Abstract:
The invention relates to a substrate for a liquid crystal display device used as a display part of an electronic equipment and a liquid crystal display device including the same, and has an object to provide a substrate for a liquid crystal display device in which high manufacturing yield and excellent display quality can be obtained, and a liquid crystal display device including the same. The substrate for the liquid crystal display device includes a base substrate for holding a liquid crystal in cooperation with an opposite substrate arranged to be opposite thereto, and a pillar spacer provided to maintain a cell gap between the base substrate and the opposite substrate, wherein the pillar spacer includes a first layer formed on the base substrate to linearly extend in a first direction and to have an almost constant width W in a second direction orthogonal to the first direction, and a second layer which is patterned to partially overlap with the first layer at an overlap accuracy X and in which a width in the first direction is almost constant and a length L 1  in the second direction satisfies a relation of L 1 ≧W+2X.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a substrate for a liquid crystal display device used as a display part or the like of an electronic equipment and a liquid crystal display device including the same. 
     2. Description of the Related Art 
     As spacers for maintaining the cell gap of a liquid crystal display device, there are bead spacers scattered on a substrate surface, and photo spacers (pillar spacers) formed on a substrate by using a photolithography method or the like. In a recent liquid crystal display device, to use the pillar spacer is going mainstream. When the pillar spacer is used, an improvement in contrast and display grade (uneven display) is made as compared with the use of the bead spacer, and the display quality of the liquid crystal display device is improved. The pillar spacer is formed at an arbitrary position of a light shielding part on a substrate by laminating, for example, color filter (CF) resin layers or the like. 
       FIG. 20  shows a structure of an opposite substrate of a conventional liquid crystal display device including a pillar spacer.  FIG. 20  shows a region corresponding to a storage capacitor part of two pixel regions.  FIG. 21  shows a sectional structure of the opposite substrate taken along line X-X of  FIG. 20 . As shown in  FIGS. 20 and 21 , a light shielding film (BM)  148  for defining a pixel region and shading the storage capacitor part is formed on a glass substrate  111 . A CF resin layer  140  ( 140 R,  140 G and  140 B) of one color of red (R), green (G) and blue (B) is formed in each pixel region. The CF resin layers  140 R,  140 G and  140 B of the three colors are laminated in a pillar spacer formation region on the BM  148 . A common electrode  142  made of a transparent conductive film is formed on the CF resin layer  140  and on the whole surface of the substrate. Linear projections  144  extending obliquely with respect to pixel region end parts are formed on the common electrode  142  as alignment regulating structures for regulating the alignment of liquid crystal. An auxiliary spacer layer  151  is formed in the pillar spacer formation region on the common electrode  142 . By this, a pillar spacer  150  made of lamination layers of the CF resin layers  140 R,  140 G, and  140 B, and the auxiliary spacer layer  151  and having a specified height is formed in the pillar spacer formation region. When the upper bottom size (width) of the lamination part of the CF resin layers  140 R,  140 G and  140 B is made 26 μm, the upper bottom size of the pillar spacer  150  becomes about 25 μm. 
     When the opposite substrate is attached to a thin film transistor (TFT) substrate, the upper bottom surface of the pillar spacer  150  comes in contact with the TFT substrate to have a specified contact area. When the total sum of the contact areas of the plurality of pillar spacers  150  with respect to the TFT substrate is increased, a hard liquid crystal display panel excellent in pressure resistance characteristics can be obtained. 
     The auxiliary spacer layer  151  is patterned by using a mirror projection exposure system or a proximity exposure system. At the time of patterning of the auxiliary spacer layer  151 , an overlap shift can occur in the range of overlap accuracy of an exposure device. When the overlap shift occurs in the lamination part of the CF resin layer  140  at the time of patterning of the auxiliary spacer layer  151 , the shape of the pillar spacer  150  and the upper bottom size are changed. That is, the contact area of the pillar spacer  150  with respect to the TFT substrate is changed. 
       FIG. 22  shows a sectional structure of the opposite substrate in which the overlap shift occurs in the auxiliary spacer layer  151 . In an auxiliary spacer layer  151 ′, the overlap shift occurs by 4 μm in the direction of an arrow  160  with respect to the lamination part of the CF resin layer  140 . By this, the upper bottom size of the pillar spacer  150 ′ becomes about 21 μm, and as compared with the upper bottom size of the pillar spacer  150  shown in  FIGS. 20 and 21 , it is decreased by about 4 μm. For example, when it is assumed that the comparable overlap shift occurs also in the direction vertical to the paper surface of  FIG. 22 , the upper bottom area (contact area with respect to the TFT substrate) of the pillar spacer  150 ′ is decreased by about 30% as compared with the upper bottom area of the pillar spacer  150 . Accordingly, the pillar spacer  150 ′ becomes softer than the pillar spacer  150 , and becomes easy to be deformed by about 30%. 
     The pillar spacer  150  or  150 ′ is generally formed by using resin material such as acryl resin or novolac resin. The pillar spacer  150  or  150 ′ made of the resin material is not a perfect elastic body, but has an elastic deformation region and a plastic deformation region. Thus, when a local force is applied to a liquid crystal display panel, the pillar spacer  150  or  150 ′ is plastically deformed, and even if the force is removed, the pillar spacer  150  or  150 ′ is not returned to the original height. Since the soft pillar spacer is plastically deformed by a weak force, in the soft liquid crystal display panel in which the pillar spacer  150 ′ is formed, uneven cell thickness due to pressurization is apt to occur in a panel process, and manufacturing yield and display quality are degraded. Accordingly, when the overlap accuracy of the exposure device is considered, in the conventional liquid crystal display device, there arises a problem that it is difficult to obtain high manufacturing yield and excellent display quality. 
