Patent Publication Number: US-11024677-B2

Title: Organic EL display apparatus and method of manufacturing organic EL display apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation of co-pending U.S. patent application Ser. No. 15/771,392, having a filing/§ 371(c) date of 18 Jul. 2019, which is a U.S. National Stage of International Application No. PCT/JP2017/024668, filed on 5 Jul. 2017 (expired). The entire disclosure of each patent application set forth in the Cross-Reference to Related Applications section is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an organic-EL display apparatus and a method for manufacturing the organic-EL display apparatus. 
     BACKGROUND ART 
     In organic-EL display apparatuses, for example, anodes, light-emitting layers, and cathodes are formed on a surface of a substrate formed of glass or a resin film, and an organic-EL display element constituted by an anode, a light-emitting layer, and a cathode is formed in each of a plurality of sub-pixels. The light-emitting layers are formed mainly by depositing an organic material, for example, by vacuum vapor-deposition using a vapor-deposition mask, which comprises openings at positions corresponding to the positions of formation of the light-emitting layers. Since the luminance and chromaticity of the organic-EL display element during light emission and the lifetime of the organic-EL display element are affected by the thickness of the light-emitting layer, the light-emitting layer needs to be formed with a uniform thickness. For example, according to Patent Document 1, the pitch of pixels arrayed in the moving direction of an evaporation source is set larger than the pitch of pixels arrayed in a direction perpendicular to the moving direction of the evaporation source such that portions of the vapor-deposition mask around the openings do not prevent the organic material from reaching to the substrate during evaporation of the organic material. 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: JP 2007-200735 A 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     Patent Document 1 discloses suppression of a variation in the thickness of the light-emitting layer in the moving direction of an evaporation source. However, a variation of the thickness of the light-emitting layer in the direction orthogonal to the moving direction of the evaporation source can also occur. For example, in the case where a line evaporation source in which melting pots for evaporating the deposition material are linearly arrayed is used, a variation in the thickness of the light-emitting layer in the longitudinal direction of the evaporation source, which is orthogonal to the moving direction of the evaporation source, can sometimes be greater than the variation in the thickness of the light-emitting layer in the moving direction of the evaporation source, as described later. The variation in the thickness of the light-emitting layer occurring in the direction orthogonal to the moving direction of the evaporation source is not considered in the means disclosed in Patent Document 1. 
     In addition, according to the method disclosed in Patent Document 1, the pitch of the pixels arrayed in either of the horizontal and vertical directions of the screen needs to be set greater than the manufacturable pitch within the inherent capacity of the manufacturing line. Therefore, there is a possibility that the above method cannot sufficiently meet the continuing demands on the organic-EL display apparatus for improvement of the definition and resolution of the image. Further, although the “pixels” in Patent Document 1 are considered to be the “sub-pixels”, which emit inherent colors such as red, green, and blue in the case of the organic-EL display apparatus displaying color images, the plurality of “sub-pixels” having rectangular shapes are formed such that the long-side directions of the respective sub-pixels are aligned to an identical direction. Therefore, for example, it is necessary that three sub-pixels  301  to  303 , for red, green, and blue, be arranged in parallel, as illustrated in  FIG. 12 , at a small pitch in one pixel  200  which is downsized with higher-definition in resolution. Thus, in some cases, strict control of condition or a high-performance device is needed in manufacture of the organic-EL display apparatus. Consequently, neither an organic-EL display apparatus nor a manufacturing method for such an organic-EL display apparatus that is easy to manufacture and is little affected by a variation in the thickness of the light-emitting layer without running counter to downsizing or resolution improvement has ever been proposed. 
     In view of the above, an object of the present invention is to provide an organic-EL display apparatus and a method for manufacturing the organic-EL display apparatus in which manufacturing of sub-pixels is easy even for higher-definition pixels, and the display quality and the like are less affected by a variation in the thickness of the organic layer. 
     Means to Solve the Problem 
     An organic-EL display apparatus according to an embodiment of the present invention comprises: a substrate comprising a first electrode; an organic layer formed of organic materials so as to form a plurality of pixels arrayed in a matrix form, the organic material being vapor-deposited on the first electrode; and a second electrode formed on the organic layer, wherein each of the plurality of pixels comprises at least three sub-pixels having substantially rectangular shapes; a first sub-pixel and a second sub-pixel among the at least three sub-pixels are arranged in parallel with each other such that a long side of the first sub-pixel and a long side of the second sub-pixel are substantially parallel with each other; a third sub-pixel among the at least three sub-pixels is formed such that a long side of the third sub-pixel is substantially parallel with a short side of the first sub-pixel and a short side of the second sub-pixel; in the first sub-pixel and the second sub-pixel, a variation in a thickness of the organic layer through a long-side direction is larger than a variation in the thickness of the organic layer through a short-side direction; and in the third sub-pixel, a variation in a thickness of the organic layer through a short-side direction is larger than a variation in the thickness of the organic layer through a long-side direction. 
     A method for manufacturing organic-EL display apparatus according to an embodiment of the present invention comprises: preparing a first vapor-deposition mask provided with a first opening having a substantially rectangular shape, a second vapor-deposition mask provided with a second opening having a substantially rectangular shape, and a third vapor-deposition mask provided with a third opening having a substantially rectangular shape; overlapping the first vapor-deposition mask with a surface of a target substrate for vapor deposition, positioning the first vapor-deposition mask above a linear evaporation source such that a long side of the first opening and a longitudinal direction of the linear evaporation source are substantially parallel with each other, and vapor-depositing, on the surface, an organic material from the linear evaporation source; overlapping the second vapor-deposition mask with the surface of the target substrate for vapor deposition, positioning the second vapor-deposition mask above the linear evaporation source such that a long side of the second opening and the longitudinal direction of the linear evaporation source are substantially parallel with each other, and vapor-depositing, on the surface, an organic material from the linear evaporation source; and overlapping the third vapor-deposition mask with the surface of the target substrate for vapor deposition, positioning the third vapor-deposition mask above the linear evaporation source such that a short side of the third opening and the longitudinal direction of the linear evaporation source are substantially parallel with each other, and vapor-depositing, on the surface, an organic material from the linear evaporation source. 
     Effects of the Invention 
     According to an embodiment of the present invention, an organic-EL display apparatus in which manufacturing of sub-pixels is easy even for small pixels, and the display quality and the like are less affected by a variation in the thickness of the organic layer is provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 2  is a plan view of one pixel of the organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 3A  is a cross-sectional view along a IIIA-IIIA line in  FIG. 2 . 
         FIG. 3B  is a cross-sectional view along a IIIB-IIIB line in  FIG. 2 . 
         FIG. 3C  is a cross-sectional view along a IIIC-IIIC line in  FIG. 2 . 
         FIG. 3D  is a cross-sectional view along a IIID-IIID line in  FIG. 2 . 
         FIG. 4  is a cross-sectional view of an example of a vapor-deposition mask used for vapor deposition of an organic material in a manufacturing process for the organic-EL display apparatus. 
         FIG. 5A  is a diagram showing circumstances of flight of organic material in the longitudinal direction of the linear evaporation source in a vapor-deposition process. 
         FIG. 5B  is a diagram showing circumstances of flight of organic material in the direction of movement of the linear evaporation source in the vapor-deposition process. 
         FIG. 6A  is a diagram showing a region of the organic layer in the first sub-pixel, the region being formed with thicknesses of 95% or larger of the maximum thickness of the organic layer, in the organic-EL display apparatus according to Embodiment 1. 
         FIG. 6B  is a diagram showing a region of the organic layer in the third sub-pixel, the region being formed with thicknesses of 95% or larger of the maximum thickness of the organic layer, in the organic-EL display apparatus according to Embodiment 1. 
         FIG. 7  is a diagram showing, side by side, cross sections of the respective sub-pixels in the organic-EL display apparatus according to Embodiment 1. 
         FIG. 8  is a plan view of a pixel in an organic-EL display apparatus according to Embodiment 2 of the present invention. 
         FIG. 9A  is a diagram showing an example of a preparation process for a first vapor-deposition mask in a method for manufacturing organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 9B  is a diagram showing an example of a second vapor-deposition mask prepared by the method for manufacturing organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 9C  is a diagram showing an example of a third vapor-deposition mask prepared by the method for manufacturing organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 10  is a diagram showing an example of arranging the first vapor-deposition mask above a target substrate for vapor deposition and aligning the first vapor-deposition mask to the substrate, in the method for manufacturing organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 11A  is a diagram showing an example of vapor-depositing an organic material by using the first vapor-deposition mask in the method for manufacturing organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 11B  is a diagram showing an example of vapor-depositing an organic material by using the second vapor-deposition mask in the method for manufacturing organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 11C  is a diagram showing an example of vapor-depositing an organic material by using the third vapor-deposition mask in the method for manufacturing organic-EL display apparatus according to Embodiment 1 of the present invention. 
