Patent Publication Number: US-2022216282-A1

Title: Organic light emitting display device and method of manufacturing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 16/727,798 filed on Dec. 26, 2019, which claims priority under 35 USC § 119 to Korean Patent Application No. 10-2019-0006110 filed on Jan. 17, 2019 in the Korean Intellectual Property Office (KIPO); the prior applications are incorporated by reference. 
    
    
     BACKGROUND 
     1. Field 
     The technical field relates to an organic light emitting display device and a method of manufacturing an organic light emitting display device. 
     2. Description of the Related Art 
     Organic light emitting display (OLED) devices are self-luminous display devices that use organic light emitting diodes to emit light to display images. An OLED device does not require a separate light source; thus, the thickness and weight of the OLED device can be minimized. 
     An OLED device may include a plurality of pixels. If electric charges undesirably flow from one pixel (of a certain color) into another pixel (of another color) during operation of the OLED device, the quality of images displayed by the OLED device may be unsatisfactory. 
     SUMMARY 
     Embodiments may be related to an organic light emitting display (OLED) device in which lateral leakage current between pixels may be minimized. 
     Embodiments may be related to a method of manufacturing the OLED device. 
     An OLED device according to embodiments may include the following elements: a substrate including a first pixel area, a second pixel area, a third pixel area, and a peripheral area surrounding the first to third pixel areas; a first pixel electrode, a second pixel electrode, and a third pixel electrode disposed on the substrate, the first pixel electrode, the second pixel electrode, and the third pixel electrode respectively overlapping the first pixel area, the second pixel area, and the third pixel area; a pixel defining layer disposed on the substrate, the pixel defining layer overlapping the peripheral area and having an upper surface at which an uneven structure is formed between the first pixel area and the second pixel area; a hole injection layer disposed on the first to third pixel electrodes and the pixel defining layer, the hole injection layer being formed along a profile of the upper surface of the pixel defining layer; a first emission layer, a second emission layer, and a third emission layer disposed on the hole injection layer, the first emission layer, the second emission layer, and the third emission layer respectively overlapping the first pixel area, the second pixel area, and the third pixel area; and a common electrode disposed on the first to third emission layers and the hole injection layer. 
     In an embodiment, the uneven structure may be formed only between the first pixel area and the second pixel area. 
     In an embodiment, the upper surface of the pixel defining layer between the first pixel area and the third pixel area may be flat. 
     In an embodiment, a distance between the first pixel area and the second pixel area may be less than a distance between the first pixel area and the third pixel area. 
     In an embodiment, the uneven structure may be further formed at the upper surface of the pixel defining layer between the first pixel area and the third pixel area. 
     In an embodiment, a portion of the upper surface of the pixel defining layer at which the uneven structure is not formed may be flat. 
     In an embodiment, the second pixel area may be located in a first direction from the first pixel area, and the uneven structure may include concave portions and convex portions alternatively arranged along the first direction. 
     In an embodiment, each of the concave portions may extend in a second direction perpendicular to the first direction and parallel to the substrate. 
     In an embodiment, lengths of the concave portions may be uniform. 
     In an embodiment, lengths of the concave portions may increase as being away from the first pixel area or the second pixel area. 
     In an embodiment, the OLED device may further include a spacer disposed between the pixel defining layer and the hole injection layer, the spacer overlapping the peripheral area and not overlapping the uneven structure. 
     In an embodiment, the first emission layer, the second emission layer, and the third emission layer may respectively emit a red light, a green light, and a blue light. 
     In an embodiment, the OLED device may further include a hole transport layer disposed between the hole injection layer and the first to third emission layers, the hole transport layer being formed along a profile of the upper surface of the pixel defining layer. 
     In an embodiment, the OLED device may further include an electron transport layer disposed between the first to third emission layers and the common electrode, the electron transport layer being formed along a profile of the upper surface of the pixel defining layer. 
     An OLED device according to embodiments may include the following elements: a plurality of pixels each including a pixel electrode, a hole injection layer, an emission layer, and a common electrode which are sequentially stacked; and a pixel defining layer dividing the plurality of pixels, the pixel defining layer having an upper surface at which an uneven structure is formed between the plurality of pixels. The hole injection layer may be formed commonly over the plurality of pixels and along a profile of the upper surface of the pixel defining layer. 
     In an embodiment, a portion of the upper surface of the pixel defining layer at which the uneven structure is not formed may be flat. 
     In an embodiment, the uneven structure may include concave portions and convex portions alternatively arranged between the plurality of pixels. 
     A method of manufacturing an OLED device according to embodiments may include the following steps: forming a first pixel electrode, a second pixel electrode, and a third pixel electrode on the substrate, the first pixel electrode, the second pixel electrode, and the third pixel electrode respectively overlapping the first pixel area, the second pixel area, and the third pixel area; forming a pixel defining layer on the substrate, the pixel defining layer overlapping a peripheral area surrounding the first to third pixel areas and having an upper surface at which an uneven structure is formed between the first pixel area and the second pixel area; forming a hole injection layer on the first to third pixel electrodes and the pixel defining layer, the hole injection layer being formed along a profile of the upper surface of the pixel defining layer; forming a first emission layer, a second emission layer, and a third emission layer on the hole injection layer, the first emission layer, the second emission layer, and the third emission layer respectively overlapping the first pixel area, the second pixel area, and the third pixel area; and forming a common electrode on the first to third emission layers and the hole injection layer. 
     In an embodiment, the second pixel area may be located in a first direction from the first pixel area, and the uneven structure may include concave portions and convex portions alternatively arranged along the first direction. 
     In an embodiment, forming the pixel defining layer may include forming a preliminary pixel defining layer on the substrate on which the first to third pixel electrodes are formed, providing a halftone mask over the preliminary pixel defining layer, and exposing and developing the preliminary pixel defining layer using the halftone mask. 
     In an embodiment, the halftone mask may include light transmitting portions, light shielding portions, and semi-light transmitting portions. The light transmitting portions may correspond to opening portions of the pixel defining layer respectively exposing the first to third pixel electrodes, the light shielding portions may correspond to the convex portions of the uneven structure, and the semi-light transmitting portions may correspond to the concave portions of the uneven structure. 