       FIG. 23  shows a structure of one pixel of another conventional liquid crystal display device.  FIG. 24  shows a sectional structure of the liquid crystal display device taken along line Y-Y of  FIG. 23 . As shown in  FIGS. 23  and  24 , the liquid crystal display device includes a thin film transistor (TFT) substrate  102 , an opposite substrate  104 , and a liquid crystal  106  sealed between both the substrates  102  and  104 . The TFT substrate  102  includes a plurality of gate bus lines  112  extending in the horizontal direction in  FIG. 23 , a plurality of drain bus lines  114  intersecting with the gate bus lines  112  through an insulating film  130  and extending in the vertical direction in  FIG. 23  on a glass substrate  110 . A TFT  120  is formed in the vicinity of each of the intersecting positions of the gate bus lines  112  and the drain bus lines  114 . Pixel regions are defined by the gate bus lines  112  and the drain bus lines  114 . A storage capacitor bus line  118  extending in parallel to the gate bus line  112  is formed to cross each of the pixel regions. The storage capacitor bus line  118  functions as one electrode of a storage capacitor part. A storage capacitor electrode  119  is formed on the storage capacitor bus line  118  through an insulating film  130 . The storage capacitor electrode  119  is formed in each of the pixel regions, and functions as the other electrode of the storage capacitor part. A protection film  132  is formed on the storage capacitor electrode  119  and on the whole surface of the substrate. A pixel electrode  116  is formed on the protection film  132  in each of the pixel regions. In the storage capacitor part, the height from the surface of the glass substrate  110  is higher than a peripheral opening part by the formation of the storage capacitor bus line  118  and the storage capacitor electrode  119 . 
     On the other hand, a pillar spacer  150  made of a single resin layer is formed at the side of the opposite substrate  104 . The pillar spacer  150  is arranged in a light shielding region of the opposite substrate  104  and at a position which is opposed to the storage capacitor part when the opposite substrate is attached to the TFT substrate  102 . Almost the whole region of the upper bottom surface (the lower surface in  FIG. 24 ) of the pillar spacer  150  is in contact with the pixel electrode  116  on the storage capacitor part. 
     Here, when the TFT substrate  102  and the opposite substrate  104  are attached to each other, an attaching shift can occur in the range of attaching accuracy of a substrate attaching device.  FIG. 25  shows a sectional structure of the liquid crystal display device in which the attaching shift occurs. As shown in  FIG. 25 , the relative attaching shift occurs in the direction of a thick arrow between both the substrates  102  and  104 . Since a part of the upper bottom surface of the pillar spacer  150  does not come in contact with the pixel electrode  116  on the storage capacitor part, the contact area of the pillar spacer  150  with respect to the TFT substrate  102  is decreased. When the contact area of the pillar spacer  150  with respect to the TFT substrate  102  becomes small, the liquid crystal display panel becomes soft and its pressure resistance characteristics are low. 
     In the structure shown in  FIG. 24 , in addition to the attaching shift of the substrates  102  and  104 , due to factors such as an overlap shift of the respective layers of the storage capacitor part, and variations in the sizes of the pillar spacer  150 , the storage capacitor bus line  118  and the storage capacitor electrode  119 , there is also a case where the contact area of the pillar spacer  150  with respect to the TFT substrate  2  is decreased. 
     The soft liquid crystal display panel causes a poor display and degradation in pressure resistance characteristics due to local uneven cell thickness. Accordingly, when the attaching accuracy and the like of the substrates  102  and  104  are considered, in the conventional liquid crystal display device, there arises a problem that it is difficult to obtain high manufacturing yield and excellent display quality. The problem can be avoided by securing a sufficient design margin for the position and size of the pillar spacer  150 . However, in order to secure the design margin without decreasing the upper bottom area of the pillar spacer  150 , it is necessary to widen the width of the storage capacitor part, and therefore, there arises newly a problem that the aperture ratio of a pixel is lowered. 
     [Patent document 1] JP-A-2000-298280 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a substrate for a liquid crystal display device in which high manufacturing yield and excellent display quality can be obtained, and a liquid crystal display device including the same. 
     The above object is achieved by a substrate for a liquid crystal display device, which includes a base substrate for holding a liquid crystal in cooperation with an opposite substrate arranged to be opposite thereto, and a pillar spacer provided to maintain a cell gap between the base substrate and the opposite substrate, wherein the pillar spacer includes a first layer formed on the base substrate to linearly extend in a first direction and to have an almost constant width W in a second direction orthogonal to the first direction, and a second layer which is patterned to partially overlap with the first layer at an overlap accuracy X and in which a width in the first direction is almost constant and a length L 1  in the second direction satisfies a relation of L 1 ≧W+2X. 