         FIG. 12  is a diagram showing an example of a pixel in a conventional organic-EL display apparatus. 
     
    
    
     EMBODIMENT FOR CARRYING OUT THE INVENTION 
     Next, referring to the drawings, an organic-EL display apparatus and a method for manufacturing organic-EL display apparatus according to the present invention are explained. However, materials and shapes of respective constituents, and the relative positions thereof in the embodiments explained below are only examples, and the organic-EL display apparatus and the method for manufacturing organic-EL display apparatus according to the present invention are not construed to be limited. 
     Embodiment 1 
       FIG. 1  shows a plan view of an organic-EL display apparatus  1  according to Embodiment 1, and  FIG. 2  schematically shows a plan view of one of a plurality of pixels  2  provided in the organic-EL display apparatus  1 . In addition,  FIGS. 3A to 3D  are cross-sectional views respectively along IIIA-IIIA to IIID-IIID lines indicated in  FIG. 2 . As illustrated in  FIG. 1 , the organic-EL display apparatus  1  comprises a display portion D, which displays images based on video signals generated inside or outside the organic-EL display apparatus  1 , and the display portion D comprises the plurality of pixels  2 , which are arrayed in a matrix form and have substantially square shapes. As illustrated in  FIG. 2 , each of the plurality of pixels  2  is constituted by at least three sub-pixels having substantially rectangular shapes. In the example of  FIG. 2 , the pixel  2  comprises a first sub-pixel  31 , a second sub-pixel  32 , and a third sub-pixel  33 . However, the number of the sub-pixels constituting the pixel  2  is construed to be not limited to three, and each of the plurality of pixels  2  in the present embodiment can have an arbitrary number, three or more, of sub-pixels. As illustrated in  FIGS. 3A to 3D , the organic-EL display apparatus  1  comprises: a substrate  4  provided with first electrodes  5 ; an organic layer  6  formed of organic materials which are vapor-deposited on the first electrodes  5  to form each of the plurality of pixels  2 ; and a second electrode  7  formed on the organic layer  6 . The organic layer  6  comprises a light-emitting layer  6   b  which emits light as energy emission from an excited luminescent material. (Although not shown in  FIG. 3A to 3D , the organic layer  6  can have a multilayer structure comprising the light-emitting layer  6   b  as illustrated in  FIG. 7  described later.) Each of the first to third sub-pixels  31 ,  32 , and  33  emits light from the organic layer  6 , for example, by supplying current to the first electrodes  5 , so that, as a result, a desired image is displayed on the display portion D in the organic-EL display apparatus  1 . In  FIG. 2 , for clearly showing each sub-pixel, the second electrode  7  is not shown. 
     The “substantially rectangular shape” is not construed to be limited to rectangles which are surrounded by four straight lines and the interior angles of which are all right angles. As long as the longitudinal direction can be perceived, the “substantially rectangular shape” encompasses, for example, the shape in which all or part of the four edges are slightly curved, and the shape in which all or part of the four corners are rounded. 
     As illustrated in  FIG. 2 , the first sub-pixel  31  and the second sub-pixel  32  are arranged in parallel with each other such that the respective long sides of the first sub-pixel  31  and the second sub-pixel  32  are substantially parallel. In other words, the first sub-pixel  31  and the second sub-pixel  32 , each having a substantially rectangular shape, are arranged such that one of the two long sides of the first sub-pixel  31  is opposed to one of the two long sides of the second sub-pixel  32 . That is, the orientations of the first and second sub-pixels  31  and  32  are aligned such that the long sides of the first sub-pixel  31  and the second sub-pixel  32  extend in an identical direction, and the first and second sub-pixels  31  and  32  are arrayed in the direction orthogonal to the long sides of the first sub-pixel  31  and the second sub-pixel  32 . 
     On the other hand, the third sub-pixel  33  is formed such that the long sides of the third sub-pixel  33  are substantially parallel to a short side of the first sub-pixel  31  and a short side of the second sub-pixel  32 . In other words, the third sub-pixel  33  having a substantially rectangular shape is formed such that one of the two long sides of the third sub-pixel  33  is opposed to one of the two short sides of the first sub-pixel  31  and one of the two short sides of the second sub-pixel  32 . That is, the third sub-pixel  33  is arranged such that the one of the two long sides of the third sub-pixel  33  is along the one of the two short sides of each of the first sub-pixel  31  and the second sub-pixel  32 , and the third sub-pixel  33  is arrayed with each of the first and second sub-pixels  31  and  32  in the long-side direction of the first and second sub-pixels  31  and  32 . In addition, in the case where the pixel  2  comprises four or more sub-pixels, sub-pixels other than the first to third sub-pixels  31 ,  32 , and  33  can be arrayed in parallel with one another such that the sub-pixels other than the first to third sub-pixels  31 ,  32 , and  33  are substantially parallel to the first and second sub-pixels  31  and  32 , or the sub-pixels other than the first to third sub-pixels  31 ,  32 , and  33  can be formed such that the sub-pixels other than the first to third sub-pixels  31 ,  32 , and  33  are substantially parallel to the third sub-pixel  33 . 
     The expression “substantially parallel” compresses not only the positional relationship being strictly parallel geometrically, and also the positional relationships in which a long side or a short side of one sub-pixel is inclined from any side of the other sub-pixel arranged opposed to the one sub-pixel at such a degree that the long side or the short side of the one sub-pixel is not in contact with a long side or a short side of the other sub-pixel. 
     As described above, in the present embodiment, not all of the first to third sub-pixels  31 ,  32 , and  33  are arranged in parallel along an identical direction in the pixel  2 . That is, at least one sub-pixel is arranged to be arrayed with the other sub-pixels in a direction different from the direction in which the other sub-pixels are arrayed with each other. Even in the case where four or more sub-pixels are provided in the pixel  2 , the sub-pixels are arranged in the same manner as above. Therefore, an arrangement pitch PI between the sub-pixels (for example, the first and second sub-pixels  31  and  32 ) can be set large in comparison with the case where all of the sub-pixels  301  to  303  are arrayed in an identical direction (for example, in the vertical direction in  FIG. 12 ) in the pixel  200  as shown previously in  FIG. 12 . That is, even in the case where the pixel  2  is downsized, the widths of the first and second sub-pixels  31  and  32  and/or the spacings between the first and second sub-pixels  31  and  32 , in the direction in which the first and second sub-pixels  31  and  32  are arrayed, can be set relatively large. Thus, openings  110  (see  FIG. 4 ) in a vapor-deposition mask used in formation of the organic layer  6  can be relatively easily formed, and the positions of the substrate  4  and the vapor-deposition mask can be easily aligned. Further, the influence, on the characteristic features of the organic-EL display apparatus  1 , of a variation in the dimensions, the positions, and the like of the first to third sub-pixels  31 ,  32 , and  33 , which are caused by a manufacturing variation and the like, can be made relatively small. In other words, a larger variation can be allowed in manufacture of the organic-EL display apparatus  1 , so that the organic-EL display apparatus  1  achieving high resolution can be easily manufactured. 
     The pixel  2  can have arbitrary size according to the screen size and the resolution of the organic-EL display apparatus  1 . For example, the pixel  2  can have dimensions of 20 μm square to 500 μm square. The first to third sub-pixels  31 ,  32 , and  33  are arranged with spacings of 5 μm to 50 μm between each other inside the pixel  2  having the dimensions as above. For example, the lengths of the long sides of the first and second sub-pixels  31  and  32  are 0.5×C or more and 0.9×C or less, and the lengths of the short sides of the first and second sub-pixels  31  and  32  are 0.1×C or more and 0.5×C or less, where C is the length of a side of the pixel  2 . In addition, the lengths of the long sides of the third sub-pixel  33  are 0.5×C or more and 0.9×C or less, and the lengths of the short sides of the third sub-pixel  33  are 0.1×C or more and 0.5×C or less. The ratio (L 1 :W 3 ) of the length L 1  of the long sides of the first and second sub-pixels  31  and  32  to the length W 3  of the short sides of the third sub-pixel  33  is, for example, 1:1 or more and 9:1 or less. However, the lengths of the long sides and short sides of the first to third sub-pixels  31 ,  32 , and  33  are not construed to be limited to the above examples. Unlike the example of  FIG. 2 , the first sub-pixel  31  and the second sub-pixel  32  can be different in their dimensions, and in their positions in the long-side direction of the first sub-pixel  31  and the second sub-pixel  32 . Further, the long side of the first sub-pixel  31  and the short side of the third sub-pixel  33  that face an outer edge of the pixel  2  is not necessarily aligned in the long-side direction of the third sub-pixel  33 . 