     An embodiment may be related to an organic light emitting display (OLED) device. The OLED device may include the following elements: a substrate; a first pixel electrode, a second pixel electrode, and a third pixel electrode each overlapping the substrate; a pixel defining layer including a first opening, a second opening, and a third opening respectively partially exposing the first pixel electrode, the second pixel electrode, and the third pixel electrode, wherein the pixel defining layer may include a first uneven surface and a first flat face, wherein the first uneven surface may be opposite the first flat face and may be positioned between the first opening and the second opening, and wherein the first flat face may be positioned between the first pixel electrode and the second pixel electrode and may be positioned between the first uneven surface and the substrate; a first emission layer, a second emission layer, and a third emission layer respectively corresponding to the first opening, the second opening, and the third opening; and a common electrode overlapping each of the first emission layer, the second emission layer, and the third emission layer. 
     The first uneven surface may be only positioned between the first emission layer and the second emission layer. 
     The first uneven surface may be positioned between two opposite parallel faces of the first emission layer. 
     A surface of the pixel defining layer may be positioned not farther from the common electrode than any other surfaces of the pixel defining layer, may be positioned between the first opening and the third opening, and may be flat. 
     A minimum distance between the first emission layer and the second emission layer may be less than a minimum distance between the first emission layer and the third emission layer. 
     The pixel defining layer may include a second uneven surface and a second flat face. The second uneven surface may be positioned between the first opening and the third opening and may be opposite the second flat face. The second flat face may be positioned between the first pixel electrode and the third pixel electrode and may be positioned between the second uneven surface and the substrate. 
     A surface of the pixel defining layer may be positioned not farther from the common electrode than any other surfaces of the pixel defining layer, may be positioned between the second opening and the third opening, and may be flat. 
     The first uneven surface may include cavities and protrusions alternatively arranged between the first opening and the second opening. 
     A lengthwise direction of each of the cavities may be parallel to an edge of the first opening and may be parallel to the substrate. 
     Lengths of the cavities may be equal. 
     The cavities include a first cavity and a second cavity. The first cavity may be positioned closer to the first opening than the second cavity and may be shorter than the second cavity. 
     The OLED device may include the following elements: a hole injection layer directly contacting each of the first pixel electrode, the second pixel electrode, the third pixel electrode, and the pixel defining layer; and a spacer disposed between the pixel defining layer and the hole injection layer and directly contacting a second flat face of the pixel defining layer. The hole injection layer may include cavities. The cavities may be positioned between the first opening and the second opening. The second flat face of the pixel defining layer may extend from an edge of the second opening to an edge of the third opening and may be spaced from the first uneven surface. 
     The first emission layer, the second emission layer, and the third emission layer may be respectively configured to emit a red light, a green light, and a blue light. The first emission layer and the second emission layer may immediately neighbor each other with no intervening emission layer between the first emission layer and the second emission layer. 
     The OLED device may include the following elements: a hole injection layer directly contacting each of the first pixel electrode, the second pixel electrode, the third pixel electrode, and the pixel defining layer; and a hole transport layer disposed between the hole injection layer and each of the first emission layer, the second emission layer, and the third emission layer. The hole transport layer may overlap the pixel defining layer and may include cavities. The cavities may be positioned between the first opening and the second opening. 
     The OLED device may include an electron transport layer disposed between the common electrode and each of the first emission layer, the second emission layer, and the third emission layer, the electron transport layer overlapping the pixel defining layer. 
     An embodiment may be related to an OLED device. The OLED device may include the following elements: a common electrode; a first pixel electrode overlapping the common electrode; a first emission layer positioned between the first pixel electrode and the common electrode; a second pixel electrode; a second emission layer positioned between the second pixel electrode and the common electrode; and a pixel defining layer including a first opening, a second opening, a first flat face, and an uneven surface structure, wherein the first opening partially exposes the first pixel electrode, wherein the second opening partially exposes the second pixel electrode, wherein the first flat face may be opposite the uneven surface, may be positioned between the first pixel electrode and the second pixel electrode, and may extend from the first pixel electrode to the second pixel electrode, and wherein the uneven surface may be positioned between the first opening and the second opening. 
     The OLED device may include the following elements: a third pixel electrode; and a third emission layer positioned between the third pixel electrode and the common electrode. The pixel defining layer may include a third opening, a second flat face, and a third flat face. The third opening may partially expose the third pixel electrode. The second flat face may be opposite the third flat face, may be positioned between the second pixel electrode and the third pixel electrode, and may extend from the second pixel electrode to the third pixel electrode. The third flat face may be positioned between the second opening and the third opening and may extend from the second opening to the third opening. 
     The uneven surface may include cavities and protrusions alternatively arranged between the first opening and the second opening. 
     An embodiment may be related to a method of manufacturing an OLED device. The method may include the following steps: forming a first pixel electrode, a second pixel electrode, and a third pixel electrode on a substrate; forming a pixel defining layer on the substrate, wherein the pixel defining layer may include a first opening, a second opening, and a third opening respectively partially exposing the first pixel electrode, the second pixel electrode, and the third pixel electrode, wherein the pixel defining layer may include an uneven surface and a first flat face, wherein the uneven surface may be opposite the first flat face and may be positioned between the first opening and the second opening, and wherein the first flat face may be positioned between the first pixel electrode and the second pixel electrode and may be positioned between the uneven surface and the substrate; forming a first emission layer, a second emission layer, and a third emission layer that respectively correspond to the first opening, the second opening, and the third opening; and forming a common electrode that overlaps each of the first emission layer, the second emission layer, and the third emission layer. 
     The uneven surface may include cavities and protrusions alternatively arranged between the first opening and the second opening. 
     Forming the pixel defining layer may include the following steps: forming a material layer on the substrate, the first pixel electrode, the second pixel electrode, and the third pixel electrode; providing a halftone mask over the material layer; and exposing and developing the material layer using the halftone mask. 
     The halftone mask may include light transmitting portions, light shielding portions, and semi-light transmitting portions. The light transmitting portions may correspond to the first opening, the second opening, and the third opening. The light shielding portions may correspond to the protrusions of the uneven surface structure. The semi-light transmitting portions may correspond to the cavities of the uneven surface structure. 
     An OLED device according to an embodiment may include a pixel defining layer having an upper surface with an uneven structure between pixels, and a hole injection layer may be formed on the pixel defining layer. Accordingly, an electrical path of the hole injection layer between the pixels may lengthen, and lateral leakage current between the pixels through the hole injection layer may decrease. 
