KR20170123902A - Organic light emitting display device - Google Patents

Abstract

An organic light emitting display according to an embodiment of the present invention includes a substrate having a pixel region, an anode on the substrate, a light emitting portion on the anode, the light emitting portion including a hole injection layer, a light emitting layer, and an electron transporting layer, A bank in contact with the anode, and a charge blocking layer on the bank and in contact with the hole injection layer, thereby improving the light emitting performance and lifetime of the OLED display.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light-

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting diode (OLED) display, and more particularly, to an organic light emitting diode (OLED) display capable of minimizing lifetime and performance degradation of a display device due to UV (Ultra Violet)

The organic light emitting display device is a self light emitting display device, unlike a liquid crystal display device, a separate light source is not required, and thus the light emitting device can be manufactured in a light and thin shape. Further, the organic light emitting display device is not only advantageous from the viewpoint of power consumption by low voltage driving but also has excellent color reproduction, response speed, viewing angle, and contrast ratio (CR) and is developed as a next- have.

In an organic light emitting display, an emission layer (EML) using organic materials is disposed between two electrodes made of an anode and a cathode, a hole is injected from the anode into the light emitting layer, Is injected from the cathode into the light emitting layer, the injected electrons and holes are recombined with each other, and an exciton is formed to generate light.

A host material and a dopant material are included in the light emitting layer of the organic light emitting display, and light is emitted through interaction of the two materials. At this time, the host generates an exciton from electrons and holes and transfers energy to the dopant. A dopant is a dye organic substance added to a host in a small amount, and plays a role of receiving energy from a host and converting it into light.

Generally, a light emitting portion of an organic light emitting diode display includes a hole transport layer (HTL) between an anode and a light emitting layer, and an electron transport layer (ETL) between a cathode and a light emitting layer. So that electrons can be smoothly injected and moved.

[Prior Art Literature]

[Patent Literature]

White organic light emitting device (Patent Application No. 10-2007-0053472)

The conventional organic light emitting display has a deteriorated light emitting performance and a short life span when the organic light emitting display is used for a long time. The reasons for such deterioration in light emitting performance and lifetime are various. Among them, the continuous exposure of the organic light emitting display device to the external light such as sunlight degrades the light emitting performance and the life span. Especially, UV (Ultra Violet) included in external light such as sunlight has a fatal effect on the organic light emitting display .

When strong UV is applied to the organic light emitting display device or when the organic light emitting display device is exposed to UV for a long time, an outgasing phenomenon occurs inside the organic light emitting display device. The planarization layer formed of polyimide or PhotoAcryl forms a negative charge (-) gas compound such as N-methylpyrrolidone (NMP) or hexanitrile by UV irradiation. The gaseous compound having negative charge (-) is discharged to the outside and reacts with the light emitting portion formed adjacent to the planarization layer and formed of an organic material.

In particular, a negative charge (-) generated by the outgassing phenomenon reacts with a substance having a positive charge (+) constituting a hole injection layer disposed at the outermost portion of the light emitting portion, and the characteristics of the hole injection layer are degraded, The layer can not be injected into the light emitting layer smoothly.

As described above, when the number of holes migrating to the light emitting layer decreases due to insufficient injection of holes, the recombination region of holes and electrons becomes smaller in area than the recombination region before UV irradiation. As the area of the recombination region becomes smaller, the density of the excitons increases. At this time, triplet-triplet collision annihilation (TTA) rapidly progresses compared with the conventional recombination region of a large area, . In other words, due to the collision between the excessively fast excitons, the number of excitons capable of emitting light at the same driving voltage eventually decreases significantly, and the lifetime of the organic light emitting display device is reduced.

When the organic light emitting display device is exposed to strong UV rays or the organic light emitting display device is exposed to UV for a long time, the hole injection performance of the hole injection layer is lowered, and the light emitting performance and life .

Accordingly, the inventors of the present invention have recognized the above-mentioned problems and invented a new organic light emitting display device through various experiments to improve the light emitting performance and lifetime of the organic light emitting display.

The solutions according to the embodiments of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

An organic light emitting display according to an embodiment of the present invention includes a substrate having a pixel region, an anode on the substrate, a light emitting portion including a hole injection layer, a light emitting layer and an electron transporting layer, a cathode on the light emitting portion, A bank in contact with the anode, and a charge blocking layer on the bank and in contact with the hole injection layer.

