KR20160036941A - Organic light emitting display device - Google Patents

Abstract

An organic light emitting display device according to an embodiment of the present invention, as an organic light emitting display device including a first sub-pixel, a second sub-pixel, and a third sub-pixel, includes a hole injecting layer commonly disposed in the first sub-pixel, the second sub-pixel, and the third sub-pixel and including a p-type dopant; a first hole transport layer and a second hole transport layer disposed in the first sub-pixel and the second sub-pixel, respectively, on the hole injecting layer; a first organic light emitting layer and a second organic light emitting layer disposed on the first hole transport layer and the second hole transport layer, respectively; and a third organic light emitting layer disposed in the third sub-pixel on the hole injecting layer. The organic light emitting device satisfies at least one from condition 1) that the homo level of the hole injecting layer is higher than the homo levels of the first hole transport layer and the second hole transport layer, and condition 2) that the mobility of the hole injecting layer is higher than the mobility of the first hole transport layer and the second hole transport layer. The organic light emitting device according to an embodiment of the present invention can restrain light from being emitted from an adjacent pixel in which driving is not intended, due to a current leakage phenomenon.

Description

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

The present invention relates to an organic light emitting diode (OLED) display, and more particularly, to an OLED display capable of minimizing the emission of light in an organic light emitting layer which is not intended to be driven due to current leakage in a hole injection layer.

The organic light emitting diode (OLED) is a self-emissive type display device, and unlike a liquid crystal display (LCD), a separate light source is not required, so that it can be manufactured in a light and thin shape. Further, the organic light emitting display device is not only advantageous from the viewpoint of power consumption by low voltage driving, but also excellent in color implementation, response speed, viewing angle, and contrast ratio (CR), and is being studied as a next generation display.

The organic light emitting display generally comprises a red organic light emitting layer for emitting red light, a green organic light emitting layer for emitting green light, and a blue organic light emitting layer for emitting blue light. In each of the red organic light emitting layer, the green organic light emitting layer and the blue organic light emitting layer, holes and electrons supplied through the electrodes are coupled to each other to emit light. A hole transport layer is generally disposed between the red organic emission layer, the green organic emission layer, and the blue organic emission layer in order to facilitate the movement of holes.

Recently, a technique of adding a p-type dopant to a hole transporting layer disposed between an electrode and an organic light emitting layer has been introduced to further accelerate the movement of holes. When the p-type dopant is added to the hole transport layer, holes can be more smoothly supplied to the organic light emitting layers, thereby improving the lifetime and efficiency of the organic light emitting display.

However, since the mobility of the hole transporting layer is greatly improved by the p-type dopant, a current flows in the green organic light emitting layer and the red organic light emitting layer when a current is applied to drive the blue organic light emitting layer, The green organic light emitting layer and the red organic light emitting layer adjacent to the blue organic light emitting layer are simultaneously driven. Such a current leakage phenomenon causes a decrease in brightness and power consumption of the organic light emitting display device by causing other organic light emitting layers, which are not intended to be driven, to emit light, which is a main cause of manufacturing a low quality organic light emitting display device.

[Related Technical Literature]

1. Organic memory light emitting device and display device (Patent Application No. 10-2009-0107998)

The inventors of the present invention have recognized that the above-described problems are solved by providing a novel structure capable of minimizing light emission in the red organic light emitting layer and the green organic light emitting layer due to the current leakage phenomenon in the hole injection layer when driving the blue organic light emitting layer Of the present invention.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic light emitting display device in which the phenomenon that light is emitted from neighboring pixels whose current is leaked and which is not intended to be driven is suppressed.

Another problem to be solved by the present invention is to provide an organic light emitting display in which light is emitted only in a target pixel, brightness can be improved, and power consumption can be reduced.

The problems 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 OLED display according to an embodiment of the present invention includes a first sub-pixel, a second sub-pixel, and a third sub-pixel, wherein the first sub-pixel, the second sub- And a first hole transporting layer and a second hole transporting layer, a first hole transporting layer, and a second hole transporting layer disposed in the first sub-pixel and the second sub-pixel, respectively, on the hole injection layer and the hole injection layer, And a third organic light emitting layer disposed on the third sub-pixel on the first organic light emitting layer and the second organic light emitting layer disposed on each of the two hole transporting layers, and 1) the HOMO level of the hole injection layer is the first The first hole transport layer and the second hole transport layer each have a HOMO level higher than that of the first hole transport layer and the second hole transport layer and the mobility of the hole injection layer is greater than the mobility of the first hole transport layer and the second hole transport layer, that . In the organic light emitting diode display according to an embodiment of the present invention, light emission from neighboring pixels that are not intended to be driven due to a current leakage phenomenon can be minimized.

