Patent Publication Number: US-2016231616-A1

Title: Display device

Description:
CLAIM OF PRIORITY 
     The present application claims priority from Japanese patent application JP 2014-147724 filed on Jul. 18, 2014 the content of which is hereby incorporated by reference into this application. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display device. 
     2. Description of the Related Art 
     A touch panel is configured to recognize a position on the touch panel touched by a pen or a finger and to use the positional information as an input signal for driving. A display device having such a touch panel has become popular because it does not need an external input device such as a keyboard or a mouse, and there has also been developed a liquid crystal display device incorporating a touch sensor in a liquid crystal panel (see, for example, Japanese Patent Application Laid-Open No. 2009-151138). 
     The inventors reviewed a display device structured to have a metal wiring (hereinafter, referred to as auxiliary wiring or light-blocking metal layer) in a region with the light blocked out by a black matrix in order to reduce resistance of a transparent electrode (ITO) used as a touch sensor wiring in a display device incorporating the touch sensor therein. 
     The display device reviewed by the inventors is described with reference to  FIGS. 10A and 10B . 
       FIG. 10A  is a plan view for illustrating a configuration of the display device in its display area.  FIG. 10B  is a cross-sectional view along a line A-A′ in  FIG. 10A  (some parts such as the black matrix are omitted in the plan view). 
     The display device  100  includes subpixels of red (R), green (G), blue (B), and white (W) in a vertical stripe shape, where RGB and RGW are respectively regarded as a single pixel, and the RGB pixels and the RGW pixels are arranged alternately. The number of each of B and W is half of that of R or G. The display device  100  includes a TFT substrate (array substrate)  101 , a counter substrate  200 , and a liquid crystal  300  arranged between the array substrate  101  and the counter substrate  200 . 
     In the array substrate  101 , a common electrode  120  is placed on a signal wiring (video signal line)  115  via an organic flattened film (HRC)  110 . A pixel electrode  150  is placed on the common electrode  12   0  via an interlayer insulating film (an inorganic insulating film such as SiN)  140 . The common electrode  120  extends in a direction parallel to a video signal line  115  (vertical direction in  FIG. 10A ) and is divided in a direction perpendicular to the video signal line  115  (lateral direction in  FIG. 10A ) by a common electrode slit portion  121  to be periodically arranged, and an auxiliary wiring  130  is arranged on the video signal line  115  in electrical contact with the common electrode  120 . The auxiliary wiring  130  is arranged in a position overlapping a black matrix  210  as seen vertically from above between subpixels of different colors. In order that the divided common electrodes  120  may not short-circuit one another, however, the auxiliary wiring  130  is not arranged in the divided region (common electrode slit portion)  121  of the common electrode  120 . The common electrode  120  and the pixel electrode  150  are formed of a translucent conductor film such as ITO (Indium Tin Oxide), and the auxiliary wiring  130  and the video signal line  115  are formed of a light-blocking conductor film (low-resistance conductor film, metal film). 
     The counter substrate  200  includes the black matrix (BM, light-blocking layer)  210  and RGBW color filters (colored layer)  220 . The color filters  220  are arranged in the order of R, G, B, R, G, W in the extending direction of the video signal line  115  and the vertical direction (lateral direction in  FIG. 10A ) in the repeated manner. As for R and G color filters  220 , those of the same color are aligned in the extending direction of the video signal line  115 , whereas B and W filters are alternately arranged. 
     In the conventional display device without a touch sensor, a source metal wiring (signal wiring, video signal line) or the like is arranged on the array substrate side and the black matrix or the like is arranged on the counter substrate (CF substrate) side between subpixels of different colors, thereby blocking the light from an adjacent subpixel to prevent color mixture. However, as the high definition is developed, it is required to reduce the width of the metal wiring or the width of the black matrix, and the color mixture has been prevented by improving the effect of blocking the light from the adjacent subpixel by increasing the thickness of the metal wire, the thickness of the black matrix, or the both. 
