KR20170074468A - Organic light emitting display device - Google Patents

Abstract

An organic light emitting display according to an embodiment of the present invention includes a first electrode on a first pixel and a second pixel, a leakage current reducing layer on the first electrode and including an aromatic amine derivative having a carbazole skeleton, A first light emitting layer on the leakage current reducing layer corresponding to the first pixel, a second light emitting layer on the leakage current reducing layer corresponding to the second pixel, and a second light emitting layer on the first light emitting layer and the second light emitting layer Lt; RTI ID = 0.0 > a < / RTI >

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 The present invention relates to an organic light emitting display, and more particularly, to an organic light emitting display capable of minimizing a leakage current generated between a plurality of pixels.

An organic light-emitting display device (OLED device) is a next-generation display device having self-luminance characteristics. The organic light emitting display includes an organic light-emitting element including two electrodes and an organic light emitting layer disposed between the two electrodes. The organic light emitting device utilizes the principle that light is generated by injecting electrons and holes from two electrodes into an organic light emitting layer and combining injected electrons and holes.

Unlike a liquid crystal display device, an organic light emitting display does not require a separate light source, and thus can be manufactured in a light weight and thin form. In addition, the organic light emitting display device is advantageous in terms of viewing angle, contrast, response speed, and power consumption as compared with a liquid crystal display device, and has been attracting attention as a next generation display device.

1. [White Organic Light Emitting Device] (Patent Application No. 10-2009-0092596)

The organic light emitting display may have a patterened emission layer structure according to a design. The organic light emitting display device of the pattern light emitting layer structure may have a structure in which a light emitting layer emitting light of different colors, for example, red, blue, and green light emitting layers, between the two electrodes is separated for each pixel. Each of the light emitting layers may be pattern-deposited using a pixel-by-pixel mask, for example, a fine metal mask (FMM).

In addition to the light emitting layer, organic layers such as an injecting layer and a transporting layer for improving the device characteristics, for example, the driving voltage and the light emitting efficiency, may be further disposed between the two electrodes. In consideration of the characteristics of the respective light emitting layers patterned for each pixel, for example, the wavelength or material of the light emitted, the lamination structure of the light emitting devices or the lamination structure of the organic layers may be different for each pixel.

Recently, a technique of doping a hole transport layer disposed between an electrode and a light emitting layer with a p-type dopant has been introduced to further improve the hole transport. When the hole transport layer is doped with a p-type dopant, the holes are more smoothly supplied to the light emitting layers, so that the lifetime and efficiency of the organic light emitting display can be improved.

Such a hole transport layer doped with a p-type dopant (hereinafter referred to as a p-type hole transport layer) may have a common structure in an organic light emitting display having a pattern light emitting layer structure.

The layer having a common structure can be formed using a common mask in which all the pixels are opened, and can be laminated to all the pixels in the same structure without a pattern for each pixel. That is, the layer having a common structure is shared by a plurality of pixels because it is connected or extended without any break from one pixel to neighboring pixels. The layer having a common structure may be hereinafter referred to as a common layer or a layer of a common structure.

However, when the p-type hole transporting layer is formed in a common structure and is shared by a plurality of pixels, when the organic light emitting display device is driven, some current is leaked through the p-type hole transporting layer having a well- A problem may arise that not only pixels which are adjacent to each other but also neighboring pixels emit light. That is, since light is emitted from undesired pixels, color mixture may occur between the pixels, and display quality and image quality of the organic light emitting display may be deteriorated.

In particular, the inventors of the present invention have recognized that the problem of inter-pixel color mixture due to leakage current may be more problematic in low gray scale driving. In other words, the inventors of the present invention have found that the inter-pixel color mixing problem occurs more severely in accordance with the difference in the turn-on voltage of the neighboring pixels at the initial time when the voltage across the two electrodes exceeds the turn on voltage . This will be described in detail as follows.

The turn-on voltage refers to a driving voltage between two electrodes applied at a time when light is defined to emit light in one pixel. As described above, in the organic light emitting display device having the pattern light emitting layer structure, the stacking structure of the organic layers for each pixel may be different depending on the characteristics of the light emitting layer. The turn-on voltage of the pixel may vary depending on the characteristics of the light-emitting layer or the lamination structure of the organic layers.

When a pixel having a large turn-on voltage is driven in a structure in which the turn-on voltage of neighboring pixels is different from that of the neighboring pixels, a pixel having a small turn-on voltage disposed adjacent thereto may be greatly affected. The reason for this is that since the voltage value applied to the pixel having a large turn-on voltage is high, the amount of current leaking through the organic layer of the common structure is also increased, and the current flowing in the organic layer of the common structure is higher than that of the pixel having the large turn- This is because the turn-on voltage that is considered low is more easily leaked into a small pixel.

Also, when one pixel is driven with a low gray scale, since the luminance of the driven pixel is low, the color mixture of light can be more easily recognized by the user when the light of neighboring pixels is unnecessarily emitted . That is, at the initial point in time when the drive voltage applied between the two electrodes exceeds the turn-on voltage, the color mixture between neighboring pixels can be perceived more seriously.

In contrast, when a pixel having a relatively low turn-on voltage is driven, a pixel having a large turn-on voltage adjacent thereto may be relatively less affected. This is because the applied voltage has a low value for driving neighboring pixels having a large turn-on voltage, and the amount of current flowing through the organic layer of the common structure is relatively small and leakage is also reduced. Since the current flowing in the organic layer having the common structure flows more easily to the pixel having the low turn-on voltage than the pixel having the large turn-on voltage, which is considered to have a relatively high barrier for the current to flow, Can be reduced.

In addition, when one pixel is driven with a high gray scale, a high voltage exceeding the turn-on voltage is applied to the pixel and a large amount of current flows, so that the luminance of the driven pixel becomes high. Even if the current leaks to neighboring pixels, it may be hardly recognized by the user. Therefore, the color mixture due to the leakage current can be perceived more seriously at low gradations than at high gradations.

In addition, when driving at a high temperature, the leakage current increases with an increase in temperature, which causes a problem that the light is emitted simultaneously when neighboring pixels emit light. In recent years, image quality problems caused by leakage currents generated during high temperature driving have been raised as demands of consumers and customers.

Accordingly, the inventors of the present invention recognized the above-mentioned problems and experimented to improve the material of the organic layer constituting the organic light emitting display device to reduce the leakage current of the organic light emitting display device. In order to reduce the leakage current of the organic light emitting diode display, various organic light emitting display devices have been developed. To this end, the organic light emitting display device includes a leakage current reduction layer as an organic layer. The leakage current reduction layer is configured to reduce the leakage current from the p-type hole transporting layer to the light emitting layer, improve the hole transporting property to the light emitting layer, and reduce the driving voltage.

A problem to be solved by the present invention is to provide a leakage current reduction layer capable of reducing a leakage current while having a hole transporting characteristic from a p-type hole transporting layer to a light emitting layer, And an organic light emitting display device in which leakage current can be reduced.

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 first electrode on a first pixel and a second pixel, and a second electrode on the first electrode, the leakage current reducing layer including an aromatic amine derivative having a carbazole skeleton, A first light emitting layer on the leakage current reducing layer corresponding to the first pixel, a second light emitting layer on the leakage current reducing layer corresponding to the second pixel, and a second light emitting layer on the first light emitting layer and the second And a second electrode on the light emitting layer.

The leakage current-reducing layer may include a compound represented by the following formula (1).

[Chemical Formula 1]

Wherein R 1 is an aryl group and R 2 is one of an aryl group, an alkyl group, an alkoxy group, and an aryloxy group, and L 1 is an arylene group ( a fluorenylene group, and a heteroarylene group, and Ar1 and Ar2 are each independently an aryl group or a heteroaryl group.

The leakage current-reducing layer may further include a compound represented by the following formula (2).

(2)

The aromatic amine derivative may be doped with the compound of Formula 2 to form at least one p-type hole transporting layer on the first electrode.

Hole mobility of the leakage current reduction layer may be 4.7 × 10 ^-4 cm ² / Vs to 5.0 × 10 ^-4 cm ² / Vs range.

And a hole transporting layer between the leakage current reducing layer and at least one light emitting layer of the first light emitting layer and the second light emitting layer.

