Organic light-emitting display device

Abstract

An organic light-emitting display device (300, 600) comprising: a coating layer (360, 660) arranged on a substrate (310) and having a plurality of concave regions (361) and a plurality of convex regions (362); a first electrode (341, 641) having concave regions and convex regions arranged on the concave regions (361) and convex regions (362) of the coating layer (360, 660), respectively; a dam layer (336) arranged on the coating layer (360, 660) and the first electrode (341, 641) and having an opening (336a) through which the first electrode (341, 641) is exposed; a structural layer (337, 637) arranged on the first electrode (341, 641) is arranged in the concave areas of the first electrode (341, 641) which is exposed through the opening (336a) of the dam layer (336);an organic emission layer (342, 642) arranged on the convex regions of the first electrode (341, 641) and the structural layer (337, 637); and a second electrode (343, 643) arranged on the organic emission layer (342, 642), wherein the structural layer (337, 637) is filled into all or some of the majority of concave regions (361) of the first electrode (341, 641), wherein an upper surface of the structural layer (337, 637) contacting the organic emission layer (342, 642) is flat, and wherein both the organic emission layer (342, 642) and the second electrode (343, 643) have a flat surface on the structural layer (337, 637) and convex regions on the convex regions of the first electrode (341, 641) in an emission region overlapping with the opening (336a) of the dam layer (336).

Description

BACKGROUND OF THE INVENTIONField of the InventionThe present invention relates to an organic light emitting display device that displays an image.Description of Related ArtAn organic light emitting display device that has recently attracted much attention as a display device uses a self-emitting organic light emitting diode (OLED), and thus has advantages of high speed response and increased contrast ratio, luminous efficiency, brightness, and viewing angle.Light emitted from an organic emission layer of the organic light emitting display device is output to the outside of the organic light emitting display device passing through various elements in the organic light emitting display device. However, a part of the light emitted from the organic emission layer may not be output to the outside of the organic light emitting display device, but may be included in the organic light emitting display device, which creates a problem with the extraction efficiency of the organic light emitting display device. In order to improve the light extraction efficiency of the organic light emitting display device, a method of attaching a microlens array (MLA) to an outer surface of a substrate of the organic light emitting display device has been used.US 2008 / 0122347 A1 describes an organic light emitting device including a first passivation layer having a concave-convex surface, a first electrode formed on the passivation layer, a partition formed on the first electrode and having an opening extending to the first electrode, and a light emitting element formed in the opening and covered by a second electrode.US 2014 / 0306200 A1 describes a display unit including a plurality of insulating layers, wherein one of the insulating layers is structured to include a plurality of windows in a part of a region where the anode is formed, and wherein a light emitting layer is formed to cover the plurality of windows.CN 104659070 A describes a display panel having an organic common layer disposed on pixel regions defined in a pixel defining layer, wherein a thickness of at least one region of the organic common layer corresponding to the pixel defining layer is less than the thickness of at least one region of the organic common layer corresponding to the pixel region.US 2010 / 0176717 A1 describes an organic light emitting display device having a plurality of structures formed on a first insulating layer and first electrode, organic light emitting layer and second electrode formed on the structures, the structures and the first insulating layer together forming a surface having a corrugated cross section.US 2004 / 0169465 A1 describes an electroluminescence display device whose substrate has a corrugated structure, wherein a first electrode layer, a first insulating layer, a fluorescent layer, a second insulating layer and a second electrode layer are sequentially formed on the substrate so as to follow the shape of the corrugated structure.SUMMARY OF THE INVENTIONAn aspect of the present invention provides an organic light emitting display device that can improve external luminous efficiency and also reduce power consumption.There is provided an organic light emitting display device according to the main claim and an organic light emitting display device according to the sub-claim 12.According to the present exemplary embodiments, it is possible to provide an organic light emitting display device that can improve external luminous efficiency and also decrease power consumption.BRIEF DESCRIPTION OF THE DRAWINGSThe above and other aspects, features and other advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a cross-sectional view of an organic light emitting display device; FIG. 2 is an enlarged cross-sectional view of a region X of FIG. 1 ; FIG. 3 is a cross-sectional view of an organic light emitting display device according to an exemplary embodiment; FIG. 4A is an enlarged cross-sectional view of a region Y of FIG. 3 ; FIG. 4B is a partial plan view of a plating layer, a first electrode, and a pattern layer in the region Y of FIG. 3 ; FIG. 5 is a partial cross-sectional view of an organic light emitting display device according to Comparative Example; FIG. 6 is a cross-sectional view illustrating an example of a coating layer in a conventional organic light emitting display device; FIG. 7 is a cross-sectional view illustrating a modified example of a coating layer in the organic light emitting display device according to another