KR20170123896A - Organic light emitting display device - Google Patents

Abstract

An organic light emitting display device according to an embodiment of the present invention includes a thin film transistor disposed on a substrate, a planarization layer disposed on the thin film transistor, a first electrode disposed on the planarization layer and connected to the thin film transistor, a bank disposed on one side of the first electrode and exposing a part of the first electrode, a light emitting unit disposed on the first electrode, a second electrode disposed on the light emitting unit, and a charge blocking layer disposed between the planarization layer and the bank. Accordingly, the present invention can minimize the reduction of the lifetime of the organic light emitting display device due to external light.

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 display, and more particularly, to an organic light emitting diode display capable of minimizing lifetime degradation due to external light.

The organic light emitting diode (OLED) is a self-luminous display device in which electrons and holes are injected into the light emitting layer from an anode for injecting electrons and an anode for injecting holes, And emits light when an exciton in which injected electrons and holes are coupled falls from an excited state to a ground state.

The organic light emitting display device is classified into a top emission type, a bottom emission type, and a dual emission type depending on a direction in which light is emitted, and a passive matrix type Matrix) and an active matrix (active matrix).

Unlike a liquid crystal display (LCD), an organic light emitting display does not require a separate light source and can be manufactured in a light and thin shape. In addition, 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 being studied as a next generation display device.

According to the use purpose of the organic light emitting display, if the organic light emitting display is used for a long period of time and exposed to external light for a long time, the light emitting performance and lifetime of the organic light emitting display may be reduced.

Particularly, when the organic light emitting display device is continuously exposed to UV (Ultra Violet) included in natural light, the organic light emitting device included in the organic light emitting display device may be damaged and the lifetime of the organic light emitting display device may be reduced .

Accordingly, the inventor of the present invention has invented an organic light emitting display device capable of minimizing the deterioration of lifetime due to external light.

A problem to be solved by the present invention is to provide an organic light emitting display device capable of minimizing damage to organic light emitting devices due to external light and minimized lifetime by forming a charge blocking layer made of an inorganic insulating material below the organic light emitting devices .

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.

In order to solve the above-described problems, an organic light emitting display device capable of minimizing the lifetime of the organic light emitting device due to external light is provided.

An organic light emitting display according to an embodiment of the present invention includes a thin film transistor on a substrate, a planarization layer disposed on the thin film transistor, a first electrode connected to the thin film transistor and a first electrode connected to the planarization layer, A bank for exposing a portion of the first electrode, a light emitting portion disposed on the first electrode, a second electrode disposed on the light emitting portion, and a charge blocking layer disposed between the planarization layer and the bank.

According to another aspect of the present invention, there is provided an organic light emitting diode display including an organic light emitting diode comprising at least one organic layer and an organic light emitting layer between a first electrode and a second electrode according to an embodiment of the present invention, And a charge blocking layer configured to prevent the lifetime of the organic light emitting device from being degraded by out-gassing occurring in the layer.

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

The organic light emitting diode display according to an embodiment of the present invention includes a charge blocking layer made of an inorganic insulating material formed under the light emitting portion, and a negative charge by out-gassing of a planarization layer generated by external light is injected through the bank, By minimizing the movement to the layer, the hole injection characteristic to the light emitting portion can be improved.

Also, the organic light emitting diode display according to an embodiment of the present invention includes a charge blocking layer formed at a lower portion of a light emitting portion to block a negative charge transfer path due to outgassing and to maintain a recombination region of the organic light emitting diode, Can be improved.

In addition, the organic light emitting display device according to an embodiment of the present invention improves the performance and reliability of the OLED display by protecting the OLED from the outgassing of the planarization layer generated by the external light, .

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 for explaining a phenomenon in which the lifetime of the organic light emitting diode display device is degraded by external light.
2 is a cross-sectional view illustrating an organic light emitting display according to an exemplary embodiment of the present invention.
3 is an enlarged view of a cross-sectional structure of an organic light emitting diode of an OLED display according to an exemplary embodiment of the present invention.
FIG. 4 is an enlarged view of an X region of the organic light emitting diode display according to the embodiment of the present invention shown in FIG. 2. Referring to FIG.
FIGS. 5A and 5B are graphs showing the evaluation results of the life before and after UV irradiation of the organic light emitting diode display according to the comparative example and the present invention. FIG.

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. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose 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.

Also, 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.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a schematic cross-sectional view for explaining a phenomenon in which the lifetime of the organic light emitting diode display device is degraded by external light.