       FIGS. 3A to 3D  illustrate cross sections of the pixel  2 , specifically, cross sections parallel to the long-side direction of the first and second sub-pixels  31  and  32  and cross sections parallel to the long-side direction of the third sub-pixel  33 . The organic-EL display apparatus  1  is provided with an insulation bank  8 , which is formed of an insulating material and functions as partitions between the respective sub-pixels, and an organic layer  6  is formed in the respective areas surrounded by the insulation bank  8 . In the first to third sub-pixels  31 ,  32 , and  33 , the organic layer  6  comprises portions S 1  to S 6  having thickness reduction in the vicinities of both ends in the long-side directions and the short-side directions of the first to third sub-pixels  31 ,  32 , and  33 . (Hereinafter, the portions of the organic layer  6  having thickness reduction can be referred to as shadow portions.) The “thickness” of the organic layer  6  is the distance from the upper surface of the first electrode  5  that opposes the organic layer  6  to the upper end (upper surface) of the organic layer  6  that opposes the second electrode  7 . Therefore, the expressions “a variation in the thickness” or “a reduction in the thickness” means a variation or a reduction in the height of the upper end of the organic layer  6  from the upper surface of the first electrode  5 . 
     The reason why the shadow portions S 1  to S 6  are formed in the organic layer  6  in the first to third sub-pixels  31 ,  32 , and  33  is explained below. An example of a vapor-deposition mask  11  used in formation of the organic layer  6  is shown in  FIG. 4 . The vapor-deposition mask  11  is constituted by a resin film  111 , a metal support layer  112  reinforcing the resin film  111 , and a frame  113  formed around the resin film  111  and the metal support layer  112  and used for fixing the vapor-deposition mask  11  to a vapor-deposition apparatus (not shown). Openings  110  are arranged in positions of the resin film  111  corresponding to the positions in which the organic layer  6  is to be formed. In addition, openings  112   a , which envelopes the openings  110  in the resin film  111 , are arranged in the metal support layer  112 . When the organic layer  6  is formed, only the organic material passing through the openings  110  reaches the substrate  4  (see  FIG. 3A ) to form the organic layer  6  in given positions. 
     The substrate  4  and the vapor-deposition mask  11  that have been arranged inside the vapor-deposition apparatus to form the organic layer  6  are shown in  FIG. 5A . The first electrodes  5  and the insulation bank  8  are formed on the substrate  4 . The cross section of the pixel  2  shown in  FIG. 5A  is a cross section at a position similar to  FIG. 3A . The vapor-deposition mask  11  is a vapor-deposition mask for the first sub-pixel  31 , and comprises the openings  110  corresponding to the first sub-pixel  31 . The vapor-deposition mask  11  and the substrate  4  are aligned and closely contact with each other such that the openings  110  in the vapor-deposition mask  11  are located right under the areas surrounded by the insulation bank  8 . The first electrode  5  arranged in the first sub-pixel  31  is exposed in the openings  110  in the vapor-deposition mask  11 . On the other hand, the third sub-pixel  33  is covered by the vapor-deposition mask  11 . Although the organic layer  6  is not yet formed and the respective sub-pixels do not yet exist in the structures shown in  FIG. 5A  and in  FIG. 5B  which is explained later, the regions in which the first to third sub-pixels  31 ,  32 , and  33  are to be formed will be respectively referred to as the first to third sub-pixels  31 ,  32 , and  33 , for convenience, in the explanations with reference to  FIGS. 5A and 5B . 
     A linear evaporation source  16  having a plurality of linearly arrayed melting pots  16   a  is arranged below the vapor-deposition mask  11 . The plurality of melting pots  16   a  are arranged from one end to the opposite end of the linear evaporation source  16  with proper spacings. The positions and the angles of the melting pots  16   a  are adjusted such that the evaporated material (organic material)  61  with a certain thickness can be adhered to a strip-like area of the substrate  4  in the longitudinal direction of the linear evaporation source  16 . Then, the linear evaporation source  16  moves relative to the substrate  4  in a direction orthogonal to the longitudinal direction of the linear evaporation source  16  (in the back-and-forth direction, which is orthogonal to the plane of the illustration of  FIG. 5A ) across the full length (or full width) of the substrate  4 . Consequently, the organic material  61  is vapor-deposited, ideally in a substantially uniform manner, on the surfaces of the first electrodes  5  excluding the portions covered by the vapor-deposition mask  11  across the entire surface of the substrate  4 . 
     In the longitudinal direction of the linear evaporation source  16 , the organic material  61  that comes flying to, for example, the first sub-pixel  31  on the right side in  FIG. 5A  (hereinafter, when  FIG. 5A  is referred to, the first sub-pixel on the right side is simply referred to as the first sub-pixel) from not only melting pot  16   a   2  located in the vicinity of the first sub-pixel  31  but also all other melting pots  16   a  including the melting pot  16   a   1  and the melting pot  16   a   3 . However, the incident angle θ of the organic material  61  that comes flying from a melting pot  16   a  decreases with an increase in the distance of the melting pot  16   a  from the first sub-pixel  31 . The organic material  61  that comes flying at an incident angle θ smaller than a taper angle α of the opening  110  of the vapor-deposition mask  11  or a taper angle of the insulation bank  8  is obstructed by the vapor-deposition mask  11  or the insulation bank  8  and cannot reach the first sub-pixel  31 . 
     For example, although the organic material  61  that comes flying from the melting pot  16   a   1  reaches the point P 1 , the organic material  61  that comes flying from melting pot  16   a   2  cannot reach the point P 1 . In other words, while the organic material  61  that comes flying from melting pot  16   a   1  reaches the point P 1 , it cannot reach the point P 2 . Similarly, while the organic material  61  that comes flying from melting pot  16   a   3  reaches the point P 3 , it cannot reach the point P 4 . That is, the position in the first sub-pixel  31  is more difficult to be reached by the organic material  61  when the position is nearer to each end of the first sub-pixel  31 . This phenomenon similarly occurs in the cases of the organic material  61  that comes flying from other plurality of melting pots  16  that are arrayed in the longitudinal direction of the linear evaporation source  16 . Therefore, shadow portions having a relatively large width and greatly reduced thicknesses (e.g., the shadow portions S 2  (see  FIG. 3A )) occur in vicinities of both ends, in the longitudinal direction of the linear evaporation source  16 , of the first sub-pixel  31 . In a similar manner, large shadow portions (e.g., the shadow portions S 4  and S 5  (see  FIG. 3B )) occur in vicinities of both ends, in the longitudinal direction of the linear evaporation source  16 , of the second and third sub-pixels  32  and  33 . 
     On the other hand, in the moving direction of the linear evaporation source  16 , perpendicular to the longitudinal direction of the linear evaporation source  16 , a portion in which the thickness is greatly reduced is unlikely to occur at both ends of the first to third sub-pixels  31 ,  32 , and  33 . This phenomenon is explained below with reference to  FIG. 5B . In  FIG. 5B , the substrate  4 , the vapor-deposition mask  11 , and the linear evaporation source  16  which are shown in  FIG. 5A  are drawn from a viewpoint at the sideward area of the linear evaporation source  16 . That is, the linear evaporation source  16  extends in the direction perpendicular to the plane of illustration of  FIG. 5B , and moves relative to the substrate  4  in the left-right direction in the plane of illustration of  FIG. 5B . The cross section of the pixel  2  shown in  FIG. 5B  is a cross section at a position similar to  FIG. 3C . The second sub-pixel  32  is covered by the vapor-deposition mask  11 . 
     As illustrated in  FIG. 5B , the organic material  61  comes flying to the first sub-pixel  31  from a very small extent in the moving direction of the linear evaporation source  16 , compared with aforementioned extent in the longitudinal direction of the linear evaporation source  16 . Even in the case where more than one melting pot  16   a  is arrayed in the width direction of the linear evaporation source  16  (the moving direction of the linear evaporation source  16 ), the organic material  61  comes flying from a very small extent compared with the extent in the longitudinal direction of the linear evaporation source  16 . Therefore, the amount of the organic material  61  which comes flying at small incident angles is small, and the amount of the organic material  61  that is blocked by the vapor-deposition mask  11  or the insulation bank  8  is small. Thus, only small shadow portions having a relatively small width and little thickness reduction (e.g., the shadow portions S 1  (see  FIG. 3C )) occur in vicinities of both ends, in the moving direction of the linear evaporation source  16 , of the first sub-pixel  31 . Due to similar situations, only small shadow portions having a relatively small width and little thickness reduction (e.g., the shadow portions S 3  and S 6  (see  FIGS. 3C and 3D )) occur in vicinities of both ends, in the moving direction of the linear evaporation source  16 , of the second and third sub-pixels  32  and  33 . 
