Patent Publication Number: US-9904095-B2

Title: Display device and liquid crystal display device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 14/203,724 filed on Mar. 11, 2014. Further, this application claims priority from Japanese Application No. 2013-49075 filed on Mar. 12, 2013, the contents of which are hereby incorporated by reference into this application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display device and a liquid crystal display device. 
     2. Description of the Related Art 
     It is known that a black matrix is formed from resin on a color filter substrate of a liquid crystal display panel (JP 9-15403A). The resin is a photoresist, and the photoresist is patterned by photolithography. The black matrix is originally designed so that an opening has corners. 
     In a photolithography step, since a photomask has a shape almost equal to a designed shape, at an exposure step, exposure can be performed in the shape in which the opening has corners. However, at a development step, since developing liquid is hard to enter the corners, the opening is rounded and becomes small. As a result, there is a problem that light transmittance is reduced. 
     SUMMARY OF THE INVENTION 
     The invention has an object to provide a black matrix in which corners of an opening are not rounded. 
     (1) According to an aspect of the invention, a liquid crystal display device includes a first substrate, a partition layer provided on the first substrate and defining plural pixel regions, colored layers of plural colors constituting color filters in the plural pixel regions, a second substrate opposite to the first substrate, and a liquid crystal material arranged between the first substrate and the second substrate, the partition layer includes a longitudinal light-shielding part made of a light-shielding resin and extending in a longitudinal direction, a lateral light-shielding part made of the light-shielding resin and extending in a lateral direction, and a light reducing part in which the colored layers including two or more of the colors overlap each other, at least one of the longitudinal light-shielding part and the lateral light-shielding part has a space to avoid contact with the other, and the light reducing part fills the space between the longitudinal light-shielding part and the lateral light-shielding part. According to the invention, since the longitudinal light-shielding part and the lateral light-shielding part are arranged with the space therebetween, even if the partition layer is formed by photolithography, corners are not formed, and the opening is not rounded. Besides, since the light reducing part fills the space between the longitudinal light-shielding part and the lateral light-shielding part, the partition layer has sufficient characteristics as the black matrix. 
     (2) The liquid crystal display device as recited in (1) may be configured such that one of the longitudinal light-shielding part and the lateral light-shielding part has the space, and the other crosses the space as seen in planar view. 
     (3) The liquid crystal display device as recited in (2) may be configured such that widths of the longitudinal light-shielding part and the lateral light-shielding part in directions perpendicular to the extending directions are different from each other, and one of the longitudinal light-shielding part and the lateral light-shielding part, which has the smaller width, is interrupted. 
     (4) The liquid crystal display device as recited in any one of (1) to (3) may be configured such that the light reducing part includes the two colored layers arranged in the adjacent pixel regions of different colors. 
     (5) The liquid crystal display device as recited in any one of (1) to (4) may be configured such that each of the colored layers is arranged to overlap the longitudinal light-shielding part and the lateral light-shielding part. 
     (6) The liquid crystal display device as recited in (5) may be configured such that the two colored layers arranged in the adjacent pixel regions of different colors are adjacent not to overlap each other on the longitudinal light-shielding part and the lateral light-shielding part. 
     (7) According to another aspect of the invention, a display device includes plural pixels, a substrate, partition layers provided on the substrate and defining the plural pixels, a first color filter layer formed on the substrate, a second color filter layer formed on the substrate, and an overlapping part in which a part of the first color filter layer and a part of the second color filter layer overlap each other, the partition layers include plural first partition layers extending in a first direction, plural second partition layers extending in a second direction intersecting with the first direction, and plural third partition layers including the overlapping part, each of the plural first partition layers includes plural spaces arranged in the first direction, and each of the plural third partition layers is arranged in each of the plural spaces. 
     (8) The display device as recited in (7) may be configured such that the plural first partition layers and the plural second partition layers are made of a light-shielding resin. 
     (9) The display device as recited in (7) may be configured such that each of the plural second partition layers crosses each of the spaces. 
     (10) The display device as recited in (9) may be configured such that a whole region of each of the spaces is covered with the second partition layer and the third partition layer. 
     (11) The display device as recited in (7) may be configured such that widths of the first partition layers are smaller than widths of the second partition layers. 
     (12) The display device as recited in (7) may be configured such that the first color filter layer includes a first convex part extending in the first direction and protruding in the second direction, the second color filter layer includes a second convex part adjacent to the first color filter layer, extending in the first direction and protruding in the second direction, and the overlapping part includes the first convex part and the second convex part overlapping each other. 
     (13) The display device as recited in (7) may be configured such that the overlapping part does not overlap the plural first partition layers and the plural second partition layers as seen in planar view. 
     (14) The display device as recited in (7) may be configured such that the plural pixels include two pixels arranged in the first direction, and the space includes a part of a boundary part of the two pixels. 
     (15) The display device as recited in (7) may be configured such that each of the first partition layers is bent. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view showing a liquid crystal display device of an embodiment of the invention. 
         FIG. 2  is a plan view of a first substrate including a partition layer. 
         FIG. 3  is a III-III line sectional view of the first substrate shown in  FIG. 2 . 