According to another aspect of the present invention, a common hole transport layer disposed in common to the first sub-pixel, the second sub-pixel, and the third sub-pixel may be further included on the hole injection layer.

According to another aspect of the present invention, the hole injection layer and the common hole transport layer may be made of the same host material.

According to another aspect of the present invention, each of the hole injection layer, the first hole transporting layer, and the second hole transporting layer may be formed of an aromatic amine-based material.

According to another aspect of the present invention, the material constituting the hole injecting layer, the material constituting the first hole transporting layer, and the material constituting the second hole transporting layer may have the same main chain and have different substituents.

According to another aspect of the present invention, the HOMO level of the hole injection layer may be at least 0.2 eV or more higher than the HOMO level of each of the first hole transport layer and the second hole transport layer.

According to another aspect of the present invention, the mobility of the hole injection layer may be 10 times larger than the mobility of each of the first hole transport layer and the second hole transport layer.

According to another aspect of the present invention, each of the first organic light emitting layer and the second organic light emitting layer emits light of different colors, and may emit light of one of red and green.

According to another aspect of the present invention, the third organic emission layer may emit blue light.

According to another aspect of the present invention, the turn-on voltage of each of the first organic emission layer and the second organic emission layer may be higher than the turn-on voltage of the third organic emission layer.

According to another aspect of the present invention, the thickness of each of the first hole transporting layer and the second hole transporting layer may form an optical distance of microcavity.

According to another aspect of the present invention, the thicknesses of the first hole transporting layer and the second hole transporting layer may be different from each other.

According to another aspect of the present invention, the organic light emitting display may be a top emission organic light emitting display.

The organic light emitting display according to an embodiment of the present invention includes a substrate on which a first anode, a second anode and a third anode are disposed, a first anode, a second anode, and a third anode, and includes a p-type dopant A green organic light emitting layer and a blue organic light emitting layer disposed on the first anode, the second anode and the third anode, a first hole transporting layer disposed between the red organic light emitting layer and the hole injecting layer, a green organic light emitting layer A second hole transporting layer disposed between the organic light emitting layer and the hole injection layer, and a cathode commonly disposed on the red organic light emitting layer, the green organic light emitting layer, and the blue organic light emitting layer, wherein 1) Transporting layer and the second hole transporting layer and the mobility of the hole injecting layer is greater than the mobility of each of the first and second hole transporting layers, Is satisfied. The organic light emitting display according to an embodiment of the present invention has an effect of suppressing light emission from the red organic light emitting layer and the green organic light emitting layer when driving the blue organic light emitting layer.

According to another aspect of the present invention, each of the first anode, the second anode, and the third anode may include a reflective layer and a transparent conductive layer formed on the reflective layer.

According to another aspect of the present invention, when a current flows between the third anode and the cathode, the flow of current to the red organic light emitting layer and the green organic light emitting layer can be suppressed by the first hole transporting layer and the second hole transporting layer, respectively .

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

The present invention is effective in suppressing driving of adjacent red and green subpixels when the blue subpixel is driven by controlling at least one of the HOMO level and the mobility of each of the first hole transporting layer and the second hole transporting layer have.

The present invention is directed to an organic light emitting display device having a high luminance and a low driving voltage by allowing the holes to be more smoothly moved from the hole injection layer to the first organic light emitting layer and the second organic light emitting layer through the first hole transporting layer and the second hole transporting layer There is an effect that can be done.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.