Referring to FIG. 1, a conventional organic light emitting display includes a planarization layer 34 for planarizing an upper portion of a substrate, an anode 40 for supplying holes to the organic light emitting layer 53, and an organic light emitting layer 53. A cathode 50 for sequentially supplying electrons to the organic light emitting layer 53 and a cathode 60 for supplying electrons to the organic light emitting layer 53 are sequentially stacked and include a bank 45 for separating a plurality of adjacent sub pixel regions.

1, the light emitting unit 50 may include a plurality of organic layers including the hole injecting layer 51, the hole transporting layer 52, and the electron transporting layer 54, and the organic light emitting layer 53.

When the organic light emitting display device is exposed to UV for a long time, the light emitting portion 50 may be damaged by out gassing generated from the organic material layer adjacent to the light emitting portion 50 or the anode 40.

More specifically, the planarization layer 34 disposed under the anode 40 adjacent to the light emitting portion 50 is generally formed of an organic material such as polyimide (PI) or acryl. Such an organic material such as polyimide or acrylic forms a partially negatively charged gaseous compound 70 such as NMP (N-Methyl-2-Pyrrolidone), hexanitrile by UV irradiation.

Specifically, the nitrile group (-CN) of hexanitrile has a charge distribution in which a positive charge is blocked by carbon atoms and a negative charge protrudes to the outside. The gaseous compound 70 having a negative charge is discharged from the planarization layer 34 to the outside. As shown in FIG. 1, the gaseous compound 70 constitutes the light emitting portion 50 through the bank 45 positioned adjacent thereto To the organic layer.

At this time, the gaseous compound 70 reacts with the positively charged compound constituting the hole injection layer 51 located at the lowermost end of the light emitting portion 50 and disposed adjacent to the bank 45. Due to the reaction with the gaseous compound 70, the materials forming the hole injection layer 51 lose their positive charge, and holes can not be injected into the organic light emitting layer 53 smoothly.

As described above, 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, the hole injection performance of the hole injection layer 51 into the organic light emitting layer 53 is decreased, , Degradation of luminance, and deterioration of lifetime may occur.

Further, in the case of the lifetime of the organic light emitting diode included in the organic light emitting display, the hole and the electron may recombine to form an exciton, which may be influenced by the position of the recombination zone emitting light.

In the organic light emitting diode display, holes formed in the anode and electrons formed in the cathode move to the organic light emitting layer, and holes and electrons recombine in the organic light emitting layer to emit light by forming excitons. Here, the recombination region means a region in which an exciton is formed by recombination of holes and electrons in the organic light emitting layer.

Referring to FIG. 1, when strong UV is applied to the organic light emitting display through external light or when the organic light emitting display is exposed to UV for a long time, The hole injecting layer 51 is damaged by the outgassing occurring in the disposed planarization layer 34, and the hole injecting performance is deteriorated.

When the hole injection characteristics in the organic light emitting layer are deteriorated, a recombination region of holes and electrons is formed in the organic light emitting layer close to the hole injection layer 51 side. In this case, when the recombination region is formed at the center of the organic luminescent layer, the excitons disappear more quickly and the lifetime of the organic luminescent display device may be shortened.

Particularly, in the case where the organic light emitting layer 53 is an organic light emitting layer of a phosphorescent material, triplet-triplet annihilation (TTA) due to exciton collision may rapidly proceed and deterioration may occur. Due to the collision between the excessively fast excitons, the number of the excited excitons which can emit light at the same driving voltage is considerably reduced, and the lifetime of the organic light emitting display device may be shortened.

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

2, an OLED display 200 according to an embodiment of the present invention includes a substrate 210, a thin film transistor 220 and a first electrode 240 disposed on the substrate 210, And a light emitting unit 250 disposed between the first electrode 260 and the second electrode 260 and including a plurality of organic layers and an organic emission layer.

The OLED display 200 includes a plurality of sub pixels. The sub-pixel is a minimum unit area in which the actual light is emitted. In addition, a plurality of sub-pixels may be gathered to form a minimum group capable of expressing white light. For example, three sub-pixels may be a group, and a red sub-pixel, a green sub- Of the population. However, the present invention is not limited thereto, and various sub-pixel designs are possible. In FIG. 2, only one sub-pixel of the plurality of sub-pixels of the organic light emitting display device 200 is shown for convenience of explanation.

In the organic light emitting diode display 200 according to the embodiment of the present invention, the substrate 210 is formed of an insulating material for supporting various components of the organic light emitting diode display 200. For example, the substrate 210 may be formed of not only glass but also a plastic substrate such as PET (Polyethylen Terephthalate), PEN (Polyethylen Naphthalate), and polyimide.