     In the structure reviewed by the inventors, when the common electrode is not divided between adjacent subpixels as shown in  FIGS. 7A and 7B , the auxiliary wiring (light-blocking metal layer)  130  is arranged in a position overlapping the black matrix  210  as seen vertically from above. Thus, the display device having this structure can use the auxiliary wiring (light-blocking metal layer) as a member for blocking the light from an adjacent subpixel. This point is explained with reference to  FIG. 9A .  FIG. 9A  shows an exemplary case in which a blue filter  22 OB and a red filter  220 R are adjacent to each other. When a light  410  that should pass through the blue filter  220 B advances toward the adjacent red filter  22 OR, there can be a risk of color mixture. In such a case, by arranging the auxiliary wiring (light-blocking metal layer)  130 , the light that would cause color mixture if there is no auxiliary wiring is blocked by the auxiliary wiring. Furthermore, it is possible to prevent color mixture because the light  410  having passed by the auxiliary wiring is blocked by the black matrix. Thus, the display device having the structure reviewed by the inventors is effective for prevention of color mixture. It should be noted that the reference numeral  411  denotes the light that is not able to pass therethrough but is blocked. 
     However, if higher definition is required for the display device and, for example, the width of the black matrix is reduced (width:t 1 &gt;width:t 2 ) in the future, there can be a risk of color mixture between the adjacent subpixels as shown in  FIG. 9B . Such measures can be contemplated as to increase the thickness of the metal wiring as shown in  FIG. 9C  or to increase the thickness of the black matrix, but they may involve other issues that processing of the metal wiring and the black matrix should be time-consuming and cause side etching to make it difficult to obtain a desired shape. 
     Moreover, as shown in  FIGS. 8A and 8B , it is required to provide the common electrode slit portion  121  for dividing the common electrode  120  used for the touch sensor, but the auxiliary wiring  130  cannot be arranged that has the same potential, which brings the risk of color mixture between the adjacent subpixels. 
     It is an object of the present, invention to provide a display device inhibiting color mixture between the adjacent subpixels to obtain a high-quality image. 
     SUMMARY OF THE INVENTION 
     One embodiment of the invention to achieve the above object is a display device including: a first substrate including a thin-film transistor and a light-blocking metal layer; a second substrate including a black matrix; and a display area formed on a substrate made by laminating the first substrate and the second substrate together and on which a plurality of subpixels are arranged, wherein 
     the plurality of subpixels are arranged adjacent to one another via the black matrix as seen vertically from above, 
     the black matrix and the light-blocking metal layer are arranged to overlap one another as seen vertically from above, and 
     the light-blocking metal layer is arranged on a bank formed on a lower side of the light-blocking metal layer of the first substrate. 
     Furthermore, a display device includes: a first substrate including a thin-film transistor, a light-blocking metal layer, and a pixel electrode electrically connected to a drain electrode of the thin-film transistor; a second substrate including a black matrix; and a display area formed on a substrate made by laminating the first substrate and the second substrate together and on which a plurality of subpixels are arranged, wherein 
     the plurality of subpixels are arranged adjacent to one another via the black matrix as seen vertically from above, 
     the black matrix and the light-blocking metal layer are arranged to overlap one another as seen vertically from above, and 
     the light-blocking metal layer is arranged on a bank formed on a lower side of the light-blocking metal layer of the first substrate with a bottom face of the light-blocking metal layer arranged at a level higher than the pixel electrode. 
     Moreover, a display device includes: a first substrate including a thin-film transistor, a scanning signal line electrically connected to a gate electrode of the thin-film, transistor, a pixel electrode electrically connected to a drain electrode of the thin-film transistor, a video signal line electrically connected to a source electrode of the thin-film transistor, and a light-blocking metal layer; a second substrate including a black matrix; and a display area formed on a substrate made by laminating the first substrate and the second substrate together and on which a plurality of subpixels are arranged, wherein 
     the plurality of subpixels are arranged adjacent to one another via the black matrix as seen vertically from above, 
     the black matrix, the video signal line, and the light-blocking metal layer are arranged to overlap one another as seen vertically from above, and 
     the light-blocking metal layer is arranged on a bank formed on a lower side of the light-blocking metal layer of the first substrate with a bottom face of the light-blocking metal layer arranged at a level higher than the pixel electrode, and inhibits color mixture between the plurality of adjacent subpixels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a plan view schematically showing a main part of a display device according to a first embodiment of the present invention; 
         FIG. 1B  is a cross-sectional view schematically showing the main part of the display device according to the first embodiment of the present invention; 
         FIG. 2A  is a plan view schematically showing a main part of a display device according to a second embodiment of the present invention; 