     In a method of manufacturing the OLED device according to an embodiments, the pixel defining layer may be formed using a halftone mask so that the pixel defining layer having opening portions and an uneven upper surface may be formed by single photolithography process. Therefore, manufacturing time and/or cost of the OLED device may be minimized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view illustrating an organic light emitting display (OLED) device according to an embodiment. 
         FIG. 2  is a cross-sectional view taken along a line II-II′ in  FIG. 1  according to an embodiment. 
         FIG. 3  is a cross-sectional view illustrating a pixel defining layer and a hole injection layer in  FIG. 2  according to an embodiment. 
         FIG. 4  is a plan view illustrating an OLED device according to an embodiment. 
         FIG. 5  is a plan view illustrating an OLED device according to an embodiment. 
         FIG. 6  is a cross-sectional view taken along a line VI-VI′ in  FIG. 5  according to an embodiment. 
         FIGS. 7, 8, 9, 10, and 11  are cross-sectional views illustrating structures formed in a method of manufacturing an OLED device according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments are explained with reference to the accompanying drawings. 
     Although the terms “first,” “second,” etc. may be used to describe various elements, these elements, should not be limited by these terms. These terms may be used to distinguish one element from another element. A first element may be termed a second element without departing from teachings of one or more embodiments. The description of an element as a “first” element may not require or imply the presence of a second element or other elements. The terms “first,” “second,” etc. may be used to differentiate different categories or sets of elements. For conciseness, the terms “first,” “second,” etc. may represent “first-type (or first-set),” “second-type (or second-set),” etc., respectively. 
       FIG. 1  is a plan view illustrating an OLED according to an embodiment.  FIG. 2  is a cross-sectional view taken along a line II-II′ in  FIG. 1  according to an embodiment.  FIG. 3  is a cross-sectional view illustrating a pixel defining layer and a hole injection layer in  FIG. 2  according to an embodiment. 
     Referring to  FIGS. 1, 2, and 3 , the OLED device may include a substrate  100 , a plurality of pixel electrodes  201 ,  202 , and  203 , a pixel defining layer  300 ; a spacer  400 , a hole injection layer  510 , a hole transport layer  520 , a plurality of emission layers  531 ,  532 , and  533 ; an electron transport layer  540 , and a common electrode  600 . The OLED device may include a plurality of pixels PX 1 , PX 2 , and PX 3  defined by the plurality of pixel electrodes  201 ,  202 , and  203 , the hole injection layer  510 , the hole transport layer  520 , the plurality of emission layers  531 ,  532 , and  533 , the electron transport layer  540 , and the common electrode  600 . Boundaries of the pixels and/or boundaries of pixel areas associated with the pixels may correspond to edges of openings of the pixel defining layer  300 . 
     The substrate  100  may be substantially formed of transparent glass containing SiO x . The substrate  100  may be formed of a plastic material. Although not shown in the figures, the substrate  100  may include at least one thin film transistor and/or a capacitor for driving each pixel; a circuit for driving the pixel may use the thin film transistor, the capacitor, and the like. 
     The substrate  100  may include a plurality of pixel areas PXA 1 , PXA 2 , and PXA 3  and a peripheral area PPA. The pixel areas PXA 1 , PXA 2 , and PXA 3  may include a plurality of first pixel areas PXA 1 , a plurality of second pixel areas PXA 2 , and a plurality of third pixel areas PXA 3 . A first pixel area PXA 1 , a second pixel area PXA 2 , and a third pixel area PXA 3  may be spaced apart from each other. For example, when the first pixel area PXA 1  is spaced from the second pixel area PXA 2  in a first direction DR 1 , the third pixel area PXA 3  may be spaced from the second pixel area PXA 2  in a second direction DR 2  perpendicular to the first direction DR 1 . For example, when the first pixel area PXA 1  is spaced from the second pixel area PXA 2  in the second direction DR 2 , the third pixel area PXA 3  may be spaced from the second pixel area PXA 2  in the first direction DR 1 . Further, the third pixel area PXA 3  may be spaced from the first pixel area PXA 1  in a third direction DR 3  or in a fourth direction DR 4  perpendicular to the third direction DR 3 . For example, the third direction DR 3  may be inclined by about 45 degrees in a clockwise direction from the first direction DR 1 , and the fourth direction DR 4  may be inclined by about 45 degrees in a clockwise direction from the second direction DR 2 . Boundaries of the pixel areas PXA 1 , PXA 2 , and PXA 3  may respectively correspond to (bottom) boundaries of openings OP 1 , OP 2 , and OP 3  of the pixel defining layer  300 . 
     In an embodiment, a distance between the first pixel area PXA 1  and the second pixel area PXA 2  is less than a distance between the first pixel area PXA 1  and the third pixel area PXA 3 . For example, a distance D 12  between the first pixel area PXA 1  and the second pixel area PXA 2  may be about 19.2 μm, and a distance D 13  between the first pixel area PXA 1  and the third pixel area PXA 3  may be about 25.9 μm. The peripheral area PPA may surround the pixel areas PXA 1 , PXA 2 , and PXA 3 . 
     The pixel electrodes  201 ,  202 , and  203  may be disposed on the substrate  100 . The pixel electrodes  201 ,  202 , and  203  may include a first pixel electrode  201 , a second pixel electrode  202 , and a third pixel electrode  203 . The first pixel electrode  201 , the second pixel electrode  202 , and the third pixel electrode  203  may overlap the first pixel area PXA 1 , the second pixel area PXA 2 , and the third pixel area PXA 3 , respectively. The first to third pixel electrodes  201 ,  202 , and  203  may include at least one of a reflective conductive material, a transparent conductive material, a semi-transparent conductive material, etc. 
     The pixel defining layer  300  may be disposed on the substrate  100 . The pixel defining layer  300  may include a plurality of opening portions OP 1 , OP 2 , and OP 3  (or openings OP 1 , OP 2 , and OP 3 ). The opening portions OP 1 , OP 2 , and OP 3  may include a first opening portion OP 1 , a second opening portion OP 2 , and a third opening portion OP 3 . The first opening portion OP 1 , the second opening portion OP 2 , and the third opening portion OP 3  may expose the first pixel electrode  201 , the second pixel electrode  202 , and the third pixel electrode  203 , respectively. For example, the first to third opening portions OP 1 , OP 2 , and OP 3  may respectively cover edge portions of the first to third pixel electrodes  201 ,  202 , and  203 , and may respectively expose central portions of the first to third pixel electrodes  201 ,  202 , and  203 . The pixel defining layer  300  may overlap the peripheral area PPA. The opening portions OP 1 , OP 2 , and OP 3  may define the pixels PX 1 , PX 2 , and PX 3 , respectively. In other words, the pixel defining layer  300  may divide the pixels PX 1 , PX 2 , and PX 3  from each other. The pixel defining layer  300  may include a photosensitive organic insulation material. 
     The pixels PX 1 , PX 2 , and PX 3  may include a first pixel PX 1 , a second pixel PX 2 , and a third pixel PX 3  emitting different colors of light. In an embodiment, the first pixel PX 1 , the second pixel PX 2 , and the third pixel PX 3  may be a red pixel emitting red light, a green pixel emitting green light, and a blue pixel emitting blue light, respectively. Each of the pixels PX 1 , PX 2 , and PX 3  may include one of the pixel electrode  201 ,  202 , and  203 , a portion of the hole injection layer  510 , a portion of the hole transport layer  520 , one of the emission layer  531 ,  532 , and  533 , a portion of the electron transport layer  540 , and a portion of the common electrode  600 . 