An OLED display according to an exemplary embodiment of the present invention includes a bank, an anode, and a bank that are in contact with the anode and define a first pixel region, a second pixel region, and a third pixel region. The OLED display includes a first pixel region, And a first hole transport layer, a second hole transport layer, and a third hole transport layer, which are disposed on the first pixel region, the second pixel region, and the third pixel region, respectively, A first light emitting layer, a second light emitting layer, and a third light emitting layer, which are respectively disposed on the first pixel region, the second pixel region, and the third pixel region on the first hole transporting layer, the first hole transporting layer, the second hole transporting layer, , An electron transporting layer disposed on the first pixel region, the second pixel region, and the third pixel region on the first light emitting layer, the second light emitting layer, and the third light emitting layer, the first pixel region, And a cathode arranged in the third pixel region, A and it includes a charge blocking layer in contact with the hole injection layer.

An organic light emitting display according to an exemplary embodiment of the present invention includes a substrate having a pixel region, a planarization layer on the substrate, an anode on the planarization layer, and a light emitting portion that is on the anode and includes a hole injection layer, A cathode on the light emitting portion, a bank disposed in contact with the anode on the planarization layer, and a charge blocking layer on the bank and in contact with the hole injection layer to prevent light emission performance and lifetime from being deteriorated by outgassing occurring in the planarization layer .

The details of other embodiments are included in the detailed description and drawings.

The organic light emitting display device including the charge blocking layer according to an embodiment of the present invention can prevent the influence of outgassing caused by strong UV irradiation from the outside of the organic light emitting display device or exposure of the organic light emitting display device to UV for a long time, Layer, so that the light emitting performance and lifetime can be improved.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

The scope of the claims is not limited by the matters described in the contents of the invention, as the contents of the invention described in the problems, the solutions to the problems and the effects to be solved do not specify essential features of the claims.

1 is a schematic cross-sectional view illustrating an organic light emitting display according to an embodiment of the present invention.
2 is a cross-sectional view illustrating a phenomenon that occurs when UV light is irradiated to an organic light emitting display according to an embodiment of the present invention.
3 is a cross-sectional view illustrating a pixel region of an OLED display according to an exemplary embodiment of the present invention.
4 is a cross-sectional view illustrating a bank region of an OLED display according to an exemplary embodiment of the present invention.
5A and 5B are views for explaining the lifespan of the organic light emitting diode display according to an embodiment of the present invention, which is measured before and after UV irradiation.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Where the terms "comprises", "having", "done", and the like are used in this specification, other portions may be added unless "only" is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

1 is a schematic cross-sectional view illustrating an organic light emitting display according to an embodiment of the present invention.

Referring to FIG. 1, the OLED display 100 may include a substrate 110, a thin film transistor 120, an anode 140, a light emitting portion 150, and a cathode 160.

The substrate 110 may be a glass substrate or a plastic substrate having a flexible property so that components can be easily formed on the substrate 110.

A buffer layer 131 for suppressing the penetration of moisture (H ₂ O) or the like from the outside of the substrate 110 may be disposed on the substrate 110. However, the buffer layer 131 may be omitted depending on the structure and characteristics of the OLED display 100.

The thin film transistor 120 may include a gate electrode 121, a source electrode 124, a drain electrode 123, and a semiconductor layer 122.

The semiconductor layer 122 may be formed of amorphous silicon, polycrystalline silicon having better mobility than amorphous silicon, or ZnO or IGZO (indium-gallium-zinc oxide) having excellent mobility and uniformity characteristics, But the present invention is not limited thereto.

The gate electrode 121 serves as a switch of the thin film transistor 120. The gate electrode 121 may be made of a conductive metal, for example, copper (Cu), aluminum (Al), molybdenum (Mo), or the like, but is not limited thereto.

The gate insulating layer 132 prevents a current flowing in the semiconductor layer 122 from flowing to the gate electrode 121. The gate insulating layer 132 may be an insulating film composed of a single layer or a plurality of layers of silicon oxide (SiOx) or silicon nitride (SiNx).

The source electrode 124 and the drain electrode 123 serve to transmit an external electrical signal from the thin film transistor 120 to the light emitting unit 150. At this time, the source electrode 124 and the drain electrode 123 may be formed of a metal material such as a conductive metal such as copper (Cu), aluminum (Al), or molybdenum (Mo) or an alloy thereof, It is not.

