KR20230144512A - Organic light emitting display device - Google Patents

Abstract

An organic light emitting display device according to the present specification comprises: a first electrode and a second electrode; and at least two light emitting parts between the first electrode and the second electrode, wherein the at least two light emitting parts comprise different light emitting layers from each other, and any one among the at least two light emitting parts may comprise a dark blue color light emitting layer. Therefore, the present invention is capable of having an effect of improving element lifespan.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

This specification relates to an organic light emitting display device, and more specifically, to an organic light emitting display device that can improve efficiency and color gamut.

Recently, as we have entered the information age, the field of displays that visually express electrical information signals has developed rapidly, and in response to this, various flat display devices with excellent performance such as thinness, lightness, and low power consumption have been developed. Device) is being developed.

Specific examples of such flat panel displays include Liquid Crystal Display devices (LCD), Plasma Display Panel devices (PDP), Field Emission Display devices (FED), and organic light emitting display devices. (Organic Light Emitting Device: OLED), etc.

In particular, organic light emitting display devices are self-emitting devices and have the advantages of fast response speed, high luminous efficiency, brightness, and viewing angle compared to other flat panel display devices.

An organic light emitting display device forms an organic light emitting layer between two electrodes. Electrons and holes are injected from two electrodes, respectively, into the organic light-emitting layer to generate excitons due to the combination of electrons and holes. Additionally, it is a device that uses the principle that light is generated when the generated excitons fall from the excited state to the ground state.

1. [White organic light emitting device] (Patent Application No. 10-2009-0092596)

Organic light emitting display devices implement full color through subpixels that emit red (R), green (G), and blue (B) colors. The subpixels that emit red (R), green (G), and blue (B) colors can express color gamut with respective color coordinates of red (R), green (G), and blue (B).

Since the color gamut is affected by the material of the organic light-emitting layer that makes up the organic light-emitting display device or the structure of the device, there is a problem in that it is difficult to express the desired color. Accordingly, efforts to improve the color coordinate characteristics and color gamut of organic light emitting display devices are continuing in response to consumer demands for excellent image quality.

One way is to use the light emitting layer as a single layer. This method can produce a white organic light-emitting device by using a single material or doping two or more materials. For example, there is a method of using red and green dopants in a blue host or by adding red, green, and blue dopants to a host material with a large band gap energy. However, this method has problems in that energy transfer to the dopant is incomplete and it is difficult to control the white balance.

In addition, there is a limit to the components of the dopant included in the corresponding light-emitting layer due to the characteristics of the dopant itself. In addition, when mixing each emitting layer, the focus is on realizing white light, so wavelength characteristics are displayed at wavelengths other than red, green, and blue. Therefore, there was a problem in that the luminous efficiency of red, green, and blue was reduced due to undesired peak wavelength values. In addition, the range of colors that can be expressed was narrowed due to the difference between the wavelength range corresponding to the peak wavelength and the transmission area of the color filter, causing problems in realizing the desired color gamut.

Accordingly, the inventors of this specification recognized the problems mentioned above and invented an organic light emitting display device with a new structure that can improve efficiency and color gamut.

The problem to be solved according to the embodiments of the present specification is to provide an organic light emitting display device that can improve red efficiency and green efficiency and improve color gamut by configuring two light emitting layers in at least two light emitting parts.

The problem to be solved according to the embodiment of the present specification is an organic light emitting display device that can improve efficiency and color gamut by configuring two light emitting layers in at least two light emitting parts, and the two light emitting layers are composed of dopants with the same light emitting characteristics. is to provide.

The problems to be solved according to the embodiments of the present specification are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

The organic light emitting display device according to the present specification includes a first electrode and a second electrode, and at least two light emitting parts between the first electrode and the second electrode, the at least two light emitting parts include different light emitting layers, and at least two light emitting parts Any one of the light emitting units may include a dark blue light emitting layer.

According to the organic light emitting display device according to the present specification, the other one of the at least two light emitting units may include two light emitting layers.

According to the organic light emitting display device according to the present specification, the other one of the at least two light emitting units may include a green light emitting layer and a red light emitting layer.

According to the organic light emitting display device according to the present specification, the two light emitting layers may be composed of dopants having the same light emitting characteristics.

According to the organic light emitting display device according to the present specification, the dopant may be a phosphorescent dopant.

According to the organic light emitting display device according to the present specification, it further includes a first light emitting unit between the first electrode and another one of at least two light emitting units, the other one of the at least two light emitting units is a second light emitting unit, and at least One of the two light emitting units may be a third light emitting unit.

According to the organic light emitting display device according to the present specification, the first light emitting unit may include a dark blue light emitting layer.

According to the organic light emitting display device according to the present specification, the first light emitting part may include a dark blue light emitting layer and a green light emitting layer.

According to the organic light emitting display device according to the present specification, the first light emitting part and the second light emitting part may be composed of dopants having different light emitting characteristics.

According to the organic light emitting display device according to the present specification, the first light emitting unit may include two light emitting layers.

According to the organic light emitting display device according to the present specification, the two light emitting layers of the first light emitting part may be composed of dopants having the same light emitting characteristics.

According to the organic light emitting display device according to the present specification, the dopant may be a fluorescent dopant.

According to the organic light emitting display device according to the present specification, the thickness between the first electrode and the second electrode may be in the range of 3200Å to 3500Å.

According to the organic light emitting display device according to the present specification, it further includes a first light emitting part between the first electrode and another one of the at least two light emitting parts, and the light emitting layer constituting the first light emitting part is 100 Å to 700 Å from the first electrode. can be located

According to the organic light emitting display device according to the present specification, the other one of the at least two light emitting units is a second light emitting unit, and the light emitting layer constituting the second light emitting unit may be located at 1700 Å to 2400 Å from the first electrode.

According to the organic light emitting display device according to the present specification, one of the at least two light emitting units is a third light emitting unit, and the light emitting layer constituting the third light emitting unit may be located at 2400 Å to 2800 Å from the first electrode.

According to the organic light emitting display device according to the present specification, the first light emitting unit, the second light emitting unit, and the third light emitting unit may have three emission peaks in the range of 440 nm to 480 nm, 530 nm to 580 nm, and 600 nm to 650 nm.

According to the organic light emitting display device according to the present specification, one of the at least two light emitting units may further include a hole transport layer and an electron transport layer.

According to the organic light emitting display device according to the present specification, the triplet energy of the hole transport layer and the electron transport layer may be 0.01 eV to 0.4 eV higher than the triplet energy of the deep blue light emitting layer.