A buffer layer 231 may be formed on the substrate 210 to prevent penetration of impurities from the substrate 210 and external components and to protect various components of the OLED display 200. The buffer layer 231 may be formed as a single layer or a multilayer structure of, for example, a silicon oxide film (SiOx) or a silicon nitride film (SiNx). The buffer layer 231 may be omitted depending on the structure and characteristics of the organic light emitting diode display 200.

A semiconductor layer 222, a gate insulating layer 232, a gate electrode 221, an interlayer insulating layer 233, a source electrode 223 and a drain electrode 224 are arranged on the buffer layer 231, and a gate electrode 221 A thin film transistor 220 including a semiconductor layer 222, a source electrode 223 and a drain electrode 224 is formed.

Specifically, a semiconductor layer 222 is formed on the substrate 210, and a gate insulating layer 232 is formed on the semiconductor layer 222 to insulate the semiconductor layer 222 from the gate electrode 221. An interlayer insulating layer 233 for insulating the gate electrode 221 from the source electrode 223 and the drain electrode 224 is formed on the gate electrode 221. A source electrode 223 and a drain electrode 224 which are in contact with the semiconductor layer 222 are formed on the interlayer insulating layer 233, respectively. The source electrode 223 and the drain electrode 224 are electrically connected to the semiconductor layer 222 through the contact hole.

The semiconductor layer 222 may be formed of an amorphous silicon (a-Si), a polycrystalline silicon (poly-Si), an oxide semiconductor, an organic semiconductor, or the like. When the semiconductor layer 222 is made of an oxide semiconductor, it may be made of any one of indium gallium zinc oxide (IGZO), zinc tin oxide (ZTO), indium zinc oxide (IZO), and indium tin zinc oxide But is not limited thereto.

The gate insulating layer 232 may be formed of a single layer or a multilayer structure of an inorganic insulating material such as a silicon oxide film (SiOx), a silicon nitride film (SiNx), or the like.

The gate electrode 221 functions to transfer a gate signal to the thin film transistor 220 and is made of at least one metal or alloy of aluminum (Al), molybdenum (Mo), titanium (Ti), and copper And may be formed of a single layer or a multi-layer structure of the metal or the material.

The source electrode 224 and the drain electrode 223 serve to transmit an external electrical signal from the thin film transistor 220 to the light emitting unit 250. The source electrode 224 and the drain electrode 223 may be made of at least one metal or alloy of aluminum (Al), molybdenum (Mo), titanium (Ti), copper (Cu) Or a multi-layer structure.

Only the driving thin film transistor 220 connected to the first electrode 240 among the various thin film transistors that can be included in the organic light emitting diode display 200 is illustrated. Each sub-pixel may further include a switching thin-film transistor, a capacitor, and the like.

A protective layer 270 and a planarization layer 234 are formed on the thin film transistor 220. The protective layer 270 may be made of an inorganic insulating material. For example, the protective layer 270 may be formed of a silicon oxide film (SiOx), a silicon nitride film (SiNx), or the like, but is not limited thereto. The planarization layer 234 functions to planarize the upper surface of the substrate 210. The planarization layer 234 may be composed of a single layer or a plurality of layers, and may be formed of an organic material. For example, the planarization layer 234 may be made of polyimide or photoacryl. The passivation layer 270 and the planarization layer 234 include contact holes for electrically connecting the thin film transistor 220 and the first electrode 240 in each sub-pixel.

Referring to FIG. 2, a charge blocking layer 235 is formed on the planarization layer 234 of the OLED display 200 according to an embodiment of the present invention. That is, the charge blocking layer 235 may be disposed between the planarization layer 234 and the first electrode 240, and between the planarization layer 234 and the bank 245.

The charge blocking layer 235 is formed by a negative charge generated by the out-gassing of the planarization layer 234 made of an organic material by external light or UV by the organic light emitting diode display 200 through the bank 245, The hole injection layer 251, which is a hole injection layer, is minimized.

The charge blocking layer 235 may be formed of an inorganic insulating material so as to block a path of negative charges due to out-gassing occurring in the planarization layer 234. [ For example, the charge blocking layer 235 may include at least one of a silicon oxide film (SiOx) and a silicon nitride film (SiNx).

In addition, the charge blocking layer 235 may have a structure in which a plurality of inorganic insulating layers including at least one of a silicon oxide film (SiOx) and a silicon nitride film (SiNx) are stacked in accordance with the charge blocking property required in the organic light emitting display .

Also, the charge blocking layer 235 may be formed to have a thickness of 500 ANGSTROM to 5000 ANGSTROM considering a charge blocking property and a process aspect required in the OLED display.