     An uneven structure  310  may be formed at an upper surface of the pixel defining layer  300 . The uneven structure  310  may be formed between the pixels PX 1 , PX 2 , and PX 3 . In an embodiment, one or more uneven structures  310  may be formed between the first pixel area PXA 1  and other pixel areas PXA 2  and PXA 3 . In other words, one or more uneven structures  310  may be formed between the first pixel area PXA 1  and the second pixel area PXA 2  and/or between the first pixel area PXA 1  and the third pixel area PXA 3 . In another embodiment, an uneven structure  310  may also be formed between the second pixel area PXA 2  and the third pixel area PXA 3 . An upper surface of the pixel defining layer  300  at which no uneven structure  310  is formed may be substantially flat (or planarized). 
     In an embodiment, the uneven structure  310  may be formed only between the first pixel area PXA 1  and the second pixel area PXA 2 , and no uneven structure  310  may be formed between the first pixel area PXA 1  and the third pixel area PXA 3 . In such an embodiment, an upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the third pixel area PXA 3  may be substantially flat (or planarized). 
     The uneven structure  310  may include a plurality of concave portions  311  (or cavities  311 ) and a plurality of convex portions  312  (or protrusions  312 ). The concave portions  311  may be recessed from the upper surface of the pixel defining layer  300  toward the substrate  100 , and the convex portions  312  may protrude toward the common electrode  600 . The concave portions  311  and the convex portions  312  may be alternatively arranged along the first direction DR 1  or the second direction DR 2  in which the second pixel area PXA 2  is spaced from the first pixel area PXA 1 . 
     The uneven structure  310  may have a predetermined thickness TH. For example, the thickness TH of the uneven structure  310  may be about 1.4 μm. For example, the thickness TH of the uneven structure  310  may correspond to a depth of the concave portion  311  of the uneven structure  310 . The uneven structure  310  may include uneven units periodically formed by the concave portions  311  and the convex portions  312  which are alternatively arranged, and the uneven unit may have a predetermined width WD. For example, the width WD of the uneven unit may be about 2.9 μm. For example, the width WD of the uneven unit may correspond to a sum of a width of the concave portion  311  and a width of the convex portion  312 . Because the uneven structure  310  is formed at the upper surface of the pixel defining layer  300 , an electrical path length of the upper surface of the pixel defining layer  300  which is defined along the concave portions  311  and the convex portions  312  of the uneven structure  310  may increase. 
     Each of the concave portions  311  may extend along a direction perpendicular to a direction along which the concave portions  311  and the convex portions  312  are alternatively arranged and parallel to the substrate  100 . For example, when the concave portions  311  and the convex portions  312  are alternatively arranged along the first direction DR 1 , each of the concave portions  311  may extend in the second direction DR 2  and may extend perpendicular to the nearest edges of the openings of the pixel defining layer  300 ; the lengthwise directions of the concave portions  311  may be the second direction DR 2 . Further, when the concave portions  311  and the convex portions  312  are alternatively arranged along the second direction DR 2 , each of the concave portions  311  may extend in the first direction DR 1 ; the lengthwise directions of the concave portions  311  may be the first direction DR 1 . 
     In an embodiment, lengths L 1  of the concave portions  311  may be substantially equal to one another. For example, the length L 1  of the concave portion  311  may be a length in a lengthwise direction of the concave portion  311 . The concave portions  311  may have substantially the same lengths L 1 . 
     Spacers  400  may be disposed on the pixel defining layer  300 . A spacer  400  may overlap the peripheral area PPA. The spacer  400  may not overlap the uneven structure  310 . No spacer  400  may be formed between the first pixel area PXA 1  and other pixel areas PXA 2  and PXA 3 . The spacer  400  may support an encapsulation substrate, an encapsulation layer, etc. formed over the pixels PX 1 , PX 2 , and PX 3 , and may separate the encapsulation substrate, the encapsulation layer, etc. from the pixels PX 1 , PX 2 , and PX 3  to protect the pixels PX 1 , PX 2 , and PX 3 . The spacer  400  may include a photosensitive organic insulation material. In an embodiment, the spacer  400  may include substantially the same material as that of the pixel defining layer  300  and may be significantly wider than each concave portion  311 , each convex portion  312 , multiple concave portions  311 , and/or multiple convex portions  312  in a width direction of each concave portion  311  or each convex portion  312 . 
     The hole injection layer  510  may be disposed on the first to third pixel electrodes  201 ,  202 , and  203 , the pixel defining layer  300 , and the spacer  400 . The hole injection layer  510  may be commonly formed over the first to third pixels PX 1 , PX 2 , and PX 3 . The hole injection layer  510  may be located over an entire upper surface of the substrate  100 . 
     The hole injection layer  510  may serve to improve the injection of holes from each of the pixel electrodes  201 ,  202 , and  203  to the hole transport layer  520 . The hole injection layer  510  may include one or more phthalocyanine compounds such as at least one of copper phthalocyanine, polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), 4,4′,4″-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine (2TNATA), 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA), 4,4′4″-Tris(N,N-diphenylamino)triphenylamine (TDATA), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), N,N-diphenyl-N,N-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine (DNTPD), and poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS). 
     The hole injection layer  510  may be formed along profiles of the first to third pixel electrodes  201 ,  202 , and  203  and the pixel defining layer  300  on the substrate  100 . The hole injection layer  510  may be formed along a profile of the upper surface of the pixel defining layer  300 . The hole injection layer  510  may be formed along a profile of the uneven structure  310  formed at the upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the second pixel area PXA 2 . Further, the hole injection layer  510  may be formed along a profile of the substantially flat (or planarized) upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the third pixel area PXA 3 . 
     Since the hole injection layer  510  is formed between the first pixel area PXA 1  and the second pixel area PXA 2  along a profile of the upper surface of the pixel defining layer  300  at which the uneven structure  310  is formed, a length of the hole injection layer  510  between the first pixel area PXA 1  and the second pixel area PXA 2  may increase. For example, when a horizontal distance D 12  between the first pixel area PXA 1  and the second pixel area PXA 2  is about 19.2 μm, if an upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the second pixel area PXA 2  is substantially flat (or planarized) in a comparative example, a length of the hole injection layer  510  between the first pixel area PXA 1  and the second pixel area PXA 2  may be about 21.5 μm. In an embodiment, the uneven structure  310  is formed at the upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the second pixel area PXA 2 , such that a length of the hole injection layer  510  between the first pixel area PXA 1  and the second pixel area PXA 2  may be about 28.0 μm. Therefore, when the uneven structure  310  is formed at the upper surface of the pixel defining layer  300 , the length of the hole injection layer  510  may increase by about 1.3 times. 
     The hole injection layer  510  may be formed of a material having a relatively high charge mobility. When formed as a common layer over the pixels PX 1 , PX 2 , and PX 3 , the hole injection layer  510  may become a path for the movement of electric charges (holes) between the pixels PX 1 , PX 2 , and PX 3 . Accordingly, when one pixel is driven, lateral leakage current may flow through an adjacent pixel via the hole injection layer  510  if the hole injection layer  510  provides a sufficiently short electrical path. The hole injection layer  510  may function as a conductive medium between the adjacent pixels PX 1 , PX 2 , and PX 3 , and an electrical resistance R of the hole injection layer  510  that functions as the conductive medium is illustrated in a mathematical equation below. 
     