The absolute value of the HOMO energy level of the hole transport layer and the absolute value of the HOMO energy level of the leakage current reduction layer may be the same.

The first light emitting layer may emit red or green light, and the second light emitting layer may emit blue light.

A charge generation layer, a third light emitting layer, and a fourth light emitting layer on the first light emitting layer and the second light emitting layer.

The charge generation layer includes an n-type charge generation layer and a p-type charge generation layer, and the p-type charge generation layer may include the aromatic amine derivative.

The aromatic amine derivative includes a compound represented by Formula 3 below, and the p-type charge generating layer may further include a compound represented by Formula 4 below.

(3)

[Chemical Formula 4]

Wherein R 1 is an aryl group and R 2 is one of an aryl group, an alkyl group, an alkoxy group, and an aryloxy group, and L 1 is an arylene group, a fluorenylene group, and a heteroarylene group, and Ar1 and Ar2 are each independently an aryl group or a heteroaryl group.

The third light emitting layer is a layer emitting the same color as the first light emitting layer, and the fourth light emitting layer may be a layer emitting the same color as the second light emitting layer.

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

By constituting the leakage current reducing layer having hole transporting characteristics, the present invention can easily transfer holes to the light emitting layer, and the leakage current from the p-type hole transporting layer to the light emitting layer can be reduced.

The present invention also relates to a process for producing a quinone derivative, which comprises an aromatic amine derivative and a quinone derivative,

The leakage current from the p-type hole transporting layer to the light emitting layer can be reduced since the shift layer can be constituted and the movement of holes due to the p-type dopant can be reduced by the aryl group or the heteroaryl group contained in the aromatic amine derivative. Accordingly, since the organic light emitting display device can realize a desired color, the reliability of the organic light emitting display device can be improved.

Further, according to the present invention, when the low-gradation driving is performed, it is possible to suppress the flow of the holes of the light emitting element having a large turn-on voltage through the p-type hole transporting layer to the light emitting element having a relatively low turn- have. Accordingly, color mixing between neighboring pixels is improved, and display quality and reliability of the organic light emitting display device can be improved.

Further, the present invention can reduce the movement of holes due to the p-type hole transport layer during high-temperature and low-gradation driving, thereby reducing the leakage current from the p-type hole transporting layer to the light emitting layer. Accordingly, since the leakage current is reduced as the temperature increases, the amount of change in the color coordinates at high temperatures and low gradations is reduced, so that the display quality and reliability of the OLED display 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.

FIG. 1 is a view illustrating an organic light emitting diode display according to first and second embodiments of the present invention. Referring to FIG.
FIG. 2 is a view illustrating components of an OLED display according to a first embodiment of the present invention. Referring to FIG.
FIG. 3 is a view illustrating components of an OLED display according to a second embodiment of the present invention. Referring to FIG.
4 is a graph showing the voltage-current density characteristics according to the comparative example and the embodiment of the present invention.

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. In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can 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.

In the case of a description of a temporal relationship, for example, if the temporal relationship is described by 'after', 'after', 'after', 'before', etc., May not be continuous unless they are not used.

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, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings and embodiments.

1 is a diagram illustrating an organic light emitting diode display 1000 according to a first embodiment and a second embodiment of the present invention.

Referring to FIG. 1, an OLED display 1000 includes a plurality of pixels P1 and P2 that are adjacent to each other. A pixel is a minimum unit area in which actual light is emitted, and may be referred to as a sub-pixel or a pixel area. In addition, a plurality of pixels may be grouped into a minimum group capable of expressing white light. For example, three pixels may be grouped as a red pixel, a green pixel, pixel, and a blue pixel. However, the present invention is not limited thereto, and various pixel designs are possible. In FIG. 1, for convenience of explanation, only two neighboring pixels P1 and P2, in which light L1 of the first color and light L2 of the second color emit light, are shown.

As shown in FIG. 1, the OLED display 1000 includes a thin film transistor (TFT) 300 and a light-emitting element 400P1 and 400P2 for each pixel. The thin film transistor 300 is disposed on the substrate 100 and supplies a signal to the light emitting elements 400P1 and 400P2. The thin film transistor 300 shown in FIG. 1 may be a driving thin film transistor connected to the first electrode 410 of the light emitting devices 400P1 and 400P2. Each of the pixels P1 and P2 may further include a switching thin film transistor or a capacitor for driving the light emitting devices 400P1 and 400P2.

The substrate 100 may be composed of an insulating material, or a material having flexibility. Glass, metal, plastic, or the like, but is not limited thereto. When the organic light emitting display is a flexible organic light emitting display, it may be made of a flexible material such as plastic. In addition, when the organic light emitting device that is easy to implement flexible is applied to a vehicle lighting device, various degrees of freedom in designing and designing the vehicle lighting device can be ensured in accordance with the structure of the vehicle or the shape of the external appearance.

The thin film transistor 300 includes a gate electrode 310, an active layer 320, a source electrode 330, and a drain electrode 340. Referring to FIG. 1, a gate electrode 310 is formed on a substrate 100, and a gate insulating layer 210 covers a gate electrode 310. An active layer 320 is disposed on the gate insulating layer 210 so as to overlap with the gate electrode 310. A source electrode 330 and a drain electrode 340 are disposed on the active layer 320, do.

In the present invention, the overlapping of two objects may mean that at least a part of the two objects overlap each other regardless of the presence or absence of another object in the vertical relationship between them. In addition, .

The gate electrode 310, the source electrode 330, and the drain electrode 340 may be formed of a conductive material. For example, the gate electrode 310, the source electrode 330, and the drain electrode 340 may be formed of a metal such as molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti) Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. However, it is not limited thereto, and it can be formed of various materials.

The active layer 320 may be formed of any one of amorphous silicon (a-Si), polycrystalline silicon (poly-Si), oxide, and organic materials .

The gate insulating layer 210 may be composed of a single layer or a plurality of layers made of an inorganic material, and may be formed of silicon oxide (SiOx), silicon nitride (SiNx), or the like.

Although the thin film transistor 300 is shown as a staggered structure in FIG. 1, it is not limited thereto, and may be formed in a coplanar structure.

A planarization layer 220 exposing a part of the source electrode 330 is disposed on the thin film transistor 300. The planarization layer 220 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 220 may be formed of polyimide, acryl, or the like, but is not limited thereto.

A passivation layer may be further formed between the planarization layer 220 and the thin film transistor 300. The passivation layer is made of an inorganic material and protects the thin film transistor 300 and exposes a part of the source electrode 330 like the planarization layer 220.

The bank 230 can distinguish the pixels P1 and P2. The bank 130 may be formed of an organic material, for example, polyimide or photoacryl. However, the present invention is not limited thereto.

The light emitting devices 400P1 and 400P2 are disposed on the planarization layer 220 and include a first electrode 410, a light emitting unit 420, and a second electrode 430. [ The organic light emitting display 1000 according to the exemplary embodiment of the present invention is top emission and the light of the light emitting unit 420 is emitted upward through the second electrode 430. 1, the first light emitting device 400P1 of the organic light emitting display 1000 is located in the first pixel P1 and the second light emitting device 400P2 is located in the second pixel P2 Located. The first pixel P1 and the second pixel P2 are pixels that emit light L1 of the first color and light L2 of the second color, respectively, and the light L1 of the first color and the light L2 of the second color, The light L2 of the light source 2 emits different colors.

A specific structure of a light emitting element disposed in three neighboring pixels will be described with reference to FIG.

FIG. 2 is a view showing the components of the OLED display 1000 according to the first embodiment of the present invention. More specifically, it is a view for explaining components of three light emitting elements located in each of a plurality of pixels R, G, B of the organic light emitting diode display 1000. 2 shows the components of the organic light emitting display device, and the thickness of each component does not limit the content of the present invention.

The organic light emitting display 1000 according to the first embodiment of the present invention includes a plurality of neighboring pixels R, G and B and specifically includes a red pixel R, a green pixel G, And pixel (B). The three pixels R, G and B are the smallest group expressing white light and three pixels R, G and B are repeatedly arranged in the organic light emitting diode display 1000, Can be displayed.

Referring to FIG. 2, a red light emitting element is located in the red pixel R. The red light emitting device includes a light emitting portion 420 including a p-type hole transporting layer 425, a leakage current reducing layer 421, a hole transporting layer 423R, a red light emitting layer 424R, and an electron transporting layer 426.