exemplary embodiment; FIGS. 8A to 8C are graphs comparatively illustrating an external light extraction efficiency and a distribution (viewing angle) depending on a location of an emission surface of an organic emission layer (matching an effective emission region) with a matched thickness of a pattern layer disposed on a concave region of a cladding layer; FIG. 9 is a cross-sectional view provided for explaining an organic light emitting display device including a coating layer including a plurality of convex portions according to still another exemplary embodiment; and FIG. 10 is a schematic view of the system configuration of an organic light emitting display device according to the present exemplary embodiments.DETAILED DESCRIPTION OF THE INVENTIONHereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. When reference numerals refer to components of each drawing, although the same components are illustrated in different drawings, the same components will be denoted by the same reference numerals as appropriate. Further, the description will be omitted when it is determined that a description of a related known arrangement or function obscures the important aspect of the present invention.Furthermore, in describing components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are used only to distinguish the components from other components. Accordingly, the constitution, order, sequence, or number of the respective components is not limited by these terms. It should be noted that when an element is referred to as being "connected to" or "coupled to" another element, it may be directly connected or directly coupled to another element, connected or coupled to another element, yet another element may be "interposed" therebetween, or may be "connected to" or "coupled to" via yet another element.FIG. 1 is a cross-sectional view of an organic light emitting display device. FIG. 2 is an enlarged cross-sectional view of a region X of FIG. 1.Referring to FIGS. 1 and 2, an organic light emitting display device 100 includes a substrate 110, a thin film transistor 120, a color filter 150, a coating layer 160, a pattern layer 137, and an organic light emitting diode 140.The thin film transistor 120 including a gate electrode 121, an active layer 122, a source electrode 123, and a drain electrode 124 is disposed on the substrate 110.Specifically, the gate electrode 121 is disposed on the substrate 110, and a gate insulating layer 131 configured to isolate the gate electrode 121 and the active layer 122 is disposed on the gate electrode 121 and the substrate 110. Further, the active layer 122 is disposed on the gate insulating layer 131, and an etching stopper 132 is disposed on the active layer 122. Moreover, the source electrode 123 and the drain electrode 124 are disposed on the active layer 122 and the etching stopper 132. The source electrode 123 and the drain electrode 124 are electrically connected to the active layer 122 so as to be in contact with the active layer 122, and are disposed on a portion of the etching stopper 132. The etching stopper 132 may not be disposed.In the present specification, among various thin film transistors that may be included in the organic light emitting display device 100, only one driving thin film transistor is illustrated for ease of explanation. Furthermore, in the present specification, the thin film transistor 120 is illustrated as having an inverted stacked structure or a bottom gate structure in which the gate electrode 121 is disposed opposite to the source electrode 123 and the drain electrode 124 with the active layer 122 interposed therebetween. However, a thin film transistor having a coplanar structure or a top gate structure in which the gate electrode 121 is disposed on the same side of the active layer 122 as the source electrode 123 and the drain electrode 124 may be used.A passivation layer 133 is disposed on the thin film transistor 120, and the color filter 150 is disposed on the passivation layer 133.The color filter 150 is configured to convert a color of light emitted from an organic emission layer 142, and may be one of a red color filter, a green color filter, and a blue color filter.The overcoat layer 160 is disposed on the color filter 150 and the passivation layer 133. The overcoat layer 160 has a flat top surface.The organic light emitting diode 140, which includes a first electrode 141, the organic emission layer 142, and a second electrode 143, a bank layer 136, and a pattern layer 137, are disposed on the overcoat layer 160.The dam layer 136 is disposed on the coating layer 160 and the first electrode 141, and has an opening 346 athrough which the first electrode 141 is exposed. The bank layer 136 is configured to demarcate adjacent pixel regions (or sub-pixel regions) and may be disposed between the adjacent pixel regions (or sub-pixel regions).The pattern layer 137 is disposed on the first electrode 150. The pattern layer 137 is disposed in an island shape on the first electrode 150 exposed through the opening 136 aof the bank layer 136.The structure layer 137 may include the same material as the bank layer 136. As for processes, after the flat coating layer 160 is formed, the first electrode 141 is formed on the coating layer 160. An original material of the bank layer 136 and the pattern layer 137 is coated on the coating layer 160 and the entire surface of the first electrode 141. Then, using a mask corresponding to the opening 136 aof the bank layer 136 and the pattern layer 137, an irradiation and development process is performed. Here, a location corresponding to the pattern layer 137 is irradiated and developed with a smaller amount of light than a conventional process. Thus, the bank layer 136 and the pattern layer 137 of the same material as the bank layer 136 may be formed simultaneously without a specifically added process or mask.The organic emission layer 142 is disposed on the first electrode 141 and the pattern layer 137, and the second electrode 143 configured to supply one of an electron or a hole to the organic emission layer 142 is