         FIG. 2B  is a cross-sectional view schematically showing the main part of the display device according to the second embodiment of the present invention; 
         FIG. 3  is a main part cross-sectional view for illustrating an effect to inhibit color mixture between adjacent subpixels in the display device according to the first embodiment of the present invention; 
         FIG. 4A  is a manufacturing process flowchart of display device according to the first embodiment of the present invention (convex portion (bank) forming process on an organic flattened film); 
         FIG. 4B  is a manufacturing process flowchart of display device according to the first embodiment of the present invention (common electrode forming process); 
         FIG. 4C  is a manufacturing process flowchart of display device according to the first embodiment of the present invention (interlayer insulating film forming process); 
         FIG. 4D  is a manufacturing process flowchart of display device according to the first embodiment of the present invention (interlayer insulating film forming process); 
         FIG. 4E  is a manufacturing process flowchart of display device according to the first embodiment of the present invention (pixel electrode forming process); 
         FIG. 4F  is a manufacturing process flowchart of display device according to the first embodiment of the present invention (alignment film forming process); 
         FIG. 5A  is a manufacturing process flowchart of display device according to the second embodiment of the present invention (convex portion (bank) forming process on an organic flattened film); 
         FIG. 5B  is a manufacturing process flowchart of display device according to the second embodiment of the present invention (common electrode forming process); 
         FIG. 5C  is a manufacturing process flowchart of display device according to the second embodiment of the present invention (auxiliary wiring forming process); 
         FIG. 5D  is a manufacturing process flowchart of display device according to the second embodiment of the present invention (interlayer insulating film forming process); 
         FIG. 5E  is a manufacturing process flowchart of display device according to the second embodiment of the present invention (pixel electrode forming process); 
         FIG. 5F  is a manufacturing process flowchart of display device according to the second embodiment of the present invention (alignment film forming process); 
         FIG. 6  is a general schematic plan view of the display device according to each embodiment of the present invention; 
         FIG. 7A  is a plan view schematically showing the main part (a region in which a common electrode is not divided) of a display device incorporating a touch panel therein as reviewed by the inventors; 
         FIG. 7B  is a cross-sectional view schematically showing the main part (the region in which the common electrode is not divided) of the display device incorporating the touch panel therein as reviewed by the inventors; 
         FIG. 8A  is a plan view schematically showing the main part (when the common electrode is divided) of the display device incorporating the touch panel therein as reviewed by the inventors; 
         FIG. 8B  is a cross-sectional view schematically showing the main part (when the common electrode is divided) of the display device incorporating the touch panel therein as reviewed by the inventors; 
         FIG. 9A  is a main part cross-sectional view for illustrating the effect to inhibit color mixture between the adjacent subpixels in the display device incorporating the touch panel therein as reviewed by the inventors; 
         FIG. 9B  is a main part cross-sectional view for illustrating a problem of color mixture between the adjacent subpixels in the display device incorporating the touch panel therein as reviewed by the inventors; 
         FIG. 9C  is a main part cross-sectional view for illustrating a measure for inhibiting color mixture between adjacent subpixels in the display device incorporating the touch panel therein as reviewed by the inventors; 
         FIG. 10A  is a main part schematic plan view of the display device incorporating the touch panel therein as reviewed by the inventors; and 
         FIG. 10B  is a main part schematic cross-sectional view of the display device incorporating the touch panel therein as reviewed by the inventors. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     After reviewing a structure that inhibits color mixture between adjacent subpixels, the inventors focused on the fact that an organic flattened film is relatively easy to process. The present invention has been made on the basis of this new finding, in which a convex portion (bank) is formed by an organic flattened film arranged on an array substrate instead of metal or a black matrix difficult to process, and as thin auxiliary wiring as possible is arranged thereon taking into account the light blocking property and electrical conductivity. This makes it possible to easily inhibit color mixture between the adjacent subpixels. It should be noted that any film can be used to form the convex portion as long as it is easy to process and it is not limited to the organic flattened film. Furthermore, formation of the auxiliary wiring on the bank having a height different from that of the common electrode requires a larger margin compared with the case of forming the auxiliary wiring on a slit portion coplanar with the common electrode, and thus reduces short circuit caused by the auxiliary wiring of the common electrode divided by the slit portion. Note that color mixture caused by the light passing through the bank portion of the organic flattened film at a lower portion of the auxiliary wiring can be ignored. 