An interlayer insulating layer 133 may be disposed to insulate the gate electrode 121 from the source electrode 123 and the drain electrode 124. [ At this time, the source electrode 123 and the drain electrode 124, which are in contact with the active layer 122, respectively, may be disposed on the interlayer insulating layer 133.

The passivation layer 134 may prevent unwanted electrical connection between the elements of the TFT 120 and prevent contamination or damage from the outside. The passivation layer 134 may be formed of an inorganic insulating film such as silicon oxide (SiOx) or silicon nitride (SiNx).

The thin film transistor 120 may be classified into an inverted staggered structure and a coplanar structure depending on the positions of the constituent elements of the thin film transistor 120. In a thin film transistor of an inverted staggered structure, a gate electrode is located on the opposite side of the source electrode and the drain electrode with respect to the semiconductor layer 122. Further, in the thin film transistor of the coplanar structure, the gate electrode is located on the same side as the source electrode and the drain electrode with respect to the semiconductor layer.

Although the thin film transistor 120 is shown as a thin film transistor having a coplanar structure in FIG. 1, the thin film transistor may also be formed of a thin film transistor having an inverted staggered structure.

1, only driving thin film transistors among various thin film transistors that can be included in the organic light emitting display 100 are shown, but various driving elements such as switching thin film transistors, capacitors, ).

The planarization layer 135 may be disposed on the top of the thin film transistor 120 to protect the thin film transistor 120 and alleviate the step caused by the thin film transistor 120. [ At this time, the planarizing layer 135 may be formed of an organic material such as polyimide or photo acryl.

The anode 140 may be disposed on the planarization layer 135. The anode 140 is an electrode serving to supply holes to the light emitting portion 150. The anode 140 may be electrically connected to the thin film transistor 120 through a contact hole in the planarization layer 135.

The anode 140 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), or the like, which is a transparent conductive material.

When the organic light emitting diode display 100 is a top emission type top emission type light emitting device, the light emitted from the light emitting portion of the anode 140 is reflected by the anode 140, So that the light emitting layer 135 can be emitted upward. At this time, the anode 140 may have a two-layer structure in which a transparent conductive layer composed of a transparent conductive material and a reflective layer are sequentially stacked, or a three-layer structure in which a transparent conductive layer, a reflective layer, and a transparent conductive layer are sequentially stacked. The reflective layer may be made of silver (Ag) or an alloy containing silver.

A bank 136 is disposed on the anode 140 and the planarizing layer 135. The bank 135 serves to define a pixel region for actually emitting light and define a pixel region corresponding thereto. The bank 136 may be formed of an organic material such as polyimide, acryl, or benzocyclobutene (BCB) resin.

The cathode 160 is disposed on the light emitting portion 150 and serves to supply electrons to the light emitting portion 150. Since the cathode 160 must supply electrons, the cathode 160 may be formed of a metal material such as magnesium (Mg), silver-magnesium (Ag: Mg) or the like, which is a conductive material having a low work function.

When the OLED display 100 is a top-mounted type, the cathode 160 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITO), zinc oxide (Zinc Oxide), and tin oxide (TiO 2) based transparent conductive oxide.

A light emitting portion 150 is disposed between the anode 140 and the cathode 160. The light emitting part 150 includes various organic layers including a light emitting layer as necessary, and the detailed structure and function of the light emitting part 150 will be described in detail with reference to FIGS. 2 to 4. FIG.

FIG. 2 is an enlarged cross-sectional view of an X region of FIG. 1 to explain a phenomenon that occurs when UV light is irradiated to an organic light emitting display according to an exemplary embodiment of the present invention.

2, an anode 140 may be disposed on the planarization layer 135, and a bank 136 may be disposed on the anode 140 and the planarization layer 135 in the OLED display 100 have.

The bank 136 serves to define a region for emitting light. A region where the bank 136 is disposed between the anode 140 and the light emitting portion 150 to define no light is defined as a bank region and a region where the anode 140 and the light emitting portion 150 are in contact with each other, . ≪ / RTI >

When a strong UV due to external light is irradiated from the upper part of the organic light emitting diode display device 100 or when the organic light emitting diode display device 100 is exposed to UV for a long time, the planarization layer 135 of the OLED display 100 Polyimide or photoacryl can react with UV to cause outgassing. When outgassing occurs in this way, negatively charged gaseous compounds such as Nmethylpyrrolidone (NMP) or hexanitrile may be generated. A negative charge can be moved on the bank 136 disposed above the planarization layer 135 while the gaseous compound having a negative charge is discharged to the outside of the planarization layer.