disposed on the organic emission layer 142.In the opening 136 aof the bank layer 136, the first electrode 141 disposed on the overcoat layer 160 has a shape corresponding to the surface topology of the overcoat layer 160. That is, the first electrode 141 disposed on the plating layer 160 has a flat shape having a flat bottom surface and a top surface in the opening 136 aof the bank layer 136. The organic emission layer 142 and the second electrode 143 are disposed along a shape of the upper surface of the first electrode 141 according to the surface morphology of the coating layer 160 and a shape of an upper surface of the structure layer 137, and thus have non-flat upper surface and lower surface. Thus, the first electrode 141 has a flat shape, while the organic emission layer 142 and the second electrode 143 have a convex shape on the pattern layer 137. As a result, in the organic light emitting display device 100, the pattern layer 137 is disposed on the first electrode 141, and the organic emission layer 142 and the second electrode 143 have bends. Thus, the organic light emitting display device 100 has a microlens array structure.In the organic light emitting display device 100, a concave portion or a convex portion is not formed on the overcoat layer 160, and the bank layer 136 and the pattern layer 137 are formed simultaneously. Thus, it is possible to form a microlens array structure without an additional process. Since the microlens array structure is formed using the pattern layer 137, the external light extraction efficiency can be improved.FIG. 3 is a cross-sectional view of an organic light emitting display device according to an exemplary embodiment. FIG. 4A is an enlarged cross-sectional view of a region Y of FIG. 3, FIG. 4B is a partial plan view of a plating layer, a first electrode, and a pattern layer in the region Y of FIG. 3.Referring to FIGS. 3 and 4A, an organic light emitting display device 300 includes a substrate 310, a thin film transistor 320, a color filter 350, a coating layer 360, a pattern layer 337, and an organic light emitting diode 340.The organic light emitting display device 300 illustrated in FIGS. 3 and 4A is a bottom emission organic light emitting display device. However, the organic light emitting display device 300 according to an exemplary embodiment may be a top emission organic light emitting display device in which the color filter 350 is disposed opposite to the substrate 310.The thin film transistor 320, which includes a gate electrode 321, an active layer 322, a source electrode 323, and a drain electrode 324, is disposed on the substrate 310.Specifically, the gate electrode 321 is disposed on the substrate 310, and a gate insulating layer 331 configured to isolate the gate electrode 321 and the active layer 322 is disposed on the gate electrode 321 and the substrate 310. Further, the active layer 322 is disposed on the gate insulating layer 331, and an etching stopper 332 is disposed on the active layer 322. Moreover, the source electrode 323 and the drain electrode 324 are disposed on the active layer 322 and the etching stopper 332. The source electrode 323 and the drain electrode 324 are electrically connected to the active layer 322 so as to be in contact with the active layer 322, and are disposed on a portion of the etching stopper 332. The etching stopper 332 may not be disposed.A passivation layer 333 is disposed on the thin film transistor 320, and the color filter 350 is disposed on the passivation layer 333.FIG. 4A shows that the passivation layer 333 smoothes an upper part of the thin film transistor 320. However, the passivation layer 333 may not smooth the upper part of the thin film transistor 320, but may be disposed according to the surface morphology of elements disposed under the passivation layer 333.The color filter 350 is configured to convert a color of light emitted from an organic emission layer 342, and may be one of a red color filter, a green color filter, and a blue color filter.The color filter 350 is disposed on the passivation layer 333 at a position corresponding to an emission region. Here, the emission region refers to a region where a light is emitted from the organic emission layer 342 via the first electrode 341 and the second electrode 343. The color filter 350 is disposed at a position corresponding to the emission region, which means that the color filter 350 is disposed so as to suppress occurrence of a blurring phenomenon or ghost phenomenon caused by mixing of light emitted from adjacent emission regions.For example, the color filter 350 may be disposed so as to overlap with the emission region. Here, a position and a size of the color filter 350 may be determined by various factors including a size and a position of the emission region, a distance between the color filter 350 and the first electrode 341, a distance between the color filter 350 and a concave region 361, or a convex region (since "363" is not illustrated in FIG. 4A ) of the overcoat layer 360, and a distance between emission regions.The overcoat layer 360 is disposed on the color filter 350 and the passivation layer 333. FIG. 4A shows that the passivation layer 333 (see FIG. 3 ) is included in the organic light emitting display device 300. However, the passivation layer 333 may not be used, and the overcoat layer 360 may be directly disposed on the thin film transistor 320. Further, FIG. 4A shows that the color filter 350 is disposed on the passivation layer 333 (see FIG. 3 ), but the present invention is not limited thereto. The color filter 350 may be disposed at any position between the overcoat layer 360 and the substrate 310.The overcoat layer 360 includes a plurality of concave portions 361 disposed to overlap with the color filter 350, and a first connection portion 362 connecting the concave portions 361 adjacent to each other. FIG. 4A is a cross-sectional view of the plurality of concave portions 361 having a hexagonal shape. The first connecting portion 362 is a higher portion between the concave portions 361 adjacent to each other. The overcoat