     Hereinafter, embodiments of the present invention will be described with reference to drawings. It should be noted that the present disclosure is merely an example and that any changes that can easily be contemplated by those skilled in the art without departing from the spirit of the invention should naturally fall within the scope of the invention. Moreover, although the drawings may be more schematically represented in terms of the width, thickness, shape, or the like of each portion compared with an actual aspect for more explicit illustration, it is merely an example but not intended to limit the interpretation of the present invention. It should also be noted that elements similar to those already illustrated with reference to a previous drawing are denoted by the same reference numerals throughout the drawings, thereby omitting detailed description thereof. 
     First Embodiment 
     A display device according to a first embodiment of the present invention is described with reference to  FIGS. 1A, 1B, 3, 4A to 4F, and 6 . 
       FIG. 6  is a schematic plan view of the display device according to this embodiment. As shown in  FIG. 6 , this display device  100  includes a TFT substrate (array substrate)  101 , a counter substrate (CF substrate)  200 , and a liquid crystal sandwiched between the TFT substrate and the counter substrate. The TFT substrate  101  and the counter substrate  200  are adhered by a sealing material  104 . Formed in a display area  105  are a scanning signal line, a video signal line, and pixels arranged in a matrix form. The pixels include a TFT, a pixel electrode, a common electrode, and an auxiliary wiring for reducing resistance of the common electrode. The scanning signal wiring is connected to a gate electrode of the TFT, and formed on the array substrate using the same process and the same material. The video signal line is connected to a source electrode of the TFT, and formed on the array-substrate using the same process and the same material. Furthermore, the pixel electrode is connected to a drain electrode of the TFT. It should be noted that the terms such as “source” and “drain” are merely for descriptive purposes and that either one can be referred to as a drain if the other one is referred to as a source. For example, aluminum-silicon alloy (AlSi alloy) or molybdenum-tungsten alloy (Mow alloy) can be used for the source electrode and the drain electrode. For the pixel electrode and the common electrode, a transparent conductive film such as ITO (Indium Tin Oxide) and IZO (Indium Zinc Oxide) can be used. The counter substrate  200  includes a black matrix arranged at a position corresponding to the video signal line, the scanning signal line, the auxiliary wiring, and the like, and a color filter arranged at a position corresponding to a transmissive area of the pixel. 
     The TFT substrate  101  is larger than the counter substrate  200  and includes a region having only one TFT substrate, in which region a substrate terminal portion  103  being connected to an IC driver (drive circuit)  102  and a flexible wiring board (not shown) is arranged. A backlight, an outer frame, and. the like can be combined depending on the application. 
       FIG. 1A  shows a plan view of the proximity of the auxiliary wiring of the liquid crystal display device according to this embodiment, and  FIG. 1B  shews a cross-sectional view of the same. It should be noted, however, that a configuration of the counter substrate is omitted in the plan view. The display device includes the TFT substrate (array substrate), the counter substrate, and a liquid crystal  300  arranged between the array substrate and the counter substrate. 
     On the array substrate, a common electrode  120  is arranged on the video signal line (signal wiring) via an organic flattened film (HRC)  110 . The pixel electrode  150  is arranged on the common electrode  120  via an interlayer insulating film (inorganic insulating film such as SiN)  140 . A major difference from the configuration shown in  FIGS. 7A and 7B  is that an auxiliary wiring (light-blocking metal layer)  130  arranged between the subpixels (between a blue pixel and a red pixel in  FIG. 1B ) to reduce resistance of the common electrode  120  is arranged on a convex portion (bank)  110   a  formed in the organic flattened film. This allows for inhibiting color mixture between adjacent subpixels using such a thin auxiliary wiring as shown in  FIG. 3  without using a thick auxiliary wiring as shown in  FIG. 9C . Color mixture between the subpixels caused by the light having passed through the convex portion of the organic flattened film that is the lower part of the auxiliary wiring can be reduced to a negligible degree by adjusting the height of the convex portion of the organic flattened film taking into account the positions of the black matrix and the signal wiring. Furthermore, the load of processing the auxiliary wiring can be reduced and also the processing dimensional accuracy is not reduced because the auxiliary wiring can be made thinner. By making the height of the auxiliary wiring  130  higher with respect to the pixel electrode  150  (closer to the counter substrate), the light blocking effect can be improved and color mixture between the adjacent subpixels can be reduced. It should be noted that the reference numeral  111  denotes a through hole formed in the organic flattened film and that  141  denotes a through hole formed in the inorganic insulating film. 