       
         
           
             
               
                 
                   R 
                   = 
                   
                     
                       ρ 
                       · 
                       L 
                     
                     
                       W 
                       · 
                       t 
                     
                   
                 
               
               
                 
                   [ 
                   
                     mathematical 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     equation 
                   
                   ] 
                 
               
             
           
         
       
     
     The ρ illustrates a resistivity of the hole injection layer  510 , the L illustrates an electrical path length of the hole injection layer  510 , the W illustrates an electrical path width of the hole injection layer  510 , and the t illustrates an electrical path thickness of the hole injection layer  510 . 
     The first pixel PX 1  emitting red light may have a relatively low turn-on voltage. When an electrical path between the first pixel area PXA 1  and the second pixel area PXA 2  is relatively short, according to driving of the second pixel PX 2 , the first pixel PX 1  may emit light in response to lateral leakage current transmitted from the second pixel PX 2  to the first pixel PX 1  via the hole injection layer  510 , and color-mixing may occur at low luminance According to an embodiment, the hole injection layer  510  may be formed along the upper surface of the pixel defining layer  300  at which the uneven structure  310  is formed between the first pixel area PXA 1  and the second pixel area PXA 2 , so that the electrical path length L of the hole injection layer  510  between the first pixel area PXA 1  and the second pixel area PXA 2  may increase; therefore, the electrical resistance R of the hole injection layer  510  between the first pixel area PXA 1  and the second pixel area PXA 2  may increase. Accordingly, the magnitude of the lateral leakage current between the first pixel PX 1  and the second pixel PX 2  via the hole injection layer  510  may decrease, and color-mixing at low luminance due to the lateral leakage current may be prevented. 
     The hole transport layer  520  may be disposed on the hole injection layer  510 . The hole transport layer  520  may be commonly formed over the first to third pixels PX 1 , PX 2 , and PX 3 . The hole transport layer  520  may be located over an entire upper surface of the substrate  100 . 
     The hole transport layer  520  may serve to smoothly transport holes transmitted from the hole injection layer  510 . The hole transport layer  520  may include one or more carbazole-based derivatives such as at least one of N-phenylcarbazole, polyvinylcarbazole, etc., fluorine-based derivatives, triphenylamine-based derivatives such as N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD), 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), etc., N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB), and 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC). The hole injection layer  510  may include the same material as that included in the hole transport layer  520  and may be doped with a P-type dopant for improving a hole injection characteristic by decreasing a driving voltage of each pixel. 
     The hole transport layer  520  may be formed along a profile of the hole injection layer  510  disposed on the pixel defining layer  300 . The hole transport layer  520  may be formed along a profile of the upper surface of the pixel defining layer  300 . The hole transport layer  520  may be formed along a profile of the uneven structure  310  formed at the upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the second pixel area PXA 2 . Further, the hole transport layer  520  may be formed along a profile of the substantially flat (or planarized) upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the third pixel area PXA 3 . Since the hole transport layer  520  is formed between the first pixel area PXA 1  and the second pixel area PXA 2  along a profile of the upper surface of the pixel defining layer  300  at which the uneven structure  310  is formed, a length of the hole transport layer  520  between the first pixel area PXA 1  and the second pixel area PXA 2  may increase. 
     The emission layers  531 ,  532 , and  533  may be formed on the hole transport layer  520 . The emission layers  531 ,  532 , and  533  may include a first emission layer  531 , a second emission layer  532 , and a third emission layer  533 . The first emission layer  531 , the second emission layer  532 , and the third emission layer  533  may overlap the first pixel area PXA 1 , the second pixel area PXA 2 , and the third pixel area PXA 3 , respectively. The first to third emission layers  531 ,  532 , and  533  may include a host and a dopant. The first to third emission layers  531 ,  532 , and  533  may include materials respectively emitting red color, green color, and blue color, and may be formed of a phosphorescent material or a fluorescent material. 
     The first emission layer  531  emitting red light may include a host material that includes CBP (carbazole biphenyl) or mCP (1,3-bis(carbazol-9-yl), and may be formed of a phosphorescent material including a dopant including at least one selected from PIQIr(acac) (bis(1-phenylisoquinoline)acetylacetonate iridium), PQIr(acac) (bis(1-phenylquinoline)acetylacetonate iridium), PQIr(tris(1-phenylquinoline)iridium), and PtOEP (octaethylporphyrin platinum), or may be formed of a fluorescent material including PBD:Eu(DBM)3(Phen) or perylene. 
     The second emission layer  532  emitting green light may include a host material that includes CBP or mCP, and may be formed of a phosphorescent material that includes a dopant material including Ir(ppy)3(fac-tris(2-phenylpyridine)iridium), or may be formed of a fluorescent material including Alq3(tris(8-hydroxyquinolino)aluminum). 
     The third emission layer  533  emitting blue light may include a host material including CBP or mCP, and may be formed of a phosphorescent material that includes a dopant material including (4,6-F2ppy)2Irpic, or may be formed of a fluorescent material including at least one selected from a group of spiro-DPVBi, spiro-6P, distyryl benzene (DSB), distyrylarylene (DSA), a PFO-based polymer, and a PPV-based polymer. 
     The electron transport layer  540  may be disposed on the first to third emission layers  531 ,  532 , and  533  and the hole transport layer  520 . The electron transport layer  540  may be commonly formed over the first to third pixels PX 1 , PX 2 , and PX 3 . The electron transport layer  540  may be located over an entire upper surface of the substrate  100 . 