1 is a schematic cross-sectional view for explaining a top emission type OLED display according to an embodiment of the present invention.
2A is a table showing the HOMO level and mobility of the hole injection layer, the first hole transport layer, and the second hole transport layer of the organic light emitting display device of the comparative example.
2B is a graph showing the wavelength of light emitted when the third organic light emitting layer of the organic light emitting display device of the comparative example is driven.
2C is an energy band diagram showing the HOMO level of each layer of the organic light emitting display device of the comparative example.
3A is a table showing the HOMO level and mobility of the hole injection layer, the first hole transport layer, and the second hole transport layer of the organic light emitting display device of Example 1. FIG.
FIG. 3B is a graph showing the wavelengths of light emitted when the third organic light emitting layer of the organic light emitting display devices of the comparative example and the first exemplary embodiment are driven.
4A is a table showing the HOMO level and mobility of the hole injection layer, the first hole transport layer, and the second hole transport layer of the organic light emitting diode display of Example 2. FIG.
4B is a graph showing the wavelengths of light emitted when driving the third organic light emitting layer of the organic light emitting display devices of the comparative example and the second exemplary embodiment.
5A is a table showing the HOMO level and mobility of the hole injection layer, the first hole transport layer, and the second hole transport layer of the organic light emitting display of Example 3. FIG.
5B is a graph showing the wavelengths of light emitted when driving the third organic light emitting layer of the organic light emitting display devices of the comparative example and the third exemplary embodiment.
6A is a diagram showing a current density-voltage curve (JV curve) for the first sub-pixel, the second sub-pixel and the third sub-pixel in the comparative example.
6B is a diagram showing a current density-voltage curve for the first sub-pixel, the second sub-pixel and the third sub-pixel in the third embodiment.

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

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

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

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

An element or layer is referred to as being another element or layer "on ", including both intervening layers or other elements directly on or in between.

Although the first, second, etc. are used to describe various components, 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.

Like reference numerals refer to like elements throughout the specification.

The sizes and thicknesses of the individual components shown in the figures are shown for convenience of explanation and the present invention is not necessarily limited to the size and thickness of the components shown.

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.

Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view for explaining a top emission type OLED display according to an embodiment of the present invention.

1, an OLED display 100 according to an embodiment of the present invention includes a substrate 110, a first anode 120a, a second anode 120b, a third anode 120c, The first organic light emitting layer 160b and the third organic light emitting layer 160c are formed on the first organic light emitting layer 160a, the second organic light emitting layer 160b, the third organic light emitting layer 160b, the third organic light emitting layer 160b, An electron transport layer 170, a cathode 180, and an organic material layer 190. [

The substrate 110 is a substrate for supporting various components of the organic light emitting display 100. The substrate 110 may be made of a material having transparency and flexibility.

As shown in FIG. 1, the substrate 110 includes a first sub-pixel R, a second sub-pixel G, and a third sub-pixel B as regions for displaying one color. In the first sub-pixel R, the second sub-pixel G and the third sub-pixel B, light of different colors may be emitted. Specifically, either the red light or the green light can be emitted in the first sub-pixel R and the second sub-pixel G, and the blue light can be emitted in the third sub-pixel B .

A first anode 120a, a second anode 120b, and a third anode 120c are disposed on a substrate 110. The first anode 120a, the second anode 120b, Each of the first anode 120a, the second anode 120b and the third anode 120c applies a voltage to each of the first organic light emitting layer 160a, the second organic light emitting layer 160b and the third organic light emitting layer 160c . As shown in FIG. 1, the first anode 120a, the second anode 120b, and the third anode 120c are formed separately for each sub-pixel. Specifically, the first anode 120a is arranged in the first sub-pixel R, the second anode 120b is arranged in the second sub-pixel G, the third anode 120c is arranged in the third sub- (B).

Each of the first anode 120a, the second anode 120b and the third anode 120c may be composed of a transparent conductive material having a high work function and a reflective layer capable of reflecting light. Here, the transparent conductive material may include indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin zinc oxide (ITZO). In FIG. 1, the first anode 120a, the second anode 120b, and the third anode 120c are represented as one layer for convenience of illustration.

A hole injection layer 130 is commonly disposed on the first anode 120a, the second anode 120b, and the third anode 120c. The hole injection layer 130 serves to smoothly inject holes into the first organic emission layer 160a, the second organic emission layer 160b, and the third organic emission layer 160c.