     Formed on the counter substrate side are a black matrix  210 , color filters  220  (blue filter  220 B, red filter  220 R, and the like), an overcoat  230 , an alignment film  260 , and the like. 
     A method of manufacturing the display device according to this embodiment, specifically of forming the auxiliary wiring arranged on the convex portion of the organic flattened film on the array substrate side, is now described with reference to  FIGS. 4A to 4F . 
     First, the array substrate is prepared having the organic flattened film with 3 μm thickness formed on the scanning signal line, the video signal line, the TFT, or the like. In this embodiment, the convex portion (bank)  110   a  of the organic flattened film with 500 nm height is formed by exposing the organic flattened film using a positive photosensitive material as the organic flattened film  110  and using a photomask  510  including a light-blocking portion  510   a  that fully blocks an exposure light, and a halftone portion  510   b  that transmits part of the exposure light and by performing a development and the like. The height of the convex portion  110   a  of the organic flattened film can be adjusted by an exposure amount (modifiable by changing an exposure time, an intensity of the exposure light, a transmittance of the halftone portion, and the like). This allows for thinning the auxiliary wiring to the desired thickness. The width of the convex portion (bank) is preferably smaller than the width of the black matrix. It should be noted that the convex portion of the organic flattened film can be formed in the same process as the through hole forming process performed on the organic flattened film in order to make contact with an electrode such as the TFT formed on the array substrate. In other words, the process of forming the convex portion on an organic flattened film  135  can be performed at the same time as the conventional through hole forming process on the organic flattened film  135  by using a photomask (halftone mask)  500  including not only the light-blocking portion and the transmissive portion but a 1 so the halftone portion. 
     Next, the common electrode  120  is formed by making and processing an ITO film of 50 nm thickness ( FIG. 4B ). Subsequently, by making and processing a film of metal of 230 nm thickness, the auxiliary wiring electrically connected to the common electrode is formed on top of the convex portion  110   a  of the organic flattened film ( FIG. 4C ). Processing of the auxiliary wiring is performed by lithography and etching. The width of the auxiliary wiring is preferably smaller than the width of the convex portion (bank). 
     The interlayer insulating film  140  is then formed of, for example, silicon nitride film (SiNx film) to have 180 nm thickness ( FIG. 4D ). The pixel electrode  150  connected to the drain electrode of the TFT is then formed by making and processing the ITO film ( FIG. 4E ). At. this time, the pixel electrode  150  is arranged to have its height below the level of the lower face of the auxiliary wiring  130 . An alignment film  160  is then applied and sintered ( FIG. 4F ). There is a concern about an alignment failure in the case of an alignment process based on rubbing because the alignment film is formed, on a member having a stepped shape such as an organic flattened film having a convex portion or an auxiliary wiring (light-blocking metal layer). In such a case, an optical alignment film may be used. Subsequently, the array substrate and the counter substrate arranged with the color filters and the black matrix are laminated, and the liquid crystal is sealed between the substrates to form the display device. A backlight, an outer frame, and the like can be combined depending on the application. For each manufacturing step, any known process can be used. 
     Based on the manufacturing method including the processing steps shown in  FIGS. 4A to 4F , the auxiliary wiring is formed on the convex portion provided on the organic flattened film as shown in  FIG. 1  and the liquid crystal display device is produced as shown in  FIG. 6 , whereby color mixture between the adjacent subpixels can be inhibited. In particular, by setting the height of the bottom face of the auxiliary wiring at a higher level than the pixel electrode, the color mixture can be reduced. It is also possible to improve the processing dimensional accuracy of the auxiliary wiring by making the auxiliary wiring thinner. This allows for forming a thin auxiliary wiring with less variation and reducing the distance between the adjacent subpixels, thereby achieving further miniaturization and higher definition. 
     Although the auxiliary wiring for reducing the resistance of the common electrode is used in this embodiment to reduce color mixture between the adjacent subpixels, other metal wiring formed for other purposes can also be used. Furthermore, although the convex portion (bank) for forming the auxiliary wiring is formed using the organic flattened film, it is also possible to use other types of films. 
     As described above, according to this embodiment, a display device that inhibits color mixture between the adjacent subpixels and allows for obtaining a high-quality image can be provided by arranging the auxiliary wiring (light-blocking metal layer) between the adjacent subpixels on the convex portion of the organic flattened film (convex portion formed in the lower layer). Making the bottom face of the auxiliary wiring higher than the pixel electrode is also effective in inhibiting the color mixture. It is also possible to obtain the light-blocking metal layer with a high dimensional accuracy. This is advantageous for achieving a high definition because it reduces the variation in the wirings and the distance between the subpixels. 