     As explained above, in the organic layer  6  formed by the vapor-deposition process using the linear evaporation source  16 , shadow portions (e.g., the shadow portions S 2 , S 4 , and S 5 ) occur at both ends, on the long side and the short side, of each of the first to third sub-pixels  31 ,  32 , and  33  having a substantially rectangular shape, where the shadow portions are larger at the ends on one of the long side and the short side than at the ends on the other of the long side and the short side. Hereinbelow, the explanations of the organic-EL display apparatus  1  according to the present embodiment are continued by referring to  FIGS. 3A to 3D  again. 
     As illustrated in  FIGS. 3A to 3D , in each of the first to third sub-pixels  31 ,  32 , and  33 , variations Δt 1  to Δt 6  of the thickness of the organic layer  6  in the long-side direction and the short-side direction of each sub-pixel occur mainly due to the shadow portions S 1  to S 6 . Specifically, in the first sub-pixel  31 , the variation Δt 2  of the thickness of the organic layer  6  in the long-side direction (the X direction in  FIG. 3A ) are larger than the variation Δt 1  of the thickness of the organic layer  6  in the short-side direction (the X direction in  FIG. 3C ). Similarly, in the second sub-pixel  32 , the variation Δt 4  of the thickness of the organic layer  6  in the long-side direction (the X direction in  FIG. 3B ) are larger than the variation Δt 3  of the thickness of the organic layer  6  in the short-side direction (the X direction in  FIG. 3C ). On the other hand, in the third sub-pixel  33 , the variation Δt 5  of the thickness of the organic layer  6  in the short-side direction (the X direction in  FIG. 3A  and  FIG. 3B ) are larger than the variation Δt 6  of the thickness of the organic layer  6  in the long-side direction (the X direction in  FIG. 3D ). The variation Δt 2  or Δt 4  of the thickness of the organic layer  6  in the long-side direction in each of the first and second sub-pixels  31  and  32  and the variation Δt 5  of the thickness of the organic layer  6  in the short-side direction in the third sub-pixel  33  are substantially 10% of a normal thickness of the organic layer  6  in each sub-pixel. In addition, the variation Δt 1  or Δt 3  of the thickness of the organic layer  6  in the short-side direction in each of the first and second sub-pixels  31  and  32  and the variation Δt 6  of the thickness of the organic layer  6  in the long-side direction in the third sub-pixel  33  are 5% or less of a normal thickness of the organic layer  6  in each sub-pixel. In  FIGS. 3A to 3D , the variations Δt 1  to Δt 6  of the thickness of the organic layer  6  are exaggerated in the illustration with respect to the thickness of the organic layer  6 . 
     As explained above, in the first and second sub-pixels  31  and  32 , the shadow portions S 2  and S 4  exist along the respective short sides and have greater thickness reduction and a larger width than the shadow portions S 1  and S 3  which exist along the respective long sides. Since the shadow portions S 1  to S 4  are also portions in which the light-emitting layer  6   b  is thin, an increase in the area of the shadow portions S 1  to S 4  having reduced thickness decreases the luminance and the chromaticity of the light emitted from the organic layer  6  and the lifetime. Since, in each of the first and second sub-pixels  31  and  32 , the shadow portions S 2  and S 4  that have great thickness reduction and a large width exist along the short sides that are shorter than the long sides of each sub-pixel, the influence on the luminance and the like is small, compared with the case where such shadow portions exist along the long sides. 
     As described before, in the formation of the organic layer  6  by using the linear evaporation source  16  (see  FIG. 5A ), shadow portions that occur at ends in one of a long side and a short side of the first to third sub-pixels  31 ,  32 , and  33  are larger than shadow portions that occur at ends in the other of the long side and the short side. However, it is possible to cause large shadow portions S 2  and S 4  to occur along short sides that less affect the luminance and the like by performing vapor deposition of organic material in such an arrangement that the long sides of the first and second sub-pixels  31  and  32  are substantially parallel to the longitudinal direction of the linear evaporation source  16 . 
     Unlike the first and second sub-pixels  31  and  32 , in the third sub-pixel  33 , shadow portions S 5  having great thickness reduction and a large width exist along the respective long sides. In the case where vapor deposition of organic material is performed in such an arrangement that the long sides of the first and second sub-pixels  31  and  32  are substantially parallel to the longitudinal direction of the linear evaporation source  16  (see  FIG. 5A ), in the third sub-pixel  33 , relatively large shadow portions S 5  are produced along the respective long sides which are parallel to the short sides of each of the first and second sub-pixels  31  and  32 . However, as described before, manufacture of the organic-EL display apparatus  1  can be facilitated by arranging the third sub-pixel  33  to be substantially parallel to the short sides of the first and second sub-pixels  31  and  32 . In addition, in at least first and second sub-pixels  31  and  32 , the influence on the luminance and the like caused by the relatively large shadow portions S 2  and S 4  can be reduced. 
     In the present embodiment, when a ratio of a portion of the organic layer  6  formed with a predetermined thickness or more in each sub-pixel to the entirety of each sub-pixel is considered, it can be said that the ratios in the first and second sub-pixels  31  and  32  are larger than the ratio in the third sub-pixel  33 . For example, in the present embodiment, an area ratio in the first sub-pixel  31  and an area ratio in the second sub-pixel  32  are larger than an area ratio in the third sub-pixel  33 . Each of the area ratios in the first to third sub pixels  31 ,  32 , and  33  is defined as a ratio of an area of a portion to the entire area of each of the first to third sub pixels  31 ,  32 , and  33 . The portion is a portion having thicknesses equal to or larger than 95% of the maximum thickness of the organic layer  6  in each of the first to third sub-pixels  31 ,  32 , and  33 . This point is specifically explained below with reference to  FIG. 6A  and  FIG. 6B . The “area ratio” is the ratio of the area of the portion of the organic layer  6  having thicknesses equal to or larger than 95% of the maximum thickness of the organic layer  6  to the entire area of each sub-pixel, in a pixel plane on which a plurality of pixels  2  are arrayed in a matrix form. 
     A cross-sectional view of the first sub-pixel  31  as a representative of the first and second sub-pixels  31  and  32  is shown in the lower part of  FIG. 6A , and a plan view of the first sub-pixel  31  is shown in the upper part of  FIG. 6A . In the illustration in the upper part, the portion of the organic layer  6  having thicknesses equal to or larger than 95% of the maximum thickness TM (in  FIG. 6A , a normal thickness) of the organic layer  6  is hatched (TN=0.95×TM in  FIG. 6A ). A plan view of the third sub-pixel  33  is shown in  FIG. 6B . Similar to  FIG. 6A , the portion of the organic layer  6  having thicknesses equal to or larger than 95% of the maximum thickness of the organic layer  6  is hatched. In the present embodiment, the ratio R 1  of the area A 2 =L 2 ×W 2  of the hatched portion to the total area A 1 =L 1 ×W 1  of the first sub-pixel  31  is larger than the ratio R 2  of the area A 4 =L 4 ×W 4  of the hatched portion to the total area A 3 =L 3 ×W 3  of the third sub-pixel  33 , where L 1  and W 1  respectively denote the lengths of the long side and the short side of the first sub-pixel  31 , L 2  and W 2  respectively denote the lengths of the long side and the short side of the portion having thicknesses equal to or larger than 95% of the maximum thickness in the first sub-pixel  31 , L 3  and W 3  respectively denote the lengths of the long side and the short side of the third sub-pixel  33 , and L 4  and W 4  respectively denote the lengths of the long side and the short side of the portion having thicknesses equal to or larger than 95% of the maximum thickness in the third sub-pixel  33 . 
     The chromaticity irregularity between the area in which the organic layer  6  has thicknesses equal to or larger than 95% of the maximum thickness and the portion having the maximum thickness is unlikely to be sensed by visual observation. In this respect, it is desirable for each sub-pixel to have a high area ratio of a portion having thicknesses equal to or larger than 95% of the maximum thickness to the entirety of the sub-pixel. However, even in the case where the threshold for the thickness of the organic layer  6 , which is significant with respect to the display characteristics, is a thickness other than 95% of the maximum thickness, the first and second sub-pixels  31  and  32  can have a higher area ratio of a portion having excellent display characteristics to the entirety of each sub-pixel than the third sub-pixel  33 . Thus, according to the present embodiment, a portion having excellent display characteristics can be secured with a high area ratio to the entirety of each sub-pixel in a majority of sub-pixels (the first and second sub-pixels  31  and  32 ) in one pixel  2 . 
     In the third sub-pixel  33 , relatively large shadow portions S 5  exist along the long sides. However, the influence of the shadow portions S 5  can be reduced. For example, referring to  FIGS. 3A to 3D  again, the normal thickness T 3  (see  FIG. 3A ) of the organic layer  6  in the third sub-pixel  33  is smallest among the at least three sub-pixels (the first to third sub-pixels  31 ,  32 , and  33  in the example indicated in  FIGS. 3A to 3D ) comprised in each of the plurality of pixels  2 . Therefore, the influence of the shadow portions S 5  in the third sub-pixel  33  on the luminance and the like is small, for example, in comparison with a hypothetical case where the large shadow portions S 2  and S 4  exist along the long sides of the first and second sub-pixels  31  and  32 . 