     According to the invention, the liquid crystal display device can be realized in which high manufacturing yield and excellent display quality can be obtained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A to 1C  are views showing a first basic structure of a liquid crystal display device according to an embodiment of the invention; 
         FIGS. 2A to 2C  are views showing a second basic structure of a liquid crystal display device according to the embodiment of the invention; 
         FIGS. 3A and 3B  are views showing a structure of a substrate for a liquid crystal display device according to example 1 of the embodiment of the invention; 
         FIGS. 4A and 4B  are sectional views showing a structure of the substrate for the liquid crystal display device according to example 1 of the embodiment of the invention; 
         FIG. 5  is a sectional view showing a structure of the substrate for the liquid crystal display device in which an overlap shift occurs in an auxiliary spacer layer; 
         FIGS. 6A and 6B  are views showing a manufacturing method of the substrate for the liquid crystal display device according to example 1 of the embodiment of the invention; 
         FIGS. 7A and 7B  are views showing the manufacturing method of the substrate for the liquid crystal display device according to example 1 of the embodiment of the invention; 
         FIG. 8  is a view showing the manufacturing method of the substrate for the liquid crystal display device according to example 1 of the embodiment of the invention; 
         FIG. 9  is a sectional view showing the manufacturing method of the liquid crystal display device according to example 1 of the embodiment of the invention; 
         FIG. 10  is a view showing a structure of a common electrode substrate of a liquid crystal display device according to example 2 of the embodiment of the invention; 
         FIGS. 11A and 11B  are views showing a structure of a TFT substrate of the liquid crystal display device according to example 2 of the embodiment of the invention; 
         FIG. 12  is a sectional view showing a structure of the liquid crystal display device according to example 2 of the embodiment of the invention; 
         FIG. 13  is a view showing a structure of a substrate for a liquid crystal display device according to example 3 of the embodiment of the invention; 
         FIG. 14  is a sectional view showing a structure of a liquid crystal display device according to example 3 of the embodiment of the invention; 
         FIG. 15  is a sectional view showing a structure of the substrate for the liquid crystal display device according to example 3 of the embodiment of the invention; 
         FIG. 16  is a sectional view showing a structure of the substrate for the liquid crystal display device according to example 3 of the embodiment of the invention; 
         FIG. 17  is a view showing a structure of a substrate for a liquid crystal display device according to example 4 of the embodiment of the invention; 
         FIG. 18  is a view showing a structure of the substrate for the liquid crystal display device according to example 4 of the embodiment of the invention; 
         FIGS. 19A and 19B  are views showing the arrangement of a resin layer and a storage capacitor part of a liquid crystal display device according to example 4 of the embodiment of the invention; 
         FIG. 20  is a view showing a structure of an opposite substrate of a conventional liquid crystal display device; 
         FIG. 21  is a sectional view showing a structure of the opposite substrate of the conventional liquid crystal display device; 
         FIG. 22  is a sectional view showing a structure of the opposite substrate in which an overlap shift occurs in an auxiliary spacer layer; 
         FIG. 23  is a view showing a structure of another conventional liquid crystal display device; 
         FIG. 24  is a sectional view showing a structure of the another conventional liquid crystal display device; and 
         FIG. 25  is a sectional view showing a structure of the liquid crystal display device in which an attaching shift occurs. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A substrate for a liquid crystal display device according to an embodiment of the present invention and a liquid crystal display device including the same will be described with reference to  FIGS. 1A to 19B . First, a first basic structure of this embodiment will be described with reference to  FIGS. 1A to 1C .  FIG. 1A  is a perspective view schematically showing a structure of a pillar spacer  50  which is ideally patterned and formed on one substrate.  FIG. 1B  shows a structure of the pillar spacer  50  when viewed in a direction vertical to a substrate surface, and  FIG. 1C  shows a sectional structure of the pillar spacer  50  taken along line A-A of  FIG. 1B . As shown in  FIGS. 1A to 1C , the pillar spacer  50  includes on one substrate (base substrate)  3  a first layer  51  extending linearly in the horizontal direction of  FIG. 1B , and a second layer  52  formed to partially overlap with the first layer  51  and linearly extending in the vertical direction of  FIG. 1B . A width W of the first layer  51  in the vertical direction of  FIG. 1B  is almost constant. A width of the second layer  52  in the horizontal direction of  FIG. 1B  is almost constant, and a length L 1  in the vertical direction of  FIG. 1B  satisfies a relation of L 1 ≧W+2X (here, X denotes an overlap accuracy of an exposure device used when the second layer  52  is patterned). As shown in  FIGS. 1A to 1C , in the ideally patterned state, the second layer  52  protrudes from each of side end parts at both sides of the first layer  51  by a length X 1  (≧X). In the surface of the pillar spacer  50 , a region where the first layer  51  and the second layer  52  overlap with each other is an upper bottom surface  50   a  whose height from the substrate surface is highest. When the substrate is attached to an opposite substrate arranged to be opposite thereto, the upper bottom surface  50   a  of the pillar spacer  50  comes in contact with the surface of the opposite substrate. 
     Here, the second layer  52  is patterned by using, for example, a mirror projection exposure system. The overlap accuracy X of the exposure device used in the mirror projection exposure system is about 1.5 μm at ±3σ. Accordingly, when the second layer  52  is designed, the length X 1  by which the first layer  51  protrudes from each of both the side end parts is made 1.5 μm or more, so that the length L 1  satisfies the relation of L 1 ≧W+3 μm. Since the width of the second layer  52  is almost constant, when the second layer  52  is patterned, even if a patterning shift of ±1.5 μm occurs in the vertical direction of  FIG. 1B , the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed. Besides, since the width W of the first layer  51  is almost constant, when the second layer  52  is patterned, even if a patterning shift of ±1.5 μm occurs in the horizontal direction of  FIG. 1B , the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed. That is, according to this basic structure, even if the position shift occurs in the second layer  52  in the range of the overlap accuracy X of the exposure device, the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed, and the contact area with respect to the other substrate is not also changed. Since the hardness of the liquid crystal display panel depends on the contact area of the pillar spacer  50 , according to this basic structure, even if the overlap accuracy X of the exposure device is considered, a poor display and degradation in pressure resistance characteristics due to local uneven cell thickness do not occur. Incidentally, in the case where the second layer  52  is patterned by using a proximity exposure system, since the overlap accuracy X of an exposure device used for the proximity exposure system is about 3 μm at ±3σ, it is sufficient if the length L 1  is made to satisfy the relation of L 1 ≧W+6 μm. That is, when the second layer  52  is designed, the length X 1  is made 3 μm or more. 