The first electrode 240 is formed on the planarization layer 234. The first electrode 240 may be an anode. The first electrode 240 may be formed of a conductive material having a relatively large work function and may serve to supply holes to the organic light emitting layer 253. The first electrode 240 may be electrically connected to the thin film transistor 220 through the contact hole of the planarization layer 234 and may be electrically connected to the source electrode 223 of the thin film transistor 220, for example. Also, the first electrodes 240 are spaced apart from one another by pixels. The first electrode 240 is formed of a transparent conductive material and may be formed of a material such as indium tin oxide (ITO), indium zinc oxide (IZO), or the like.

Also, when the organic light emitting diode display 200 according to the embodiment of the present invention is a top emission type, light emitted from the organic emission layer 253 is reflected by the first electrode 240, A reflective layer made of a material such as aluminum (Al) or silver (Ag) may be additionally formed on the upper or lower portion of the first electrode 240, .

For example, the first electrode 240 may have a two-layer structure in which a transparent conductive layer formed 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, for example silver (Ag) or APC (Ag / Pd / Cu).

In the description of the embodiment of the present invention, the top emission means a method in which light emitted from the organic emission layer 253 is emitted in the direction of the second electrode 260, Refers to a method in which light is emitted in the direction of the first electrode 240, which is the opposite direction to the top emission type.

A bank 245 is formed on the first electrode 240 and the charge blocking layer 235. The bank 245 divides the adjacent sub pixel regions and is disposed on one side of the first electrode 240 to expose a portion of the first electrode 240. In addition, the bank 245 may divide a pixel region constituted by a plurality of sub pixel regions. At this time, the bank 245 is in contact with the light emitting portion 250, and more specifically, can directly contact the hole injection layer 251. The bank 245 may also be made of an organic material. For example, the bank 245 may be made of polyimide, acryl or benzocyclobutene (BCB) resin, but is not limited thereto.

A second electrode (260) is formed on the first electrode (240). The second electrode 260 may be a cathode and may be formed of a conductive material having a low work function because electrons must be supplied to the organic light emitting layer 253. More specifically, the second electrode 260 may be a metal material such as magnesium (Mg), silver-magnesium (Ag: Mg), or the like.

When the OLED display 200 according to the exemplary embodiment of the present invention is a top emission type, the second electrode 260 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO) ), Indium tin zinc oxide (ITZO), zinc oxide (ZnO), and tin oxide (TiO 2) based transparent conductive oxide.

A light emitting portion 250 is formed on the first electrode 240 and the bank 245. The light emitting portion 250 may include various organic layers as necessary, and may include an organic light emitting layer 253. The organic layer may include at least one hole injection layer 251, a hole transport layer 252, and an electron transport layer 254.

3 is an enlarged view of a cross-sectional structure of an organic light emitting diode of an OLED display according to an embodiment of the present invention.

Hereinafter, the light emitting unit 250 of the OLED display 200 according to the embodiment of the present invention will be described in more detail with reference to FIG.

3, the light emitting unit 250 of the OLED display 200 includes a hole injection layer 251 (HIL) disposed on the first electrode 240, the first hole transport layer disposed on the hole injection layer ^{(251) (252a, 1 st} hole transport layer: 1 st HTL), a second hole transport layer disposed on the first hole transport layer ^{(252a) (252b, 2 nd} hole transport Layer: 2 ^nd HTL) and the third hole transport layer ^{(252c, 3 rd hole transport Layer} : 3 rd HTL), a red light emitting layer (253a), a green light emission layer (253b disposed on the hole transport layer (252a, 252b, 252c)), and An organic light emitting layer (EML) including a blue light emitting layer 253c, and an electron transport layer (ETL) 254 disposed on the organic light emitting layer.

3, an OLED display 200 according to an exemplary embodiment of the present invention includes a charge blocking layer 235 disposed between a planarization layer 234 and a first electrode 240, .

The first electrode 240 is disposed on the charge blocking layer 235 so as to correspond to each of the red sub pixel region R, the green sub pixel region G and the blue sub pixel region B defined on the substrate.

The hole injection layer 251 is disposed on the first electrode 240 as a common layer so as to correspond to both the red sub pixel region R, the green sub pixel region G and the blue sub pixel region B.