     That is, since the original thickness T 3  of the organic layer  6  in the third sub-pixel  33  is small, the absolute values of the variations Δt 5  and Δt 6  in the thicknesses of the shadow portions S 5  and S 6  are relatively small even in the case where the variation ratios of the thicknesses of the organic layer  6  in the respective sub-pixels are the same. Specifically, the variation Δt 5  in the thickness of the organic layer  6  in the shadow portions S 5  along the long sides of the third sub-pixel  33  are smaller than the variations Δt 2  and Δt 4  in the thicknesses of the organic layer  6  in the shadow portions S 2  and S 4  along the short sides of the first and second sub-pixels  31  and  32 . Since the variations in the thickness of the organic layer  6  affect the luminance and the like depending on the absolute values of the variations, the influence of the shadow portions S 5  in the third sub-pixel  33  is small, compared with the case in which the first and second sub-pixels  31  and  32  comprise, along the long sides of the first and second sub-pixels  31  and  32 , shadow portions having the same variation ratio as the shadow portions S 5 . 
     On the other hand, in the example shown in  FIGS. 3A to 3D , the normal thickness of the organic layer  6  in the first sub-pixel  31  is largest among the at least three sub-pixels (the first to third sub-pixels  31 ,  32 , and  33  in the example shown in  FIGS. 3A to 3D ) comprised in each of the plurality of pixels  2 . In addition, the normal thickness of the organic layer  6  in the second sub-pixel  32  is smaller than the normal thickness of the organic layer  6  in the first sub-pixel  31 , and is larger than the normal thickness of the organic layer  6  in the third sub-pixel  33 . Since the large shadow portions S 2  in the first sub-pixel  31  exist along the short sides of the first sub-pixel  31  as described before, the influence of the shadow portions S 2  on the luminance and the like is small. Therefore, no significant problem occurs even in the case where the organic layer  6  in the first sub-pixel  31  is formed thick. 
     Since, in the present embodiment, the shadow portions S 4  that is large exist in the second sub-pixel  32  along the short sides of the second sub-pixel  32 , the influence of the shadow portions S 4  on the luminance and the like is small. Therefore, unlike the example of  FIGS. 3A to 3D , the organic layer  6  in the second sub-pixel  32  can be equal to or larger than the thickness of the organic layer  6  in the first sub-pixel  31 . The thickness of the organic layer  6  in either of the first sub-pixel  31  and the second sub-pixel  32  can be largest among the at least three sub-pixels. 
     The first to third sub-pixels  31  to  33  preferably comprise a sub-pixel comprising a red luminescent material, a sub-pixel comprising a green luminescent material, and a sub-pixel comprising a blue luminescent material, such that light of all colors of red, green, and blue, which are the so-called three primary colors, can be emitted by the three sub-pixels. It is preferable that the thickness of the organic layer  6  correspond to the wavelength of the light emitted from the organic layer  6  such that the light emitted from the organic layer  6  is repeatedly reflected between the first electrode  5  and the second electrode  7  and, as a result, the intensity of light radiated in the directions perpendicular to the pixel surface is enhanced. The red, green, and blue light are in decreasing order of the wavelength. Therefore, in the case where the organic layer  6  in the first sub-pixel  31  has the largest thickness among the first to third sub-pixels  31 ,  32 , and  33  as in the example of  FIGS. 3A to 3D , it is preferable that the first sub-pixel  31  comprise a red luminescent material. In this case, it is preferable that the second sub-pixel  32  comprise a green luminescent material. Further, in the case where the organic layer  6  in the third sub-pixel  33  has the smallest thickness among the first to third sub-pixels  31 ,  32 , and  33 , it is preferable that the third sub-pixel  33  comprise a blue luminescent material. Furthermore, in the case where the organic layer  6  in the second sub-pixel  32  has a larger thickness than the organic layer  6  in the first sub-pixel  31  unlike the example of  FIGS. 3A to 3D , the second sub-pixel  32  can comprise a red luminescent material, and the first sub-pixel  31  can comprise a green luminescent material. Moreover, in the case where the pixel  2  comprises four or more sub-pixels, the sub-pixel(s) other than the first to third sub-pixels  31 ,  32 , and  33  can comprise a luminescent material which emits light of an arbitrary color. Examples of organic materials which emit light of each color of red, green, and blue light will be explained later. 
     The cross sections of the first to third sub-pixels  31 ,  32 , and  33  illustrated in  FIGS. 3A and 3B  are more specifically shown in  FIG. 7  than in  FIGS. 3A and 3B . In  FIG. 7 , the cross sections of the first to third sub-pixels  31 ,  32 , and  33  are arrayed for comparison of the thicknesses in the first to third sub-pixels  31 ,  32 , and  33 . As shown in  FIG. 7 , each of the first to third sub-pixels  31 ,  32 , and  33  can have a multilayer structure.  FIG. 7  shows a hole transport layer  6   a , a light-emitting layer  6   b , and an electron transport layer  6   c , on the first electrode  5 , as individual layers constituting the organic layer  6 . In this case, the first electrode  5  is an anode, and the second electrode  7  is a cathode. Although not illustrated, the organic layer  6  can comprise a hole injection layer between the first electrode  5  (anode) and the hole transport layer  6   a , and an electron injection layer between the second electrode  7  (cathode) and the electron transport layer  6   c.    
     In the example shown in  FIG. 7 , the total thicknesses of the organic layer  6  in the first to third sub-pixels  31 ,  32 , and  33  are differentiated from each other by differentiating the thickness of the light-emitting layer  6   b  and the hole transport layer  6   a . For example, in the case where the first sub-pixel  31  comprises a red luminescent material, the thickness of the hole transport layer  6   a  in the first sub-pixel  31  is, for example, 60 nm or more and 200 nm or less, and the light-emitting layer  6   b  is, for example, 30 nm or more and 60 nm or less. In addition, the total thickness of the organic layer  6  in the first sub-pixel  31  is, for example, 120 nm or more and 290 nm or less, and, preferably, 170 nm or more and 250 nm or less. Further, in the case where the second sub-pixel  32  comprises a green luminescent material, the thickness of the hole transport layer  6   a  in the second sub-pixel  32  is, for example, 60 nm or more and 170 nm or less, and the thickness of the light-emitting layer  6   b  is, for example, 20 nm or more and 40 nm or less. In addition, the total thickness of the organic layer  6  in the second sub-pixel  32  is, for example, 110 nm or more and 240 nm or less, and, preferably, 140 nm or more and 220 nm or less. Furthermore, in the case where the third sub-pixel  33  comprises a blue luminescent material, the thickness of the hole transport layer  6   a  in the third sub-pixel  33  is, for example, 60 nm or more and 140 nm or less, and the thickness of the light-emitting layer  6   b  is, for example, 10 nm or more and 30 nm or less. In addition, the total thickness of the organic layer  6  in the third sub-pixel  33  is, for example, 100 nm or more and 200 nm or less, and preferably, 110 nm or more and 190 nm or less. 
     The relationship among the thicknesses of the organic layer  6  in the first to third sub-pixels  31 ,  32 , and  33  as to which is larger or smaller is not construed to be limited to the example shown in  FIG. 7 . For example, the thicknesses of the organic layer  6  in all of the first to third sub-pixels  31 ,  32 , and  33  can be identical. Furthermore, the thickness of the electron transport layer  6   c  and the thicknesses of the hole injection layer and the electron injection layer (which are not shown) can be different among the first to third sub-pixels  31 ,  32 , and  33 . 
     The hole transport layer  6   a  constituting the organic layer  6  is formed by using, for example, amine-type material such as triphenylamine. The light-emitting layer  6   b  is formed by using a material made by doping a host material such as Alq 3  or BAlq with a fluorescent dopant corresponding to the luminescence color, for example, DCM and DCJTB for red, “coumarin 6” for green, and perylene for blue. Alternatively, a phosphorescent dopant such as an iridium complex can be used as the dopant. Alternatively, thermally activated delayed fluorescence material (TADF material) can be used as the host or the dopant. The electron transport layer  6   c  is also formed by using Alq 3  or the like. In the case where the hole injection layer or the electron injection layer (which are not shown) are provided, the hole injection layer is formed by using, for example, amine-type compound or the like, and the electron injection layer is formed by using, for example, LiF or the like. Although LiF generally belongs to inorganic material, the thickness of the electron injection layer is also included in the thickness of the organic layer  6  arranged between the first electrode  5  and the second electrode  7  in the case where the electron injection layer is provided. 