The green light emitting element is located in the green pixel G. The green light emitting device includes a light emitting portion 420 including a p-type hole transporting layer 425, a leakage current reducing layer 421, a hole transporting layer 423G, a green light emitting layer 424G, and an electron transporting layer 426.

And a blue light emitting element is located in the blue pixel (B). The blue light emitting device includes a light emitting portion 420 including a p-type hole transporting layer 425, a leakage current reducing layer 421, a blue light emitting layer 424B, and an electron transporting layer 426.

Accordingly, the organic light emitting diode display 1000 according to the first embodiment of the present invention includes neighboring first and second pixels, and the first electrode 410 on the first pixel and the second pixel 410 on the second pixel , A leakage current reduction layer (421) on the first electrode (410) and including an aromatic amine derivative having a carbazole skeleton, and a leakage current reduction layer (421) on the leakage current reduction layer A second light emitting layer on the leakage current reducing layer 421 corresponding to the second pixel, and a second electrode 430 on the first light emitting layer and the second light emitting layer. have. The first pixel may be a red pixel R or a green pixel G and the second pixel B may be a blue pixel. The first light emitting layer may be a red light emitting layer 424R or a green light emitting layer 424G that emits red or green light and the second light emitting layer may be a blue light emitting layer 424B that emits blue light.

The first electrode 410 is an electrode for supplying holes to the light emitting portion 420 and may be referred to as an anode. The first electrodes 410 may correspond to the respective pixels and may be spaced apart from each other and may be referred to as a patterned electrode.

Depending on the type of the thin film transistor 300, the first electrode 410 may be connected to the drain electrode 340. Also, since the OLED display 1000 of the present invention is a top emission type, the first electrodes 410 may each include a reflective layer. For example, the first electrode 410 may have a two-layer structure in which a transparent layer and a reflective layer are sequentially stacked, or a three-layer structure in which a transparent layer, a reflective layer, and a transparent layer are sequentially stacked. The transparent layer may be made of a transparent conductive oxide (TCO) material such as ITO (indium tin oxide) or IZO (indium zinc oxide). The reflective layer may be made of, for example, copper (Cu), silver (Ag), palladium (Pd) or the like. Therefore, the first electrode 410 may be formed of a metal such as gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), lithium (Li), calcium (Ca), lithium fluoride (Mg: LiF), silver-magnesium (Ag: Mg), indium tin oxide (ITO), indium zinc oxide (IZO), or the like. It is not. Or a single layer or multiple layers thereof, but is not limited thereto. The first electrode 410 may be a reflective electrode.

The second electrode 430 is an electrode that is commonly disposed over the plurality of pixels R, G, and B and supplies electrons to the light-emitting portion 420. The second electrode 430 may be referred to as a cathode or a common electrode. The second electrode 430 may be made of a metal material having a small thickness, for example, 15 nm or more and 25 nm or less, or may be made of a transparent material, since light from the light emitting unit 420 must pass through the second electrode 430. The second electrode 430 may be formed of, for example, gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), lithium (Li), calcium (Ca), lithium fluoride Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), and IGZO (Indium Tin Oxide), which are transparent conductive materials such as LiF, Mg-LiF, Ag-Mg and Transparent Conductive Oxide (Indium Gallium Zinc Oxide), or the like, or a single layer or multiple layers thereof. However, the present invention is not limited thereto. The second electrode 430 may be a semi-transparent electrode or a semi-transparent electrode.

A capping layer 432 may be further formed on the second electrode 430 to protect the organic light emitting device and the capping layer 432 may be omitted depending on the structure and characteristics of the organic light emitting device .

The p-type hole transporting layer 425 is a hole transporting layer doped with a p-type dopant. The hole transporting layer 425 enhances the hole mobility and allows holes from the first electrode 410 to be injected into the light emitting portion 420 more smoothly. However, due to the excellent hole transporting property of the p-type hole transporting layer 425, holes in the p-type hole transporting layer 425 leak to the light emitting layers 424R, 424G, and 424B, . In recent years, reliability and image quality have been required to be improved at high temperatures and low gradations according to demands of consumers and customers. Leakage currents have been recognized as a more important problem in recent years, especially when they occur at high temperatures or low gradations, affecting reliability or image quality. Therefore, the inventors of the present invention need to improve the organic layer adjacent to the p-type hole transport layer so that the leakage current at a high temperature or a low tone is reduced.

Therefore, the present invention constitutes the leakage current reduction layer 421 as an organic layer. The leakage current reducing layer 421 smoothly transfers the holes injected from the first electrode 410 to the red light emitting layer 424R, the green light emitting layer 424G, or the blue light emitting layer 424B, and the p-type hole transporting layer 425, Type dopant in order to reduce the leakage current in the p-type dopant. That is, the leakage current-reducing layer 421 of the present invention should be formed of a material capable of reducing leakage current while having a hole-transporting property. An aromatic amine derivative is a material capable of stabilizing a cation radical generated when holes are injected, and has a hole transporting property. In order to reduce the leakage current, it is important to construct a substituent which can slow the hole mobility in the aromatic amine derivative. Accordingly, the inventors of the present invention have introduced aryl or heteroaryl groups into aromatic amine derivatives as substituents which can lower hole mobility through various experiments. An amine derivative having an aryl group or a heteroaryl group bonded thereto may have a high hole mobility in the vertical direction and may not lower the hole transporting property and the hole mobility in the horizontal direction is low so that holes in the p- 424R, 424G, and 424B. Thereby, the leakage current from the p-type hole transporting layer 425 to the light emitting layers 424R, 424G, and 424B can be reduced. Further, when the aromatic amine derivative has a carbazole skeleton, the driving voltage can be prevented from rising. In addition, an amine derivative having an aryl group or a heteroaryl group bonded thereto can also be prevented from increasing in driving voltage.

The leakage current-reducing layer 421 may include a compound represented by the following formula (1).

 [Chemical Formula 1]

Wherein R 1 is an aryl group and R 2 is one of an aryl group, an alkyl group, an alkoxy group, and an aryloxy group, L 1 is an arylene group, Fluorenylene group, and heteroarylene group, and Ar1 and Ar2 are each independently one of an aryl group and a heteroaryl group.

That is, the aromatic amine derivative as the leakage current reducing layer 421 has L1, R1, and R2 in the carbazole skeleton so that the molecular structure has a directionality, and Ar1 and Ar2 are connected to L1 to facilitate hole transfer in the horizontal direction Do not. Accordingly, the hole mobility in the vertical direction may be high due to Ar1 and Ar2, and the hole mobility in the horizontal direction may be low, so that the holes in the p-type hole transport layer 425 may not reach the light emitting layers 424R, 424G, 424B. Thereby, there is an effect that the leakage current from the p-type hole transporting layer 425 to the light emitting layers 424R, 424G, and 424B can be reduced.

The leakage current reducing layer 421 may further include a quinone derivative. The quinone derivative can reduce the driving voltage and improve the hole transporting property. The quinone derivative may be represented by the following formula (2).

(2)

Accordingly, the leakage current-reducing layer 421 of the present invention comprises aromatic amine derivatives and quinone derivatives. The leakage current reducing layer 421 may be formed by doping an aromatic amine derivative with a quinone derivative. In this case, the p-type dopant, which is a quinone derivative, is doped to the host, which is an aromatic amine derivative, so that the p-type hole transport layer 425 can be formed on the first electrode 410. Alternatively, the quinone derivative may be included in both the p-type hole transport layer 425 and the leakage current reduction layer 421 as a p-type dopant. Therefore, the p-type hole transporting layer 425 can be formed by doping a host, which is a hole transporting material, with a quinone derivative, which is a p-type dopant, and the leakage current reducing layer 421 can be formed by doping an aromatic amine derivative with a quinone derivative. The p-type hole transport layer 425 and the leakage current reduction layer 421 can be formed in a continuous process in one process equipment. In addition, at least one p-type hole transporting layer may be formed on the first electrode 410 as the p-type hole transporting layer 425 and the leakage current reducing layer 421 are formed in a continuous process in one process equipment. Accordingly, at least one p-type hole transporting layer may be formed between the first electrode 410 and the leakage current reducing layer 421. When at least one p-type hole transport layer is formed on the first electrode 410, a leakage current is generated more than one p-type hole transport layer. Therefore, the leakage current from the at least one p-type hole transporting layer to the light emitting layers 424R, 424G, and 424B can be reduced by the aromatic amine derivative included in the leakage current reducing layer 421 of the present invention.