         FIG. 4  is a IV-IV line sectional view of the first substrate shown in  FIG. 2 . 
         FIG. 5  is a V-V line sectional view of the first substrate shown in  FIG. 2 . 
         FIG. 6  is a view for explaining a manufacturing method of the liquid crystal display device of the embodiment of the invention. 
         FIG. 7  is a view for explaining the manufacturing method of the liquid crystal display device of the embodiment of the invention. 
         FIG. 8  is a view for explaining the manufacturing method of the liquid crystal display device of the embodiment of the invention. 
         FIG. 9  is a view for explaining the manufacturing method of the liquid crystal display device of the embodiment of the invention. 
         FIG. 10  is a view for explaining a modified example of the liquid crystal display device of the embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, embodiments of the invention will be described with reference to the drawings. 
       FIG. 1  is a sectional view showing a liquid crystal display device of an embodiment of the invention. The liquid crystal display device includes a first substrate  10  which is a light transmissive substrate such as, for example, a glass substrate. A partition layer  12  is formed on the first substrate  10 . The partition layer  12  has a function as a black matrix. 
       FIG. 2  is a plan view of the first substrate  10  including the partition layer  12 . The partition layer  12  defines plural pixel regions  14 . One pixel region  14  is a sub-pixel of one color, and a full-color pixel includes plural adjacent sub-pixels. 
     The partition layer  12  includes lateral light-shielding parts  16  extending in a lateral direction (right and left direction of  FIG. 2 ). The plural lateral light-shielding parts  16  are arranged with intervals in a longitudinal direction (up and down direction of  FIG. 2 ). The longitudinal direction and the lateral direction are not limited to orthogonal directions as long as the directions cross each other. A line drawn in the direction in which the lateral light-shielding part  16  extends may be a straight line or a curved line, or may be bent. The lateral light-shielding part  16  is made of a light-shielding resin. 
     The partition layer  12  includes longitudinal light-shielding parts  18  extending in the longitudinal direction (up and down direction of  FIG. 2 ). The plural longitudinal light-shielding parts  18  are arranged with intervals in the lateral direction (right and left direction of  FIG. 2 ). The longitudinal light-shielding part  18  is interrupted in the extending direction. A line drawn in the direction in which the longitudinal light-shielding part  18  extends may be a straight line or a curved line, or may be bent. The longitudinal light-shielding part  18  is made of a light-shielding resin. 
     The longitudinal light-shielding part  18  and the lateral light-shielding part  16  are different in width (width perpendicular to the extending direction). The width of the longitudinal light-shielding part  18  is smaller than the width of the lateral light-shielding part  16 . The lateral light-shielding part  16  and the longitudinal light-shielding part  18  are arranged with a space  20  so that they do not cross each other. Particularly, the lateral light-shielding part  16  passes through a gap formed by the interruption of the longitudinal light-shielding part  18 . The longitudinal light-shielding part  18  and the lateral light-shielding part  16  do not contact each other. 
     As shown in  FIG. 1 , the liquid crystal display device includes colored layers  22 ,  24  and  26  of plural colors. The colored layers  22 ,  24  and  26  of plural colors constitute color filters in the plural pixel regions  14  shown in  FIG. 2 . The colored layers  22 ,  24   26  of plural colors are formed on the first substrate  10  so that either one of them is arranged in each of the pixel regions  14 . The plural colors are red (R), green (G) and blue (B). The colored layer of green (G) has the highest light transmittance and has high visibility. The colored layer of blue (B) has the lowest light transmittance and has low visibility. 
       FIG. 3 ,  FIG. 4  and  FIG. 5  are respectively a III-III line sectional view, a IV-IV line sectional view and a V-V line sectional view of the first substrate  10  shown in  FIG. 2 . As shown in  FIG. 3  and  FIG. 5 , each of the colored layers  22 ,  24  and  26  is arranged so as to overlap the longitudinal light-shielding part  18  and the lateral light-shielding part  16 . However, the two colored layers  22  and  24 ,  22  and  26 , or  24  and  26  arranged in the adjacent pixel regions  14  of different colors are adjacent not to overlap each other on the longitudinal light-shielding part  18  and the lateral light-shielding part  16 . 
     As shown in  FIG. 2  and  FIG. 4 , the partition layer  12  includes a light reducing part  28  having a structure in which the colored layers  22 ,  24  and  26  of two or more colors overlap each other. As shown in  FIG. 2 , the light reducing part  28  fills the space  20  between the longitudinal light-shielding part  18  and the lateral light-shielding part  16 . The light reducing part  28  includes the two colored layers  22  and  24 ,  22  and  26 , or  24  and  26  arranged in the adjacent pixel regions  14  of different colors. 
     According to this embodiment, since the longitudinal light-shielding part  18  and the lateral light-shielding part  16  are arranged with the space  20 , even if the partition layer  12  is formed by photolithography, a corner is not formed and the opening is not rounded. Besides, since the light reducing part  28  fills the space  20  between the longitudinal light-shielding part  18  and the lateral light-shielding part  16 , the partition layer  12  has sufficient characteristics as a black matrix. 