     The electron transport layer  540  may transfer electrons from the common electrode  600  to the first to third emission layers  531 ,  532 , and  533 . Further, the electron transport layer  540  may prevent or reduce instances of holes injected from the first to third pixel electrodes  201 ,  202 , and  203  from moving to the common electrode  600  via the first to third emission layers  531 ,  532 , and  533 . That is, the electron transport layer  540  may serve as a hole blocking layer, and may help combination of the holes and electrons in the first to third emission layers  531 ,  532 , and  533 . 
     The electron transport layer  540  may include, e.g., at least one of tris(8-hydroxyquinolinato)aluminum (Alq3), 1,3,5-Tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen), 3-(4-Biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(Naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD). Bis(2-methyl-8-quinolinolato-N1,O8)-(1,1′-Biphenyl-4-olato)aluminum (BAlq), beryllium bis(benzoquinolin-10-olate) (Bebq2), 9,10-di(naphthalene-2-yl)anthracene (ADN), and a mixture. 
     The OLED device may further include an electron injection layer (not shown) disposed on the electron transport layer  540 . The electron injection layer may serve to improve the injection of electrons from common electrode  600  to the electron transport layer  540 . When the OLED device includes the electron transport layer  540  and the electron injection layer, the electron transport layer  540  may be formed of a lanthanide metal such as at least one of LiF, LiQ, Li 2 O, BaO, NaCl, CsF, and Yb, or a halogenated metal such as RbCl and/or RbI. Further, the electron injection layer may be formed of a material in which an electron transfer material is mixed with an insulating organic metal salt. The organic metal salt may have an energy band gap of about 4 eV or more. For example, the organic metal salt may include a metal acetate, a metal benzoate, a metal acetoacetate, a metal acetylacetonate, or a metal stearate. 
     The electron transport layer  540  may be formed along profiles of the first to third emission layers  531 ,  532 , and  533  and the hole transport layer  520  disposed on the pixel defining layer  300 . The electron transport layer  540  may be formed along a profile of the upper surface of the pixel defining layer  300 . The electron transport layer  540  may be formed along a profile of the uneven structure  310  formed at the upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the second pixel area PXA 2 . Further, the electron transport layer  540  may be formed along a profile of the substantially flat (or planarized) upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the third pixel area PXA 3 . Since the electron transport layer  540  is formed between the first pixel area PXA 1  and the second pixel area PXA 2  along a profile of the upper surface of the pixel defining layer  300  at which the uneven structure  310  is formed, a length of the electron transport layer  540  between the first pixel area PXA 1  and the second pixel area PXA 2  may increase. 
     The common electrode  600  may be disposed on the electron transport layer  540 . The common electrode  600  may be commonly formed over the first to third pixels PX 1 , PX 2 , and PX 3 . The common electrode  600  may be located over an entire upper surface of the substrate  100 . The common electrode  600  may include at least one of a reflective conductive material, a transparent conductive material, and a semi-transparent conductive material. 
     When the OLED device is a bottom emission type in which an image may be displayed toward the substrate  100 , each of the first to third pixel electrodes  201 ,  202 , and  203  may be a transparent electrode, and the common electrode  600  may be a reflective electrode. The first to third pixel electrodes  201 ,  202 , and  203  may be formed of at least one of ITO, IZO, ZnO, and In 2 O 3  having a high work function, and the common electrode  600  may be formed of a metal having a low work function such as at least one of Ag, Mg, Al, Pt, Au, Ni, Nd, Ir, Cr, Li, and Ca. 
     When the OLED device is a top emission type in which an image may be displayed toward the common electrode  600 , each of the first to third pixel electrodes  201 ,  202 , and  203  may be a reflective electrode, and the common electrode  600  may be a transparent electrode. The first to third pixel electrodes  201 ,  202 , and  203  may include a reflective layer including at least one of Ag, Mg, Al, Pt, Au, Ni, Nd, Ir, Cr, Li, Ca, and a mixture and may include a transmitting layer including at least one of ITO, IZO, ZnO, and In 2 O 3  having a high work function. Further, the common electrode  600  may be a thin film including a metal having a low work function such as at least one of Ag, Mg, Al, Pt, Au, Ni, Nd, Ir, Cr, Li, Ca, and a mixture. 
       FIG. 4  is a plan view illustrating an organic light emitting display device according to an embodiment. 
     The OLED device described with reference to the  FIG. 4  may be substantially the same as or similar to the OLED device described with reference to  FIGS. 1 to 3  except shapes and dimensions of the uneven structure. Accordingly, descriptions on above-described elements may not be repeated. 
     Referring to  FIG. 4 , lengths L 2  of the concave portions  311  of the uneven structure  310  formed at the upper surface of the pixel defining layer  300  may increase as being away from the first pixel area PXA 1  or the second pixel area PXA 2 . For example, a length L 2  of a concave portion  311  may be a length in a lengthwise direction of the concave portion  311 . For example, the lengths L 2  of the concave portions  311  may sequentially increase along the first direction DR 1  or the second direction DR 2  from the first pixel area PXA 1  to the midpoint between the first pixel area PXA 1  and the second pixel area PXA 2 , and may sequentially decrease along the first direction DR 1  or the second direction DR 2  from the midpoint to the second pixel area PXA 2 . The lengths L 2  of the concave portions  311  may decrease as approaching the first pixel area PXA 1  or the second pixel area PXA 2 , and may increase as being away from the first pixel area PXA 1  or the second pixel area PXA 2 . 
     When the uneven structure  310  is formed between the first pixel area PXA 1  and the second pixel area PXA 2 , a leakage current path bypassing the uneven structure  310  may be formed between the first pixel area PXA 1  and the second area PXA 2 . However, when the lengths of the concave portions  311  increase as being away from the first pixel area PXA 1  or the second pixel area PXA 2 , an electrical length of the leakage current path bypassing the uneven structure  310  may increase, therefore, the magnitude of the lateral leakage current between the first pixel PX 1  and the second pixel PX 2  may decrease or the generation of the lateral leakage current may be substantially prevented. 