The volume ratio of the aromatic amine derivative and the quinone derivative contained in the leakage current reduction layer 421 may be 99: 1. For example, when the thickness of the leakage current reduction layer 421 is 100 nm, the aromatic amine derivative contained in the leakage current reduction layer 421 may be 99 nm, and the quinone derivative may be 1 nm. Herein, the quinone derivative should be included in order to decrease the driving voltage or to improve the hole transporting property and to minimize the generation of leakage current to the light emitting layer by the quinone derivative. And, may be a hole mobility of leakage current reduction layer 421 is 4.7 × 10 ^-4 cm ² / Vs to 5.0 × 10 ^-4 cm ² / Vs range.

The p-type hole transport layer 425 and the leakage current reduction layer 421 are layers having a common structure and extend to the upper surface of the first electrode 410 corresponding to the plurality of pixels R, G, . The leakage current reducing layer 421 having a common structure can be formed by using a common mask with all the pixels opened and can form all the pixels R, G, and B without a pattern for each of the plurality of pixels R, G, , B) having the same structure. That is, since the leakage current reduction layer 421 is connected or extended without any break from one pixel to neighboring pixels, the leakage current reduction layer 421 shares a plurality of pixels. The p-type hole transporting layer 425 and the leakage current reducing layer 421 may be referred to as a common layer or a layer having a common structure.

The light emitting device of the organic light emitting diode display 1000 according to the first embodiment of the present invention has a patterned emission layer structure. More specifically, the light emitting layers 424R, 424G, and 424B disposed between the leakage current reducing layer 421 and the second electrode 430 have a patterned structure divided for each of the pixels R, G, .

The red light emitting layer 424R corresponding to the red pixel R, the green light emitting layer 424G corresponding to the green pixel G and the blue light emitting layer 424B corresponding to the blue pixel B emit different colors And may have a structure separated from each other by the pixels (R, G, B). Each of the light emitting layers 424R, 424G, and 424B may be pattern-deposited using a mask that is opened per pixel, for example, a fine metal mask (FMM).

The red light emitting layer 424R of the red pixel R may emit red light and may have a peak wavelength in a range of about 600 nm to 650 nm. The red luminescent layer 424R is formed of CBP (4,4'bis (carbozol-9-yl) biphenyl), MCP (1,3-bis (carbazol-9- yl) benzene), N, N'- -1-yl) -N, N'-bis (phenyl) -2,2'-dimethylbenzidine), Be complex and the like. The dopant constituting the red light-emitting layer 424R is Ir (btp) 2 (acac) (bis (2-benzo [b] thiophen-2-yl-pyridine) (acetylacetonate (Acetylacetonate) iridium (III)), Ir (piq) 3 (tris (1-phenylquinoline) iridium (III)), Pt (TPBP) (5,10,15,20 -tetraphenyltetrabenzoporphyrin platinum complex, etc. The dopant constituting the red light emitting layer 424R may be a dopant of a fluorescent material containing perylene. The red light emitting layer 424R may be composed of The material of the host or the dopant does not limit the content of the present invention.

The green light emitting layer 424G of the green pixel G may be made of a material that emits green light and has a peak wavelength in a range of about 510 nm to 590 nm. The green luminescent layer 424G is formed of CBP (4,4'bis (carbozol-9-yl) biphenyl), MCP (1,3-bis (carbazol-9- yl) benzene), N, N'- -1-yl) -N, N'-bis (phenyl) -2,2'-dimethylbenzidine, Be complex, anthracene derivatives, and the like. The dopant that constitutes the green light emitting layer 424G is Ir (ppy) 3 (tris (2-phenylpyridine) iridium (III)), Ir (ppy) ) And Ir (mppy) 3 (tris [2- (p-tolyl) pyridine] iridium (III). In addition, the dopant constituting the green light emitting layer 424G may be a dopant of a fluorescent material including Alq3 (tris (8-hydroxyquinolino) aluminum). The host or dopant material constituting the green light emitting layer 424G does not limit the content of the present invention.

The blue light emitting layer 424B of the blue pixel B may be a layer that emits blue light and may be formed of a material having a peak wavelength in a range of about 440 nm to 480 nm. The blue light emitting layer 424B may be formed of CBP (4,4'bis (carbozol-9-yl) biphenyl), MCP (1,3-bis (carbazol-9- yl) benzene), ADN (9,10- 2-yl) anthracene, anthracene derivatives, and the like. The dopant constituting the blue light emitting layer 424B is a dopant of a phosphor containing a dopant material including FIrpic (bis [2- (4,6-difluorophenyl) pyridinato-N] picolinato) iridium . The dopant constituting the blue light emitting layer 424B may be a dopant of a fluorescent material including a PFO (polyfluorene) -based polymer, a PPV (polyphenylenevinylene) -based polymer, pyrene derivatives, or the like. The host or dopant material constituting the blue light emitting layer 424B does not limit the content of the present invention.

The organic light emitting device may include a plurality of light emitting layers 424R, 424G, and 424B arranged in each of the pixels R, G, and B in consideration of the characteristics of the light emitting layers 424R, 424G, Emitting portions 420 having different stacking structures. More specifically, the light emitting portion 420 of the red light emitting device has a micro-cavity (not shown) between the first electrode 410 and the second electrode 430 according to the wavelength of the light emitted from the red light emitting layer 424R. ) May have a structure and thickness considering the distance. The micro-cavity means that the light emitted from the red light emitting layer 424R is amplified while repeating reflection and retroreflection between the two electrodes 410 and 430 to cause constructive interference, thereby improving luminous efficiency . When the first electrode 410 is formed of a transparent conductive layer such as ITO or IZO and a reflective layer of a metal material, the distance from the upper surface of the reflective layer to the lower surface of the second electrode 430 is larger than the distance between the first electrode 410 and the lower electrode. Resonance distance between the first electrode 430 and the second electrode 430.

 Specifically, the light emitting portion 420 of the red light emitting device may include a leakage current reducing layer 421 and a red light emitting layer 424R to optimize the micro-resonance distance between the first electrode 410 and the second electrode 430. [ And a hole transport layer 423R therebetween. The hole transport layer 423R serves to optimize the micro-resonance distance of the red light emitting device and to transfer the holes injected from the first electrode 410 to the red light emitting layer 424R smoothly. Likewise, the light emitting portion 420 of the green light emitting element further includes a hole transporting layer 423G for optimizing the fine-resonance distance of the green light emitting element.

The fine-resonance distance may have a thickness proportional to the wavelength of the light emitted from the light-emitting layers 424R, 424G, and 424B. 2, the thickness of the hole transport layer 423R of the red light emitting device is made thicker than the thickness of the hole transport layer 423G of the green light emitting device, so that the red light emitting device and the green light emitting device, The resonance distance can be optimized.

According to the design of the light emitting device, the blue light emitting device may further include a hole transporting layer for matching the micro-resonance distance. However, the hole transport layer of the blue light emitting device has a thickness corresponding to a range in which the light emitting portion 420 of the blue light emitting device is not thicker than the thickness of the red light emitting device or the light emitting portion 420 of the green light emitting device, The micro-resonance distance of each of the elements can be optimized.

The hole transporting layers 423R and 423G optimally transfer the holes injected from the first electrode 410 of the light emitting element to the light emitting layers 424R, 424G, and 424B, as well as optimizing the micro- . The hole transporting layers 423R and 423G may be formed of, for example, TPD (N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'- NPB (N, N'-di (naphthalen-1-yl) -N, N'- diphenyl-

Spiro-TAD (2,2 ', 7,7'-tetrakis (N, N'-diphenylamino)) -9,9-spirofluorene), and the like. Alternatively, the hole transporting layers 423R and 423G may be made of the same material as the leakage current reducing layer 421. [ The hole transporting layers 423R and 423G may be referred to as a pattern layer or a layer of a pattern structure. The hole transporting layers 423R and 423G may not be formed depending on the design of the light emitting element.