The hole injection layer 251 may function to smooth the injection of holes and may be formed of HATCN (1,4,5,8,9,11-hexaazatriphenylene-hexanitrile), CuPc (cupper phthalocyanine), PEDOT (poly , 4) -ethylenedioxythiophene, PANI (polyaniline), NPD (N, N-diphenylbenzidine), TPD (N, N'- phenyl-benzidine), α-NPB (Bis [N- (1-naphthyl) -N-phenyl] benzidine), TDAPB (1,3,5- carbazoyl-9- yl) triphenylamine), spiro-TAD (2,2 ', 7,7' '- Tetrakis (N, N-diphenylamino) -9,9-spirobifluorene) and CBP -9-yl) biphenyl), but the present invention is not limited thereto.

The hole injection layer 251 may be formed by doping a p-type dopant into the material of the first hole transport layer 252a. In this case, the hole injection layer 251 and the second hole transport layer 252a can be formed in a continuous process in one process equipment. The p-type dopant may include, but is not limited to, F ₄ -TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanl-quinidimethane).

The first hole transporting layer 252a is disposed on the hole injection layer 251 as a common layer so as to correspond to both the red sub pixel region R, the green sub pixel region G and the blue sub pixel region B. The first hole transport layer 252a plays a role of facilitating the transport of holes and includes a hole transport layer such as NPD (N, N-dinaphthyl-N, N'-diphenylbenzidine), TPD (N, (N, N-diphenylamino) -9,9-spirobifluorene) and MTDATA (4,4 ' , 4 "-Tris (N-3-methylphenyl-N-phenylamino) -triphenylamine).

The second hole transporting layer 252b is disposed on the first hole transporting layer 252a of the red sub pixel region R. And the third hole transporting layer 252c is disposed on the first hole transporting layer 252a of the green sub pixel region (G).

The second hole transport layer 252b and the third hole transport layer 252c function to smoothly transfer holes from the hole injection layer 251 to the red light emitting layer 253a and the green light emitting layer 253b, respectively.

The thickness of each of the second hole transporting layer 252b and the third hole transporting layer 252c may form an optical distance of a microcavity. The thickness of each of the second hole transporting layer 252b and the third hole transporting layer 252c is set such that the red light emitting layer 253a forms a micro cavity structure between the first electrode 240 and the second electrode 260 And the green light emitting layer 253b may be formed to form a micro cavity structure between the first electrode 240 and the second electrode 260. The red light emitting layer 253b may be formed in the red sub pixel region R and the green sub pixel region G, The efficiency of the OLED display 200 can be improved by forming the optical distance of the cavity.

The organic luminescent layer comprises a phosphorescent or luminescent layer. Specifically, the organic luminescent layer may be a red luminescent layer 253a, a green luminescent layer 253b, or a blue luminescent layer 253c, each of which may be formed of a phosphorescent material or a fluorescent material.

And the red light emitting layer 253a is disposed on the second hole transporting layer 252b of the red sub pixel region R. [ The red light emitting layer 253a may include a light emitting material that emits red light, and may be formed using a phosphor or a fluorescent material.

More specifically, the red light emitting layer 253a may include a host material including CBP (carbazole biphenyl) or mCP (1,3-bis (carbazol-9-yl) benzene), Ir (btp) (acetylacetonate) iridium (III)), Ir (piq) 2 (acac) (bis (1-phenylisoquinoline) (acetylacetonate) iridium A phosphorescent material containing a dopant including at least one of Ir (piq) 3 (tris (1-phenylquinoline) iridium (III)) and PtOEP (octaethylporphyrin platinum) (Phen) or perylene, but the present invention is not limited thereto.

The green light emitting layer 253b is disposed on the third hole transporting layer 252c of the green sub pixel region G. [ The green light emitting layer 253b may include a light emitting material that emits green light, and may be formed using a phosphor or a fluorescent material.

More specifically, the green light emitting layer 253b may include a host material including CBP or mCP, and may include Ir (ppy) 3 (tris (2-phenylpyridine) iridium (III)) or Ir (ppy) and a phosphorescent material including a dopant material such as an iridium complex containing bis (2-phenylpyridine) (acetylacetonate) iridium (III). Alternatively, Alq ₃ (tris (8-hydroxyquinolino) aluminum) But it is not limited thereto.

And the blue light emitting layer 253c is disposed on the first hole transporting layer 252a of the blue sub pixel region. The blue light emitting layer 253c may include a light emitting material that emits blue light, and may be formed using a phosphor or a fluorescent material.

More specifically, the blue light-emitting layer 253c may include a host material including CBP or mCP, and may be selected from the group consisting of FIrPic (bis (3,5) -difluoro-2- (2-pyridyl) phenyl- (2-carboxypyridyl) iridium (4,4'-bis [4-di-p-tolylamino) stryl) biphenyl), DSA (1-4-di- But is not limited to, a fluorescent material comprising any one of [4- (N, N-di-phenyl) amino] styryl-benzene, PFO (polyfluorene) polymer and PPV (polyphenylenevinylene) polymer.