       FIG. 5  is a plan view illustrating an organic light emitting display device according to an embodiment.  FIG. 6  is a cross-sectional view taken along a line VI-VI′ in  FIG. 5  according to an embodiment. 
     The OLED device described with reference to the  FIGS. 5 and 6  may be substantially the same as or similar to the OLED device described with reference to  FIGS. 1 to 3  except locations in which uneven structures are formed. Accordingly, descriptions on above-described elements may not be repeated. 
     Referring to  FIGS. 5 and 6 , the uneven structures  310  and  320  formed at the upper surface of the pixel defining layer  300  may be formed between the first pixel area PXA 1  and the third pixel area PXA 3  in addition to between the first pixel area PXA 1  and the second pixel area PXA 2 . The uneven structures  310  and  320  may include a first uneven structure  310  formed between the first pixel area PXA 1  and the second pixel area PXA 2  and may include a second uneven structure  320  formed between the first pixel area PXA 1  and the third pixel area PXA 3 . An upper surface of the pixel defining layer  300  at which no uneven structures  310  and  320  are formed may be substantially flat (or planarized). 
     The second uneven structure  320  may include a plurality of concave portions  321  and a plurality of convex portions  322 . The concave portions  321  and the convex portions  322  may be alternatively arranged along the third direction DR 3  or the fourth direction DR 4  in which the third pixel area PXA 3  is spaced from the first pixel area PXA 1 . 
     The concave portions  321  may extend along a direction perpendicular to a direction along which the concave portions  321  and the convex portions  322  are alternatively arranged, perpendicular to nearest edges of openings of the pixel defining layer  300 , and parallel to the substrate  100 . For example, when the concave portions  321  and the convex portions  322  are alternatively arranged along the third direction DR 3 , each of the concave portions  321  may extend in the fourth direction DR 4 . Further, when the concave portions  321  and the convex portions  322  are alternatively arranged along the fourth direction DR 4 , each of the concave portions  321  may extend in the third direction DR 3 . 
     In an embodiment, lengths L 3  of the concave portions  321  may be substantially equal. For example, a length L 3  of a concave portion  321  may be a length in a length direction of the concave portion  321 . The concave portions  321  may have substantially the same lengths L 3 . 
     In another embodiment, lengths L 3  of the concave portions  321  may increase as being away from the first pixel area PXA 1  or the third pixel area PXA 3 . For example, the lengths L 3  of the concave portions  321  may sequentially increase along the third direction DR 3  or the fourth direction DR 4  from the first pixel area PXA 1  to the middle between the first pixel area PXA 1  and the third pixel area PXA 3 , and may sequentially decrease along the third direction DR 3  or the fourth direction DR 4  from the middle to the third pixel area PXA 3 . The lengths L 3  of the concave portions  321  may decrease as approaching the first pixel area PXA 1  or the third pixel area PXA 3 , and may increase as being away from the first pixel area PXA 1  or the third pixel area PXA 3 . 
     The hole injection layer  510  may be formed along profiles of the first to third pixel electrodes  201 ,  202 , and  203  and the pixel defining layer  300 . The hole injection layer  510  may be formed along a profile of the upper surface of the pixel defining layer  300 . The hole injection layer  510  may be formed along a profile of the first uneven structure  310  formed at the upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the second pixel area PXA 2 . Further, the hole injection layer  510  may be formed along a profile of the second uneven structure  320  formed at the upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the third pixel area PXA 3 . Since the hole injection layer  510  is formed between the first pixel area PXA 1  and the third pixel area PXA 3  along a profile of the upper surface of the pixel defining layer  300  at which the second uneven structure  320  is formed, an electrical path length of the hole injection layer  510  between the first pixel area PXA 1  and the third pixel area PXA 3  may increase. 
     The hole transport layer  520  and the electron transport layer  540  may be formed along a profile of the upper surface of the pixel defining layer  300 . The hole transport layer  520  and the electron transport layer  540  may be formed along a profile of the second uneven structure  320  formed at the upper surface of the pixel defining layer  300  between the first pixel area PXA 1  and the third pixel area PXA 3 . Since the hole transport layer  520  and the electron transport layer  540  are formed between the first pixel area PXA 1  and the third pixel area PXA 3  along a profile of the upper surface of the pixel defining layer  300  at which the second uneven structure  320  is formed, an electrical path length of the hole transport layer  520  and an electrical path length of the electron transport layer  540  between the first pixel area PXA 1  and the third pixel area PXA 3  may increase. 
     The first pixel PX 1  emitting red light may have a relatively low turn-on voltage. When a distance between the first pixel area PXA 1  and the third pixel area PXA 3  is relatively short, according to driving of the third pixel PX 3 , the first pixel PX 1  may emit light in response to lateral leakage current transmitted from the third pixel PX 3  to the first pixel PX 1  via the hole injection layer  510 , and color-mixing may occur at low luminance. According to an embodiment, the hole injection layer  510  may be formed along the upper surface of the pixel defining layer  300  at which the uneven structure  320  is formed between the first pixel area PXA 1  and the third pixel area PXA 3 , so that the electrical path length of the hole injection layer  510  between the first pixel area PXA 1  and the third pixel area PXA 3  may increase; therefore, the electrical resistance of the hole injection layer  510  between the first pixel area PXA 1  and the third pixel area PXA 3  may increase. Accordingly, the magnitude of the lateral leakage current between the first pixel PX 1  and the third pixel PX 3  via the hole injection layer  510  may decrease, and color-mixing at low luminance due to the lateral leakage current may be prevented. 