     Second Embodiment 
     A second embodiment of the present invention is described with reference to  FIGS. 2 and 5A to 5F . It should be noted that what is described in the first, embodiment is also applicable to this embodiment unless otherwise specified. 
     Described in this embodiment is an example of inhibiting color mixture between the adjacent subpixels using the light-blocking metal layer (auxiliary wiring) formed in the slit portion of the common electrode using the same material and the same process as the auxiliary wiring. 
       FIG. 2A  is a plan view of the proximity of the auxiliary wiring of the liquid crystal display device according to this embodiment, and  FIG. 2B  is a cross-sectional view of the same. It should be noted, however, that the configuration of the counter substrate is omitted in the plan view. The display device includes the TFT substrate (array substrate), the counter substrate, and the liquid crystal  300  arranged between the array substrate and the counter substrate. 
     This embodiment is different from the first embodiment in that the common electrode is divided in the center of the drawing. In the configuration initially reviewed by the inventors as shown in  FIGS. 8A and 8B , the divided region (common electrode slit portion)  121  of the common electrode  120  is not provided with the auxiliary wiring  130  so that the common electrodes  120  may not short-circuit one another. In this embodiment, by forming the convex portion on the organic flattened film, the width of the slit portion may not be increased but the production margin for short-circuit is increased compared with the case of forming the common electrode and the auxiliary wiring on the same plane, and thus the adjacent common electrodes will not short-circuit each other even if the auxiliary wiring is formed. 
     A method of manufacturing the display device according to this embodiment, specifically of forming the auxiliary wiring arranged on the convex portion of the organic flattened film, is now described with reference to  FIGS. 5A to 5F . The description thereof is omitted because the method is basically identical to the first embodiment except the common electrode forming process. As shown in  FIG. 5A , after forming the convex portion  110   a  of the organic flattened film  110 , the film of ITO is formed all over the array substrate, the ITO on the convex portion (bank) of the organic flattened film is removed by lithography and etching, thereby forming the common electrode having the slit at the convex portion of the organic flattened film ( FIG. 5B ). The processes shown in  FIG. 5C  and after are same as those shown in  FIG. 4C  and after. In  FIG. 5C , however, it is possible to increase the production margin for short-circuit between the common electrodes formed on the organic flattened film  110  (between common electrodes divided left and right in  FIG. 5C ) because the auxiliary electrode  130  is formed on the convex portion  110   a  of the organic flattened film. This enables an arrangement of the auxiliary wiring in the slit portion of the common electrode where it would be difficult to arrange the auxiliary wiring in the configuration shown in  FIG. 8 , thereby inhibiting color mixture between the adjacent subpixels. 
     Based on the manufacturing method including the processing steps shown in  FIGS. 5A to 5F , the auxiliary wiring is formed on the convex portion provided on the organic flattened film as shown in  FIG. 2  and the liquid crystal display device is produced as shown in  FIG. 6 , whereby color mixture between the adjacent subpixels can be inhibited without short-circuiting the divided electrodes. 
     As described above, this embodiment can achieve the same effect as the first embodiment. Moreover, this embodiment can increase the production margin for short-circuit between adjacent wirings. 
     Although some embodiments of the present invention are described above, these embodiments are merely exemplary but not intended to limit the scope of the invention. The present invention consists in arranging the light-blocking metal layer on top of the underlying convex portion between the adjacent subpixels where the black matrix would be arranged. A novel embodiment that may derive from this concept can be carried out in various other forms, and an omission, replacement, or modification can be performed without departing from the spirit of the invention. These embodiments and variations thereof are included in the scope and spirit of the invention, and also included in the scope of the invention described in the appended claims and equivalents thereof. 
     Within the concept of the invention, those skilled in the art can of course come up with various modifications and alterations, which are understood to be included in the scope of the invention. For example, those skilled in the art can add constituents to, delete constituents from, modify the design of, add a processing step to, delete the step from or change a condition of each of the embodiments described above as desired within the scope of the invention as long as it stays in the spirit of the invention. Other effects brought by the aspects described in the embodiments that are apparent from the description or that can be easily contemplated by those skilled in the art are naturally understood to be brought by the invention.