layer 360 functions as a smoothing layer in a region where the plurality of concave regions 361 are disposed.As illustrated in FIG. 4B, each of the plurality of concave portions 361 (see FIG. 4A ) and the first connection portion 362 may have a total hexagonal shape in a plan view, but is not limited thereto, and may have various shapes such as a total semi-circular shape, a semi-elliptical shape, or a rectangular shape. The plurality of concave portions 361 may be arranged in a hexagonal honeycomb structure in a plan view. In other words, a hexagonal concave portion 361 shares one side with another adjacent concave portion 361 so as to be formed as a body having a hexagonal honeycomb structure.The organic light emitting diode 340, which includes a first electrode 341, the organic emission layer 342, and a second electrode 343, a bank layer 336, and a pattern layer 337, are disposed on the overcoat layer 360. Here, although not illustrated, a second insulating passivation layer (not illustrated) configured to suppress the propagation of outgassing from the overcoat layer 360 to the organic light emitting diode 340 such that the lifetime of the organic light emitting diode is reduced and having a shape corresponding to the morphology of the concave portions 361 of the overcoat layer 360 and a refractive index similar to that of the first electrode 341 may be further disposed between the overcoat layer 160 and the first electrode 341.Specifically, the first electrode 341 configured to supply one of an electron or a hole to the organic emission layer 342 is disposed on a part of the overcoat layer 360. The first electrode 341 may be a positive electrode, a pixel electrode, or an anode in a normal OLED, or may be a negative electrode, a pixel electrode, or a cathode in an inverted OLED.The first electrode 341 may be connected to the source electrode 323 of the thin film transistor 320 through a contact hole formed in the overcoat layer 360. In the present specification, the first electrode 341 is described as being connected to the source 323, assuming that the thin film transistor 320 is an N-type thin film transistor. However, when the thin film transistor 320 is a P-type thin film transistor, the first electrode 341 may be connected to the drain electrode 324. The first electrode 341 may be electrically connected to the organic emission layer 342 so as to be in direct contact with the organic emission layer 342 or so as to be in contact with the organic emission layer 342 such that a conductive material is interposed therebetween.The first electrode 341 is disposed in a shape corresponding to the surface morphology of the overcoat layer 360. Therefore, the first electrode 341 has a concave morphology on the concave portion 361 of the coating layer 360.The dam layer 336 is disposed on the coating layer 360 and the first electrode 341, and has an opening 336 athrough which the first electrode 341 is exposed. The bank layer 336 is configured to demarcate adjacent pixel regions (or sub-pixel regions) and may be disposed between the adjacent pixel regions (or sub-pixel regions). The concave portions 361 and the first connection portion 362 of the coating layer 360 are disposed so as to overlap with the opening 336 aof the dam layer 336. As described above, the concave portions 361 and the first connection portion 362 of the overcoat layer 360 are arranged so as to overlap with the color filter 350, and thus the concave portions 361 and the first connection portion 362 of the overcoat layer 360 overlap with the color filter 350 thereunder and also overlap with the opening 336 aof the bank layer 336 thereon.The pattern layer 337 is disposed on the first electrode 341. The pattern layer 337 is disposed in an island shape on the first electrode 341 exposed through the opening 336 aof the bank layer 336. That is, the pattern layer 137 on the first electrode 341 partially fills recessed portions of the plurality of concave portions 361 of the overcoat layer 360. The pattern layer 337 may be disposed in all concave portions as illustrated in FIG. 4B, but is not limited thereto. The pattern layer 337 may be disposed in some of the plurality of concave portions.The pattern layer 337 can reduce bends of a surface on which the organic light emitting diode 340 is disposed.The pattern layer 337 may include the same material as the bank layer 336. As for processes, after the plating layer 360 including the concave portions 361 and the first connection portion 362 is formed, the first electrode 341 is formed on the plating layer 360. An original material of the bank layer 336 and the pattern layer 337 is coated on the coating layer 360 and the entire surface of the first electrode 341. Then, using a mask corresponding to the opening 336 aof the bank layer 336 and the pattern layer 337, an irradiation and development process is performed. Here, a location corresponding to the pattern layer 337 is irradiated and developed with a smaller amount of light than a conventional process. Thus, the bank layer 336 and the pattern layer 337 of the same material as the bank layer 336 may be formed simultaneously without a specifically added process or mask.The organic emission layer 342 is disposed on the first electrode 341 and the pattern layer 337, and the second electrode 343 configured to supply one of an electron or a hole to the organic emission layer 342 is disposed on the organic emission layer 342. The organic emission layer 342 is arranged in a (tandem white) structure in which a plurality of organic emission layers are laminated so as to emit white light. The organic emission layer 342 includes a first organic emission layer configured to emit blue light and a second organic emission layer disposed on the first organic emission layer and configured to emit light that when mixed with blue gives white. The second organic emission layer may be, for example, an organic emission layer that emits yellow-green light. Meanwhile, the organic emission layer 342 may include only an organic emission layer that emits one of blue light, red light, and