The electron transport layer 254 includes a red light emitting layer 253a, a green light emitting layer 253b and a blue light emitting layer 253c so as to correspond to both the red sub pixel region R, the green sub pixel region G and the blue sub pixel region B, .

The thickness of the electron transport layer 254 can be controlled in consideration of the electron transporting property.

The electron transporting layer 254 functions to facilitate the electron transport, Liq (8-hydroxyquinolinolato-lithium ), Alq 3 (tris (8-hydroxyquinolino) aluminum), PBD (2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, TAZ (3- (4-biphenyl) (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum).

Further, an electron injection layer (EIL) may be further formed on the electron transport layer 254. [

The electron injection layer (EIL) may be made of metal inorganic compounds such as BaF ₂ , LiF, NaCl, CsF, Li ₂ O, and BaO, but is not limited thereto.

Here, the structure is not limited according to the embodiment of the present invention, and the structure of the hole injection layer 251, the first hole transporting layer 252a, the second hole transporting layer 252b, the third hole transporting layer 253c, (254) may be omitted. It is also possible to form one of the hole injection layer 251, the first hole transporting layer 252a, the second hole transporting layer 252b, the third hole transporting layer 253c and the electron transporting layer 254 in two or more layers It is possible.

The second electrode 260 is disposed on the electron transporting layer 254 so as to correspond to both the red sub pixel region R, the green sub pixel region G and the blue sub pixel region B.

The capping layer may be disposed on the second electrode 260. The capping layer serves to improve the light extracting effect of the organic light emitting display device and includes a first hole transporting layer 252a, an electron transporting layer 254, a red light emitting layer 253a, a green light emitting layer 253b, and a blue light emitting layer 253c Or < / RTI > The capping layer may be omitted depending on the structure and characteristics of the OLED display 200.

The organic light emitting display according to an embodiment of the present invention may be applied to various devices such as a TV, a mobile, a tablet PC, a monitor, a laptop computer, a vehicle display device, And the like. Or a wearable display device, a foldable display device, and a rollable display device.

FIG. 4 is an enlarged view of an X region of the organic light emitting diode display according to the embodiment of the present invention shown in FIG. 2. Referring to FIG.

As described above, when the organic light emitting display device is exposed to external light or UV for a long time, a gaseous compound having a negative charge generated by out-gassing of the planarization layer moves through a bank located adjacent to the planarization layer And can react with the organic material layer constituting the adjacent light emitting portion on the bank.

As a result of the reaction between the gaseous compound having a negative charge by the outgassing of the planarization layer and the adjacent hole injection layer material on the bank, the hole injection performance of the organic emission layer is lowered and the driving voltage of the organic emission display, Problems such as deterioration occurred.

Referring to FIG. 4, in the case of the OLED display 200 according to the embodiment of the present invention, a negative charge generated by the outgas of the planarization layer 234 located under the first electrode 240 due to external light And a charge blocking layer 235 that minimizes migration to the hole injection layer 251 that is an adjacent organic material layer through the bank 245. More specifically, the charge blocking layer 235 may be disposed between the planarization layer 234 and the first electrode 240 and between the planarization layer 234 and the bank 245.

The charge blocking layer 235 may be formed by a gaseous compound 290 having a negative charge generated by the out-gassing of the planarization layer 234 by the external light or UV by the organic light emitting diode display 200, The hole injection layer 251 as an organic material layer.

That is, in the organic light emitting diode display 200 according to the embodiment of the present invention, the charge blocking layer 235 made of an inorganic insulating material formed under the light emitting portion 250 is formed on the planarization layer 234, the negative charge due to the out-gassing is prevented from moving to the hole injection layer 251 through the bank 245 to minimize the reaction with the hole injection layer 251, thereby improving the hole injection property into the light emitting portion 250 .

In addition, the organic light emitting diode display 200 according to the embodiment of the present invention is configured such that the charge blocking layer 235 formed under the light emitting portion 250 blocks the path of negative charge due to outgassing, So that the lifetime of the organic light emitting display device can be improved.

The organic light emitting diode display 200 according to the exemplary embodiment of the present invention includes a charge blocking layer 235 formed under the light emitting portion 250 to protect the organic light emitting element from outgassing of the planarization layer 234 generated by external light. The performance and reliability of the organic light emitting display device can be improved.