The absolute value of the HOMO (Highest Occupied Molecular Orbital) energy level of the hole transporting layers 423R and 423G and the absolute value of the HOMO energy level of the leakage current reducing layer 421 are equal to each other. Accordingly, the holes in the leakage current reducing layer 421 are smoothly transferred to the hole transporting layers 423R and 423G, so that the efficiency of the light emitting layers 424R, 424G and 424B can be improved. The absolute value of the HOMO energy level of the hole transport layer 423R or 423G and the HOMO energy level of the leakage current reduction layer 421 may be in the range of 5.0 eV to 6.0 eV. Preferably, the absolute value of the HOMO energy level of the hole transport layer 423R or 423G and the HOMO energy level of the leakage current reduction layer 421 may be 5.5 eV.

An electron blocking layer (EBL) may further be formed between the hole transporting layers 423R and 423G and the light emitting layers 424R and 424G and between the leakage current reducing layer 421 and the light emitting layer 424B. The electron blocking layer EBL prevents the flow of electrons that can be transferred to the leakage current reducing layer 421 so that the recombination of holes and electrons is smoothly performed in the light emitting layers 424R, 424G, and 424B, Can be improved.

The electron transport layer 426 serves to smoothly transfer electrons injected from the second electrode 430 to the light emitting layers 424R, 424G, and 424B. The electron transport layer 426 is a layer having a common structure and has a shape extending to the upper surface of each of the light emitting layers 424R, 424G, and 424B. The electron transport layer 426 may be formed of, for example, Alq3 (tris (8-hydroxy-quinolinato) aluminum), PBD (2) 4-biphenyl- , Bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminum, TAZ (3- (4-biphenyl) -4- And the like. However, the present invention is not limited thereto. Further, an electron injecting layer may be further formed on the electron transporting layer 426. The electron injection layer may function to inject electrons from the second electrode 430 into the electron transport layer 426 smoothly.

FIG. 2 illustrates an organic light emitting display 1000 including one light emitting portion. The present invention may be applied to an organic light emitting display including two or more light emitting portions. This will be described with reference to FIG.

FIG. 3 is a view showing the components of the organic light emitting diode display 2000 according to the second embodiment of the present invention. The organic light emitting diode display 2000 of FIG. 3 will not be described in detail with respect to the same or corresponding components as those of the embodiments described with reference to FIGS. 1 and 2. FIG. 3 shows components of the organic light emitting display device, and the thickness of each component does not limit the content of the present invention.

The organic light emitting display 2000 according to the second embodiment of the present invention includes a plurality of neighboring pixels R, G and B and specifically includes a red pixel R, a green pixel G, And a blue pixel (B). The three pixels R, G and B are the smallest group representing white light and three pixels R, G and B are repeatedly arranged in the organic light emitting display 2000, Can be displayed.

Referring to FIG. 3, a red light emitting element is located in the red pixel R. The red light emitting element includes a first light emitting layer 523 including a p-type hole transporting layer 525, a leakage current reducing layer 521, a first hole transporting layer 523R, a first red luminescent layer 524R, and a first electron transporting layer 526 (520). The first light emitting portion 520 includes a second light emitting portion 550 including a second hole transport layer 522, a second red light emitting layer 528R, and a second electron transport layer 527. An n-type charge generation layer 541 and a p-type charge generation layer 542 are formed between the first light emitting portion 520 and the second light emitting portion 550 to control the balance of charge.

The green light emitting element is located in the green pixel G. The green light emitting device includes a first light emitting layer 523 including a p-type hole transporting layer 525, a leakage current reducing layer 521, a first hole transporting layer 523G, a first green light emitting layer 524G, and a first electron transporting layer 526 (520). The first light emitting portion 520 includes a second light emitting portion 550 including a second hole transporting layer 522, a second green light emitting layer 528G, and a second electron transporting layer 527. An n-type charge generation layer 541 and a p-type charge generation layer 542 are formed between the first light emitting portion 520 and the second light emitting portion 550 to control the balance of charge.

And a blue light emitting element is located in the blue pixel (B). The blue light emitting device includes a first light emitting portion 520 including a p-type hole transporting layer 525, a leakage current reducing layer 521, a first blue light emitting layer 524B, and a first electron transporting layer 526. The first light emitting portion 520 includes a second light emitting portion 550 including a second hole transporting layer 522, a second blue light emitting layer 528B, and a second electron transporting layer 527. An n-type charge generation layer 541 and a p-type charge generation layer 542 are formed between the first light emitting portion 520 and the second light emitting portion 550 to control the balance of charge.

Accordingly, the OLED display 2000 according to the second embodiment of the present invention includes a charge generation layer, a third emission layer, and a fourth emission layer on the first emission layer and the second emission layer. The third light emitting layer is a layer emitting the same color as the first light emitting layer, and the fourth light emitting layer may be a layer emitting the same color as the second light emitting layer. That is, the third light emitting layer may be the second red light emitting layer 528R or the second green light emitting layer 528G. The fourth light emitting layer may be the second blue light emitting layer 528B.

The first electrode 510 is an electrode for supplying holes to the first light emitting portion 520 and may be referred to as an anode. The first electrodes 510 correspond to the respective pixels and may be spaced apart from each other and may be referred to as patterned electrodes. The first electrode 510 may be a reflective electrode.

The second electrode 530 is an electrode that is commonly disposed over a plurality of pixels R, G, and B and supplies electrons to the second light emitting portion 550. The second electrode 530 may be referred to as a cathode or a common electrode. The second electrode 530 may be a semi-transparent electrode or a semi-transparent electrode. The description of the first electrode 510 and the second electrode 530 is substantially the same as that described with reference to FIG. 2, and thus a detailed description thereof will be omitted.

A capping layer 532 may be further formed on the second electrode 530 to protect the organic light emitting device and the capping layer 532 may be omitted depending on the structure or characteristics of the organic light emitting device .

The p-type hole transporting layer 525 is a hole transporting layer doped with a p-type dopant and has a function of increasing the hole mobility so that holes from the first electrode 510 are injected into the first light emitting portion 520 more smoothly .

The leakage current reduction layer 521 is disposed on the first electrode 510 across the plurality of pixels R, G, The leakage current reducing layer 521 smoothly transfers the holes injected from the first electrode 510 to the first red light emitting layer 524R, the first green light emitting layer 524G, or the first blue light emitting layer 524B, -Type hole transporting layer 525. In this case, Therefore, the leakage current reduction layer 521 should be formed of a material capable of reducing leakage current while having a hole-transporting property. That is, the leakage current reducing layer 521 includes an aryl group or a heteroaryl group in an aromatic amine derivative having a hole transporting property. The amine derivative having an aryl group or a heteroaryl group bonded thereto may have a high hole mobility in the vertical direction and may not degrade the hole transporting property and the hole mobility in the horizontal direction is low so that holes in the p- Making it difficult to move to the light emitting layers 524R, 524G, and 524B. Thereby, the leakage current from the p-type hole transporting layer 525 to the first light emitting layers 524R, 524G, and 524B can be reduced. Further, when the aromatic amine derivative has a carbazole skeleton, it is possible to prevent the drive voltage from rising. In addition, an amine derivative having an aryl group or a heteroaryl group bonded thereto can also prevent the drive voltage from rising.

The leakage current reducing layer 521 may include a compound represented by the following Chemical Formula 1 described in FIG.

 [Chemical Formula 1]

Wherein R 1 is an aryl group and R 2 is one of an aryl group, an alkyl group, an alkoxy group, and an aryloxy group, L 1 is an arylene group, Fluorenylene group, and heteroarylene group, and Ar1 and Ar2 are each independently one of an aryl group and a heteroaryl group.

That is, the aromatic amine derivative as the leakage current reducing layer 521 has L1, R1 and R2 in the carbazole skeleton so that the molecular structure has a directivity, and Ar1 and Ar2 are connected to L1 to facilitate hole transfer in the horizontal direction Do not. Accordingly, the hole mobility in the vertical direction may be high due to Ar1 and Ar2, and the hole mobility in the horizontal direction may be low, so that holes in the p-type hole transport layer 525 may be transmitted through the first light emitting layers 524R, 524G, and 524B. Thereby, there is an effect that the leakage current from the p-type hole transporting layer 525 to the first light emitting layers 524R, 524G, and 524B can be reduced.