In the conventional organic light emitting diode display, the negative charge transferred through the bank directly reacts with the light emitting portion formed on the upper portion of the bank as described above, so that the performance and lifetime of the OLED display may be degraded. However, in the organic light emitting diode display 100 according to the embodiment of the present invention, a charge blocking layer is further disposed at the lower end of the hole injection layer included in the light emitting portion 150 in order to suppress direct reaction of the negative charge with the light emitting portion .

The charge blocking layer included in the OLED display 100 is disposed in direct contact with the bank 136. [ At this time, the negative charge moving through the bank 136 is cut off before it is moved to the light emitting portion 150, so that the influence of outgassing that can be caused by UV irradiation can be minimized.

The detailed structure and function of the charge blocking layer included in the organic light emitting diode display according to the embodiment of the present invention will be described in detail with reference to FIG. 3 to FIG.

FIG. 3 is a cross-sectional view illustrating a pixel region shown in FIG. 2 in order to explain a pixel region of an organic light emitting diode display according to an exemplary embodiment of the present invention. Referring to FIG.

Referring to FIG. 3, a pixel region that emits light in the OLED display 100 may emit light of one color.

For example, red light may be emitted in the first pixel region R, green light may be emitted in the second pixel region G, and blue light may be emitted in the third pixel region B. As described above, it is possible to constitute one display unit capable of emitting white light by combining pixel regions in which lights of different colors emit light.

Each of the first pixel region R, the second pixel region G and the third pixel region B of the organic light emitting diode display 100 includes an anode 140, a charge blocking layer 220, a light emitting portion 150, A cathode 160 and a capping layer 290. The light emitting portion 150 may include a hole injecting layer 230, a hole transporting layer 240, 242 and 244, a light emitting layer 250, 252 and 254, And may further include a transport layer 260.

The anode 140 is an electrode configured to supply holes to the light emitting portion 150. The anode 140 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), or the like, which is a transparent conductive material.

The organic light emitting diode display 100 shown in FIG. 3 is a mission type in which a cathode 160 is disposed and a top light emitting cathode is disposed. At this time, the anode 140 may further include a reflective layer so that light emitted from the light emitting portion is reflected by the anode 140 and is emitted more smoothly toward the upper direction where the cathode 160 is disposed. The anode 140 may have a two-layer structure in which a transparent conductive layer composed of a transparent conductive material and a reflective layer are sequentially stacked, or a three-layer structure in which a transparent conductive layer, a reflective layer, and a transparent conductive layer are sequentially stacked. The reflective layer may be silver (Ag) or an alloy containing silver.

The charge blocking layer 220 may be disposed on the anode 140 in the first pixel region R, the second pixel region G and the third pixel region B. [ The charge blocking layer 220 serves to block negative charges generated from the planarization layer disposed below.

The charge blocking layer 220 has a property of blocking a negative charge that can be introduced from the bank while having high hole mobility so that the performance of the device is not degraded when holes are injected from the anode 140 into the hole injection layer 230 Can be selected from among materials. Therefore, the charge blocking layer 220 may be made of the same material as the hole transporting layers 240, 242, and 244. When the charge blocking layer is formed of the same material as the hole transporting layer, the process can be simplified.

Alternatively, the charge blocking layer 220 disposed on the anode 140 except the region directly in contact with the bank may be removed depending on the structure and characteristics of the OLED display 100.

The hole injection layer 230 is disposed on the anode 140 or the charge blocking layer 220. The hole injection layer 230 serves to smoothly inject holes from the anode 140. The hole injection layer 230 may be formed using, for example, dipyrazino [2,3-f: 2 ', 3'-h] quinoxaline-2,3,6,7,10.11-hexacarbonitrile, CuPc ), And NPD (N, N'-bis (naphthalene-1-yl) -N, N'-bis (phenyl) -2,2'-dimethylbenzidine).

The hole transporting layers 240, 242 and 244 are disposed on the hole injection layer 230 and serve to smoothly transfer holes from the hole injection layer 230 to the light emitting layers 250, 252 and 254. The hole transporting layers 240, 242 and 244 may be formed of, for example, NPD (N, N'-bis (naphthalene-1-yl) -N, N'- (2,2 ', 7,7'-tetrakis (N, N-dimethylamino) - N, N'-bis -9,9-spirofluorene) and MTDATA (4,4 ', 4 "-Tris (N-3-methylphenyl-N-phenyl-amino) -triphenylamine).