     Next, a second basic structure of this embodiment will be described with reference to  FIGS. 2A to 2C .  FIG. 2A  is a perspective view schematically showing a structure of a pillar spacer  60  in a state where a pair of substrates are attached to each other without a shift.  FIG. 2B  shows a structure of the pillar spacer  60  when viewed in a direction vertical to the substrate surface, and  FIG. 2C  shows a sectional structure of the pillar spacer  60  taken along line B-B of  FIG. 2B  and substrates  3  and  5 . As shown in  FIGS. 2A to 2C , the pillar spacer  60  includes a first layer  61  extending linearly in the horizontal direction of  FIG. 2B , and a second layer  62  partially overlapping with the first layer  61  and linearly extending in the vertical direction of  FIG. 2B . The first layer  61  is formed on the one substrate  3 , and the second layer  62  is formed on the other substrate  5 . The first layer  61  and the second layer  62  come in contact with each other through a contact interface  60   a  when both the substrates  3  and  5  are boned to each other. A width W of the first layer  61  in the vertical direction of  FIG. 2B  is almost constant. A width of the second layer  62  in the horizontal direction of  FIG. 2B  is almost constant, and a length L 2  in the vertical direction in  FIG. 2B  satisfies a relation of L 2 ≧W+2Y (here, Y denotes an attaching accuracy at the time when both the substrates  3  and  5  are attached). As shown in  FIGS. 2A to 2C , in the state where both the substrates  3  and  5  are attached without a shift, the second layer  62  protrudes from each of both side end parts of the firs layer  61  by a length Y 1  (≧Y). 
     The attaching accuracy Y of the substrates  3  and  5  is generally about 4 μm (±4 μm). Accordingly, when the second layer  62  is designed, the length Y 1  by which the second layer protrudes from each of both the end parts of the first layer  61  is made 4 μm or more, and the length L 2  is made to satisfy a relation of L 2 ≧W+8 μm. Since the width of the second layer  62  is almost constant, even if the attaching shift of ±4 μm occurs in the vertical direction of  FIG. 2B , the area of the contact interface  60   a  of the pillar spacer  60  is not changed. Besides, since the width W of the first layer  61  is almost constant, even if the attaching shift of ±4 μm occurs in the horizontal direction of  FIG. 2B , the area of the contact surface  60   a  of the pillar spacer  60  is not changed. That is, according to this basis structure, even if the attaching shift of the substrates  3  and  5  occurs in the range of the attaching accuracy Y, the area of the contact interface  60   a  of the pillar spacer  60  is not changed. Since the hardness of the liquid crystal display panel depends on the area of the contact interface  60   a , according to this basic structure, even if the attaching accuracy Y is considered, a poor display and degradation in pressure resistance characteristics due to local uneven cell thickness do not occur. 
     As described above, according to this embodiment, since the poor display and the degradation in pressure resistance characteristics due to the local uneven cell thickness do not occur, the liquid crystal display device can be realized in which high manufacturing yield and excellent display quality can be obtained. Herein after, a substrate for a liquid crystal display device according to this embodiment and a liquid crystal display device including the same will be described more specifically by use of examples. 
     EXAMPLE 1 
     First, a substrate for a liquid crystal display device according to example 1 of this embodiment and a liquid crystal display device including the same will be described.  FIG. 3A  shows a structure of a TFT substrate of a CF-on-TFT (COT) structure according to this example.  FIG. 3B  is an enlarged view showing a vicinity of a pillar spacer.  FIG. 4A  shows a sectional structure taken along line C-C of  FIG. 3A , and  FIG. 4B  shows a sectional structure taken along line D-D of  FIG. 3A .  FIGS. 3A to 4B  show a state in which the pillar spacer is ideally patterned. As shown in  FIGS. 3A to 4B , a TFT substrate  2  includes a plurality of gate bus lines  12  extending in the horizontal direction of the drawing, and a plurality of drain bus lines  14  intersecting with the gate bus lines  12  through an insulating film (gate insulating film)  30  and extending in the vertical direction of the drawing. A TFT  20  is formed in the vicinity of each of intersecting positions of the gate bus lines  12  and the drain bus lines  14 . A drain electrode of the TFT  20  is electrically connected to the drain bus line  14 . A part of the gate bus line  12  functions as a gate electrode of the TFT  20 . A protection film  32  is formed on the TFT  20  and on the whole surface of the substrate. 