The leakage current reducing layer 521 may further include a quinone derivative. The quinone derivative can reduce the driving voltage and improve the hole transporting property. The quinone derivative may be represented by the following formula (2) described in FIG.

(2)

Accordingly, the leakage current-reducing layer 521 of the present invention comprises aromatic amine derivatives and quinone derivatives. The leakage current reducing layer 521 may be formed by doping an aromatic amine derivative with a quinone derivative. In this case, the p-type dopant, which is a quinone derivative, is doped in the host, which is an aromatic amine derivative, so that the p-type hole transporting layer 525 may be formed on the first electrode 510. Alternatively, the quinone derivative may be contained in both the p-type hole transporting layer 525 and the leakage current reducing layer 521 as a p-type dopant. Therefore, the p-type hole transporting layer 525 can be formed by doping a host, which is a hole transporting material, with a quinone derivative, which is a p-type dopant, and the leakage current reducing layer 521 can be formed by doping an aromatic amine derivative with a quinone derivative. The p-type hole transport layer 525 and the leakage current reduction layer 521 can be formed in a continuous process in one process equipment. In addition, at least one p-type hole transport layer may be formed on the first electrode 510 as the p-type hole transport layer 525 and the leakage current reduction layer 521 are formed in a continuous process in one process equipment. Therefore, at least one p-type hole transporting layer may be formed between the first electrode 510 and the leakage current reducing layer 521. When at least one p-type hole transport layer is formed on the first electrode 510, leakage current is generated more than one p-type hole transport layer. Therefore, the leakage current from the at least one p-type hole transporting layer to the first light emitting layers 524R, 524G, and 524B can be reduced by the aromatic amine derivative contained in the leakage current reducing layer 521 of the present invention.

The volume ratio of the aromatic amine derivative and the quinone derivative contained in the leakage current reducing layer 521 may be 99: 1. For example, when the thickness of the leakage current reduction layer 521 is 100 nm, the aromatic amine derivative contained in the leakage current reduction layer 521 may be 99 nm, and the quinone derivative may be 1 nm. Herein, the quinone derivative should be included for the purpose of decreasing the driving voltage or improving the hole transporting property, but should include minimizing the generation of leakage current to the light emitting layer by the quinone derivative. And, may be a hole mobility of leakage current reduction layer 521 is 4.7 × 10 ^-4 cm ² / Vs to 5.0 × 10 ^-4 cm ² / Vs range.

The p-type hole transporting layer 525 and the leakage current reducing layer 521 are layers having a common structure and extend to the upper surface of the first electrode 510 corresponding to the plurality of pixels R, G, . The leakage current reducing layer 521 having a common structure can be formed using a common mask having all the pixels opened. The leakage current reducing layer 521 having a common structure can be formed by using a common mask having all the pixels R, G, B). ≪ / RTI > That is, the leakage current reduction layer 521 is connected or extended without a break from one pixel to neighboring pixels, so that it shares a plurality of pixels. The p-type hole transporting layer 525 and the leakage current reducing layer 521 may be referred to as a common layer or a layer having a common structure.

The light emitting device of the organic light emitting diode display 2000 according to the second embodiment of the present invention has a patterned emission layer structure. More specifically, the first light emitting layers 524R, 524G, and 524B and the second light emitting layers 528R, 528G, and 528B disposed between the leakage current reducing layer 521 and the second electrode 530, , G, and B).

Corresponding to the first and second green light emitting layers 524G and 528G and the blue pixel B corresponding to the first and second red light emitting layers 524R and 528R and the green pixel G corresponding to the red pixel R The first and second blue light-emitting layers 524B and 528B may emit light of different colors and may have a structure separated from each other by the pixels R, G, and B. Each of the light emitting layers 524R, 524G, 524B, 528R, 528G, and 528B may be pattern-deposited using a mask that is opened per pixel, for example, a fine metal mask (FMM).

The first red light emitting layer 524R and the second red light emitting layer 528R may be light emitting layers emitting the same color. Accordingly, the first and second red light-emitting layers 524R and 528R of the red pixel R emit red light, and the peak wavelength of emitted light is in a range of about 600 nm to 650 nm ≪ / RTI > The host and the dopant included in the first and second red light emitting layers 524R and 528R are substantially the same as those described with reference to FIG. 2, and a detailed description thereof will be omitted.

The first green light emitting layer 524G and the second green light emitting layer 528G may be light emitting layers emitting the same color. Therefore, the first and second green light-emitting layers 524G and 528G of the green pixel G are layers that emit green light and are formed of a material having a peak wavelength emitted in a range of about 510 nm to 590 nm . The host and the dopant included in the first and second green light emitting layers 524G and 528G are substantially the same as those described with reference to FIG. 2, and a detailed description thereof will be omitted.

The first blue light emitting layer 524B and the second blue light emitting layer 528B may be light emitting layers emitting the same color. Therefore, the first and second blue light-emitting layers 524B and 528B of the blue pixel B are layers that emit blue light and are formed of a material having a peak wavelength emitted in a range of about 440 nm to 480 nm . The host and the dopant included in the first and second blue light-emitting layers 524B and 528B are substantially the same as those described in FIG. 2, and thus a detailed description thereof will be omitted.

2, the first and second light emitting units 520 and 550 of the red light emitting device may be configured to optimize the micro-resonance distance between the first electrode 510 and the second electrode 530 And further includes a first hole transport layer 523R between the leakage current reducing layer 521 and the first red light emitting layer 524R. The first and second light emitting units 520 and 550 of the green light emitting device further include a first hole transporting layer 523G for optimizing the micro-resonance distance of the green light emitting device. The blue light emitting device may further include a first hole transport layer to optimize the micro-resonance distance.

The first hole transporting layers 523R and 523G optimize the micro-resonance distances of the three light emitting devices and the holes injected from the first electrode 510 of the light emitting device to the first light emitting layers 524R, 524G and 524B, As shown in FIG. The first hole transporting layer 523R and 523G may be formed of a material such as TPD (N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'- diamine, NPB (N, N'-di (naphthalen-1-yl) -N, N'- diphenyl-

Spiro-TAD (2,2 ', 7,7'-tetrakis (N, N'-diphenylamino)) -9,9-spirofluorene), and the like. Alternatively, the first hole transporting layer 523R, 523G may be made of the same material as the leakage current reducing layer 521. [ The first hole transporting layer 523R, 523G may be referred to as a pattern layer or a layer of a pattern structure. The first hole transporting layer 523R, 523G may not be formed depending on the design of the light emitting element.

An electron blocking layer EBL may further be formed between the first hole transporting layer 523R, 523G and the first emitting layer 524R, 524G and between the leakage current reducing layer 521 and the first emitting layer 524B . The electron blocking layer EBL prevents electrons from flowing to the leakage current reducing layer 521 to smooth the recombination of holes and electrons in the first light emitting layers 524R, 524G, and 524B, The luminous efficiency can be improved.

The absolute values of the HOMO energy levels of the first hole transporting layers 523R and 523G and the HOMO energy levels of the leakage current reducing layer 521 are equal to each other. Accordingly, the holes in the leakage current reducing layer 521 can be smoothly transferred to the first hole transporting layers 523R and 523G, thereby improving the efficiency of the first light emitting layers 524R, 524G and 524B. The absolute value of the HOMO energy level of the first hole transport layer 523R or 523G and the HOMO energy level of the leakage current reduction layer 521 may be in the range of 5.0 eV to 6.0 eV. Preferably, the absolute value of the HOMO energy level of the first hole transport layer 523R, 523G and the HOMO energy level of the leakage current reduction layer 521 may be 5.5 eV.

The first electron transport layer 526 serves to smoothly transfer electrons injected from the n-type charge generation layer 541 to the first emission layers 524R, 524G, and 524B. The first electron transporting layer 526 is a layer having a common structure and has a shape extending to the upper surface of each of the first light emitting layers 524R, 524G, and 524B. The first electron transporting layer 526 may be formed of, for example, Alq3 (tris (8-hydroxy-quinolinato) aluminum), PBD (2) 4-biphenyl- oxadiazole), TAZ (3- (4-biphenyl) -4-phenyl-5-tert-butylphenyl-1,2,4-triazole), BAlq (bis (2-methyl- aluminum, and the like, but is not limited thereto.