According to the organic light emitting display device according to the present specification, the first electrode may be a reflective electrode and the second electrode may be a transflective electrode.

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

According to the present specification, two light-emitting layers are formed within at least two of the three light-emitting parts, and the two light-emitting layers are made of dopants with the same light-emitting properties, so that exciton movement between the two light-emitting layers is easy, thereby improving efficiency and device It has the effect of improving lifespan.

Additionally, by forming a blue light-emitting layer and a green light-emitting layer within one light-emitting part, green efficiency and color gamut can be improved.

In addition, by forming a green light-emitting layer and a red light-emitting layer in one light-emitting part, green efficiency and red efficiency can be improved, and color reproduction rate can be improved.

In addition, by forming a blue light-emitting layer in the two light-emitting parts, there is an effect of improving color gamut.

In addition, by forming two light-emitting layers in at least two of the three light-emitting parts and configuring a structure with three peak wavelengths, it is possible to provide an organic light-emitting display device with improved efficiency and color gamut.

In addition, since there is no need to use a polarizer, it is possible to provide an organic light emitting display device with improved aperture ratio and luminance.

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

Since the contents of this specification described in the problem to be solved, means for solving the problem, and effects described above do not specify the essential features of the claims, the scope of the claims is not limited by the matters described in the contents of this specification.

1 is a schematic cross-sectional view showing an organic light-emitting device according to an embodiment of the present specification.
Figure 2 is a diagram showing an EL spectrum according to angle according to an embodiment of the present specification.
Figure 3 is a diagram showing the color viewing angle change rate according to angle according to an embodiment of the present specification.
Figure 4 is a schematic cross-sectional view showing an organic light-emitting device according to another embodiment of the present specification.
Figure 5 is a diagram showing the PL spectrum of a light-emitting layer according to another embodiment of the present specification.
Figure 6 is a diagram showing a Contour Map according to another embodiment of the present specification.
Figure 7 is a diagram showing the color viewing angle change rate according to angle according to an embodiment of the present specification.
Figure 8 is a diagram showing an EL spectrum according to an embodiment of the present specification.
FIG. 9 is a cross-sectional view of an organic light emitting display device according to another embodiment of the present specification.

The advantages and features of the present specification and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present specification is not limited to the embodiments disclosed below and will be implemented in various different forms, but the present embodiments only serve to ensure that the disclosure of the present specification is complete and that common knowledge in the technical field to which the present specification pertains is provided. It is provided to fully inform those who have the scope of the present specification, and the present specification is only defined by the scope of the claims.

The shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining the embodiments of the present specification are illustrative, and the present specification is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present specification, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present specification, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used.

In the case of a description of a temporal relationship, for example, if a temporal relationship is described as 'after', 'successfully after', 'after', 'before', etc., 'immediately' or 'directly' Unless used, non-consecutive cases may also be included.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are merely used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the technical idea of the present specification.

Each feature of the various embodiments of the present specification can be combined or combined with each other, partially or entirely, and various technological interconnections and operations are possible, and each embodiment may be implemented independently of each other or together in a related relationship. It may be possible.

Hereinafter, the embodiments of the present specification will be examined in detail through the attached drawings and examples.

1 is a schematic cross-sectional view showing an organic light-emitting device according to an embodiment of the present specification.

The organic light emitting device 100 shown in FIG. 1 includes a first electrode 102 and a second electrode 104 on a substrate 101 and a first light emitting unit 110 between the first and second electrodes 102 and 104. , and is provided with a second light emitting unit 120 and a third light emitting unit 130.

The first electrode 102 is an anode that supplies holes, and may be formed of a transparent conductive material such as TCO (Transparent Conductive Oxide), such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), but it must be It is not limited.

The second electrode 104 is a cathode that supplies electrons and is made of metallic materials such as gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), or one of these. It may be formed of an alloy, but is not necessarily limited thereto.

The first electrode 102 and the second electrode 104 may be referred to as an anode or a cathode, respectively. Additionally, the first electrode 102 may be referred to as a transflective electrode, and the second electrode 104 may be referred to as a reflective electrode.

Here, the bottom emission method in which the first electrode 102 is a transflective electrode and the second electrode 104 is a reflective electrode will be described.

The first light emitting unit 110 includes a first hole transport layer (HTL) 112, a first emitting layer (EML) 114, and a first electron transport layer ( It may be accomplished by including ETL (Electron Transporting Layer) (116).

The first light emitting layer (EML) 114 is composed of a blue light emitting layer.

A first charge generating layer (CGL) 140 may be further formed between the first light emitting unit 110 and the second light emitting unit 120. The first charge generation layer (CGL) 140 adjusts the charge balance between the first light emitting unit 110 and the second light emitting unit 120. The first charge generation layer 140 may include an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL).

The second light emitting part 120 includes a second hole transport layer (HTL) 122, a first emitting layer (EML) 124, and a second electron transport layer (ETL) 126. ) can be achieved including

The first light emitting layer (EML) 124 of the second light emitting unit 120 is composed of a yellow-green light emitting layer.

The third light emitting unit 130 includes a third electron transport layer (ETL) 136, a first emitting layer (EML) 134, and a third hole transport layer below the second electrode 104. (HTL; Hole Transporting Layer) (132).

The first light emitting layer (EML) 134 of the third light emitting unit 130 is composed of a blue light emitting layer.

A second charge generating layer (CGL) 150 may be further formed between the second light emitting unit 120 and the third light emitting unit 130. The second charge generation layer 150 adjusts the charge balance between the second light emitting unit 120 and the third light emitting unit 130. The second charge generation layer (CGL) 150 may include an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL).

In addition, an organic light emitting display device including an organic light emitting element according to an embodiment of the present specification includes a gate wire and a data wire that cross each other on a substrate to define each pixel area, and a power wire that extends parallel to any one of them. is located, and in each pixel area, a switching thin film transistor connected to the gate wiring and data wiring and a driving thin film transistor connected to the switching thin film transistor are located. A driving thin film transistor is connected to the first electrode 102.

Here, the electroluminescence peak (EL Peak) of the organic light emitting display device constituting the first, second, and third light emitting units is the photoluminescence peak (PL Peak), which displays the unique color of the light emitting layer, and the organic light emitting peak (PL Peak). It is determined by the product of the emission peak (EM Peak) of the organic layers that make up the light emitting device. The emission peak (EM Peak) of organic layers is affected by the thickness and optical properties of the organic layers.