     Pixel regions are defined by the gate bus lines  12  and the drain bus lines  14 . A CF resin layer  40  ( 40 R,  40 G,  40 B) of one color of R, G and B is formed in each of the pixel regions on the protection film  32 . A resin overlap part  41  in which three layers of the CF resin layers  40 R,  40 G and  40 B are laminated is formed on the gate bus line  12 . The resin overlap part  41  linearly extends along the gate bus line  12 , and has an almost constant width W. The resin overlap part  41  has a function to shade the TFT  20 . A storage capacitor bus line  18  crossing each of the pixel regions and extending in parallel to the gate bus line  12  is formed. The storage capacitor bus line  18  functions as one electrode of a storage capacitor part. A storage capacitor electrode  19  is formed on the storage capacitor bus line  18  through an insulating film. The storage capacitor electrode  19  is formed in each of the pixel regions, and functions as the other electrode of the storage capacitor part. The storage capacitor electrode  19  is electrically connected to a source electrode of the TFT  20  through a connection electrode  25 . A pixel electrode  16  is formed on the CF resin layer  40  and in each of the pixel regions. The pixel electrode  16  is electrically connected to the storage capacitor electrode  19  through a contact hole  26  opened in the CF resin layer  40  and the protection film  32 . 
     An auxiliary spacer layer  53  is formed on the resin overlap part  41  at an arrangement density of one per several to several tens of pixels. The auxiliary spacer layer  53  is almost orthogonal to the resin overlap part  41 , linearly extends, and is formed to overlap with the drain bus line  14 . The resin overlap part  41  functions as a first layer of a pillar spacer  50 , and the auxiliary spacer layer  53  functions as a second layer of the pillar spacer  50 . A width of the auxiliary spacer layer  53  is almost constant, and a length L 1  satisfies a relation of L 1 ≧W+2X (here, X denotes an overlap accuracy of an exposure device used when the auxiliary spacer layer  53  is patterned). As shown in  FIG. 3B , in a state where patterning is ideally made, the auxiliary spacer layer  53  protrudes from each of both side end parts of the resin overlap part  41  by, for example, a length of 10 μm (≧X). When the substrate is attached to a common electrode substrate (not shown) arranged to be opposite thereto, an upper bottom surface  50   a  of the pillar spacer  50  comes in contact with the surface of the common electrode substrate. 
       FIG. 5  shows a sectional structure of the TFT substrate in which an overlap shift occurs when the auxiliary spacer layer  53  is patterned. As shown in  FIG. 5 , the overlap shift occurs in the auxiliary spacer layer  53  in the direction of a thick arrow (+y direction of  FIG. 3B ) with respect to the resin overlap part  41 . However, the width of the auxiliary spacer layer  53  is almost constant, and the auxiliary spacer layer  53  is designed to protrude from each of both the side end parts of the resin overlap part  41  by the length of 10 μm which is not smaller than the overlap accuracy X of the exposure device. Accordingly, even if the overlap shift in ±y direction occurs in the auxiliary spacer layer  53 , the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed. Since the overlap shift of the auxiliary spacer layer  53  is at most about ±4 μm, even if the length L 1  is changed by about ±2 μm due to variations in sizes at the time of patterning, the area of the upper bottom surface  50   a  is not changed. Besides, since the width W of the resin overlap part  41  is almost constant, even if the overlap shift in ±x direction occurs in the auxiliary spacer layer  53 , the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed. That is, in this example, the area of the upper bottom surface  50   a  is not changed by the variations which can occur in a normal manufacturing process of the TFT substrate  2 . Accordingly, according to this example, a poor display and degradation in pressure resistance characteristics due to local uneven cell thickness do not occur, and the liquid crystal display device can be realized in which high manufacturing yield and excellent display quality can be obtained. 
     Next, a manufacturing method of the substrate for the liquid crystal display device according to this example and the liquid crystal display device including the same will be described.  FIGS. 6A to 9  show the manufacturing method of the substrate for the liquid crystal display device according to this example and the liquid crystal display device including the same.  FIGS. 6A to 8  show states when viewed in the direction vertical to the substrate surface, and  FIG. 9  is a sectional view showing a state taken at a position corresponding to line D-D of  FIG. 3A . First, as shown in  FIG. 6A , a metal layer is formed on a glass substrate  10 , and patterning is made, so that gate bus lines  12  and storage capacitor bus lines  18  are formed. Next, an insulating film, an amorphous silicon (a-Si) film and a silicon nitride film (SiN film) are continuously formed. Subsequently, the SiN film is patterned to form a channel protection film  23 . Next, an n + a-Si film and a metal layer are formed on the whole surface of the substrate. Subsequently, the metal layer, the n + a-Si film and the a-Si film are patterned to form drain bus lines  14 , drain electrodes  21 , source electrodes  22 , connection electrodes  25 , storage capacitor electrodes  19  and an operational semiconductor layer  27  (not shown in  FIG. 6A ). In the process up to now, a TFT  20  is formed at each of intersecting positions of the gate bus lines  12  and the drain bus lines  14 . Next, for example, a SiN film is formed on the whole surface of the substrate and a protection film is formed. 
     Next, as shown in  FIG. 6B , a pigment dispersion type colored resin of R or the like is coated on the whole surface of the substrate and patterning is made, so that a CF resin layer  40 R is formed. The CF resin layer  40 R is formed also in a region on the gate bus line  12  in order to shade the TFT  20  in addition to the pixel region of R. An opening part  24  is formed in a part of the CF resin layer  40 R on the storage capacitor electrode  19 . 
     Next, as shown in  FIG. 7A , a pigment dispersion type colored resin of G or the like is coated on the whole surface of the substrate and patterning is made, so that a CF resin layer  40 G is formed. The CF resin layer  40 G is formed also in a region on the gate bus line  12  in addition to the pixel region of G. An opening part  24  is formed in a part of the CF resin layer  40 G on the storage capacitor electrode  19 . 
