  24  which is applied by means of the inkjet method, like the first embodiment. Since alignment mark  70  is formed at a position still closer to pixel region  31  where alignment film  23  is to be formed, the accuracy of positioning alignment film  23  can further be improved. 
     In the example shown in  FIG. 19 , both TFT substrate  11  and opposite substrate  12  have respective alignment marks  70  formed therein. However, alignment mark  70  may be formed in one of TFT substrate  11  and opposite substrate  12 . 
     While the above description of the first and second embodiments has been given of an example where alignment film material  24  is applied by means of the inkjet method to TFT substrate  11  and opposite substrate  12  of liquid crystal display device  1 , the present invention is not limited to this use. For example, in the case where another thin film such as coloring layer  37  is to be formed on the surface of glass substrate  21 ,  22  as well, alignment mark  70  described in connection with the first and second embodiments can be applied to enable accurate inkjet application of the thin-film material. 
     Further, the present invention is applicable not only to liquid crystal display device  1  but also any use as long as a thin-film material with high flowability is to be applied by means of the inkjet method, such as ink which is dropped to land a substrate surface thereafter spreads to a greater extent than a required accuracy. For example, the present invention is applicable to application of a resist film for a semiconductor device. 
     It should be construed that the embodiments disclosed herein are by way of illustration in all respects, not by way of limitation. It is intended that the scope of the present invention is defined by claims, not by the description above, and encompasses all modifications and variations equivalent in meaning and scope to the claims. 
     REFERENCE SIGNS LIST 
       1  liquid crystal display device;  11  TFT substrate;  11   a ,  12   a  surface;  12  opposite substrate;  14  seal member;  21 ,  22  glass substrate;  23  alignment film;  24  alignment film material;  24   a  droplet;  31  pixel region;  32  border region;  60  mother glass;  61  surface;  62  thin-film-formed region;  70  alignment mark;  71  blocking portion;  72  depression-protrusion shape;  73  depression;  74  ridge-like portion  75  protrusion;  76  groove-like portion;  80  application device;  91  target position;  92  landing position