FIGS. 5A and 5B are graphs showing the evaluation results of the life before and after UV irradiation of the organic light emitting diode display according to the comparative example and the present invention. FIG.

In the case of the comparative example, the evaluation results of the life before / after UV irradiation of the organic light emitting display device not including the charge blocking layer are shown. In the case of the embodiment, before the UV irradiation of the organic light emitting display device including the charge blocking layer below the light emitting portion / After-life evaluation result.

Here, in order to evaluate the lifetime degradation phenomenon caused by UV irradiation of the organic light emitting display device, each of the organic light emitting display devices was irradiated with UV of 420 nm wavelength at an intensity of 2.4 W / m ² for 80 hours. Also, the lifetime of the organic light emitting display device was evaluated by measuring the luminance under the condition of applying current at a current density of 40 to 20.5 mA / cm ² .

Referring to FIG. 5A, the lifetime before and after the UV irradiation of the organic light emitting display according to the comparative example is about 95% of the initial light emission luminance, that is, the 95% T95) was significantly reduced to about 70% after UV irradiation compared with before UV irradiation. That is, in the case of the conventional organic light emitting display, the performance of the hole injection layer is lowered by UV irradiation, and the lifetime after UV irradiation is greatly lowered.

Referring to FIG. 5B, the lifetime before and after the UV irradiation of the organic light emitting display device including the charge blocking layer according to the embodiment of the present invention is as follows: 95% lifetime (T95) 20%, and it can be confirmed that the life degradation phenomenon after UV irradiation is improved in the examples of the comparative examples. That is, in the case of the organic light emitting display according to the embodiment of the present invention, even when exposed to UV for a long time compared to the comparative example, the lifetime is not significantly reduced, and the performance of the OLED display is maintained.

From the above results, in the OLED display according to the present invention, the charge blocking layer made of the inorganic insulating material formed at the lower part of the light emitting part has a negative charge by the out-gassing of the planarization layer generated by the external light, The hole injection characteristic to the light emitting portion can be improved by minimizing the movement of the light emitting portion to the hole injection layer.

Also, the organic light emitting diode display according to an embodiment of the present invention includes a charge blocking layer formed at a lower portion of a light emitting portion to block a negative charge transfer path due to outgassing and to maintain a recombination region of the organic light emitting diode, Can be improved.

In addition, the organic light emitting display device according to an embodiment of the present invention improves the performance and reliability of the OLED display by protecting the OLED from the outgassing of the planarization layer generated by the external light, .

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 thin film transistor on a substrate, a planarization layer disposed on the thin film transistor, a first electrode disposed on the planarization layer and connected to the thin film transistor, And a charge blocking layer disposed between the planarizing layer and the bank, wherein the bank includes a bank that is disposed and exposes a portion of the first electrode, a light emitting portion disposed on the first electrode, a second electrode disposed on the light emitting portion, The hole injection characteristic to the light emitting portion can be improved by minimizing the movement of the negative charge due to the out-gassing of the generated planarization layer to the hole injection layer through the bank. In addition, the charge blocking layer blocks the movement path of the negative charge due to the outgassing and maintains the recombination region of the organic light emitting device, thereby improving the lifetime of the OLED display. The performance and reliability of the organic light emitting display can be improved by protecting the organic light emitting element from the outgassing of the planarization layer caused by external light in the charge blocking layer.

According to another aspect of the present invention, the charge blocking layer may be made of an inorganic insulating material.

According to another aspect of the present invention, the charge blocking layer may include at least one of a silicon oxide film (SiOx) and a silicon nitride film (SiNx).

According to still another aspect of the present invention, the charge blocking layer may have a structure in which a plurality of inorganic insulating layers are stacked.

According to another aspect of the present invention, the thickness of the charge blocking layer may be 500 ANGSTROM to 5000 ANGSTROM.

According to another aspect of the present invention, the light emitting portion may include at least one hole transporting layer, an organic light emitting layer, and an electron transporting layer.

According to another aspect of the present invention, the organic light emitting layer may include a phosphorescent light emitting layer or a fluorescent light emitting layer.

According to another aspect of the present invention, the light emitting portion may include a bank and a hole injection layer disposed adjacent to the first electrode.

According to another aspect of the present invention, since the charge blocking layer minimizes the negative charge due to out-gassing of the planarization layer due to external light to the hole injection layer through the bank, Can be improved.

According to another aspect of the present invention, the planarization layer may be formed of any one of polyimide and photo acryl.