     Next, as shown in  FIG. 7B , a pigment dispersion type colored resin of B or the like is coated on the whole surface of the substrate and patterning is made, so that a CF resin layer  40 B is formed. The CF resin layer  40 B is formed also in a region on the gate bus line  12  in addition to the pixel region of B. By this, a resin overlap part  41  in which the CF resin layers  40 R,  40 G and  40 B are laminated is formed in the region on the gate bus line  12 . An opening part  24  is formed in a part of the CF resin layer  40 B on the storage capacitor electrode  19 . 
     Next, as shown in  FIG. 8 , the protection film is opened by a dry etching method, and a contact hole  26  is formed. Next, a transparent conductive film of ITO or the like is formed on the whole surface of the substrate and patterning is made, so that a pixel electrode  16  is formed in each of the pixel regions. The pixel electrode  16  is electrically connected to the storage capacitor electrode  19  through the contact hole  26 . Next, a resin film is coated on the whole surface of the substrate on the pixel electrode  16  and patterning is made, so that an auxiliary spacer layer  53  is formed. The auxiliary spacer layer  53  is arranged at an arrangement density of one per several to several tens of pixels, and is formed to intersect with the resin overlap part  41 . By this, a pillar spacer  50  including the resin overlap part (first layer)  41  and the auxiliary spacer layer (second layer)  53  is formed. As already described, even if an overlap shift occurs when the auxiliary spacer layer  53  is formed, the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed. Through the above process, the TFT substrate  2  of the COT structure shown in  FIGS. 3A and 3B  is completed. 
     Next, as shown in  FIG. 9 , the TFT substrate  2  is attached to a common electrode substrate  4  in which a common electrode  42  is formed on a glass substrate  11 , and a liquid crystal  6  is sealed between both the substrates  2  and  4 . Here, since the surface of the common electrode substrate  4  is almost flat, almost the whole surface of the upper bottom surface  50   a  of the pillar spacer  50  comes in contact with the common electrode substrate  4 . That is, when the area of the upper bottom surface  50   a  is not changed, the contact area of the pillar spacer  50  with respect to the common electrode substrate  4  is not also changed. Thereafter, through a module process in which a driver IC or the like is mounted, the liquid crystal display device is completed. Incidentally, in this example, although the resin overlap part  41  is formed by laminating the three layers of the CF resin layers  40 R,  40 G and  40 B, the resin overlap part  41  may be formed by laminating any two layers of the CF resin layers  40 R,  40 G and  40 B. The height of the pillar spacer  50  can be adjusted by changing the film thickness of the auxiliary spacer layer  53 . 
     EXAMPLE 2  
     Next, a liquid crystal display device according to example 2 of this embodiment will be described.  FIG. 10  shows a structure of three pixels of a common electrode substrate  4  of the liquid crystal display device according to this example.  FIG. 11A  shows a structure of one pixel of a TFT substrate  2  of the liquid crystal display device according to this example, and  FIG. 11B  shows a structure of a vicinity of a storage capacitor part of the TFT substrate  2 .  FIG. 12  shows a sectional structure of the liquid crystal display device taken at a position corresponding to line E-E of  FIG. 10 . 
     As shown in  FIGS. 10 to 12 , on the common electrode substrate  4 , a BM  48  for defining pixel regions and shading a storage capacitor part at the side of the TFT substrate  2  is formed of, for example, chromium (Cr). A CF resin layer  40  ( 40 R,  40 G,  40 B) of one color of R, G and B is formed in each of the pixel regions. A common electrode  42  is formed on the CF resin layer  40  and on the whole surface of the substrate. As alignment regulating structures for regulating the alignment of a liquid crystal  6 , projections  45  and  47  made of dielectric materials are formed on the common electrode  42 . In each of the R pixel and the G pixel, there are formed the dot-like projections  45  respectively arranged at two opening parts of a pixel region and the projection  47  overlapping with the region of the BM  48  for shading the storage capacitor part and arranged to protrude to both the opening parts. In the B pixel, there are formed the dot-like projections  45  respectively arranged at two opening parts. Besides, in the B pixel, there is formed a resin layer  63  functioning as a second layer of the pillar spacer  60  instead of the projection  47 . 
     A storage capacitor bus line  18  and a storage capacitor electrode  19  are formed at the center part of the pixel region at the side of the TFT substrate  2 , and a storage capacitor part  17  whose height from the surface of a glass substrate  10  is higher than a peripheral opening part is formed. The storage capacitor part  17  functions as a first layer of the pillar spacer  60 . When both the substrates  2  and  4  are attached to each other, the storage capacitor part  17  and the resin layer  63  come in contact with each other through a contact interface  60   a . A width W of the storage capacitor part  17  is almost constant. A width of the resin layer  63  is almost constant, and a length L 2  satisfies a relation of L 2 ≧W+2Y (here, Y denotes an attaching accuracy at the time when both the substrates  2  and  4  are attached). In the state where both the substrates  2  and  4  are attached to each other without a shift, the resin layer  63  protrudes from each of both side end parts of the storage capacitor part  17  by, for example, 8 μm (≧Y). 