The hole injection layer 130 is formed by adding a p-type dopant to a certain host material. When the p-type dopant is added to the hole injection layer 130, the mobility of the hole injection layer 130 is greatly improved. Therefore, the first organic emission layer 160a, the second organic emission layer 160b, and the third organic emission layer 160c, The injection of the hole into the hole can be performed more smoothly.

A common hole transport layer 140 is disposed on the hole injection layer 130. The common hole transport layer 140 receives holes from the hole injection layer 130 and transports the holes to the first organic emission layer 160a, the second organic emission layer 160b, and the third organic emission layer 160c. The common hole transport layer 140 can also prevent the hole injection layer 130 having a very high mobility from directly contacting the third organic emission layer 160c to reduce the efficiency and lifetime characteristics of the third organic emission layer 160c have.

The common hole transport layer 140 and the hole injection layer 130 may be formed of the same host material. In other words, a material in which the p-type dopant is added to the common hole transport layer 140 may be the hole injection layer 130. In this case, the hole injection layer 130 and the common hole transport layer 140 may be formed together in a continuous process in one process equipment.

The first hole transport layer 150a is disposed on the first sub pixel R and the second hole transport layer 150b is disposed on the second sub pixel G on the common hole transport layer 140. [ Each of the first hole transport layer 150a and the second hole transport layer 150b serves to smoothly transfer holes to the first organic emission layer 160a and the second organic emission layer 160b.

The thickness of each of the first hole transporting layer 150a and the second hole transporting layer 150b may form an optical distance of microcavity. Specifically, the thicknesses of the first and second hole transporting layers 150a and 150b are set such that the first organic light emitting layer forms a micro-cavity structure between the first anode and the cathode, Lt; RTI ID = 0.0 > micro-cavity < / RTI >

Since the light of different colors is emitted in the first sub-pixel R and the second sub-pixel G, the thicknesses of the first hole transporting layer 150a and the second hole transporting layer 150b may be different from each other. It is assumed in FIG. 1 that the first organic light emitting layer 160a is a red organic light emitting layer and the second organic light emitting layer 160b is a green organic light emitting layer and the thickness of the first hole transporting layer 150a is set to be a thickness of the second hole transporting layer 150b Respectively.

The hole injection layer 130 is formed on the first anode 120a, the second anode 120b, and the third anode 120c in common, and has a relatively high mobility due to the p-type dopant. Accordingly, when a current flows vertically between the third anode 120c and the cathode 180 so that light is emitted from the third organic emission layer 160c, the current flows horizontally in the hole injection layer 130 having a high mobility, The current flows through the first organic emission layer 160a and the second organic emission layer 160b, that is, a so-called current leakage phenomenon occurs. The current leakage phenomenon causes the light to be emitted also in the adjacent first sub-pixel R and the second sub-pixel G when the third sub-pixel B is to be driven, thereby lowering the brightness of the organic light emitting display device Which is a major cause of increasing power consumption.

In order to solve the current leakage phenomenon due to the high movement of the hole injection layer 130, the OLED display 100 according to an embodiment of the present invention may employ at least the following structures.

The organic light emitting diode display 100 according to an embodiment of the present invention may be configured such that the HOMO level of the hole injection layer 130 is higher than the HOMO level of the first hole transport layer 150a and the second hole transport layer 150b A configuration higher than the HOMO level can be adopted. When the HOMO level of the hole injection layer 130 becomes higher than the HOMO level of each of the first hole transport layer 150a and the second hole transport layer 150b, holes are injected from the hole injection layer 130 into the first organic emission layer 160a and the second organic emission layer 160b, The light is emitted from the first organic light emitting layer 160a and the second organic light emitting layer 160b, which are not intended to be driven when the third organic light emitting layer 160c is driven, because the light is less smoothly supplied to the second organic light emitting layer 160b Can be minimized.

Numerically, the HOMO level of the hole injection layer 130 may be at least 0.2 eV or more higher than the HOMO level of each of the first hole transport layer 150a and the second hole transport layer 150b, but is not limited thereto.

The organic light emitting diode display 100 according to an exemplary embodiment of the present invention may also have a structure in which the mobility of the hole injection layer 130 is greater than the mobility of the first hole transport layer 150a and the second hole transport layer 150b A large configuration can be adopted. When the mobility of the hole injection layer 130 is greater than the mobility of each of the first and second hole transporting layers 150a and 150b, the first organic emission layer 160a and the second Since holes are supplied slowly to the organic light emitting layer 160b, light emission in the first sub-pixel R and the second sub-pixel G adjacent to the third sub-pixel B can be suppressed due to the current leakage phenomenon .