       FIGS. 7, 8, 9, 10, 11, and 2  are cross-sectional views illustrating structures formed in a method of manufacturing an organic light emitting display device according to an embodiment. A method of manufacturing the OLED device described with reference to  FIGS. 1 to 3  is described with reference to  FIGS. 7 through 11 . The method of manufacturing the OLED device described with reference to  FIGS. 7 through 11  may also apply to the OLED device described with reference to  FIG. 4  and the OLED device described with reference to  FIGS. 5 and 6 . 
     Referring to  FIG. 7 , a conductive material may be deposited on the substrate  100 , and may be patterned to form the first to third pixel electrodes  201 ,  202 , and  203 . 
     Referring to  FIG. 8 , a photosensitive organic material may be deposited on the substrate  100  and on the first to third pixel electrodes  201 ,  202 , and  203  to form a preliminary pixel defining layer  301 . In an embodiment, the preliminary pixel defining layer  301  may include a positive photosensitive organic material in which a portion exposed to light is removed. In another embodiment, the preliminary pixel defining layer  301  may include a negative photosensitive organic material in which a portion exposed to light is hardened. 
     A halftone mask  700  may be disposed over the preliminary pixel defining layer  301 , and the preliminary pixel defining layer  301  may be exposed using the halftone mask  700 . The halftone mask  700  may include a light transmitting portion  710  (or transparent portion  710 ), a light shielding portion  720 , and a semi-light transmitting portion  730  (or translucent portion  730  or semitransparent portion  730 ). The light transmitting portion  710  may transmit light, the light shielding portion  720  may block light, and the semi-light transmitting portion  730  may transmit a part of light. A light transmittance of the semi-light transmitting portion  730  may be less than a light transmittance of the light transmitting portion  710  and greater than a light transmittance of the light shielding portion  720 . 
     Referring to  FIG. 9 , the pixel defining layer  300  may be formed on the substrate  100  and may partially expose the first to third pixel electrodes  201 ,  202 , and  203 . 
     The preliminary pixel defining layer  301  irradiated with light through the halftone mask  700  may be developed to form the pixel defining layer  300 . A portion of the preliminary pixel defining layer  301  corresponding to the light transmitting portion  710  may be substantially entirely removed, and a portion of the preliminary pixel defining layer  301  corresponding to the light shielding portion  720  may substantially remain. A portion of the preliminary pixel defining layer  301  corresponding to the semi-light transmitting portion  730  may be partially removed. Accordingly, the pixel defining layer  300  may include the first to third opening portions OP 1 , OP 2 , and OP 3  corresponding to light transmitting portion  710  and respectively exposing the first to third pixel electrodes  201 ,  202 , and  203 , may include portions corresponding to the light shielding portion  720  and having a first thickness, and may include portions corresponding to the semi-light transmitting portion  730  and having a second thickness less than the first thickness. Portions in the pixel defining layer  300  having the first thickness may correspond to convex portions of the uneven structure  310  and the substantially flat (or planarized) upper surface, and portions in the pixel defining layer  300  having the second thickness may correspond to concave portions of the uneven structure  310 . 
     The pixel defining layer  300  may be formed using the halftone mask  700 , so that the opening portions OP 1 , OP 2 , and OP 3  and the upper surface at which the uneven structure  310  may be formed by single photolithography process. Therefore, manufacturing time and cost of the OLED device may be minimized. 
     Referring to  FIG. 10 , a photosensitive organic material may be deposited on the pixel defining layer  300 , and may be patterned to form the spacer  400 . Then, a hole injecting material may be deposited on the pixel defining layer  300  and on the spacer  400  to form the hole injection layer  510 . The hole injection layer  510  may be formed using at least one of various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging. The hole injection layer  510  may be formed along profiles of the first to third pixel electrodes  201 ,  202 , and  203  and the pixel defining layer  300 . The hole injection layer  510  may be formed along a profile of the uneven structure  310  formed at the upper surface of the pixel defining layer  300 . 
     Referring to  FIG. 11 , a hole transporting material may be deposited on the hole injection layer  510  to form the hole transport layer  520 . The hole transport layer  520  may be formed along a profile of the hole injection layer  510 . The hole transport layer  520  may be formed along a profile of the uneven structure  310  formed at the upper surface of the pixel defining layer  300 . Then, an organic light emitting material may be injected on the hole transport layer  520  to form the first to third emission layers  531 ,  532 , and  533 . The hole transport layer  520  and the first to third emission layers  531 ,  532 , and  533  may be formed using at least one of various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging. 
     Referring to  FIG. 2 , an electron transporting material may be deposited on the hole transport layer  520  and on the first to third emission layers  531 ,  532 , and  533  to form the electron transport layer  540 . The electron transport layer  540  may be formed using at least one of various methods such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging. When the OLED device includes an electron injection layer, an electron injecting material may be deposited on the electron transport layer  540  to form the electron injection layer. Then, a conductive material may be deposited on the electron transport layer  540  to form the common electrode  600 . The electron transport layer  540  and the common electrode  600  may be formed along profiles of the first to third emission layers  531 ,  532 , and  533  and the hole transport layer  520 . The electron transport layer  540  and the common electrode  600  may be formed along a profile of the uneven structure  310  formed at the upper surface of the pixel defining layer  300 . 
     An organic light emitting display device according to an embodiment may be applied to a display device included in a computer, a notebook, a mobile phone, a smartphone, a smart pad, a PMP, a PDA, an MP3 player, or the like. 
     Although example embodiments have been described with reference to the drawings, the example embodiments may be modified without departing from the scope defined in the following claims.