In the structure shown in Figure 1, the thickness of the organic layers constituting the first, second, and third light emitting units is set according to the efficiency of the device, but there is a problem in that it is difficult to secure the color viewing angle for each wavelength of the light emitting units within the set thickness. there is. In order to secure the desired color viewing angle, the thickness of the organic layers can be increased, but since the cavity moves to a longer wavelength region, a problem occurs in which color purity deteriorates. In addition, when the viewing angle characteristics are maximized based on the cavity of the blue light-emitting layer, which has lower efficiency than the yellow-green light-emitting layer, the blue efficiency decreases, resulting in a problem of lowered device efficiency. In addition, in the case of the bottom emission type device of FIG. 1, a polarizer must be used to lower the reflectance to an external light source. The use of a polarizer causes a problem in which luminance is reduced by approximately 60%.

This will be described in detail with reference to FIGS. 2 and 3.

FIG. 2 is a diagram showing an EL spectrum according to angle of an organic light emitting display device according to an embodiment of the present specification. In Figure 2, the horizontal axis represents the wavelength range of light, and the vertical axis represents the intensity of light emission. The luminous intensity is a value expressed as a relative value based on the maximum value of the EL spectrum.

And, Figure 2 shows the measurement results at angles of 0 degrees, 15 degrees, 30 degrees, 45 degrees, and 60 degrees, which were measured by changing the angle from the front, with the front of the organic light emitting display device at 0 degrees.

Specifically, FIG. 2 shows the light emission peak (EL Peak) for the blue light emitting layer emitted from the first light emitting part of the organic light emitting display device and the light emission peak (EL Peak) for the yellow-green light emitting layer emitted from the second light emitting part. I'm doing it.

As shown in Figure 2, the peak wavelength of the EL Peak corresponding to the blue region is in the range of 440 nm to 480 nm, and it can be seen that the EL Peak in this wavelength region decreases with the viewing angle. In addition, the peak wavelength of the EL Peak corresponding to the yellow-green region is in the range of 530 nm to 580 nm, and it can be seen that the EL Peak in this wavelength region rapidly decreases depending on the viewing angle. Therefore, depending on the viewing angle, the EL Peak corresponding to the yellow-green region appears stronger than the EL Peak corresponding to the blue region, causing the color coordinates of white to change, thereby deteriorating the color viewing angle characteristics.

The color viewing angle change rate will be described in detail with reference to FIG. 3.

Figure 3 is a diagram showing the color viewing angle change rate (Δu'v') according to the viewing angle of the organic light emitting display device. In Figure 3, the horizontal axis represents the viewing angle, expressed as 0, 15, 30, 45, and 60 degrees, and the vertical axis represents the color viewing angle change rate (Δu'v').

That is, Figure 3 shows the color viewing angle change rate (Δu'v') measured while tilting from 0 degrees to 15 degrees, 30 degrees, 45 degrees, and 60 degrees when viewed from the front of the organic light emitting display device.

In Figure 3, ① is red, ② is green, ③ is blue, ④ is yellow, ⑤ is cyan, ⑥ is magenta, and ⑦ is white ( white).

As shown in FIG. 3, magenta (⑥, magenta) whose color viewing angle change rate (Δu'v') of the color displayed by the organic light emitting display device is 0.020 or more in the viewing angle direction of 0 degrees to 60 degrees, which is the front of the organic light emitting display device. It can be seen that appears. If the color viewing angle change rate is more than 0.020 in the viewing angle direction of 0 degrees to 60 degrees, which is the front, consumers will perceive color changes according to the viewing angle. As can be seen in Figure 2, magenta does not have an EL peak corresponding to the red region, so the color viewing angle change rate of magenta, which is caused by a mixture of red and blue, is 0.030 or more. . Additionally, magenta is a highly recognizable color in the eyes of consumers, and when magenta appears, the level of color abnormality increases. Therefore, the organic light emitting display device displays non-uniform white light, resulting in color defects.

Accordingly, the inventors of the present specification have improved luminance by applying a top emission method, and at least two of the three light emitting parts have at least two light emitting layers to improve efficiency and develop a new organic structure that can improve color gamut. Invented a light emitting display device.

This is explained with reference to Figures 4 and 5.

Figure 4 is a schematic cross-sectional view of an organic light-emitting device according to another embodiment of the present specification. And, Figure 5 is a diagram showing the PL spectrum of the light-emitting layer constituting the organic light-emitting device.

The organic light emitting device 200 shown in FIG. 4 includes a first electrode 202 and a second electrode 204 on a substrate 201, and first light emission between the first electrode 202 and the second electrode 204. It is provided with a unit 210, a second light emitting unit 220, and a third light emitting unit 230.

The first electrode 202 is an anode that supplies holes and may be formed of gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), etc., or an alloy thereof. , but is not necessarily limited to this. Alternatively, it may be formed of ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), etc., but is not necessarily limited thereto. Additionally, a reflective electrode may be additionally formed below the first electrode 202 to reflect light toward the second electrode 204.

The second electrode 204 is a cathode that supplies electrons and is formed of transparent conductive materials such as TCO (Transparent Conductive Oxide), such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and IGZO (Indium Gallium Zinc Oxide). It can be done and is not necessarily limited to this. Additionally, in order to prevent damage to the second electrode 204 due to sputtering when forming the second electrode 204, a buffer layer may be additionally formed below the second electrode 204.

The first electrode 202 and the second electrode 204 may be referred to as an anode or a cathode, respectively.

Here, the first electrode 202 is a reflective electrode, and the second electrode 204 is a transflective electrode. A top emission method is applied.

The first light emitting part 210 includes a first hole transport layer (HTL) 212, a first light emitting layer (EML) 214, a second light emitting layer (EML) 215, and a first electron transport layer (ETL) 216. It can be configured including.

Although not shown in the drawing, a hole injection layer (HIL) may be additionally formed on the first electrode 202. The hole injection layer (HIL) is formed on the first electrode 202 and serves to facilitate hole injection from the first electrode 202.

The first hole transport layer (HTL) 212 supplies holes from the hole injection layer (HIL) to the first emitting layer (EML) 214 and the second emitting layer (EML) 215. The first electron transport layer (ETL) 216 transfers electrons from the second electrode 204 to the first light emitting layer (EML) 214 and the second light emitting layer (EML) 215 of the first light emitting unit 210. supply to.