     In the case where the first electrode  5  constitutes the anode, the first electrode  5  is formed of a material selected in consideration of, for example, relationship with the organic layer  6  or the like in a work function. For example, the first electrode  5  is formed with a combination of a metal film such as Ag or APC, and an ITO film. In addition, since the present embodiment is a top-emission type, the second electrode  7  is formed of a transparent material. In the case where the second electrode  7  constitutes a cathode, the second electrode  7  is formed by using, for example, a thin Mg—Ag eutectic film, a thin A 1  film, or the like. Further, the insulation bank  8  is formed by using, for example, a resin such as a polyimide resin or an acrylic resin. Although not shown, a protective film covering the second electrode  7  is formed by using, for example, Si 3 N 4  or the like. The material forming the substrate  4  can be, for example, glass or a polyimide resin. Furthermore, although not shown, in a layer under the first electrode  5  on the substrate  4 , a drive circuit is formed for each of the pixels  2 . The drive circuit is constituted by a plurality of thin-film transistors and controls current supplied to the pixel  2 . 
     Embodiment 2 
     One of the plurality of pixels  2  constituting an organic-EL display apparatus according to Embodiment 2 is shown in  FIG. 8 . The plurality of pixels  2  each have a rectangular shape unlike Embodiment 1 described before. That is, the shape of each pixel  2  constituting the organic-EL display apparatus according to each embodiment is not construed to be limited to the square shape as long as the pixels  2  have a shape which can be arrayed in a matrix form. 
     Even in the present embodiment, each of the plurality of pixels  2  comprises three sub-pixels similar to Embodiment 1. In the example of  FIG. 8 , each of the plurality of pixels  2  comprises a first sub-pixel  31 , a second sub-pixel  32 , and a third sub-pixel  33 . In addition, in the present embodiment, the area of the third sub-pixel  33  is larger than the area of the first sub-pixel  31  and the area of the second sub-pixel  32 . 
     Like Embodiment 1, the third sub-pixel  33  comprises relatively large shadow portions S 5  along the long sides of the third sub-pixel  33 . In addition, like Embodiment 1, the third sub-pixel  33  preferably comprises a blue luminescent material, and can therefore have an organic layer  6  with a small original design thickness (see  FIG. 3A ). Thus, the volume of the organic layer  6  in the third sub-pixel  33  can be smaller than the organic layer  6  in the first and second sub-pixels  31  and  32 , and the luminance of light emitted by the third sub-pixel  33  or the lifetime of the organic layer  6  in the third sub-pixel  33  can decrease in some cases. However, as in the present embodiment, the volume of the organic layer  6  in the third sub-pixel  33  can be increased by making the area of the third sub-pixel  33  larger than the area of the first sub-pixel  31  and the area of the second sub-pixel  32 , so that the luminous characteristics and the lifetime of the third sub-pixel  33  can be improved. In the present embodiment, the structures and the materials, other than the shape of the pixels  2  and the area of the third sub-pixel  33 , are similar to Embodiment 1 described before, and are therefore not described again. 
     Manufacturing Method 
     Next, a method for manufacturing organic-EL display apparatus according to Embodiment 1 is explained. In the method for manufacturing organic-EL display apparatus according to the present embodiment, a well-known technique is used except for a preparation step for vapor-deposition masks and steps of vapor-depositing organic materials on a target substrate for vapor deposition using the vapor-deposition masks. Therefore, only the preparation step for vapor-deposition masks and the steps for vapor deposition are described below. 
     The method for manufacturing organic-EL display apparatus according to the present embodiment comprises preparing a first vapor-deposition mask  11   a  provided with first openings  31   a  having a substantially rectangular shape, a second vapor-deposition mask  11   b  provided with second openings  32   a  having a substantially rectangular shape, and a third vapor-deposition mask  11   c  provided with third openings  33   a  having a substantially rectangular shape (see  FIGS. 9A to 9C ). The method for manufacturing organic-EL display apparatus according to the present embodiment further comprises overlapping the first to third vapor-deposition masks  11   a ,  11   b , and  11   c  on a surface of a substrate (target substrate for vapor deposition)  4  in sequence, positioning above a linear evaporation source  16  the first to third vapor-deposition masks  11   a ,  11   b , and  11   c  each overlapped on the substrate  4 , and vapor-depositing organic materials  61  from the linear evaporation source  16  on the surface of the target substrate for vapor deposition  4 , in sequence (see  FIGS. 11A to 11C ). In the vapor deposition using the first vapor-deposition mask  11   a  or the second vapor-deposition mask  11   b , the first vapor-deposition mask  11   a  is arranged such that the long sides of the first openings  31   a  and the longitudinal direction of the linear evaporation source  16  are substantially parallel, and the second vapor-deposition mask  11   b  is arranged such that the long sides of the second openings  32   a  and the longitudinal direction of the linear evaporation source  16  are substantially parallel. In addition, in the vapor deposition using the third vapor-deposition mask  11   c , the third vapor-deposition mask  11   c  is arranged such that the short sides of the third openings  33   a  and the longitudinal direction of the linear evaporation source  16  are substantially parallel. Hereinbelow, the steps of preparing the first to third vapor-deposition masks  11   a ,  11   b , and  11   c  and the steps of vapor-depositing the organic materials  61  are further explained with reference to  FIGS. 9A to 11C . 
     An example of a step of preparing the first vapor-deposition mask  11   a  is shown in  FIG. 9A . As shown in  FIG. 9A , the first openings  31   a  are formed in a resin film  111  of a polyimide resin or the like having a thickness of substantially 3 to 10 μm. The resin film  111  is formed, for example, by applying a liquid polyimide resin to a dummy substrate  17  by slit coating or spin coating, and baking the resin at the temperature of substantially 450° C. The resin film  111  can be formed using a material other than the polyimide resin, such as PEN, PET, COP, COC, or PC. In addition, the baking of the liquid polyimide resin can be performed by stepwisely varying the baking temperature. Although not shown in  FIG. 9A , a metal support layer  112  (see  FIG. 4 ) can be provided on a surface, opposite to the dummy substrate  17 , of the resin film  111  by vapor deposition, sputtering, lamination of a metal foil, or the like. In that case, openings  112   a  (see  FIG. 4 ) are formed in the metal support layer  112  by etching or the like. 
     The first openings  31   a  are formed by irradiating with laser light the resin film  111  attached to the dummy substrate  17 . The resin film  111  is irradiated with the laser light, for example, through a mask  18  for laser light and an optical lens  19  as illustrated in  FIG. 9A . The mask  18  for laser light comprises patterns  181  for the first openings. The laser light passing through the patterns  181  for the first openings is collected by the optical lens  19 , and reaches the resin film  111 . Portions of the resin film  111  that are irradiated with the laser light are burned off. As a result, the first openings  31   a  are formed in the resin film  111 . A device for emitting the laser light is moved by a stepper, so that a given number of first openings  31   a  are formed in the resin film  111 . Although the optical lens  19  is not necessarily required, the optical lens  19  is effective in enhancing the irradiation energy density at the processed surface. 
     As needed, a frame  113  (see  FIG. 4 ) is adhered, by using an epoxy adhesive or the like, to the peripheral edge of the resin film  111  in which the first openings  31   a  are formed. Thereafter, the resin film  111  is peeled off from the dummy substrate  17  to complete the preparation of the first vapor-deposition mask  11   a.    
     The second vapor-deposition mask  11   b  and the third vapor-deposition mask  11   c  respectively shown in  FIGS. 9B and 9C  are prepared in manners similar to the manner in which the first vapor-deposition mask  11   a  is prepared. The first openings  31   a  in the first vapor-deposition mask  11   a  and the second openings  32   a  in the second vapor-deposition mask  11   b  are formed such that the long-side directions of the respective openings can be parallel to the longitudinal direction of the linear evaporation source  16  when organic materials  61  (see  FIGS. 11A to 11C ) are vapor-deposited. In addition, the third openings  33   a  in the third vapor-deposition mask  11   c  are formed such that the short-side directions of the respective third openings can be parallel to the longitudinal direction of the linear evaporation source  16  when an organic material  61  is vapor-deposited. 
     For example, it is supposed that all of the first to third vapor-deposition masks  11   a  to  11   c  have a rectangular planar shape, and each vapor-deposition mask is set in a vapor-deposition apparatus (not shown) such that the long-side direction of each vapor-deposition mask is orthogonal to the longitudinal direction of the linear evaporation source  16 . In such a case, the first openings  31   a  and the second openings  32   a  are formed such that the longitudinal direction of each opening is perpendicular to the longitudinal direction of the corresponding one of the first vapor-deposition mask  11   a  and the second vapor-deposition mask  11   b . In addition, the third openings  33   a  are formed such that the longitudinal directions of the third openings  33   a  are parallel to the longitudinal direction of the third vapor-deposition mask  11   c . On the other hand, in the case where each vapor-deposition mask is set in the vapor-deposition apparatus such that the long-side direction of each vapor-deposition mask is parallel to the longitudinal direction of the linear evaporation source  16 , the third openings  33   a  are formed such that the longitudinal directions of the third openings  33   a  are orthogonal to the longitudinal direction of the third vapor-deposition mask  11   c . In addition, the first openings  31   a  and the second openings  32   a  are formed such that the longitudinal direction of each opening is parallel to the longitudinal direction of the corresponding one of the first vapor-deposition mask  11   a  and the second vapor-deposition mask  11   b.    