green light. In this case, the color filter 350 may not be provided. The second electrode 343 may be a negative electrode, a common electrode, or a cathode in a normal OLED, or may be a positive electrode, a common electrode, or an anode in an inverted OLED.The organic emission layer 342 and the second electrode 343 are disposed along a shape of the upper surface of the first electrode 341 corresponding to the surface morphology of the coating layer 360 and a shape of an upper surface of the structure layer 337 that is disposed on the first electrode 341 and partially fills the recessed portions of the plurality of concave portions 361 of the coating layer 360, and thus have a non-flat upper surface and a lower surface. For example, when the organic emission layer 342 and the second electrode 343 are deposited by deposition, the organic emission layer 342 and the second electrode 343 are arranged according to the morphology of the upper surface of the first electrode 341 and the pattern layer 337.Referring to FIG. 4A, a thickness of the organic emission layer 342 between the concave portion 361 and the first connection portion 362 of the overcoat layer 360 may be less than a thickness of the organic emission layer 342 at the lower edge of the concave portion 361 or the tip of the first connection portion 362 of the overcoat layer 360. In particular, the organic emission layer 342 may have the smallest thickness at a location where the organic emission layer 342 has the greatest gradient between the concave portion 361 and the first connection portion 362 of the overcoat layer 360.For example, when the organic emission layer 342 is formed by deposition, the organic emission layer 342 disposed in a direction perpendicular to the substrate 310 has the same thickness. However, the organic emission layer 342 has a shape corresponding to the morphology of the overcoat layer 360. Thus, the organic emission layer 342 actually has the smallest thickness for current driving between the first electrode 341 and the second electrode 342 at a location where the organic emission layer 342 has the greatest inclination, and has the largest thickness at a location where the organic emission layer 342 has the smallest inclination, i.e., at the bottom edge or the top.As for an emission amount of the organic emission layer 342 depending on a thickness of the organic emission layer 342, an emission amount per unit area of the organic emission layer 342 between the concave portion 361 and the first connection portion 362 of the overcoat layer 360 may be larger than an emission amount per unit area of the organic emission layer 342 at the bottom edge of the concave portion 361 or the tip of the first connection portion 362. Specifically, the organic emission layer 342 may have the largest emission amount at a location where the organic emission layer 342 has the largest gradient between the concave portion 361 and the first connection portion 362 of the overcoat layer 360.FIG. 5 is a partial cross-sectional view of an organic light emitting display device according to Comparative Example.Referring to FIG. 5, an organic light emitting display device 500 according to Comparative Example includes a color filter 550 and a coating layer 560 including concave portions 561 and a first connection portion 562. Furthermore, the organic light emitting display device 500 includes an organic light emitting diode 540 including a first electrode 541, an organic emission layer 542, and a second electrode 543 arranged in this order on the overcoat layer 560. The organic light emitting display device 500 according to Comparative Example does not include the pattern layer 337 included in the organic light emitting display device 300 according to the exemplary embodiment, and the first electrode 541, the organic emission layer 542, and the second electrode 543 have a shape corresponding to the surface topology of the overcoat layer 560.When the organic light emitting diode 540 has a microlens array structure for improving external light extraction efficiency, concave bends are formed on a surface of the organic light emitting diode 540 by the concave portions 561 of the overcoat layer 560 due to characteristics of the structure as illustrated in FIG. 5. As the slope increases, a thickness of the organic emission layer 542 between the first electrode 541 and the second electrode 543 is decreased, so that an effective emission region C in which an electric field is locally concentrated, i.e., a region between the concave region 561 and the first connection region 562 of the overcoat layer 560, is generated. When the organic light emitting diode 540 is driven, an electric field is locally concentrated and a main current path is formed in the effective emission region, so that emission mainly occurs in the effective emission region. However, the concave portion 561 of the overcoat layer 560 is a non-effective emission region D, and hardly couples light out of the non-effective emission region D. Although the non-effective emission region D consumes energy, light is hardly extracted from the non-effective emission region D. Thus, the external light extraction efficiency is lowered.Further, the bends of the concave portions 561 of the coating layer 560 substantially reflect external light, thus causing an increase in reflectivity.As illustrated in FIGS. 4A and 4B, an area A where the pattern layer 337 is not disposed on the first electrode 341 exposed through the opening 336 aof the bank layer 336 corresponds to an effective emission area that emits light because the pattern layer 337 is not disposed between the first electrode 341 and the organic emission layer 342 and the second electrode 343. A region B where the pattern layer 337 is disposed on the first electrode 341 exposed through the opening 336 aof the bank layer 336 corresponds to a non-effective emission region that does not emit light because the pattern layer 337 is disposed between the first electrode 341 and the organic emission layer 342 and the second electrode 343.In the organic light emitting