The hole injection layer (HIL) is MTDATA (4,4',4"-tris(N-3-methylphenyl-N-phenylamino)triphenylamine), CuPc (phthalocyanine, copper complex), or PEDOT/PSS(poly(3,4 -ethylenedioxythiphene/polystyrene sulfonate), etc., but is not necessarily limited thereto.

In the first emitting layer (EML) 214 and the second emitting layer (EML) 215, holes supplied through the first hole transport layer (HTL) 212 and the first electron transport layer (ETL) 216 are formed. Light is generated because the electrons supplied through are recombined.

The first hole transport layer (HTL) 212 may be formed by applying one or more layers or one or more materials. The first hole transport layer (HTL) 212 is NPD (N,N-dinaphthyl-N,N'-diphenylbenzidine), TPD (N,N'-diphenyl-N,N'-di(3-methylphenyl)-1 ,1'biphenyl-4,4'-diamine), Spiro-TAD(2,2'7,7'tetrakis(N,N-diphenlylamino)-9,9'spirofluorene and MTDATA(4,4',4"- It may be composed of one or more selected from the group consisting of tris(N-3-methylphenyl-N-phenylamino)triphenylamine), but is not limited thereto.

The first electron transport layer (ETL) 216 may be formed by applying one or more layers or one or more materials. The first electron transport layer (ETL) 216 is Alq ₃ (tris(8-hydroxyquinolino)aluminum), PBD (2-(4-biphenyl)5-)4-tert-butylphenyl)-1,34-oxadiazole), TAZ(3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), BAlq(Bis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium), It may be made of one or more selected from the group consisting of Liq (8-hydroxyquinolinolato-lithium) and BAlq (Bis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminum), but is not limited thereto.

The first light emitting layer (EML) 214 constituting the first light emitting part 210 is composed of a deep blue light emitting layer, and the second light emitting layer (EML) 215 is composed of a green light emitting layer. The dark blue emission layer and the green emission layer are composed of at least one host and a dopant, and this will be explained with reference to FIG. 5.

In Figure 5, the horizontal axis represents the wavelength of light, and the vertical axis represents the intensity of light emission. The luminescence intensity is a value expressed as a relative value based on the maximum value of the PL spectrum.

Figure 5a is a diagram showing PL spectra of a phosphorescent green dopant (marked ①), a fluorescent green dopant (marked ②), and a fluorescent red dopant (marked ③).

Figure 5b is a diagram showing the PL spectrum of a blue dopant (marked ④) and a deep blue dopant (marked ⑤).

As already explained, an organic light emitting device emits light as excitons created by recombination of holes and electrons emit energy. There are two types of luminescence characteristics that emit light. Fluorescence is when an exciton falls from a singlet level to an excited state and emits light. Phosphorescence is the emission of light when an exciton falls from the triplet level to an excited state. In this embodiment, a structure of an organic light emitting display device with improved efficiency and color gamut is proposed by configuring at least one light emitting unit with two light emitting layers having the same light emitting characteristics.

As shown in Figure 5a, the phosphorescent green dopant (①) has better efficiency than the fluorescent green dopant (②), but has the disadvantage of having a short lifespan. In order to increase green efficiency, when a green light-emitting layer containing a phosphorescent green dopant is additionally formed in the second light-emitting part 220 in addition to the first light-emitting part 210, the lifespan of the phosphorescent green dopant (①) is reduced. If it is short, the device lifespan may be reduced. Therefore, in order to improve device lifespan, a fluorescent green dopant is applied to the first light emitting unit 210. Additionally, by applying a phosphorescent green dopant to the second light emitting unit 220 to supplement green efficiency, both green efficiency and device lifespan can be improved.

And, as shown in FIG. 5B, since the deep blue dopant (⑤) is located in a shorter wavelength region than the blue dopant (④), it can be advantageous for improving color gamut and luminance. When the blue cavity is moved to a longer wavelength region to improve color gamut, the problem that color coordinate characteristics may deteriorate due to changes in the thickness of the entire organic layer can be solved. Therefore, by applying a dark blue light emitting layer containing a deep blue dopant to the first light emitting layer (EML) 214, color gamut and luminance can be improved.

Accordingly, the first light emitting layer (EML) 214 of the first light emitting part 210 is composed of a deep blue light emitting layer, and the second light emitting layer (EML) 215 is composed of a green light emitting layer. . A first light emitting layer (EML) 214 using a dark blue dopant with a maximum wavelength of the photoluminescence peak (PL Peak) of 444 nm, and a second light emitting layer (EML) using a green dopant with a maximum wavelength of the photoluminescence peak (PL Peak) of 542 nm. 215 constitutes a first light emitting part 210, which is one light emitting part.

And, the wavelength of the dopant included in the first emitting layer (EML) 214 may be in the range of 440 nm to 480 nm. The wavelength of the dopant included in the second emitting layer (EML) 215 may be in the range of 530 nm to 580 nm. Accordingly, the first emitting layer (EML) 214 and the second emitting layer (EML) 215 can emit light in the range of 440 nm to 580 nm, thereby increasing the light emitting area and improving efficiency. In addition, dopants with the same light-emitting properties can emit light from the same host, allowing control of charge balance within the light-emitting layer, which can be advantageous in improving efficiency. In addition, by using the same fluorescent dopant, excitons can easily move between the two light-emitting layers, thereby increasing the light-emitting area, thereby improving efficiency. Accordingly, two light-emitting layers are applied to the first light-emitting part 210 and the second light-emitting part 220.

Of the two light-emitting layers, the deep blue light-emitting layer may be closer to the first electrode 202 than the green light-emitting layer. Alternatively, the green light emitting layer may be configured closer to the first electrode 202 than the deep blue light emitting layer.

Therefore, in another embodiment of the present specification, the first light emitting layer (EML) 214 of the first light emitting unit 210 may be composed of a green light emitting layer. The wavelength of the dopant included in the first emitting layer (EML) 214 may be in the range of 530 nm to 580 nm. Additionally, the second light emitting layer (EML) 215 of the first light emitting unit 210 may be composed of a deep blue light emitting layer. The wavelength of the dopant included in the second emitting layer (EML) 215 may be in the range of 440 nm to 480 nm. In another embodiment of the present specification, the first light emitting layer (EML) 214 and the second light emitting layer (EML) 215 can emit light in the range of 440 nm to 580 nm, so the light emitting area can be increased to improve efficiency. there is. In another embodiment of the present specification, the dopant included in the green emitting layer of the first emitting layer (EML) 214 and the deep blue emitting layer of the second emitting layer (EML) 215 is composed of a fluorescent dopant. .