     Alternatively, the first openings  31   a  and the second openings  32   a  can be formed such that the first openings  31   a  and the second openings  32   a  are arrayed in parallel and the long sides of the first openings  31   a  and the second openings  32   a  are substantially parallel when the first to third vapor-deposition masks  11   a  to  11   c  are overlapped each other in such a way as to align the longitudinal directions of each vapor-deposition mask or in such a way as to align the positions of the fiducial marks  114  on each vapor-deposition mask. On the other hand, the third openings  33   a  can be formed such that the long sides of the third openings  33   a  are substantially parallel to the short sides of the first openings  31   a  and the short sides of the second openings  32   a  when the first to third vapor-deposition masks  11   a  to  11   c  are overlapped each other in such a way as to align the longitudinal directions of each vapor-deposition mask or in such a way as to align the positions of the fiducial marks  114  on each vapor-deposition mask. 
     The condition for the laser-light irradiation is appropriately selected according to the material and thickness of the resin film  111  to be processed and the dimensions and shapes of the first to third openings  31   a ,  32   a , and  33   a  to be formed. Generally, the laser-light irradiation is performed under the conditions that the pulse frequency of the laser light is 1 Hz or more and 60 Hz or less, the pulse width is 1 nanosecond or more and 15 nanoseconds or less, and the energy density per one pulse of the laser light at the surface to be irradiated is 0.01 J/cm 2  or more and 1 J/cm 2  or less. For example, YAG laser, excimer laser, He—Cd laser, or other laser-light sources can be used as the laser-light source. 
     It is preferable that the dimensions of the first to third openings  31   a ,  32   a , and  33   a  decrease, from a surface of the resin film  111  facing the linear evaporation source  16  in the steps of vapor deposition (see  FIGS. 11A to 11C ), toward the opposite surface of the resin film  111  facing the target substrate for vapor deposition  4 . That is, it is preferable that the first to third openings  31   a ,  32   a , and  33   a  be formed in tapered shapes. The first to third openings  31   a ,  32   a , and  33   a  having such tapered shapes are formed, for example, by forming in the laser mask  18  the respective patterns for the openings (e.g., the patterns  181  for the first openings) in such a manner that the transmittance of the laser light decreases in the vicinity of the peripheral edges of the patterns are approached. 
     The first openings  31   a , the second openings  32   a , and the third openings  33   a  are openings through which the organic materials forming the organic layer  6  in the first sub-pixel  31 , the second sub-pixel  32 , and the third sub-pixel  33  (see  FIGS. 3A to 3D ) respectively pass during vapor deposition of the organic materials. Although not shown, a vapor-deposition mask which is provided with all of the first openings  31   a , the second openings  32   a , and the third openings  33   a  can be prepared, in addition to the vapor-deposition masks in each of which the first openings  31   a  only, the second openings  32   a  only, or the third openings  33   a  only are provided. That is, a vapor-deposition mask for use in vapor deposition of an organic material used in common for the organic layer  6  in each of the first to third sub-pixels  31 ,  32 , and  33  (e.g., an organic material used for the electron transport layer) can be prepared. In this case, the first openings  31   a  and the second openings  32   a  are formed to be arrayed in parallel such that the long sides of the first openings  31   a  and the long sides of the second openings  32   a  are substantially parallel, and the third openings  33   a  are formed such that the long sides of the third openings  33   a  are substantially parallel to the short sides of the first openings  31   a  and the short sides of the second openings  32   a . However, for the electron transport layer and the like, the vapor deposition can also be performed for each sub-pixel using the first to third vapor-deposition masks  11   a  to  11   c  in sequence. In addition, in manufacture of the organic-EL display apparatus, a plurality of organic-EL display apparatuses can be manufactured on a single substrate  4  (see  FIG. 10 ), where the plurality of organic-EL display apparatuses are arrayed in the longitudinal and lateral directions on the substrate  4 . In this case, in each of the first to third vapor-deposition masks  11   a  to  11   c , a plurality of sets of the first openings  31   a , the second openings  32   a , or the third openings  33   a , in the number of the pixels in each organic-EL display apparatus, are formed along the longitudinal and lateral directions, in correspondence with the array of the plurality of organic-EL display apparatuses to be manufactured using the single substrate for vapor deposition  4 . 
     As shown in  FIG. 10 , the target substrate for vapor deposition  4  is positioned above a surface of the first vapor-deposition mask  11   a , and the first vapor-deposition mask  11   a  is overlapped with a surface of the target substrate for vapor deposition  4 . Although not shown, a plurality of thin-film transistors constituting drive circuits for organic-EL display elements are formed in the target substrate for vapor deposition  4 , and the first electrodes  5  (see  FIG. 3A ) are formed on a flattening layer provided over the drive circuits. In addition, the areas on which the organic layer  6  (see  FIG. 3A ) in each of the first to third sub-pixels  31 ,  32 , and  33  is to be formed are partitioned by the insulation bank  8  (see  FIG. 3A ). As described before, a plurality of organic-EL display apparatuses, arrayed in parallel in the longitudinal and lateral directions, can be manufactured by using a single target substrate for vapor deposition  4 . In this case, a plurality of sets of multiple areas for the first to third sub-pixels  31 ,  32 , and  33  to be provided in each organic-EL display apparatus are partitioned, in correspondence with the array of the plurality of organic-EL display apparatuses, on the single target substrate for vapor deposition  4 . 
     The positions of the first openings  31   a  in the first vapor-deposition mask  11   a  and the first sub-pixels  31  on the target substrate for vapor deposition  4  are aligned. This position alignment can be performed by image recognition of the first sub-pixels  31  and the first openings  31   a , or by image recognition of the fiducial marks  114  that are respectively arranged on the target substrate for vapor deposition  4  and the first vapor-deposition mask  11   a.    
     Then, as shown in  FIG. 11A , the first vapor-deposition mask  11   a  is positioned above the linear evaporation source  16  such that the long-side directions of the first openings  31   a  and the longitudinal direction of the linear evaporation source  16  are substantially parallel with each other. The linear evaporation source  16  is provided with the plurality of melting pots  16   a  arrayed along the longitudinal direction of the linear evaporation source  16 . A vaporized or sublimed organic material  61  is scattered from each of the plurality of melting pots  16   a  toward the target substrate for vapor deposition  4 , and is vapor-deposited on a surface of the target substrate for vapor deposition  4 . During the vapor-deposition process, the linear evaporation source  16  is moved relative to the target substrate for vapor deposition  4  in a direction orthogonal to the longitudinal direction of the linear evaporation source  16  (the direction indicated with an arrow M in  FIG. 11A ). When the linear evaporation source  16  moves by a moving distance corresponding to the length of the target substrate for vapor deposition  4  in the moving direction of the linear evaporation source  16 , the vapor deposition of the organic material  61  over the entire surface of the target substrate for vapor deposition  4  (excluding the areas masked by the first vapor-deposition mask  11   a ) is completed. In other words, the organic material  61  is vapor-deposited on the first sub-pixels  31  on the entire surface of the target substrate for vapor deposition  4 . 
     Vapor deposition of an organic material  61  using the second vapor-deposition mask  11   b  (see  FIG. 9B ) is also performed in a similar manner to the vapor deposition using the first vapor-deposition mask  11   a . Specifically, the second vapor-deposition mask  11   b  is overlapped with the surface of the target substrate for vapor deposition  4 , and the positions of the second openings  32   a  and the second sub-pixels  32  are aligned, in a similar manner to the example shown in  FIG. 10  mentioned before. Then, the second vapor-deposition mask  11   b  is positioned above the linear evaporation source  16  such that the long-side directions of the second openings  32   a  and the longitudinal direction of the linear evaporation source  16  are substantially parallel with each other as shown in  FIG. 11B , and the organic material  61  from the linear evaporation source  16  is vapor-deposited on the surface of the target substrate for vapor deposition  4 . 