     As shown in  FIG. 1 , a first alignment film  32  is formed through an over coat layer  30  so as to cover the colored layers  22 ,  24  and  26 . A second substrate  34 , which is a light transmissive substrate such as, for example, a glass substrate, is formed to face the first substrate  10 . A second alignment film  36  is formed on a surface of the second substrate  34  opposite to the first substrate  10 . A cell gap is formed by a not-shown spacer between the first alignment film  32  and the second alignment film  36 , and a liquid crystal material  38  is arranged between the first substrate  10  and the second substrate  34 . Particularly, the liquid crystal material  38  is arranged between the first alignment film  32  and the second alignment film  36 . 
       FIG. 6  to  FIG. 9  are views for explaining a manufacturing method of the liquid crystal display device of the embodiment of the invention. In this embodiment, as shown in  FIG. 6 , the first substrate  10  is prepared in which the light reducing part  28  of the partition layer  12  is not provided, but the lateral light-shielding parts  16  and the longitudinal light-shielding parts  18  are formed. The lateral light-shielding parts  16  and the longitudinal light-shielding parts  18  are formed by patterning a photoresist as a light-shielding resin by photolithography. Since the lateral light-shielding parts  16  and the longitudinal light-shielding parts  18  are arranged with the spaces  20 , corners are not formed, and it does not occur that developing liquid is hard to enter in development performed after exposure. Accordingly, the lateral light-shielding parts  16  and the longitudinal light-shielding parts  18  can be formed into a precise shape corresponding to the shape of an exposure mask. 
     Next, the colored layers  22 ,  24  and  26  of plural colors are formed. The photolithography can be applied also to the formation of the colored layers  22 ,  24  and  26 . In that case, the colored layers  22 ,  24   26  are also formed of a photoresist. 
     As shown in  FIG. 7 , the colored layer  22  which is a first color is formed. The colored layer  22  is arranged so as to extend in the longitudinal direction. Particularly, the colored layer  22  is arranged between the longitudinal light-shielding parts  18  adjacent to each other in the lateral direction. The colored layer  22  includes a stripe-shaped main body part  40 . The main body part  40  is formed so that both ends thereof extending in the length direction are respectively placed on ends of the adjacent longitudinal light-shielding parts  18 . The colored layer  22  includes convex parts  42  protruding from both the ends of the main body part  40  in directions opposite to each other. The convex parts  42  are arranged in the space  20  ( FIG. 6 ) for forming the light reducing part  28 , that is, in the space  20  formed between the lateral light-shielding part  16  and the longitudinal light-shielding part  18  by the interruption of one of them. 
     As shown in  FIG. 8 , the colored layer  24  which is a second color is formed. The second color colored layer  24  has the same details as the first color colored layer  22 , and is formed adjacent to the first color colored layer  22 . The second color colored layer  24  also includes convex parts  44 . The convex parts  44  are arranged in the space  20  ( FIG. 6 ) for forming the light reducing part  28 , that is, in the space  20  formed between the lateral light-shielding part  16  and the longitudinal light-shielding part  18  by the interruption of one of them. Accordingly, the convex part  42  of the first color colored layer  22  and the convex part  44  of the second color colored layer  24  overlap each other, and the light reducing part  28  ( FIG. 4 ) is formed. 
     As shown in  FIG. 9 , the colored layer  26  which is a third color is formed. The third color colored layer  26  has the same details as the first color colored layer  22 , and is formed between the first color and the second color colored layers  22  and  24 . The third color colored layer  26  also includes convex parts  46 . The convex parts  46  are arranged in the space  20  ( FIG. 6 ) for forming the light reducing part  28 , that is, in the space  20  formed between the lateral light-shielding part  16  and the longitudinal light-shielding part  18  by the interruption of one of them. Accordingly, the convex part  42  ( FIG. 7 ) of the first color colored layer  22  and the convex part  46  ( FIG. 9 ) of the third color colored layer  26  overlap each other, and the light reducing part  28  is formed ( FIG. 4 ). Besides, the convex part  44  ( FIG. 8 ) of the second color colored layer  24  and the convex part  46  ( FIG. 9 ) of the third color colored layer  26  overlap each other, and the light reducing part  28  is formed ( FIG. 4 ) 
     By the above process, the partition layer  12  functioning as the black matrix and the colored layers  22 ,  24  and  26  are formed. Further, the manufacturing method of the liquid crystal display device includes contents obvious from the foregoing description of the liquid crystal display device. 
     Modified Example 
       FIG. 10  is a view for explaining a modified example of the liquid crystal display device of the embodiment of the invention. In the modified example, the shape of a partition layer  112  is different from that of the above embodiment. That is, a pixel region  114  has such a shape that a convex part  152  is provided at one side in a lateral direction, and a concave part  154  is provided at the other side. In other words, a longitudinal light-shielding part  118  of the partition layer  112  is bent between adjacent lateral light-shielding parts  116 . The partition layer  112  has the shape as stated above because a multi-domain system for expanding a viewing angle is applied. In the multi-domain system, two or more regions in which alignment states of liquid crystal molecules are different exist in one pixel region  114 . 
     While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.