The dopant included in the dark blue light emitting layer, which is the first light emitting layer (EML) 214, is BCzVBi (4,4'bis(9-ethyl-3-carbazovinylene)-1,1'biphenyl), perylene, and DPAVBi ( 4,4'bis[4-(di-p-tolylamino)styryl]biphenyl), N-BDAVBi(N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl )naphthalene-2-yl)vinyl)phenyl)-N-phenylbenzneamine), etc., but is not limited thereto. In addition, the dopant included in the green light-emitting layer, which is the second light-emitting layer (EML) 215, may be made of an iridium-based material, but is not limited thereto.

A first charge generating layer (CGL) 240 may be further formed between the first light emitting unit 210 and the second light emitting unit 220. The first charge generation layer (CGL) 240 adjusts the charge balance between the first light emitting unit 210 and the second light emitting unit 220. The first charge generation layer 240 may include an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL). The N-type charge generation layer (N-CGL) serves to inject electrons into the first light emitting part 210, and the P-type charge generation layer (P-CGL) serves to inject electrons into the second light emitting part 220. It serves to inject holes. Additionally, the first charge generation layer (CGL) 240 may be formed as a single layer.

The second light emitting part 220 includes a second hole transport layer (HTL) 222, a third light emitting layer (EML) 224, a fourth light emitting layer (EML) 225, and a second electron transport layer (ETL) 226. It can be configured including. Although not shown in the drawing, an electron injection layer (EIL) may be additionally formed on the second electron transport layer (ETL) 226. Additionally, a hole injection layer (HIL) may be additionally configured.

The second hole transport layer (HTL) 222 may be made of the same material as the first hole transport layer (HTL) 212, but is not necessarily limited thereto.

The second hole transport layer (HTL) 222 may be formed by applying one or more layers or one or more materials, but is not necessarily limited thereto.

The second electron transport layer (ETL) 226 may be made of the same material as the first electron transport layer (ETL) 216, but is not necessarily limited thereto.

The second electron transport layer (ETL) 226 may be formed by applying one or more layers or one or more materials.

*The third light emitting layer (EML) 224 of the second light emitting unit 220 is composed of a green light emitting layer, and the fourth light emitting layer (EML) 225 is composed of a red light emitting layer. This will be explained with reference to FIG. 5A. As shown in Figure 5a, a green emitting layer using a phosphorescent green dopant (①) with a maximum wavelength of the photoluminescence peak (PL Peak) of 532 nm and a red dopant (③) with a maximum wavelength of the photoluminescence peak (PL Peak) of 620 nm. The second light emitting part 220, which is one light emitting part, is formed with a red light emitting layer to which is applied. As already explained, the phosphorescent green dopant has better efficiency than the fluorescent green dopant, but has the disadvantage of having a shorter lifespan. Therefore, in order to improve device lifespan, a fluorescent green dopant is applied to the first light emitting part 210, and a phosphorescent green dopant is applied to the second light emitting part 220 to supplement green efficiency, thereby improving green efficiency and device lifespan. Everything can be improved.

And, the wavelength of the dopant included in the third emitting layer (EML) 224 may be in the range of 530 nm to 580 nm. The wavelength of the dopant included in the fourth emitting layer (EML) 225 may be in the range of 600 nm to 650 nm. Accordingly, the third light emitting layer (EML) 224 and the fourth light emitting layer (EML) 225 can emit light in the range of 530 nm to 650 nm, thereby increasing the light emitting area and improving efficiency.

In addition, dopants with the same light-emitting properties can emit light from the same host, allowing control of charge balance within the light-emitting layer, which can be advantageous in improving efficiency. In addition, by using the same phosphorescent dopant, excitons can easily move between the two light-emitting layers, thereby increasing the light-emitting area, thereby improving efficiency.

The dopant included in the third emitting layer (EML) 224 may be made of Ir(ppy) ₃ (Tris(2-phenylpyridine)iridium(III)), but is not limited thereto. And, the dopant included in the fourth emitting layer (EML) 225 is Ir(piq) ₃ (Tris(1-phenylisoquinoline)iridium(III)), Ir(piq) ₂ (acac)(Bis(1-phenylisoquinoline)) (acetylacetonate)iridium(III)), Ir(btp) ₂ (acac)(Bis)2-benzo[b]thiophen-2-yl-pyridine)(acetylacetonate)iridium(III)), Ir(BT) ₂ (acac) )(Bis(2-phenylbenzothazolato)(acetylacetonate)iridium(III)), etc., but is not limited thereto.

The third light emitting unit 230 may include a third hole transport layer (HTL) 232, a fifth light emitting layer (EML) 234, and a third electron transport layer (ETL) 236. Although not shown in the drawing, an electron injection layer (EIL) may be additionally formed on the third electron transport layer (ETL) 236. Additionally, a hole injection layer (HIL) may be additionally configured.

The third hole transport layer (HTL) 232 is TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-bi-phenyl-4,4'-diamine) or It may be composed of NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), but is not necessarily limited thereto.

The third hole transport layer (HTL) 232 may be formed by applying one or more layers or one or more materials.

The third electron transport layer (ETL) 236 may be made of the same material as the first electron transport layer (ETL) 216, but is not necessarily limited thereto.

The third electron transport layer (ETL) 236 can be formed by applying one or more layers or one or more materials.

A second charge generating layer (CGL) 250 may be further formed between the second light emitting unit 220 and the third light emitting unit 230. The second charge generation layer 250 adjusts the charge balance between the second light emitting unit 220 and the third light emitting unit 230. The second charge generation layer (CGL) 250 may include an N-type charge generation layer (N-CGL) and a P-type charge generation layer (P-CGL).

The N-type charge generation layer (N-CGL) serves to inject electrons into the second light emitting part 220, and the P-type charge generation layer (P-CGL) serves to inject electrons into the third light emitting part 230. It serves to inject holes. Additionally, the second charge generation layer (CGL) 250 may be formed as a single layer.

The first charge generation layer (CGL) 240 may be made of the same material as the N-type charge generation layer and the P-type charge generation layer of the second charge generation layer (CGL) 250, but is not necessarily limited thereto. no.

In this specification, the structure of the charge generation layer (CGL) was optimized. Here, the charge generation layer is described including the first charge generation layer and the second charge generation layer. As already described, the first charge generation layer and the second charge generation layer include an N-type charge generation layer and a P-type charge generation layer.