The second hole transport layer 522 is located on the p-type charge generation layer 542. The second hole transport layer 522 injects holes of the p-type charge generation layer 542 into the second light emitting layers 528R, 528G, and 528B. The second hole transporting layer 522 is a layer having a common structure and has a shape extending to the upper surface of each of the second light emitting layers 528R, 528G, and 528B. The second hole transport layer 522 may include, for example, TPD (N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1'- NPB (N, N'-diphenyl-benzidine), Spiro-TAD (2,2 ', 7,7'-tetrakis (N, 9,9-spirobifluorene), and the like, but is not limited thereto.

The second electron transport layer 527 serves to smoothly transfer electrons injected from the second electrode 530 to the second emission layers 528R, 528G, and 528B. The second electron transporting layer 527 is a layer having a common structure and has a shape extending to the upper surface of each of the second light emitting layers 528R, 528G, and 528B. The second electron transport layer 527 may be formed of, for example, Alq3 (tris (8-hydroxy-quinolinato) aluminum), PBD oxadiazole, TAZ (3- (4-biphenyl) -4-phenyl-5-tert-butylphenyl-1,2,4-triazole), and bis (2-methyl-8- quinolinolate) -4- (phenylphenolato ) aluminum), but the present invention is not limited thereto. Further, an electron injecting layer may be further formed on the second electron transporting layer 527. The electron injection layer may function to inject electrons from the second electrode 530 into the second electron transport layer 527 smoothly.

An n-type charge generation layer 541 and a p-type charge generation layer 542 are formed between the first light emitting portion 520 and the second light emitting portion 550. The n-type charge generation layer 541 may be formed by doping an anthracene derivative with an alkali metal or an alkaline earth metal, but is not limited thereto. The p-type charge generation layer 542 may be formed by doping a host with a p-type dopant, but is not limited thereto. The host of the p-type charge generation layer 542 is NPD (N, N'-bis (naphthanlen-1-yl) -N, N'- '-bis (naphthanlen-1-yl) -N, N'-bis (phenyl) -benzidine). A leakage current may also be generated in the p-type charge generation layer 542 by the p-type dopant contained in the p-type charge generation layer 542. the p-type charge generation layer 542 may be formed of the same material as the leakage current reduction layer 521 so that the leakage current due to the p-type dopant is prevented from being transferred to the second light emitting layers 528R, 528G, and 528B.

The p-type charge generation layer 542 may include a compound represented by the following formula (3).

 (3)

Wherein R 1 is an aryl group and R 2 is one of an aryl group, an alkyl group, an alkoxy group, and an aryloxy group, L 1 is an arylene group, A fluorenylene group, and a heteroarylene group, and Ar1 and Ar2 are each independently an aryl group or a heteroaryl group.

That is, the aromatic amine derivative which is the p-type charge generation layer 542 has L1, R1 and R2 in the carbazole skeleton so that the molecular structure has a directionality, and Ar1 and Ar2 are connected to L1 to facilitate hole transfer in the horizontal direction Do not. Accordingly, the hole mobility in the vertical direction may be high due to Ar1 and Ar2, and the hole mobility in the horizontal direction may be low, so that the holes of the p-type dopant are injected into the second light emitting layers 528R, 528G, and 528B It becomes difficult to move. Thereby, the leakage current from the p-type charge generation layer 542 to the second light emitting layers 528R, 528G, and 528B can be reduced.

The p-type charge generation layer 542 may further include a quinone derivative. The quinone derivative can reduce the driving voltage and improve the hole transporting property. The quinone derivative may be represented by the following formula (4).

[Chemical Formula 4]

Accordingly, the p-type charge generation layer 542 of the present invention comprises aromatic amine derivatives and quinone derivatives. The p-type charge generation layer 542 may be formed by doping a quinone derivative with a host that is an aromatic amine derivative. That is, the quinone derivative may function as a p-type dopant of the p-type charge generation layer.

The volume ratio of the aromatic amine derivative to the quinone derivative may be 99: 1. For example, when the thickness of the p-type charge generation layer 542 is 100 nm, the aromatic amine derivative contained in the p-type charge generation layer 542 may be 99 nm, and the quinone derivative may be 1 nm. Herein, the quinone derivative should be included in order to decrease the driving voltage or to improve the hole transporting property and to minimize the generation of leakage current to the light emitting layer by the quinone derivative. The hole mobility of the p-type charge generation layer 542 may range from 4.7 x 10 ^-4 cm ² / Vs to 5.0 x 10 ^-4 cm ² / Vs.

Accordingly, since the leakage current due to the p-type dopant included in the p-type charge generation layer 542 can be reduced, it is possible to provide an organic light emitting display device capable of further improving reliability at high temperatures and low gradations.

In the case of the second embodiment of the present invention comprising two light emitting portions, the light emitting element can emit light in the high luminance region while keeping the current density low by constructing the charge generation layer between the two light emitting portions. Therefore, the organic light emitting display device having improved lifetime can be provided because the current density is kept low.

In the organic light emitting display according to the first embodiment and the second embodiment of the present invention, depending on the lamination structure of the light emitting portions for each of the pixels (R, G, B) or the characteristics of the light emitting layer, Lt; / RTI > Specifically, the turn-on voltage of the blue light emitting element is the largest, the turn-on voltage of the red light emitting element is the smallest, and the turn-on voltage of the green light emitting element is smaller than the turn-on voltage of the blue light emitting element but larger than the turn- The turn-on voltage refers to a driving voltage between two electrodes applied at a time when light is defined to emit light in one pixel.

As described above, in a structure in which the turn-on voltages of two neighboring pixels are different from each other, when a pixel having a large turn-on voltage is driven among the two pixels, the other pixels disposed adjacent to each other, A problem that unwanted light is emitted may occur. Specifically, the amount of current leaking through the common layer is also increased because the voltage value hanging on the pixel having a large turn-on voltage is high, and the current flowing in the common layer is small when the turn- The current can leak more easily into the pixel. As a result, undesired pixels may emit light, resulting in a problem of color mixture between neighboring pixels. Therefore, in the present invention, a leakage current reduction layer can be applied to reduce the leakage current in a blue light emitting device having a relatively large turn-on voltage.

The results of measurement of voltage, efficiency, chromaticity coordinate, current density, and chromaticity coordinate change according to the comparative example and the embodiment of the present invention will be described with reference to Tables 1 to 3 and FIG.

Table 1 below is a measurement of voltage, efficiency, and color coordinates according to the comparative example and the embodiment of the present invention.

Table 1

In the organic EL display device of Comparative Example 1, the hole transport layer was formed on the first electrode in the organic light emitting display of FIG. 2 by using N-bis (naphthylen-1-yl) ) Is doped with a quinone derivative. In the organic light emitting diode display of FIG. 2, an aromatic amine derivative and a quinone derivative are applied to the first electrode as a leakage current reducing layer. The driving voltage and efficiency in Table 1 were measured at a current density of 10 mA / cm < 2 >.

As shown in Table 1, it can be seen that the driving voltage is comparable to the comparative example and the embodiment of the present invention. The efficiency (cd / A) shows that the embodiment of the present invention is increased as compared with the comparative example. The blue color coordinates show that the comparative example and the embodiment of the present invention are at almost the same level. Therefore, when applying the leakage current reduction layer of the present invention, the leakage current reduction layer of the present invention can be applied to an organic light emitting display device because it exhibits drive voltage, efficiency, and color coordinates substantially equivalent to those of the conventional OLED display. . The same result can be measured even when the second embodiment of the present invention is applied, and the leakage current reduction layer can be applied to the OLED display device including two light emitting portions.

4 is a graph showing the voltage-current density characteristics according to the comparative example and the embodiment of the present invention. In Fig. 4, the horizontal axis represents voltage (V), and the vertical axis represents current density (mA / cm < 2 >).

The comparative example and the example of Fig. 4 were constructed in the same manner as the contents described in Table 1.

It can be seen that the embodiment of the present invention at a voltage of 2 V is formed to have a lower current density as compared with the comparative example, so that the leakage current is lowered. That is, it can be understood that the leakage current reducing layer of the present invention is applied to suppress, reduce, or prevent a current leaked by the p-type hole transporting layer from flowing into the light emitting layer.