Numerically, the mobility of the hole injection layer 130 may be 10 times or more larger than the mobility of the first hole transport layer 150a and the second hole transport layer 150b, but is not limited thereto.

The HOMO level of the hole injection layer 130 may be set higher than the HOMO level of each of the first hole transport layer 150a and the second hole transport layer 150b or the mobility of the hole injection layer 130 may be set higher than the HOMO level of the first hole transport layer 150a, The turning-on voltage for driving the first sub-pixel R and the second sub-pixel G is set to be larger than the mobility of each of the third sub-pixel R1 and the second hole transport layer 150b, On voltage for driving the transistor (B). When the turn-on voltage of the first sub-pixel R and the turn-on voltage of the second sub-pixel G are higher than the turn-on voltage of the third sub-pixel B, the third sub- Therefore, it is possible to solve the problem that the luminance of the organic light emitting diode display is lowered due to the leakage current.

The HOMO level of the hole injection layer 130 may be higher than the HOMO level of each of the first hole transport layer 150a and the second hole transport layer 150b or the mobility of the hole injection layer 130 may be higher than the HOMO level of the first hole transport layer 150a, The material constituting the first hole transporting layer 150a and the material constituting the second hole transporting layer 150b constitute the material constituting the hole injecting layer 130 and the material constituting the second hole transporting layer 150b, Material can be selected.

The material of the selected hole injection layer 130, the material of the first hole transporting layer 150a, and the material of the second hole transporting layer 150b may have the same main chain and different substituents from each other. For example, the hole injection layer 130, the first hole transport layer 150a, and the second hole transport layer 150b may all be composed of aromatic amine-based materials having different substituents.

A first organic light emitting layer 160a is disposed on the first hole transport layer 150a in the first sub pixel R and a second organic light emitting layer 160b is formed on the second hole transport layer 150b in the second sub pixel G And the third organic light emitting layer 160c is disposed on the common hole injection layer 140 in the third sub-pixel B. [ Each of the first organic light emitting layer 160a, the second organic light emitting layer 160b and the third organic light emitting layer 160c applies a voltage from each of the first anode 120a, the second anode 120b and the third anode 120c And serves to emit light. The first organic light emitting layer 160a, the second organic light emitting layer 160b, and the third organic light emitting layer 160c emit light of different colors. The first organic light emitting layer 160a and the second organic light emitting layer 160b may emit red light or green light and the third organic light emitting layer 160c may emit blue light.

The electron transport layer 170 is disposed on the first organic light emitting layer 160a, the second organic light emitting layer 160b, and the third organic light emitting layer 160c in common. The electron transport layer 170 serves to smooth the movement of electrons to the first organic emission layer 160a, the second organic emission layer 160b, and the third organic emission layer 160c. The electron transport layer 170 may be formed of at least one selected from the group consisting of Alq3, PBD, TAZ, spiro-PBD, BAlq, lithium quinolate, BMB-3T, PF-6P, TPBI, COT, But the present invention is not limited thereto.

The cathodes 180 are disposed on the electron transport layer 170 in common to the first sub pixel R, the second sub pixel G and the third sub pixel B, respectively. The cathode 180 applies a voltage to each of the first organic light emitting layer 160a, the second organic light emitting layer 160b, and the third organic light emitting layer 160c. The cathode 180 is formed of a conductive material having a low work function since electrons must be supplied. For example, the cathode 180 may be formed of an alloy of magnesium (Mg) and silver (Ag). The work function of the cathode 180 may be about 4.1 eV. Since the OLED display 100 according to an embodiment of the present invention is a top emission type OLED display 100, the cathode 180 may be formed to have a very thin thickness and be substantially transparent.

The organic layer 190 is disposed on the cathode 180 in common to the first sub-pixel R, the second sub-pixel G and the third sub-pixel B. The organic material layer 190 may serve to flatten the stepped portion of the cathode 180 and compensate for the foreign material. The organic material layer 190 may be formed of an acrylic resin or an epoxy resin, but is not limited thereto.