Micro Cavity means that light of a specific wavelength is amplified by constructive interference by being repeatedly reflected between two layers where the light is separated by an optical length.

3, since the wavelength of light emitted when the organic light emitting diode display 100 emits different light for each pixel region is different, in order to realize a micro cavity, the wavelength of light emitted from each pixel region The resonance distance should be set as much as possible. In the organic light emitting diode display 100, the thicknesses of the hole transporting layers 240, 242, and 244 may be adjusted to different resonance distances for respective pixel regions.

The optimal thickness of the first hole transport layer 240, the second hole transport layer 242 and the third hole transport layer 244 can be independently determined within a thickness range capable of forming the optical distance of the micro cavities.

The light emitting layers 250, 252, and 254 are disposed on the hole transporting layers 240, 242, and 244. The light emitting layers 250, 252, and 254 may include a material capable of emitting light of a specific color, and the light emitting material may be formed using a phosphor or a fluorescent material.

In the case where the first light emitting layer 250 emits red light, it includes a host material including CBP (carbazole biphenyl) or mCP (1,3-bis (carbazol-9-yl) wherein the dopant comprises at least one selected from the group consisting of Phenyl-quinoline, Phenyl-quinoline, Acetylacetonate iridium, PQIracac bis (1-phenylquinoline) acetylacetonate iridium, PQIr The first light emitting layer 250 may be made of a fluorescent material containing PBD: Eu (DBM) 3 (Phen) or Perylene.

When the second light emitting layer 252 emits green light, a dopant material such as Ir complex including a host material including CBP or mCP and containing Ir (ppy) 3 (fac tris (2-phenylpyridine) iridium) Or a phosphorescent material. In addition, the second light emitting layer 252 may be formed of a fluorescent material containing Alq3 (tris (8-hydroxyquinolino) aluminum).

When the third light emitting layer 254 emits blue light, it may include a phosphorescent material including a host material including CBP or mCP and a dopant material including (4,6-F2ppy) 2Irpic. Further, the third light emitting layer 254 may include spiro-DPVBi (2,2-diphenyl-ethen-1-yl) biphenyl, DSA (1-4-di- [4- -di-phenyl) amino] styryl-benzene, a PFO-based polymer, and a PPV-based polymer.

The electron transport layer 260 is disposed on the emission layers 250, 252, and 254 and serves to transfer electrons from the electron injection layer to the emission layers 250, 252, and 254. The thickness of the electron transporting layer 260 can be adjusted in consideration of the electron transporting property. The electron transport layer 260 may be formed of, for example, Liq (8-hydroxyquinolinolato-lithium), PBD (2- (4-biphenyl) -5- 4-phenyl-5-tert-butylphenyl-1,2,4-triazole, spiro-PBD, 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline and And BAlq (bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum). The electron transport layer 260 may be omitted depending on the structure and characteristics of the OLED display 100.

Although not shown in FIG. 3, the electron injection layer may be disposed on the electron transport layer 260. The electron injection layer is an organic layer that facilitates the injection of electrons from the cathode 160 to the light emitting layers 250, 252, and 254. The electron injection layer may be a metal inorganic compound such as BaF2, LiF, NaCl, CsF, Li2O and BaO, and may be a dipyrazino [2,3-f: 2 ', 3'-h] quinoxaline- 6,7,10.11-hexacarbonitrile), CuPc (phthalocyanine), and NPD (N, N'-bis (naphthalene-1-yl) -N, N'- The organic compound may be at least one organic compound selected from the group consisting of

The cathode 160 is disposed on the light emitting portion 150 and supplies electrons to the light emitting portion 150. Since the cathode 160 must supply electrons, the cathode 160 may be formed of a metal material such as magnesium (Mg), silver-magnesium (Ag: Mg) or the like, which is a conductive material having a low work function.

The organic light emitting diode display 100 shown in FIG. 3 is of a mission type in which a cathode 160 is disposed and a top light is emitted to the top. That is, the light emitted from the light emitting unit 150 is emitted to the outside of the OLED display 100 through the cathode 160. In this case, the cathode 160 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (ZnO) And a transparent conductive oxide of a tin oxide (TiO) -based type.

A capping layer 290 may be further disposed on the cathode 160 to protect the organic light emitting display 100 and to allow light emitted from the light emitting unit 150 to be more easily taken out. However, the capping layer 432 may be omitted depending on the structure and characteristics of the OLED display 100.