     When an attaching shift of ±5 μm of the substrates  2  and  4  occurs, a size variation of ±1 μm of the resin layer  63  occurs, and an overlap shift of ±4 μm of the resin layer  63  with respect to the common electrode substrate  4  occurs, there is a possibility that a shift of about ±6.5 (=√(5 2 +1 2 +4 2 ) μm occurs between the storage capacitor part  17  and the resin layer  63 . Since the width of the resin layer  63  is almost constant, and the resin layer  63  is designed to protrude from each of both side end parts of the storage capacitor part  17  by 8 μm, even if the shift of ±6.5 μm occurs in the vertical direction of  FIG. 11B , the area of the contact interface  60   a  of the pillar spacer  60  is not changed. Besides, since the width W of the storage capacitor part  17  is almost constant, even if the shift of ±6.5 μm occurs in the horizontal direction of  FIG. 11B , the area of the contact interface  60   a  of the pillar spacer  60  is not changed. 
     According to this example, even if the attaching shift between the substrates  2  and  4  occurs in the range of the attaching accuracy Y, the area of the contact interface  60   a  of the pillar spacer  60  is not changed. Besides, when the length L 2  is made further long, in addition to the attaching shift, even if the size variation of the resin layer  63 , the overlap shift of the resin layer  63  and the like occur, the area of the contact interface  60   a  of the pillar spacer  60  is not changed. Since the hardness of the liquid crystal display panel depends on the area of the contact interface  60   a , according to this example, even if the attaching accuracy Y, the size accuracy, the overlap accuracy and the like are considered, a poor display and degradation in pressure resistance characteristics due to local uneven cell thickness do not occur. Accordingly, the liquid crystal display device can be realized in which high manufacturing yield and excellent display quality can be obtained. 
     Incidentally, in the structure of this example, the resin layer  63  functions as an alignment regulating structure. Thus, although the resin layer  63  is arranged to protrude from the BM  48  to the opening part, degradation in display quality hardly occurs. However, as compared with the projection  47 , the alignment regulating force on the liquid crystal  6  is high, and there is a case where a light leak of backlight occurs. Accordingly, it is desirable that the resin layer  63  is formed in the B pixel whose transmittance is lowest among the three colors of R, G and B. 
     Besides, in this example, although the resin layer  63  is designed to protrude from each of both the side end parts of the storage capacitor part  17  by 8 μm, in view of the magnitude of a manufacture variation, it may be smaller than 8 μm. For example, in the case where the attaching shift of the substrates  2  and  4  is ±4 μm, the overlap shift of the resin layer  63  with respect to the common electrode substrate  4  is ±3 μm, and the size variation of the resin layer  63  is ±1 μm, there is a possibility that a shift of about ±5 (=√(4 2 +3 2 +1 2 )) μm occurs between the storage capacitor part  17  and the resin layer  63 . Accordingly, in this case, the length by which the resin layer  63  protrudes from each of both the side end parts of the storage capacitor part  17  may be 5 μm. 
     EXAMPLE 3 
     Next, a substrate for a liquid crystal display device according to example 3 of this embodiment and a liquid crystal display device including the same will be described.  FIG. 13  shows a structure of a TFT substrate of a COT structure according to this example.  FIG. 14  shows asectional structure of a liquid crystal display device taken along line F-F of  FIG. 13 , and  FIG. 15  shows a sectional structure of the TFT substrate taken at the same position.  FIG. 16  shows a sectional structure of the TFT substrate taken along line G-G of  FIG. 13 . 
     As shown in  FIGS. 13 to 16 , in this example, a resin overlap part  41  in which adjacent two layers among CF resin layers  40 R,  40 G and  40 B are laminated is formed on a drain bus line  14 . The resin overlap part  41  linearly extends along the drain bus line  14 , and has an almost constant width W. An auxiliary spacer layer  53  is formed on the resin overlap part  41 . The auxiliary spacer layer  53  is almost orthogonal to the resin overlap part  41 , and extends along a gate bus line  12 . The resin overlap part  41  functions as a first layer of a pillar spacer  50 , and the auxiliary spacer layer  53  functions as a second layer of the pillar spacer  50 . A width of the auxiliary spacer layer  53  is almost constant, and its length L 1  satisfies a relation of L 1 ≧W+2X (here, X denotes an overlap accuracy of an exposure device used when the auxiliary spacer layer  53  is patterned). As shown in  FIG. 15 , in the state where ideal patterning is made, the auxiliary spacer layer  53  protrudes from a side end of the auxiliary spacer  41  at a TFT  20  side by 40 μm (≧X), and is arranged so as to cover the TFT  20 . Besides, the auxiliary spacer layer  53  protrudes from the other side end of the resin overlap part  41  by, for example, a length of 20 μm (≧X). When the substrate is attached to a common electrode substrate  4 , an upper bottom surface  50   a  of the pillar spacer  50  comes in contact with the surface of the common electrode substrate  4 . 
     In this example, since the width of the auxiliary spacer layer  53  is almost constant, and the auxiliary spacer layer  53  is designed to protrude from each of both the side end parts of the resin overlap part  41  by the length not smaller than the overlap accuracy X of the exposure device, even if an overlap shift in the horizontal direction in  FIG. 13  occurs in the auxiliary spacer layer  53 , the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed. Besides, since the width W of the resin overlap part  41  is almost constant, even if an overlap shift in the vertical direction in  FIG. 13  occurs in the auxiliary spacer layer  53 , the area of the upper bottom surface  50   a  of the pillar spacer  50  is not changed. Accordingly, according to this example, similarly to example 1, a poor display and degradation in pressure resistance characteristics due to local uneven cell thickness do not occur, and the liquid crystal display device can be realized in which high manufacturing yield and excellent display quality can be obtained. 