Though not shown in FIG. 1, a thin film transistor connected to the first anode 120a, the second anode 120b, and the third anode 120c may be further disposed on the substrate 110.

In order to examine the effect of the present invention, organic light emitting display devices of Comparative Examples, Examples 1, 2, and 3 were manufactured by varying the HOMO level and mobility of the first hole transporting layer and the second hole transporting layer. Specifically, in the comparative example, the HOMO level and the mobility of the hole injection layer, the first hole transporting layer, and the second hole transporting layer were made the same to manufacture an organic light emitting display device. In Example 1, the HOMO level of the first hole transport layer and the second hole transport layer was gradually lowered, rather than the hole injection layer, and the organic light emitting display was manufactured. In Example 2, the mobility of the first hole transporting layer and the second hole transporting layer was gradually reduced, and the organic light emitting display device was manufactured. In Example 3, the HOMO level of the first hole transporting layer and the second hole transporting layer was lowered and the mobility was lowered than that of the hole injection layer, thereby manufacturing an organic light emitting display device.

The organic light emitting display devices of the comparative example, the first embodiment, the second embodiment, and the third embodiment are all manufactured to have the same structure as the organic light emitting display as shown in FIG. 1, and the first hole transport layer and the second hole Except that the HOMO level and the mobility of the transport layer were the same. In the organic light emitting display devices of Comparative Examples 1, 2, and 3, the first organic light emitting layer is a red organic light emitting layer, the second organic light emitting layer is a green organic light emitting layer, Organic light emitting layer.

FIGS. 2A to 2C show experimental data for an organic light emitting display device of a comparative example. 2A is a table showing the HOMO level and mobility for the hole injection layer, the first hole transporting layer and the second hole transporting layer of the organic light emitting display device of the comparative example, and FIG. 2B is a table showing the HOMO level and mobility for the third hole transporting layer FIG. 2C is an energy band diagram showing the HOMO level of each layer of the organic light emitting display device of the comparative example. FIG. 2C is a graph showing the wavelength of light emitted when the organic light emitting layer is driven.

Referring to FIGS. 2A and 2C, the hole injection layer, the first hole transport layer, and the second hole transport layer in the organic light emitting display of the comparative example have the same HOMO level and mobility.

Referring to FIG. 2B, in driving the third organic light emitting layer, that is, the blue organic light emitting layer in the organic light emitting display device of the comparative example, not only blue light having a wavelength of 450 to 495 nm is emitted but also green light having a wavelength of 495 nm to 780 nm And red light are also emitted at a considerable level. As a result, in driving the third organic light emitting layer, that is, the blue organic light emitting layer in the organic light emitting display device of the comparative example, the first organic light emitting layer and the second organic light emitting layer such as the red organic light emitting layer and the green organic light emitting layer It can be seen that light is emitted.

FIGS. 3A and 3B show experimental data for the OLED display of Example 1. FIG. 3A is a table showing the HOMO level and mobility of the hole injection layer, the first hole transport layer, and the second hole transport layer of the organic light emitting display devices of Example 1. FIG. FIG. 5 is a graph showing the wavelength of light emitted when the third organic light emitting layer of the organic light emitting display devices is driven. FIG. For reference, the energy band diagram is not separately shown in the first embodiment.

Referring to FIG. 3A, in the organic light emitting display devices of Example 1, the hole injection layer has a higher HOMO level than the first hole transport layer and the second hole transport layer.

Referring to FIG. 3B, in driving the third organic light emitting layer, that is, the blue organic light emitting layer in the organic light emitting display devices of Example 1, green light having a wavelength of 495 nm to 780 nm, It can be seen that the red light is emitted at a very low level. Further, it can be seen that as the HOMO level difference between the hole injection layer, the first organic light emitting layer, and the second organic light emitting layer increases, green and red light having a wavelength of 495 nm to 780 nm are emitted less. From these facts, when the HOMO level of the hole injection layer is set to be higher than the HOMO level of the first organic light emitting layer and the second organic light emitting layer, the third organic light emitting layer, for example, It can be seen that light emission can be suppressed in the first and second organic light emitting layers, for example, the red organic light emitting layer and the green organic light emitting layer, which are not intended.