In FIG. 3, the OLED display 100 has a top emission structure. Alternatively, the OLED display 100 may have a bottom emission structure.

4 is a cross-sectional view illustrating a bank region shown in FIG. 2 in order to explain a bank region of the OLED display according to an exemplary embodiment of the present invention.

4, a planarization layer 135, a bank 136, a charge blocking layer 330, a hole injection layer 340, an electron transport layer 350, a cathode (not shown) 160 and a capping layer 370 may be disposed. At this time, the hole transport layer and the light emitting layer described in FIG. 3 may be further included in a part of the bank region.

A bank 136, which is composed of polyimide, acrylic or benzocyclobutene (BCB) resin and serves to partition the pixel region, is disposed on the planarization layer 135 composed of an organic material such as polyimide or photoacryl .

The charge blocking layer 330 may be disposed on the bank 136.

When a strong UV due to external light is irradiated from the upper part of the organic light emitting diode display device 100 or when the organic light emitting diode display device 100 is exposed to UV for a long time, the planarization layer 135 of the OLED display 100 Polyimide or photoacryl can react with UV to cause outgassing. When outgassing occurs in this way, negatively charged gaseous compounds such as Nmethylpyrrolidone (NMP) or hexanitrile may be generated. The gaseous compound having a negative charge may be discharged to the outside of the planarization layer, and may move on the bank 136 disposed on the planarization layer 135. At this time, the charge blocking layer 330 disposed directly in contact with the upper portion of the bank 136 blocks the negative charge moving through the bank 136 before it moves to the light emitting portion, thereby minimizing the influence of outgassing .

The material used for the charge blocking layer 330 may be selected from materials having a property of blocking a negative charge that can be introduced from the bank 136 while having high hole mobility. Therefore, the charge blocking layer 330 can be made of the same material as the hole transporting layer in the pixel region.

The hole injection layer 340 is disposed on the charge blocking layer 330 and is formed of a material such as HAT-CN (dipyrazino [2,3-f: 2 ', 3'-h] quinoxaline- 7,10.11-hexacarbonitrile), CuPc (phthalocyanine), and NPD (N, N'-bis (naphthalene-1-yl) -N, N'- And may be made of any one or more selected.

The electron transport layer 350 may be disposed on the hole injection layer 340 in the bank region and may be formed of a material such as Liq (8-hydroxyquinolinolato-lithium), PBD (2- (4-biphenyl) tert-butylphenyl) -1,3,4oxadiazole), TAZ (3- (4-biphenyl) 4-phenyl-5-tert-butylphenyl-1,2,4- Dimethyl-4,7-diphenyl-1,10-phenanthroline and bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum. The electron transporting layer 350 may be omitted depending on the structure and characteristics of the OLED display 100.

Although not shown in FIG. 4, the electron injection layer may be disposed on the electron transporting layer 350 and may be a metal inorganic compound such as BaF2, LiF, NaCl, CsF, Li2O and BaO, HAT-CN (dipyrazino [ , 3-f: 2 ', 3'-h] quinoxaline-2,3,6,7,10.11-hexacarbonitrile, CuPc (phthalocyanine), and NPD (N, N, N'-bis (phenyl) -2,2'-dimethylbenzidine).

The cathode 160 may be formed of a metal material such as magnesium (Mg), silver-magnesium (Ag: Mg) or the like, which is a conductive material having a low work function. Alternatively, when the organic light emitting diode display 100 is a mission type in which light is emitted to the top, the cathode 160 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO) Or a transparent conductive oxide of indium tin zinc oxide (ITZO), zinc oxide (ZnO), and tin oxide (TiO 2).

A capping layer 370 may be further formed on the cathode 160 to protect the OLED display 100. The capping layer 370 may be omitted depending on the structure or characteristics of the OLED display 100.

5A and 5B are views for explaining the lifespan of the organic light emitting diode display according to an embodiment of the present invention, which is measured before and after UV irradiation.

At this time, the lifetime of the organic light emitting display was evaluated by measuring the luminance under the condition of applying current at a current density of 20.5 mA / cm ² at 40 캜. The horizontal axis represents the time (Time, h) and the vertical axis represents the luminance reduction rate (L / L0), that is, the luminance L at the time relative to the initial luminance L0.