The N-type charge generation layer (N-CGL) is an alkali metal such as lithium (Li), sodium (Na), potassium (K), or cesium (Cs), or magnesium (Mg), calcium (Ca), or strontium ( It may be made of an organic layer doped with an alkaline earth metal such as Sr), barium (Ba), or radium (Ra), but is not necessarily limited thereto. Alkali metal or alkaline earth metal may be doped at a rate of 0.6% or more and 2.0% or less.

The P-type charge generation layer (P-CGL) may be composed of a P host of at least one organic material and a P dopant of at least one organic material. At least one P host material may be composed of the same material as the adjacent hole transport layer (HTL), the second hole transport layer (HTL) 222 or the third hole transport layer (HTL) 232, or a different material from the hole transport layer (HTL). You can. In addition, the triplet energy of the hole transport layer (HTL) is 2.5 eV or more, and when it is within this range, there is an effect of preventing electron movement and diffusion of triplet exciton. In addition, by adjusting the HOMO (Highest Occupied Molecular Orbital) level of the P host to be close to the HOMO level of the second hole transport layer 222, injection of holes into the light emitting layer is possible, and the triplet of the phosphorescent light emitting layer of the second light emitting part is made possible. By preventing diffusion of triplet exciton into the second hole transport layer (HTL) 222, the device lifespan can be improved. For example, the HOMO level of the P host may range from 4.5 eV to 6.0 eV, and the LUMO (Lowest Unoccupied Molecular Orbital) level of the P dopant may range from 4.5 eV to 6.0 eV.

And, the fifth light emitting layer (EML) 234 of the third light emitting unit 230 is composed of a deep blue light emitting layer. The wavelength of the dopant included in the fifth emitting layer (EML) 234 may be in the range of 440 nm to 480 nm. By configuring the deep blue light emitting layer in the third light emitting unit 230, it is possible to compensate for the decrease in blue efficiency due to the deep blue light emitting layer and the green light emitting layer being used together in the first light emitting part 210. It can be a structure that can be used. Additionally, by adding a dark blue light-emitting layer to the third light-emitting part in addition to the first light-emitting part of the organic light-emitting device, the color temperature can be increased, thereby improving the color gamut.

The dopant included in the fifth emitting layer (EML) 234 is BCzVBi (4,4'bis(9-ethyl-3-carbazovinylene)-1,1'biphenyl), perylene, and DPAVBi(4,4 'bis[4-(di-p-tolylaino)styryl]biphenyl), N-BDAVBi(N-(4-((E)-2-(6-((E)- 4-(diphenylamino)styryl)naphthalene- 2-yl)vinyl)phenyl)-N-phenylbenzneamine), etc., but is not limited thereto.

As already explained, an organic light emitting device emits light as excitons created by recombination of holes and electrons emit energy. There are two ways to emit light. Fluorescence is when an exciton falls from a singlet level to an excited state and emits light. Phosphorescence is the emission of light when an exciton falls from the triplet level to an excited state. Here, at the singlet level, one exciton is dropped, and at the triplet level, three excitons are dropped, so fluorescence has an efficiency of 25% and phosphorescence has an efficiency of 75%. To increase the internal quantum efficiency of fluorescent light emission, triplet-triplet annihilation (TTA) and delayed fluorescence must be used. TTA is a phenomenon in which long-lived triplet excitons are adjacent to each other at high density, causing collisions between excitons, and some triplet excitons transition to singlet excitons and emit light. Triplet excitons are converted to singlets by TTA, contributing to light emission, thereby improving internal quantum efficiency. In particular, transition and collision of singlet excitons due to collisions of triplet excitons, which have a lifetime much longer than the lifetime of directly excited singlet excitons, produce delayed fluorescence. Luminous efficiency can be further improved by this delayed fluorescence.

Therefore, in order to further improve the efficiency of the blue light emitting layer, which is the fifth light emitting layer (EML) 234 of the third light emitting unit 230, TTA and delayed fluorescence are applied. The internal quantum efficiency (IQE) can be improved from the existing 25% to 40% due to the contribution of delayed fluorescence through TTA to light emission by singlet excitons. In order for TTA to occur efficiently in the emitting layer, the smaller the energy difference (singlet-triplet exchange energy; ΔEst) between the singlet level and triplet level of the host and dopant of the emitting layer, the lower the energy transfer from triplet to singlet through TTA. It's easy. In order to effectively form triplet excitons in the emitting layer, the triplet energy of the hole transport layer (HTL) and the electron transport layer (ETL) must be higher than the triplet energy of the host of the emitting layer. That is, the triplet energy of the third hole transport layer (HTL) 232 and the third electron transport layer (ETL) 236 is 0.01 eV to 0.01 eV higher than the triplet energy of the host of the blue light-emitting layer, which is the fifth light-emitting layer (EML) 234. By increasing it by 0.4 eV, blue efficiency can be further improved.

In addition, an organic light emitting display device including an organic light emitting device according to another embodiment of the present specification includes a gate wire and a data wire that cross each other on the substrate to define each pixel area, and a power wire that extends parallel to any one of them. is located, and in each pixel area, a switching thin film transistor connected to the gate wiring and data wiring and a driving thin film transistor connected to the switching thin film transistor are located. A driving thin film transistor is connected to the first electrode 202.

In addition, an optimized structure of this specification is proposed through a contour map through optical simulation applying the organic light-emitting device shown in FIG. 4. After setting the thickness of the organic layer located between the first electrode and the second electrode, the positions of the light emitting layers constituting each light emitting unit were optically simulated. The description will be made with reference to FIGS. 4 and 6 together.

Figure 6 is a diagram showing a Contour Map according to another embodiment of the present specification.

As described in FIG. 4, in another embodiment of the present specification, the first light emitting layer of the first light emitting part 210 is composed of a dark blue light emitting layer, the second light emitting layer is composed of a green light emitting layer, and the third light emitting layer of the second light emitting part 220 is composed of a green light emitting layer. The fourth light emitting layer is composed of a green light emitting layer, the fourth light emitting layer is composed of a red light emitting layer, and the fifth light emitting layer of the third light emitting unit 230 is composed of a dark blue light emitting layer.

In Figure 6, the horizontal axis represents the wavelength, and the vertical axis represents the thickness of the organic material. In FIG. 6, the unit of thickness of the organic material is described in nanometers (nm), but hereinafter, it is converted to angstroms (Å) instead of nanometers (nm).