FIGS. 4A and 4B show experimental data for the organic light emitting display of Example 2. FIG. 4A is a table showing the HOMO level and mobility of the hole injection layer, the first hole transport layer, and the second hole transport layer of the organic light emitting display device of Example 2. FIG. FIG. 5 is a graph showing the wavelength of light emitted when the third organic light emitting layer of the organic light emitting display devices is driven. FIG. For reference, the energy band diagram is not separately shown in the second embodiment.

Referring to FIG. 4A, in the OLED display of Example 2, the hole injection layer has a larger mobility than the first hole transport layer and the second hole transport layer.

Referring to FIG. 4B, in driving the third organic light emitting layer, that is, the blue organic light emitting layer in the organic light emitting display devices of Example 2, green and blue light having a wavelength of 495 nm to 780 nm, It can be seen that the red light is emitted at a very low level. Further, it can be seen that green and red light having a wavelength of 495 nm to 780 nm are emitted less as the mobility difference between the hole injection layer, the first organic light emitting layer, and the second organic light emitting layer becomes larger. From these facts, when the mobility of the hole injection layer is configured to be larger than the mobility of the first organic light emitting layer and the second organic light emitting layer, when the third organic light emitting layer, for example, the blue organic light emitting layer is driven, It can be seen that light emission can be suppressed in the first and second organic light emitting layers, for example, the red organic light emitting layer and the green organic light emitting layer, which are not intended.

FIGS. 5A and 5B show experimental data for the organic light emitting display devices of Example 3. FIG. 5A is a table showing the HOMO level and mobility of the hole injection layer, the first hole transport layer, and the second hole transport layer of the organic light emitting display device of Example 3. FIG. 5B is a table showing the HOMO level and mobility of the organic light emitting display of Example 3 Is a graph showing the wavelength of light emitted when the third organic light emitting layer of the devices is driven. For reference, the energy band diagram is not separately shown in the third embodiment.

Referring to FIG. 5A, in the OLED display of Example 3, the hole injection layer has a higher HOMO level and a higher mobility than the first hole transport layer and the second hole transport layer.

Referring to FIG. 5B, when a third organic light emitting layer, that is, a blue organic light emitting layer, is driven in the organic light emitting display devices of Example 3 as compared with the organic light emitting display device of the comparative example, green and blue light of wavelengths of 495 nm to 780 nm It can be seen that the red light is emitted at a very low level. From this fact, the HOMO level of the hole injection layer is set to be higher than the HOMO level of the first organic emission layer and the second organic emission layer, and the mobility of the hole injection layer is made larger than the mobility of the first organic emission layer and the second organic emission layer Light is emitted from the first organic light emitting layer and the second organic light emitting layer, for example, the red organic light emitting layer and the green organic light emitting layer, which are not intended to be driven due to a leakage current when the third organic light emitting layer, It can be seen that the light emission can be further minimized.

6A is a diagram showing a current density-voltage curve (JV curve) for the first sub-pixel, the second sub-pixel and the third sub-pixel in the comparative example, Pixel and the third sub-pixel according to the first embodiment of the present invention. 6A and 6B, the first sub-pixel is a red sub-pixel, the second sub-pixel is a green sub-pixel, and the third sub-pixel is a blue sub-pixel.

6A, the turn-on voltage of each of the first organic light emitting layer of the first sub-pixel and the second organic light emitting layer of the second sub-pixel in the organic light emitting display of the comparative example is lower than that of the third organic light emitting layer of the third sub- On voltage is lower than the turn-on voltage. On the other hand, referring to FIG. 6B, in the OLED display of Example 3, the turn-on voltage of each of the first organic light emitting layer of the first sub-pixel and the second organic light emitting layer of the second sub- On voltage of the third organic emission layer is higher than the turn-on voltage of the third organic emission layer. From this fact, it can be seen that, in the third embodiment of the present invention, the phenomenon that light is emitted from unintended sub-pixels due to the current leakage phenomenon can be effectively minimized as compared with the comparative example.