Referring to FIG. 5A for explaining lifetime characteristics of an organic light emitting display device not including a conventional charge blocking layer, the time until the light emission luminance of 95% of the initial light emission luminance after UV irradiation, It can be confirmed that the organic EL display device reaches the 95% lifetime (T95) of the organic light emitting display device sooner. That is, in the conventional organic light emitting display, it can be seen that the luminance decreases more rapidly after the UV irradiation than before the UV irradiation. Therefore, in the conventional organic light emitting display device, the performance of the hole injection layer is lowered by UV irradiation, and the lifetime after UV irradiation is greatly reduced.

Referring to FIG. 5B for explaining lifetime characteristics of the organic light emitting display device including the charge blocking layer according to the embodiment of the present invention, it can be seen that the lifetime of the organic light emitting display device before and after the UV light irradiation is substantially unchanged. That is, even if the organic light emitting display according to the embodiment of the present invention is exposed to UV for a long time, the lifetime can be maintained and the performance can be continuously maintained.

The organic light emitting display according to embodiments of the present invention can be described as follows.

An OLED display according to an embodiment of the present invention includes a substrate having a pixel region, an anode on the anode, a light emitting portion including a hole injecting layer, a light emitting layer, and an electron transporting layer, A bank in contact with the anode, and a charge blocking layer on the bank and in contact with the hole injection layer, thereby improving the light emitting performance and lifetime of the organic light emitting display device.

According to another aspect of the present invention, the OLED display further includes a planarization layer on the substrate, and the anode and the bank may be disposed on the planarization layer.

According to another aspect of the present invention, the planarization layer may be composed of one of polyimide and photoacrylic.

According to another aspect of the present invention, the light emitting portion further includes a hole transporting layer, and the charge blocking layer may be made of the same material as the hole transporting layer.

According to another aspect of the present invention, the pixel region may be configured to emit light having one of red, green, and blue colors.

According to another aspect of the present invention, light may be emitted to the outside through the cathode.

An OLED display according to an exemplary embodiment of the present invention includes a bank, an anode, and a bank that are in contact with the anode and define a first pixel region, a second pixel region, and a third pixel region. The OLED display includes a first pixel region, And a first hole transport layer, a second hole transport layer, and a third hole transport layer, which are disposed on the first pixel region, the second pixel region, and the third pixel region, respectively, A first light-emitting layer, a second light-emitting layer, and a third light-emitting layer that are disposed on the first pixel region, the second pixel region, and the third pixel region, respectively, on the first hole transport layer, the second hole transport layer, An electron transporting layer disposed on the first pixel region, the second pixel region, and the third pixel region, which is on the first light emitting layer, the second light emitting layer, and the third light emitting layer, the first pixel region, And a cathode arranged in the third pixel region, It was it is possible to, by including the charge blocking layer in contact with the hole injection layer, a light emission improving the performance and life of the OLED display.

According to another aspect of the present invention, the first pixel region, the second pixel region, and the third pixel region may be configured to emit light having red, green, and blue, respectively.

According to another aspect of the present invention, the OLED display may further include a planarization layer disposed under the anode and the bank.

According to another aspect of the present invention, the planarization layer may be composed of one of polyimide and photoacrylic.

According to another aspect of the present invention, the light emitted from the first, second and third light emitting layers may be emitted to the outside through the cathode.

According to another aspect of the present invention, the charge blocking layer may be made of a material such as a first hole transporting layer, a second hole transporting layer, and a third hole transporting layer.

According to another aspect of the present invention, the first hole transporting layer, the second hole transporting layer, and the third hole transporting layer may have different thicknesses.

An organic light emitting display according to an exemplary embodiment of the present invention includes a substrate having a pixel region, a planarization layer on the substrate, an anode on the planarization layer, and a light emitting portion that is on the anode and includes a hole injection layer, A cathode on the light emitting portion, a bank in contact with the anode on the planarization layer, and a charge blocking layer on the bank and in contact with the hole injection layer to prevent light emission performance and lifetime from being deteriorated by outgassing occurring in the planarization layer. As a result, the charge blocking layer is blocked by the charge caused by the outgassing, so that the light emitting performance and lifetime of the organic light emitting display device can be improved.

According to another aspect of the present invention, the light emitting portion further includes a hole transporting layer, and the charge blocking layer may be made of the same material as the hole transporting layer.

According to another aspect of the present invention, the pixel region may be configured to emit light having one of red, green, and blue colors.