display device 300 according to an exemplary embodiment, the organic emission layer 342 has a non-uniform thickness due to the bends of the surface of the organic light emitting diode 340 caused by the bends of the concave portions 361 of the overcoat layer 360, and an applied current is concentrated in a region having a large slope so that the light is emitted only from the effective emission region A. However, in the non-effective emission region B, the pattern layer 337 is disposed between the first electrode 341 and the organic emission layer 342 and the second electrode 343, so that light cannot be emitted. Consequently, it is possible to reduce or suppress most of the light from being included in the organic light emitting diode 340 without contributing to improvement in light extraction efficiency in a non-effective emission region D as illustrated in FIG. 5. Further, it is possible to reduce or suppress light included in the organic light emitting diode 340 from remaining as light leakage components in the non-effective emission region D as illustrated in FIG. 5. Accordingly, the external light extraction efficiency of the organic light emitting diode 340 can be maximized.In the organic light emitting display device 300 according to an exemplary embodiment, the pattern layer 337 disposed on the concave portion 561 of the overcoat layer 560 reduces bends of the overcoat layer 560. Thus, a reflectivity of external light can be reduced.Table 1 lists a measurement result of a driving voltage V, a current density J, a luminous efficiency cd / A, and an external quantum efficiency EQE of the organic light emitting display device 300 according to the exemplary embodiment illustrated in FIGS. 3 to 4B and the organic light emitting display device 500 according to the comparative example illustrated in FIG. 5. In Table 1, the external quantum efficiency EQE may be defined by multiplying the internal quantum efficiency IQE and a light extraction efficiency with each other. [Table 1] Table 1] [Table 1] Table 1]Organic Light Emitting Display Device 500 according to Comparative Example7.431085.4136.133.0741.6Organic light emitting display device 300 according to7.5510100.4145.639.0850.6Exemplary EmbodimentAs can be seen from Table 1, the organic light emitting display device 300 according to the exemplary embodiment illustrated in FIGS. 3 to 4B is improved in luminous efficiency and external quantum efficiency by 10% or more, for example, about 15%, as compared with the organic light emitting display device 500 according to the comparative example illustrated in FIG. 5.Meanwhile, in the organic light emitting display device 300 according to the exemplary embodiment described with reference to FIGS. 3 to 4B, the color filter 350 disposed under the overcoat layer 360 so as to overlap with the opening 336 aof the bank layer 336 is not in contact with the first electrode 341.When the plurality of concave portions 361 are formed in the overcoat layer 360 using a negative resist material by photolithography or the like, as illustrated in FIG. 6, the simplest way to form the concave portions 361 of the overcoat layer 360 with good uniformity on the entire substrate is to expose the lower edges 361 aof the concave portions 361. Here, when the bottom edges 361 aof the concave portions 361 are exposed, the color filter 350 is also exposed. Consequently, a great problem may arise with the reliability of the organic light emitting diode 340. For this reason, even if the concave portions 361 of the overcoat layer 360 are satisfactory in shape, the concave portions 361 of the overcoat layer 360 cannot be applied to the organic light emitting display device 300.As illustrated in FIG. 7, in the organic light emitting display device 300 according to another exemplary embodiment, the bottom edges 361 aof the plurality of concave portions 361 of the overcoat layer 360 are opened, and the first electrode 341 may be in contact with the color filter 350 through the open concave portions 361.Consequently, when the plurality of concave portions 361 are formed in the overcoat layer using a negative photoresist material by photolithography or the like, the concave portions 361 of the overcoat layer 360 are formed with good uniformity of the entire substrate, and the pattern layer 337 is disposed on the concave portions 361 of the overcoat layer 360 so that a non-effective emission region is formed. Thus, the reliability of the organic light emitting diode 340 can be maintained.FIGS. 8A to 8C are graphs comparatively illustrating an external light extraction efficiency and a distribution (viewing angle) depending on a location of an emission surface of an organic emission layer (matching an effective emission region) with a matched thickness of a pattern layer disposed on a concave region of a cladding layer.Assuming that a height from a lower edge of the concave portion 361 of the overcoat layer 360 to the tip of the first connection portion 362 is H, the organic emission layer 342 is divided into four equal portions from the lower edge of the concave portion 361 as illustrated in FIG. 8A, and external light extraction efficiency and a distribution (viewing angle) depending on a location of an emission surface of the organic emission layer 342 (adjustment of an effective emission range) are measured using a conventional simulation tool at each location between the lower edge of the concave portion 361 and 1H / 4 (portion 1), between 1H / 4 and 2H / 4 (portion 2), between 2H / 4 and 3H / 4 (section 3) and between 3H / 4 and H (section 4). Here, a conventional organic light emitting display device in which a microlens array structure is not applied to the overcoat layer 360 and the organic light emitting diode 340 is set as a reference Ref.As illustrated in FIGS. 8B and 8C, it can be determined that, at any position between the lower edge of the concave portion 361 and 1H / 4 (portion 1), between 1H / 4 and 2H / 4 (portion 2), between 2H / 4 and 3H / 4 (portion 3), and between 3H / 4 and H (portion 4) illustrated in FIG. 8A, a front-side light