As shown in FIGS. 4 and 6, the thickness (T0) of the organic layer located between the first electrode 202 and the second electrode 204 may be 3200 Å to 3500 Å.

The position 214E of the dark blue light emitting layer, which is the first light emitting layer (EML) 214 of the first light emitting unit 210, is located at 100 Å to 500 Å from the first electrode 202. Preferably, the position 214E of the dark blue light emitting layer, which is the first light emitting layer (EML) 214, is located at 300 Å from the first electrode 202. And, the position 215E of the green light-emitting layer, which is the second light-emitting layer (EML) 215, is located at 300 Å to 700 Å from the first electrode 202. Preferably, the position 215E of the green light-emitting layer, which is the second light-emitting layer (EML) 215, is located at 500 Å from the first electrode 202. It can be seen that in the range corresponding to this thickness, the wavelength region corresponding to blue is 440 nm to 480 nm, and the wavelength region corresponding to green is 530 nm to 580 nm. Therefore, as shown in FIG. 6, it can be seen that light emission occurs in the wavelength region corresponding to blue and the wavelength region corresponding to green.

Additionally, the thickness of the first emitting layer (EML) 214 may range from 200 Å to 300 Å, and the thickness of the second emitting layer (EML) 215 may range from 200 Å to 300 Å.

The position 224E of the green light-emitting layer, which is the third light-emitting layer (EML) 224 of the second light-emitting part, is located at 1700 Å to 2100 Å from the first electrode 202. Preferably, the location 224E of the green light-emitting layer, which is the third light-emitting layer (EML) 224, is located at 1900 Å from the first electrode 202. And, the position 225E of the red light emitting layer, which is the fourth light emitting layer (EML) 225, is located at 2000 Å to 2400 Å from the first electrode 202. Preferably, the position 225E of the red light emitting layer (EML) 225 is located at 2200 Å from the first electrode 202. It can be seen that in the range corresponding to this thickness, the wavelength region corresponding to green is 530 nm to 580 nm, and the wavelength region corresponding to red is 600 nm to 650 nm. Therefore, as shown in FIG. 6, it can be seen that light emission occurs in the wavelength region corresponding to green and the wavelength region corresponding to red.

Additionally, the thickness of the third emitting layer (EML) 224 may be in the range of 200 Å to 300 Å, and the thickness of the fourth emitting layer (EML) 225 may be in the range of 50 Å to 100 Å.

The dark blue light emitting layer, which is the fifth light emitting layer (EML) 234 of the third light emitting part, is located at 2400 Å to 2800 Å from the first electrode 202 . Preferably, the deep blue light emitting layer, which is the fifth light emitting layer (EML) 234, is located at 2600 Å from the first electrode 202. It can be seen that the wavelength region corresponding to blue in the range corresponding to this thickness is 440 nm to 480 nm. Therefore, as shown in FIG. 6, it can be seen that light emission occurs in the wavelength region corresponding to blue. Additionally, the thickness of the fifth light emitting layer (EML) 234 may be in the range of 200Å to 300Å.

Although only another embodiment of the present specification is shown in FIG. 6, the contour map according to another embodiment of the present specification also shows the same contour map as that of FIG. 6. In another embodiment of the present specification, the first light-emitting layer of the first light-emitting part 210 is a green light-emitting layer and the second light-emitting layer is a dark blue light-emitting layer, and the third light-emitting layer of the second light-emitting part 220 is a green light-emitting layer and a fourth light-emitting layer. The light emitting layer is composed of a red light emitting layer, and the fifth light emitting layer of the third light emitting unit 230 is composed of a dark blue light emitting layer. In another embodiment of the present specification, only the position of the light emitting layer of the first light emitting unit is changed, and the description of the second light emitting unit and the third light emitting unit is the same as that of FIG. 6, which is another embodiment of the present specification, and is therefore omitted here. The position 214E of the green light-emitting layer, which is the first light-emitting layer (EML) 214 of the first light-emitting part 210, is located at 300 Å from the first electrode 202. The position 215E of the dark blue light emitting layer, which is the second light emitting layer (EML) 215, is located at 500 Å from the first electrode 202. It can be seen that within the range corresponding to this thickness, the wavelength region corresponding to the green region is 530 nm to 580 nm, and the wavelength region corresponding to the blue region is 440 nm to 480 nm.

The results of measuring efficiency, color coordinates, luminous intensity, and color viewing angle change rate according to the embodiments of the present specification are described with reference to Table 1 and FIGS. 7 and 8.

In Table 1, the first embodiment is an organic light emitting display device using the organic light emitting device shown in FIG. 1, and the second and third embodiments are organic light emitting display devices using the organic light emitting device shown in FIG. 4. In the second embodiment, the first light emitting layer of the first light emitting part is composed of a dark blue light emitting layer and the second light emitting layer is composed of a green light emitting layer, the third light emitting layer of the second light emitting section is composed of a green light emitting layer, and the fourth light emitting layer is composed of a red light emitting layer. The negative fifth emitting layer is composed of a dark blue emitting layer. And, in the third embodiment, the first light emitting layer of the first light emitting part is composed of a green light emitting layer and the second light emitting layer is composed of a dark blue light emitting layer, the third light emitting layer of the second light emitting section is composed of a green light emitting layer, and the fourth light emitting layer is composed of a red light emitting layer. 3 The fifth light emitting layer of the light emitting part is composed of a dark blue light emitting layer.

Looking at efficiency, the values of the second and third embodiments are shown when the efficiency of the first embodiment is set to 100%. It can be seen that the red efficiency of the second embodiment was improved by 12% compared to the first embodiment, and the third embodiment was improved by 10% compared to the first embodiment. It can be seen that in the second and third embodiments, red efficiency was improved by forming a red light emitting layer as the fourth light emitting layer of the second light emitting unit.

And, it can be seen that the green efficiency of the second embodiment was improved by 5% compared to the first embodiment, and the third embodiment was improved by 4% compared to the first embodiment. It can be seen that in the second and third embodiments, green efficiency was improved by forming a green light-emitting layer with the first light-emitting layer of the first light-emitting part and the third light-emitting layer of the second light-emitting part.

It can be seen that blue efficiency was slightly reduced in the second and third embodiments compared to the first embodiment. It can be seen that white efficiency was slightly reduced in the second and third embodiments compared to the first embodiment. Therefore, in terms of efficiency, it can be seen that the red efficiency and green efficiency of the second and third embodiments are improved compared to the first embodiment.