According to another aspect of the present invention, the light emitted from the light emitting portion may be emitted to the outside through the cathode.

The OLED display according to an exemplary embodiment of the present invention can be applied to a display device including a TV, a mobile, a tablet PC, a monitor, a laptop computer, a vehicle display, have. Alternatively, the OLED display according to the exemplary embodiment of the present invention may be applied to a wearable display device, a foldable display device, and a rollable display device.

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those embodiments and various changes and modifications may be made without departing from the scope of the present invention. . Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

100: organic light emitting display
110: substrate 120: thin film transistor
121: gate electrode 122: semiconductor layer
123: drain electrode 124: source electrode
131: buffer layer 132: gate insulating layer
133: interlayer insulating layer 134: passivation layer
135: planarization layer 136: bank
140: anode 150:
220, 330: charge blocking layer 230, 340: hole injection layer
240, 242, 244: hole transport layer
250, 252, 254: light emitting layer
260, 350: electron transport layer 160: cathode
290, 370: capping layer

Claims (17)

A substrate having a pixel region;
An anode on the substrate;
A light emitting portion on the anode, the light emitting portion including a hole injection layer, a light emitting layer, and an electron transporting layer;
A cathode on the light emitting portion;
A bank in contact with the anode; And
And a charge blocking layer on the bank and in contact with the hole injection layer. The method according to claim 1,
Further comprising a planarization layer on the substrate,
Wherein the anode and the bank are disposed on top of the planarization layer. 3. The method of claim 2,
Wherein the planarizing layer is made of one of polyimide and photoacryl. The method according to claim 1,
The light emitting unit may further include a hole transport layer,
Wherein the charge blocking layer is made of the same material as the hole transporting layer. The method according to claim 1,
Wherein the pixel region is configured to emit light having one of red, green, and blue colors. 6. The method of claim 5,
And the light is emitted to the outside through the cathode. A bank which is in contact with the anode and which divides the first pixel region, the second pixel region and the third pixel region;
A hole injection layer disposed on the anode and the bank, the hole injection layer being disposed in the first pixel region, the second pixel region, and the third pixel region;
A first hole transporting layer, a second hole transporting layer, and a third hole transporting layer disposed on the hole injection layer and disposed in the first pixel region, the second pixel region, and the third pixel region, respectively;
A first light emitting layer and a second light emitting layer which are respectively disposed on the first hole transporting layer, the second hole transporting layer and the third hole transporting layer and are respectively disposed in the first pixel region, the second pixel region and the third pixel region, And a third light emitting layer;
An electron transport layer disposed on the first, second, and third pixel regions on the first, second, and third emission regions, the first pixel region, the second pixel region, and the third pixel region;
A cathode disposed on the electron transporting layer and disposed in the first pixel region, the second pixel region, and the third pixel region; And
And a charge blocking layer on the bank and in contact with the hole injection layer. 8. The method of claim 7,
Wherein the first pixel region, the second pixel region, and the third pixel region are configured to emit light having red, green, and blue, respectively. 8. The method of claim 7,
And a planarization layer disposed below the anode and the bank. 10. The method of claim 9,
Wherein the planarizing layer is made of one of polyimide and photoacryl. 8. The method of claim 7,
Wherein light emitted from the first light emitting layer, the second light emitting layer, and the third light emitting layer is emitted to the outside through the cathode. 8. The method of claim 7,
Wherein the charge blocking layer is made of the same material as the first hole transporting layer, the second hole transporting layer, and the third hole transporting layer. 8. The method of claim 7,
Wherein the first hole transporting layer, the second hole transporting layer, and the third hole transporting layer have different thicknesses. A substrate having a pixel region;
A planarization layer on the substrate;
An anode on the planarization layer;
A light emitting portion on the anode, the light emitting portion including a hole injection layer, a light emitting layer, and an electron transporting layer;
A cathode on the light emitting portion;
A bank disposed in contact with the anode on the planarization layer; And
And a charge blocking layer on the bank and in contact with the hole injection layer to prevent light emission performance and lifetime from being deteriorated by outgasing occurring in the planarization layer. 15. The method of claim 14,
The light emitting unit may further include a hole transport layer,
Wherein the charge blocking layer is made of the same material as the hole transporting layer. 15. The method of claim 14,
Wherein the pixel region is configured to emit light having one of red, green, and blue colors. 17. The method of claim 16,
And the light emitted from the light emitting portion is emitted to the outside through the cathode.

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