     Further, vapor deposition of an organic material  61  using the third vapor-deposition mask  11   c  (see  FIG. 9C ) is also performed in a similar manner to the vapor deposition using the first vapor-deposition mask  11   a . Specifically, the third vapor-deposition mask  11   c  is overlapped with the surface of the target substrate for vapor deposition  4 , and the positions of the third openings  33   a  and the third sub-pixel  33  are aligned, in a similar manner to the example shown in  FIG. 10  mentioned before. Then, the third vapor-deposition mask  11   c  is positioned above the linear evaporation source  16  such that the short-side directions of the third openings  33   a  and the longitudinal direction of the linear evaporation source  16  are substantially parallel with each other as illustrated in  FIG. 11C , and the organic material  61  from the linear evaporation source  16  is vapor-deposited on the surface of the target substrate for vapor deposition  4 . 
     During the vapor deposition illustrated in  FIGS. 11A to 11C , as described before, relatively large shadow portions occur along the sides, perpendicular to the longitudinal direction of the linear evaporation source  16 , of each of the first to third sub-pixels  31 ,  32 , and  33 . On the other hand, only relatively small shadow portions occur along the sides, parallel to the longitudinal direction of the linear evaporation source  16 , of each of the first to third sub-pixels  31 ,  32 , and  33 . That is, only relatively small shadow portions S 1  and S 3  (see  FIG. 2 ) occur along the long sides of the first and second sub-pixels  31  and  32 , and relatively large shadow portions S 5  (see  FIG. 2 ) occur along the long sides of the third sub-pixel  33 . 
     The vapor depositions using the first to third vapor-deposition masks  11   a  to  11   c  can be performed in an arbitrary order. In addition, a vapor deposition using a vapor-deposition mask other than the first to third vapor-deposition masks  11   a  to  11   c  is appropriately performed as needed. As a result, the organic layer  6  (see  FIG. 3A ) consisting of the organic materials  61  each vapor-deposited in the first to third sub-pixels  31 ,  32 , and  33  are formed. 
     Thereafter, the second electrode  7  (see  FIG. 3A ) is formed over the entire surface by a method such as vacuum deposition or sputtering, and a protective layer (not shown) is formed over the second electrode  7 . Then, the target substrate for vapor deposition  4  is divided, and, preferably, the entirety of each of pieces respectively comprising the divided portions of the substrate is sealed with a sealing layer (not shown) of glass, a resin film, or the like. Further, a source driver, a gate driver, and the like for supplying drive signals and electric power to the aforementioned drive circuits are provided. The organic-EL display apparatus is completed, for example, through the above steps of operations. 
     SUMMARY 
     An organic-EL display apparatus according to a first aspect of the present invention comprises: a substrate comprising a first electrode; an organic layer formed of organic materials so as to form a plurality of pixels arrayed in a matrix form, the organic material being vapor-deposited on the first electrode; and a second electrode formed on the organic layer, wherein each of the plurality of pixels comprises at least three sub-pixels having substantially rectangular shapes; a first sub-pixel and a second sub-pixel among the at least three sub-pixels are arranged in parallel with each other such that a long side of the first sub-pixel and a long side of the second sub-pixel are substantially parallel with each other; a third sub-pixel among the at least three sub-pixels is formed such that a long side of the third sub-pixel is substantially parallel with a short side of the first sub-pixel and a short side of the second sub-pixel; in the first sub-pixel and the second sub-pixel, a variation in a thickness of the organic layer through a long-side direction is larger than a variation in the thickness of the organic layer through a short-side direction; and in the third sub-pixel, a variation in a thickness of the organic layer through a short-side direction is larger than a variation in the thickness of the organic layer through a long-side direction. 
     According to the configuration of the first aspect of the present invention, it is possible to facilitate manufacture of the sub-pixels and to reduce influence, on the display quality, of a variation in the thickness of the organic layer. 
     In the organic-EL display apparatus according to a second aspect of the present invention, in the above-mentioned first aspect 1, the area of the third sub-pixel can be larger than the area of the first sub-pixel and the area of the second sub-pixel. 
     According to the configuration of the second aspect of the present invention, it is possible to improve the luminous characteristics and the lifetime of the third sub-pixel. 
     In the organic-EL display apparatus according to a third aspect of the present invention, in the above-mentioned first or second aspect, the at least three sub-pixels can comprise a sub-pixel comprising a red luminescent material, a sub-pixel comprising a green luminescent material, and a sub-pixel comprising a blue luminescent material, and the first sub-pixel or the second sub-pixel can comprise the red luminescent material. 
     According to the configuration of the third aspect of the present invention, it is possible to reduce influence of the shadow portions in the sub-pixels emitting red light even in the case where the thickness of the organic layer is set large in order to obtain an optical resonance effect. 
     In the organic-EL display apparatus according to a fourth aspect of the present invention, in the above-mentioned third aspect, the third sub-pixel can comprise the blue luminescent material. 
     According to the configuration of the fourth aspect of the present invention, it is possible to reduce influence of the shadow portions in the third sub-pixel while benefiting from the optical resonance effect. 
     In the organic-EL display apparatus according to a fifth aspect of the present invention, in the above-mentioned first or second aspect, the thickness of the organic layer in the first sub-pixel or the second sub-pixel can be largest among the at least three sub-pixels comprised in each of the plurality of pixels. 
     According to the configuration of the fifth aspect of the present invention, it is possible to reduce influence of the shadow portions in the sub-pixels having an organic layer with a large thickness. 
     In the organic-EL display apparatus according to a sixth aspect of the present invention, in the above-mentioned first or second aspect, the thickness of the organic layer in the third sub-pixel can be smallest among the at least three sub-pixels comprised in each of the plurality of pixels. 
     According to the configuration of the sixth aspect of the present invention, it is possible to reduce influence of the shadow portions in the third sub-pixel. 
     In the organic-EL display apparatus according to a seventh aspect of the present invention, in any one of the above-mentioned aspects 1 to 6, an area ratio in the first sub-pixel and an area ratio in the second sub-pixel can be larger than an area ratio in the third sub-pixel, each of the area ratios in the first to third sub pixels being defined as a ratio of an area of a portion to the entire area of each of the first to third sub pixels, the portion having thicknesses equal to or larger than 95% of the maximum thickness of the organic layer in each of the first to third sub-pixels. 
     According to the configuration of the seventh aspect of the present invention, it is possible to obtain pixels having excellent luminous characteristics. 
     A method for manufacturing organic-EL display apparatus according to one aspect of the present invention comprises: preparing a first vapor-deposition mask provided with a first opening having a substantially rectangular shape, a second vapor-deposition mask provided with a second opening having a substantially rectangular shape, and a third vapor-deposition mask provided with a third opening having a substantially rectangular shape; overlapping the first vapor-deposition mask with a surface of a target substrate for vapor deposition, positioning the first vapor-deposition mask above a linear evaporation source such that a long side of the first opening and a longitudinal direction of the linear evaporation source are substantially parallel with each other, and vapor-depositing, on the surface, an organic material from the linear evaporation source; overlapping the second vapor-deposition mask with the surface of the target substrate for vapor deposition, positioning the second vapor-deposition mask above the linear evaporation source such that a long side of the second opening and the longitudinal direction of the linear evaporation source are substantially parallel with each other, and vapor-depositing, on the surface, an organic material from the linear evaporation source; and overlapping the third vapor-deposition mask with the surface of the target substrate for vapor deposition, positioning the third vapor-deposition mask above the linear evaporation source such that a short side of the third opening and the longitudinal direction of the linear evaporation source are substantially parallel with each other, and vapor-depositing, on the surface, an organic material from the linear evaporation source. 
     According to the method for manufacturing organic-EL display apparatus of the one aspect of the present invention, it is possible to easily manufacture an organic-EL display apparatus in which the display quality and the like is less affected by a variation in the thickness of the organic layer. 
     DESCRIPTION OF REFERENCE NUMERAL 
     
         
           1  Organic-EL display apparatus 
           2  Pixel 
           31  First sub-pixel 
           31   a  First opening 
           32  Second sub-pixel 
           32   a  Second opening 
           33  Third sub-pixel 
           33   a  Third Opening 
           4  Substrate (Target substrate for vapor deposition) 
           5  First electrode 
           6  Organic layer 
           61  Organic material 
           7  Second electrode 
           11  Vapor-deposition mask 
           11   a  First vapor-deposition mask 
           11   b  Second vapor-deposition mask 
           11   c  Third vapor-deposition mask 
           16  Linear evaporation source 
         Δt 1  Variation in thickness of first sub-pixel in short-side direction 
         Δt 2  Variation in thickness of first sub-pixel in long-side direction 
         Δt 3  Variation in thickness of second sub-pixel in short-side direction 
         Δt 4  Variation in thickness of second sub-pixel in long-side direction 
         Δt 5  Variation in thickness of third sub-pixel in short-side direction 
         Δt 6  Variation in thickness of third sub-pixel in long-side direction 
         T 3  Thickness of organic layer of third sub-pixel 
         TM Maximum thickness of organic layer 
         TN 95% of maximum thickness of organic layer