     Incidentally, in this example, although the resin overlap part  41  is formed on the drain bus line  14 , the resin overlap part  41  may be formed on both the gate bus line  12  and the drain bus line  14 . In this case, the auxiliary spacer layer  53  is arranged on an intersecting point of the lattice-like resin overlap parts  41 , and is formed into, for example, a square shape. The width (length) of the auxiliary spacer layer  53  in the direction parallel to the gate bus line  12  and the width (length) in the direction parallel to the drain bus line  14  are respectively made not smaller than the sum of the width W of the resin overlap part  41  and twice the overlap accuracy X of the exposure device used when the auxiliary spacer layer  53  is patterned. 
     EXAMPLE 4  
     Next, a liquid crystal display device according to example 4 of this embodiment will be described.  FIG. 17  shows a structure of three pixels of a common electrode substrate  4  of the liquid crystal display device according to this example. As shown in  FIG. 17 , as alignment regulating structures for regulating the alignment of liquid crystal, the common electrode substrate  4  includes a linear projection  43  extending obliquely with respect to a pixel region end part and an auxiliary projection  44  branching from the linear projection  43  and extending in parallel to the pixel region end part. The linear projection  43  and the auxiliary projection  44  are formed at the same time by using, for example, a positive resist. In a part of a B pixel, instead of the linear projection  43 , there is formed a resin layer  63  extending almost in parallel to the linear projection  43  and functioning as a second layer of a pillar spacer  60 . The resin layer  63  is formed of, for example, acryl resin. 
       FIG. 18  shows a structure of three pixels of a TFT substrate  2 . As shown in  FIG. 18 , a slit  46  extending obliquely with respect to a pixel region end part and functioning as an alignment regulating structure is formed in a pixel electrode  16  on the TFT substrate  2 . When the TFT substrate  2  and the common electrode substrate  4  are attached to each other, the linear projection  43  and the slit  46  are shifted from each other by a half pitch and are arranged in parallel to each other. Besides, a storage capacitor part  17  whose height from a glass substrate surface is higher than a peripheral opening part is formed on the TFT substrate  2 . The storage capacitor part  17  functions as a first layer of the pillar spacer  60 . A width of the storage capacitor part  17  is almost constant. Besides, a width W 2  of the resin layer  63  in the direction in which the storage capacitor part  17  extends is almost constant, and its length L 2  in the direction orthogonal to the direction in which the storage capacitor part  17  extends satisfies a relation of L 2 ≧W+2Y (here, Y denotes an attaching accuracy when both the substrates  2  and  4  are attached). 
       FIG. 19A  shows the arrangement of the resin layer  63  and the storage capacitor part  17  at the time when the TFT substrate  2  and the common electrode substrate  4  are attached to each other without a shift. As shown in  FIG. 19A , the resin layer  63  protrudes from each of both side end parts of the storage capacitor part  17  by a length Y 1  (for example, 8 μm or more).  FIG. 19B  shows a state in which the common electrode substrate  4  is shifted from the TFT substrate  2  by about 8 μm in the direction of an arrow in the drawing (upper left direction) and is attached thereto. In the structure of this example, the width W 2  of the resin layer  63  is almost constant, and the resin layer  63  is designed to protrude from each of both the side end parts of the storage capacitor part  17  by the length Y 1 . Accordingly, even if an attaching shift occurs in the vertical direction in the drawing, the area of the contact interface  60   a  of the pillar spacer  60  is not changed. Besides, since the width W of the storage capacitor part  17  is almost constant, even if the attaching shift occurs in the horizontal direction in the drawing, the area of the contact interface  60   a  of the pillar spacer  60  is not changed. That is, as shown in  FIG. 19B , even if the attaching shift occurs in the oblique direction, the area of the contact interface  60   a  of the pillar spacer  60  is not changed. Since the shift amount occurring actually when the substrates  2  and  4  are attached is 8 μm or less, a sufficient attaching margin is secured. According to this example, a poor display and degradation in pressure resistance characteristics due to local uneven cell thickness do not occur, and the liquid crystal display device can be realized in which high manufacturing yield and excellent display quality can be obtained. 
     Incidentally, in the structure of this example, the resin layer  63  functions also as the alignment regulating structure. Thus, although the resin layer  63  is arranged to protrude from the BM 48  to the opening part, degradation in display quality hardly occurs. However, as compared with the linear projection  43 , the alignment regulating force on the liquid crystal  6  is high, and there is a case where a light leak of backlight occurs, and accordingly, it is desirable that the resin layer  63  is formed in the B pixel whose transmittance is lowest among the three colors of R, G and B. 
     The invention is not limited to the above embodiment, but can be variously modified. 
     For example, in the embodiment, although the transmissive liquid crystal display device is cited as the example, the invention is not limited to this, but can also be applied to a reflective or semi-transparent liquid crystal display device. 
     Besides, in the above embodiment, although the liquid crystal display device including the channel protection film type TFTs is cited as the example, the invention is not limited to this, but can be applied to a liquid crystal display device including channel etch type TFTs. 
     Further, in the above embodiment, although the liquid crystal display device in which the electrode is formed on each of the opposite surfaces of the pair of substrates arranged to be opposite to each other is cited as the example, the invention is not limited to this, but can be applied to a liquid crystal display device of an IPS mode in which an electrode is formed on only one of a pair of substrates.