An organic light emitting display device including an organic light emitting device including at least one organic layer and an organic light emitting layer between a first electrode and a second electrode according to an exemplary embodiment of the present invention includes a light emitting layer formed in a planarization layer located under the organic light emitting device, Since the charge blocking layer is provided to prevent the lifetime of the organic light emitting diode from being deteriorated by out-gassing, a negative charge due to out-gassing of the planarization layer generated by external light is transmitted through the bank to the hole injection layer And the hole injection characteristic to the light emitting portion can be improved. In addition, the charge blocking layer blocks the movement path of the negative charge due to the outgassing and maintains the recombination region of the organic light emitting device, thereby improving the lifetime of the OLED display. The performance and reliability of the organic light emitting display can be improved by protecting the organic light emitting element from the outgassing of the planarization layer caused by external light in the charge blocking layer.

According to another feature of the invention, the charge blocking layer may be located adjacent to the planarization layer.

According to another aspect of the present invention, the charge blocking layer may be located under the organic layer.

According to another aspect of the present invention, the charge blocking layer can block the negative charge of the planarization layer from moving to the organic layer.

According to another aspect of the present invention, the charge blocking layer may include at least one of a silicon oxide film (SiOx) and a silicon nitride film (SiNx).

According to another aspect of the present invention, the organic light emitting layer may include a red light emitting layer in a red sub pixel region, a green light emitting layer in a green sub pixel region, and a blue light emitting layer in a blue sub pixel region.

According to another aspect of the present invention, the organic layer may include a hole injection layer.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, have. 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.

200: organic light emitting display
210: substrate
220: thin film transistor
221: gate electrode
222: semiconductor layer
223: source electrode
224: drain electrode
231: buffer layer
232: gate insulating layer
233: Interlayer insulating layer
234: planarization layer
235 charge blocking layer
240: first electrode
245: Bank
250:
251: Hole injection layer
252a: first hole transporting layer
252b: second hole transport layer
252c: Third hole transport layer
253: Organic light emitting layer
254: electron transport layer
260: second electrode
270: protective layer
R: Red sub pixel area
G: green sub pixel area
B: blue sub pixel area

Claims (17)

A thin film transistor on a substrate;
A planarization layer disposed on the thin film transistor;
A first electrode disposed on the planarization layer and connected to the thin film transistor;
A bank disposed on one side of the first electrode and exposing a part of the first electrode;
A light emitting portion disposed on the first electrode;
A second electrode disposed on the light emitting portion; And
And a charge blocking layer disposed between the planarization layer and the bank. The method according to claim 1,
Wherein the charge blocking layer is made of an inorganic insulating material. The method according to claim 1,
Wherein the charge blocking layer comprises at least one of a silicon oxide film (SiOx) and a silicon nitride film (SiNx). The method according to claim 1,
Wherein the charge blocking layer has a structure in which a plurality of inorganic insulating layers are stacked. The method according to claim 1,
Wherein the thickness of the charge blocking layer is in the range of 500 to 5000 ANGSTROM. The method according to claim 1,
Wherein the light emitting portion includes at least one hole transporting layer, an organic light emitting layer, and an electron transporting layer. The method according to claim 6,
Wherein the organic light emitting layer comprises a phosphorescent light emitting layer or a fluorescent light emitting layer. The method according to claim 1,
Wherein the light emitting portion includes a bank and a hole injection layer disposed adjacent to the first electrode. 9. The method of claim 8,
The charge blocking layer minimizes the movement of negative charge caused by out-gassing of the planarization layer to the hole injection layer through the bank due to external light, Display device. The method according to claim 1,
Wherein the planarization layer is made of any one of polyimide and photoacid. An organic light emitting diode display comprising an organic light emitting diode comprising at least one organic layer and an organic light emitting layer between a first electrode and a second electrode,
And a charge blocking layer to prevent lifetime of the organic light emitting device from being deteriorated by out-gassing occurring in a planarization layer located under the organic light emitting device due to external light. 12. The method of claim 11,
Wherein the charge blocking layer is positioned adjacent to the planarization layer. 13. The method of claim 12,
Wherein the charge blocking layer is positioned below the organic material layer. 12. The method of claim 11,
Wherein the charge blocking layer blocks a negative charge of the planarization layer from moving to the organic material layer. 12. The method of claim 11,
Wherein the charge blocking layer comprises at least one of a silicon oxide film (SiOx) and a silicon nitride film (SiNx). 12. The method of claim 11,
Wherein the organic light emitting layer includes a red light emitting layer in a red sub pixel region, a green light emitting layer in a green sub pixel region, and a blue light emitting layer in a blue sub pixel region. 12. The method of claim 11,
Wherein the organic material layer includes a hole injection layer.

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