Table 2 below is a table for measuring the amount of change in white color coordinates according to the comparative example when driving at room temperature and high temperature and the embodiment of the present invention. The comparative example and the embodiment of the present invention were constructed from the same organic light emitting display device as in Table 1.

Table 2

In Table 2, the room temperature refers to 25 ° C and the high temperature refers to 70 ° C.

The temperature range of the high temperature required for the organic light emitting display may be 60 ° C or higher or 105 ° C or lower. This temperature range is a temperature range for use in an environmental condition of the user using the organic light emitting display, and the temperature range may be changed according to the user's environment condition. When applied to a vehicle lighting apparatus, the temperature range is required to be 105 ° C or less at -40 ° C (minus 40 ° C) depending on the temperature change of the external environment. The results of the present invention were measured at 70 ° C due to equipment limitations, but even when measured at 105 ° C, the leakage current can be reduced as at 70 ° C. Therefore, the present invention can provide an organic light emitting display device or a vehicle lighting device in which the leakage current can be reduced even at a high temperature of 105 ° C.

Table 2 shows the measured values in the low gradation range. A level corresponding to about 30% of the total gray level of the light emitting device is called a low gray scale, and a level corresponding to about 30% of the brightness level is called a high gray scale. In Table 2, it is measured at, for example, 31 gradations. The amount of change in color coordinates refers to a difference between a color coordinate at a high temperature and a color coordinate at a normal temperature. As the amount of change in the color coordinate increases, the amount of leakage current increases, thereby decreasing the reliability. That is, neighboring pixels are emitted by the leakage current, so that the desired white color can not be realized by changing the color of the OLED display.

As shown in Table 2, the white color coordinate variation amounts Wx and Wy in the comparative example are (0.033 and 0.046), and the white color coordinate variation amounts Wx and Wy in the embodiment of the present invention are (0.015 and 0.013), respectively. Therefore, in the embodiment of the present invention, the amount of change of the white color coordinates (Wx, Wy) from the high temperature to the room temperature is small compared with the comparative example, so that the amount of the leakage current at the low gray level is small. When the blue light emitting element having a large turn-on voltage is driven, and particularly when driven at a low gray scale, the leakage current reducing layer of the present invention is applied so that the turn-on voltage leaked through the p- The current of the large blue light emitting element can be suppressed, reduced, or prevented from flowing into the blue light emitting layer. Therefore, color mixture between pixels due to a leakage current is prevented, and reliability and display quality of the organic light emitting display device can be improved. The same result can be measured even when the second embodiment of the present invention is applied, and the leakage current reduction layer can be applied to the OLED display device including two light emitting portions.

Table 3 is a table for measuring the amount of change in white color coordinates according to the comparative example when driving at room temperature and high temperature in 15 gradations with a low gradation and the embodiment of the present invention. The comparative example and the embodiment of the present invention were constructed from the same organic light emitting display device as in Table 1.

Table 3

As shown in Table 3, it can be seen that the white color coordinate variation amounts (Wx, Wy) in the comparative example are (0.058, 0.062) and the white color coordinate variation amounts (Wx, Wy) in the embodiment are (0.035, 0.035). Therefore, the amount of change in the white color coordinates (Wx, Wy) from the high temperature to the room temperature is small in the example of the comparative example, so that the amount of the leakage current in the low gradation is small. When the blue light emitting element having a large turn-on voltage is driven, particularly when driven at a low gray scale, by applying the leakage current reducing layer of the present invention, the turn-on voltage leaked through the p- The current of the large blue light emitting element can be suppressed, reduced, or prevented from flowing into the blue light emitting layer. Therefore, color mixture between pixels due to a leakage current is prevented, and reliability and display quality of the organic light emitting display device can be improved. The same result can be measured even when the second embodiment of the present invention is applied, and the leakage current reduction layer can be applied to the OLED display device including two light emitting portions.

INDUSTRIAL APPLICABILITY As described above, the present invention can facilitate the hole transfer into the light emitting layer and reduce the leakage current from the p-type hole transporting layer to the light emitting layer by constituting the leakage current reducing layer having hole transporting characteristics.

In addition, the present invention constitutes a leakage current-reducing layer including an aromatic amine derivative and a quinone derivative, and the movement of holes due to the p-type dopant can be reduced by the aryl group or the heteroaryl group contained in the aromatic amine derivative. The leakage current from the hole transporting layer to the light emitting layer can be reduced. Accordingly, since the organic light emitting display device can realize a desired color, the reliability of the organic light emitting display device can be improved.

Further, according to the present invention, when the low-gradation driving is performed, it is possible to suppress the flow of the holes of the light emitting element having a large turn-on voltage through the p-type hole transporting layer to the light emitting element having a relatively low turn- have. Accordingly, color mixing between neighboring pixels is improved, and display quality and reliability of the organic light emitting display device can be improved.

Further, the present invention can reduce the movement of holes due to the p-type hole transport layer during high-temperature and low-gradation driving, thereby reducing the leakage current from the p-type hole transporting layer to the light emitting layer. Accordingly, since the leakage current is reduced as the temperature increases, the amount of change in the color coordinates at high temperatures and low gradations is reduced, so that the display quality and reliability of the OLED display can be improved.

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.

1000, 2000: organic light emitting display device 100: substrate
300: Thin film transistor 400: Light emitting element
410, 510: first electrode 420, 520, 550:
421, 521: Leakage current reduction layer 430, 530: Second electrode

Claims (12)

1. An organic light emitting diode display comprising a first pixel and a second pixel which are adjacent to each other,
A first electrode on the first pixel and the second pixel;
A leakage current reduction layer on the first electrode, the leakage current reduction layer comprising an aromatic amine derivative having a carbazole skeleton;
A first light emitting layer on the leakage current reducing layer corresponding to the first pixel;
A second light emitting layer on the leakage current reducing layer corresponding to the second pixel; And
And a second electrode on the first light-emitting layer and the second light-emitting layer. The method according to claim 1,
Wherein the leakage current-reducing layer comprises a compound represented by the following formula (1).
[Chemical Formula 1]

Wherein R1 is an aryl group and R2 is one of an aryl group, an alkyl group, an alkoxy group, and an aryloxy group, L1 is an arylene group, a fluorenylene group, and a heteroarylene group, Ar1 and Ar2 are each independently one of an aryl group and a heteroaryl group, The method according to claim 1,
Wherein the leakage current-reducing layer further comprises a compound represented by the following formula (2).
(2)

The method of claim 3,
Wherein the aromatic amine derivative is doped with the compound of Formula 2 to form at least one p-type hole transporting layer on the first electrode. The method according to claim 1,
And the hole mobility of the leakage current reduction layer is in the range of 4.7 x 10 ^-4 cm ² / Vs to 5.0 x 10 ^-4 cm ² / Vs. The method according to claim 1,
Further comprising a hole transporting layer between the leakage current reducing layer and at least one light emitting layer of the first light emitting layer and the second light emitting layer. The method according to claim 6,
Wherein an absolute value of a HOMO energy level of the hole transport layer is equal to an absolute value of a HOMO energy level of the leakage current reduction layer. The method according to claim 1,
Wherein the first light emitting layer is a layer that emits red or green light, and the second light emitting layer is a layer that emits blue light. The method according to claim 1,
And a charge generation layer, a third light emitting layer, and a fourth light emitting layer on the first light emitting layer and the second light emitting layer. 10. The method of claim 9,
Wherein the charge generation layer comprises an n-type charge generation layer and a p-type charge generation layer, and the p-type charge generation layer comprises the aromatic amine derivative. 11. The method of claim 10,
Wherein the aromatic amine derivative comprises a compound represented by Formula 3 below, and the p-type charge generation layer further comprises a compound represented by Formula 4 below.
(3)

[Chemical Formula 4]

(Wherein R 1 is an aryl group and R 2 is one of an aryl group, an alkyl group, an alkoxy group, and an aryloxy group, and L 1 is an arylene group, a fluorenylene group, and a heteroarylene group, Ar1 and Ar2 are each independently one of an aryl group and a heteroaryl group, 10. The method of claim 9,
Wherein the third light emitting layer is a layer emitting the same color as the first light emitting layer, and the fourth light emitting layer is a layer emitting the same color as the second light emitting layer.

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