extraction efficiency of the organic emission layer 343 significantly increases due to the microlens matrix structure from portion 1 to portion 4. Specifically, it can be determined that the front-side light extraction efficiency of Section 3 and Section 4 is improved by 30% to 40% as compared with that of the reference Ref.Thus, assuming that the height from the lower edge of the concave portion 361 of the coating layer 360 to the tip of the first connection portion 362 is H, the upper surface of the structure layer 337 may be disposed between the lower edge of the concave portion 361 and 2H / 4. Since the upper surface of the pattern layer 337 is disposed between the lower edge of the concave portion 361 and 2H / 4, the effective emission region A may be formed between the lower edge of the concave portion 361 and 2H / 4 to H. Thus, the front side light extraction efficiency can be maximized.FIG. 9 is a cross-sectional view provided for explaining an organic light emitting display device including a coating layer including a plurality of convex portions according to still another exemplary embodiment.Referring to FIG. 9, an organic light emitting display device 600 according to still another exemplary embodiment is substantially the same as the organic light emitting display device 300 illustrated in FIGS. 4A and 4B except that a coating layer 660 includes a plurality of convex portions 663 and a pattern layer 637 is disposed on a second connection portion 664 between the plurality of convex portions 663, and thus the redundant description thereof will be omitted. Other elements of the organic light emitting display device 600 whose portion is not illustrated in FIG. 9 may be identical to the elements of the organic light emitting display device 300 according to the exemplary embodiment described with reference to FIG. 3.The overcoat layer 660 includes the plurality of convex portions 663 formed so as to overlap with a color filter 650 and the second connection portion 664 connecting the adjacent convex portions 663 to each other. In other words, the coating layer 660 includes the plurality of convex portions 663 arranged to overlap with the opening 336 aof the dam layer 336 illustrated in FIG. 3, and a plurality of second connection portions 664 respectively connecting the convex portions 663.A first electrode 641 is disposed on the overcoat layer 660. A pattern layer 637 is disposed on the overcoat layer 660 and the first electrode 641, and an organic emission layer 642 and a second electrode 643 are disposed on the first electrode 641 and the pattern layer 637. The first electrode 641, the organic emission layer 642, and the second electrode 643 form an organic light emitting diode 640. The pattern layer 637 may be disposed on all or some of the plurality of second connection regions 664.Since the pattern layer 637 is disposed on all or some of the plurality of second connection regions 664, the pattern layer 637 is disposed between the first electrode 641 and the organic emission layer 642 and the second electrode 642 in a non-effective emission region in the same manner as the pattern layer 337 disposed on the concave region 361 described with reference to FIGS. 1 to 8, so that light cannot be emitted. Thus, it is possible to minimize or suppress most of the light from being included in the organic light emitting diode 640 without contributing to improvement in the light extraction efficiency in the non-effective emission region. Further, it is possible to minimize or suppress light included in the organic light emitting diode 640 from remaining as light leakage components in the non-effective emission region B. Accordingly, the external light extraction efficiency of the organic light emitting diode 640 may be maximized.FIG. 10 is a schematic view showing the system configuration of an organic light emitting display device according to the present exemplary embodiments.Referring to FIG. 10, an organic light emitting display device 700 according to the present exemplary embodiments includes an organic light emitting display panel 710 in which a plurality of data lines DL and a plurality of gate lines GL are arranged and a plurality of subpixels SP are arranged in a matrix, a data driver 720 configured to drive the plurality of data lines by supplying a data voltage to the plurality of data lines, a gate driver 730 configured to sequentially drive the plurality of gate lines GL by sequentially supplying a scan signal to the plurality of gate lines, and a controller 740 configured to control the data driver 720 and the gate driver 730.Each of a plurality of pixels arranged in the organic light emitting display panel 710 according to the present exemplary embodiments includes the thin film transistor and the organic light emitting diode described above with reference to FIGS. 1 to 9.According to the above-described exemplary embodiments, the organic light emitting display device can improve external light efficiency and also reduce power consumption.Furthermore, according to the above-described exemplary embodiments, the organic light emitting display device may improve uniformity of shapes of bends of the overcoat layer, which improve external luminous efficiency, and may also maintain reliability of the device.The foregoing description and the accompanying drawings are provided merely to illustrate the technical spirit of the present invention, but it will be understood by those skilled in the art that various modifications and changes, such as combinations, omissions, substitutions and changes of the components, can be made without departing from the scope of the present invention. Accordingly, the exemplary embodiments of the present invention are provided for illustrative purposes only, but are not intended to limit the technical spirit of the present invention. The scope of application of the technical concept of the present invention is not limited thereto. Accordingly, it is to be noted that the above-described exemplary embodiments are illustrative in all aspects and do not limit the present invention.