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 following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

110: substrate
120a: a first anode
120b: a second anode
120c: third anode
130: Hole injection layer
140: common hole transporting layer
150a: First hole transport layer
150b: second hole transport layer
160a: a first organic light emitting layer
160b: a second organic light emitting layer
160c: a third organic light emitting layer
170: electron transport layer
180: cathode
190: organic layer
R: red sub-pixel
G: green sub-pixel
B: blue sub-pixel

Claims (18)

A first sub-pixel, a second sub-pixel, and a third sub-pixel,
A hole injection layer disposed in common to the first sub-pixel, the second sub-pixel, and the third sub-pixel, the hole injection layer including a p-type dopant;
A first hole transporting layer and a second hole transporting layer disposed on the first sub-pixel and the second sub-pixel, respectively, on the hole injection layer;
A first organic light emitting layer and a second organic light emitting layer disposed on the first hole transporting layer and the second hole transporting layer, respectively; And
And a third organic emission layer disposed on the third sub-pixel on the hole injection layer,
1) the HOMO level of the hole injection layer is higher than the HOMO level of each of the first hole transport layer and the second hole transport layer; And
2) the mobility of the hole injection layer is larger than the mobility of each of the first hole transport layer and the second hole transport layer
Of the organic light emitting display device. The method according to claim 1,
And a common hole transport layer disposed in common on the first sub-pixel, the second sub-pixel, and the third sub-pixel on the hole injection layer. The method according to claim 1,
Wherein the hole injection layer and the common hole transport layer are made of the same host material. The method according to claim 1,
Wherein each of the hole injection layer, the first hole transporting layer, and the second hole transporting layer is made of an aromatic amine-based material. The method according to claim 1,
Wherein the material constituting the hole injection layer, the material constituting the first hole transporting layer and the material constituting the second hole transporting layer have the same main chain and have different substituents from each other. . The method according to claim 1,
And the HOMO level of the hole injection layer is at least 0.2 eV or more higher than the HOMO level of each of the first hole transport layer and the second hole transport layer. The method according to claim 1,
And the mobility of the hole injection layer is greater than the mobility of each of the first hole transporting layer and the second hole transporting layer by at least 10 times. The method according to claim 1,
Wherein each of the first organic emission layer and the second organic emission layer emits light of different colors and emits one of red and green light. The method according to claim 1,
And the third organic emission layer emits blue light. The method according to claim 1,
Wherein a turn-on voltage of each of the first organic emission layer and the second organic emission layer is equal to or greater than a turn-on voltage of the third organic emission layer. The method according to claim 1,
Wherein a thickness of each of the first hole transporting layer and the second hole transporting layer forms an optical distance of microcavity. 12. The method of claim 11,
Wherein a thickness of the first hole transporting layer and a thickness of the second hole transporting layer are different from each other. The method according to claim 1,
Wherein the organic light emitting display is a top emission type organic light emitting display. A substrate on which a first anode, a second anode, and a third anode are disposed;
A hole injection layer disposed on the first anode, the second anode, and the third anode, the hole injection layer including a p-type dopant;
A red organic light emitting layer, a green organic light emitting layer, and a blue organic light emitting layer disposed on the first anode, the second anode, and the third anode, respectively;
A first hole transport layer disposed between the red organic light emitting layer and the hole injection layer;
A second hole transport layer disposed between the green organic light emitting layer and the hole injection layer; And
And a cathode commonly disposed on the red organic light emitting layer, the green organic light emitting layer, and the blue organic light emitting layer,
1) the HOMO level of the hole injection layer is higher than the HOMO level of each of the first hole transport layer and the second hole transport layer; And
2) the mobility of the hole injection layer is larger than the mobility of each of the first hole transport layer and the second hole transport layer
Of the organic light emitting display device. 15. The method of claim 14,
Wherein each of the first anode, the second anode, and the third anode includes a reflective layer and a transparent conductive layer formed on the reflective layer. 15. The method of claim 14,
The flow of the current to the red organic light emitting layer and the green organic light emitting layer is suppressed by the first hole transporting layer and the second hole transporting layer, respectively, when a current flows between the third anode and the cathode , An organic light emitting display device. 15. The method of claim 14,
And the HOMO level of the hole injection layer is at least 0.2 eV or more higher than the HOMO level of each of the first hole transport layer and the second hole transport layer. 15. The method of claim 14,
And the mobility of the hole injection layer is greater than the mobility of each of the first hole transporting layer and the second hole transporting layer by at least 10 times.

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