Claims

An organic light emitting display device (300, 600) comprising: a coating layer (360, 660) disposed on a substrate (310) and including a plurality of concave portions (361) and a plurality of convex portions (362); a first electrode (341, 641) including concave portions and convex portions disposed on the concave portions (361) and the convex portions (362) of the coating layer (360, 660), respectively; a dam layer (336) disposed on the coating layer (360, 660) and the first electrode (341, 641) and including an opening (336a) through which the first electrode (341, 641) is exposed; a pattern layer (337, 637) disposed on the first electrode (341, 641) in the concave portions of the first electrode (341, 641) exposed through the opening (336a) of the bank layer (336); an organic emission layer (342, 642) disposed on the convex portions of the first electrode (341, 641) and the pattern layer (337, 637); and a second electrode (343, 643) disposed on the organic emission layer (342, 642), wherein the pattern layer (337, 637) is filled in all or some of the plurality of concave portions (361) of the first electrode (341, 641), wherein an upper surface of the pattern layer (337, 637) contacting the organic emission layer (342, 642) is flat, and wherein both the organic emission layer (342, 642) and the second electrode (343, 643) have a flat surface on the pattern layer (337, 637) and convex portions on the convex portions of the first electrode (341, 641) on an emission portion overlapping with the opening (336a) of the bank layer (336).The organic light emitting display device (300, 600) according to claim 1, wherein the pattern layer (337, 637) comprises the same material as the bank layer (336).The organic light emitting display device (300, 600) according to claim 1 or 2, wherein the organic emission layer (342, 642) is continuously planar on the pattern layer (337, 637).The organic light emitting display device (300, 600) according to any one of claims 1 to 3, wherein the first electrode (341) is disposed on the overcoat layer (360) according to the surface topology of the overcoat layer (360), and the organic emission layer (342) is disposed on the convex portions of the first electrode (341, 641) and the pattern layer (337, 637) according to a surface morphology of the convex portions of the first electrode (341, 641) and the pattern layer (337, 637).The organic light emitting display device (300, 600) according to any one of claims 1 to 4, wherein the organic emission layer (342) corresponding to the concave portions (361) of the first electrode (341, 641) is flat.The organic light emitting display device (300, 600) according to any one of claims 1 to 5, further comprising: a color filter (350) disposed below the overcoat layer (360) so as to overlap with the opening (336a) of the bank layer (336), wherein all or some of the plurality of concave portions (361) of the overcoat layer (360) are opened, and the first electrode (341, 641) is in contact with the color filter (350) through the opened concave portions (361) of the overcoat layer (360).The organic light emitting display device (300, 600) according to any one of claims 1 to 6, wherein a height from a bottom edge of a concave portion (361) of the overcoat layer (360) to a tip of a convex portion (362) of the overcoat layer (360) is H, and the pattern layer (337, 637) is disposed between the bottom edge of the concave portion (361) of the overcoat layer (360) and 2H / 4.The organic light emitting display device (300, 600) according to any one of claims 1 to 7, wherein a thickness of the organic emission layer (342) between a concave portion (361) and a convex portion (362) of the overcoat layer (360) is smaller than a thickness of the organic emission layer (342) at the bottom edge of the concave portion (361) of the overcoat layer (360) or the tip of the convex portion (362) of the overcoat layer (360).The organic light emitting display device (300, 600) according to claim 8, wherein the organic emission layer (342) has the smallest thickness at a location where the organic emission layer (342) has the greatest slope between the concave portion (361) of the overcoat layer (360) and the convex portion (362) of the overcoat layer (360).The organic light emitting display device (300, 600) according to any one of claims 1 to 9, wherein an emission amount per unit area of the organic emission layer (342) between a concave portion (361) and a convex portion (362) is larger than an emission amount per unit area of the organic emission layer (342) at a bottom edge of the concave portion (361) of the overcoat layer (360) or a tip of the convex portion (362) of the overcoat layer (360).The organic light emitting display device (300, 600) according to any one of claims 1 to 10, wherein the organic emission layer (342) has the largest emission amount per unit area at a location where the organic emission layer (342) has the largest slope between a concave portion (361) of the overcoat layer (360) and a convex portion (362) of the overcoat layer (360).An organic light emitting display device, comprising: a plurality of pixels arranged on a substrate (310) and having an emission region, wherein the emission region of each of the plurality of pixels comprises: a plurality of effective emission regions each having a convex surface shape and a non-effective emission region arranged between two of the plurality of effective emission regions and having a flat surface shape; a first electrode (341) arranged on the emission region; an organic emission layer (342) arranged on the first electrode (341); a second electrode (343) arranged on the organic emission layer (342); a pattern layer (337) arranged on the non-effective emission region between the first electrode (341) and the organic emission layer (342), wherein the first electrode (341) has a plurality of convex portions arranged convexly on the effective emission region and a plurality of concave portions arranged on the non-effective emission region, the pattern layer (337) being arranged in the concave portions of the first electrode (341), an upper surface of the pattern layer (337) contacting the organic emission layer (342) being flat, the organic emission layer (342) and the second electrode (343) having a plurality of convex portions arranged on the effective emission region and a plurality of flat portions arranged on the non-effective emission region, the pattern layer (337, 637) being filled in all or some of the plurality of concave portions (361) of the first electrode (341, 641), wherein an upper surface of the pattern layer (337, 637) contacting the organic emission layer (342, 642) is planar.

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