Looking at the white color coordinates (Wx, Wy), it can be seen that the first embodiment is (0.302, 0.338), the second embodiment is (0.283, 0.304), and the third embodiment is (0.303, 0.362). , it can be seen that the second and third embodiments are similar.

Looking at the DCI (Digital Cinema Initiatives) area ratio, it can be seen that the first embodiment is 93.2%, the second embodiment is 110.3%, and the third embodiment is 108.9%. And, looking at the DCI overlap ratio, it can be seen that the first embodiment is 92.3%, the second embodiment is 99.7%, and the third embodiment is 99.8%. From this, it can be seen that the color gamut of the second and third embodiments is improved compared to the first embodiment. This shows that the DCI area ratio and DCI overlap ratio can be improved by applying green and red dopants that affect color gamut to the second light emitting unit. In addition, it can be seen that the color gamut is improved by configuring the first and third light emitting units with a dark blue light emitting layer that affects the color gamut.

Looking at the color viewing angle change rate (Δu'v') according to the viewing angle, it can be seen that the first embodiment is 0.032, the second embodiment is 0.022, and the third embodiment is 0.017. It can be seen that the color viewing angle change rate (Δu'v') according to angle is smaller in the second and third embodiments compared to the first embodiment. This is shown in FIG. 7 and will be described in detail with reference to FIG. 7 .

Figure 7 is a diagram showing the color viewing angle change rate (Δu'v') according to the viewing angle of the organic light emitting display device. In Figure 7, the horizontal axis represents the viewing angle, and the vertical axis represents the color viewing angle change rate (Δu'v').

Figure 7 shows the color viewing angle change rate (Δu'v') measured while tilting from 0 degrees to 15 degrees, 30 degrees, 45 degrees, and 60 degrees when viewed from the front of the organic light emitting display device.

In FIG. 7, the first, second, and third embodiments are the same as those described in Table 1 and are therefore omitted. The first example is indicated by a dotted line, the second example is indicated by a solid line, and the third example is indicated by a dashed line.

As shown in FIG. 7, the color viewing angle change rate (Δu'v') in the viewing angle direction from 0 degrees to 60 degrees, which is the front of the organic light emitting display device, is 0.032 in the first embodiment, 0.022 in the second embodiment, and 0.022 in the third embodiment. The example shows that it is 0.017. If the color viewing angle change rate (Δu'v') is less than 0.022 in the viewing angle direction of 0 degrees to 60 degrees, which is the front, color defects due to color differences depending on the position can be prevented when the organic light emitting display device is viewed by position. Accordingly, it can be seen that the second and third embodiments can improve color defects of the organic light emitting display device compared to the first embodiment.

Figure 8 is a diagram showing an EL spectrum according to an embodiment of the present specification. In Figure 8, the horizontal axis represents the wavelength of light, and the vertical axis represents the intensity of light emission. The luminous intensity is a value expressed as a relative value based on the maximum value of the EL spectrum.

In FIG. 8, the first, second, and third embodiments are the same as those described in Table 1 and are therefore omitted. The first example is indicated by a dotted line, the second example is indicated by a solid line, and the third example is indicated by a dashed line. In FIG. 8, the second and third embodiments of the spectrum from wavelength 500 nm to 800 nm are displayed overlapping each other.

As shown in FIG. 8, it can be seen that the second and third examples have three emission peaks in the EL spectrum compared to the first example. That is, the first emission peak corresponds to the blue region, and the peak wavelength corresponding to the blue region may be in the range of 440 nm to 480 nm. Also, the second emission peak corresponds to the green region, and the peak wavelength corresponding to the green region may be in the range of 530 nm to 580 nm. And, the third emission peak corresponds to the red region, and the peak wavelength corresponding to the red region may be in the range of 600 nm to 650 nm.

It can be seen that in the region of the first peak wavelength, the emission intensities of the first, second, and third examples are similar. In the region of the second peak wavelength, it can be seen that the emission intensity of the second and third examples increased compared to the first example. Therefore, it can be seen that the green efficiency of the second and third embodiments is improved compared to the first embodiment. And, in the region of the third peak wavelength, it can be seen that the peak of the first example does not appear in this region, and the emission peaks of the second and third examples appear. Therefore, it can be seen that the red efficiency of the second and third embodiments is improved compared to the first embodiment.

Also, compared to the organic light emitting display device using the bottom emitting method, it was found that the aperture ratio of the organic light emitting display device applying the top emitting method according to the embodiment of the present specification was improved by more than 40%. In addition, since the luminance of the organic light emitting display device can be improved because there is no need to use a polarizer, an organic light emitting display device with improved aperture ratio and luminance, and improved efficiency and color gamut can be provided.

The organic light emitting device according to the present specification described above may be applied to a lighting device, may be used as a thin light source for a liquid crystal display device, or may be applied to a display device. Hereinafter, an embodiment in which the organic light-emitting device according to the present specification is applied to a display device will be described.

FIG. 9 is a cross-sectional view of an organic light emitting display device including an organic light emitting device according to an embodiment of the present specification, which uses the organic light emitting device according to FIG. 4 described above.

As shown in FIG. 9, the organic light emitting display device 1000 of the present specification includes a substrate 201, a thin film transistor (TFT), a first electrode 202, a light emitting unit 1180, and a second electrode 204. Includes. The thin film transistor (TFT) includes a gate electrode 1115, a gate insulating layer 1120, a semiconductor layer 1131, a source electrode 1133, and a drain electrode 1135.

In Figure 9, the thin film transistor (TFT) is shown as an inverted staggered structure, but it can also be formed as a coplanar structure.

The substrate 201 may be made of glass, metal, or plastic.

The gate electrode 1115 is formed on the substrate 201 and is connected to a gate line (not shown). The gate electrode 1115 is selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be a multi-layer made of any selected one or an alloy thereof.

The gate insulating layer 1120 is formed on the gate electrode 1115 and may be a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multilayer thereof, but is not limited thereto.

The semiconductor layer 1131 is formed on the gate insulating layer 1120 and is made of amorphous silicon (a-Si), polycrystalline silicon (poly-Si), oxide semiconductor, organic semiconductor, etc. It can be formed as When the semiconductor layer is formed of an oxide semiconductor, it may be formed of ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or ITZO (Indium Tin Zinc Oxide), but is not limited thereto. Additionally, an etch stopper (not shown) may be formed on the semiconductor layer 1131 to protect the semiconductor layer 1131, but may be omitted depending on the configuration of the device.

The source electrode 1133 and the drain electrode 1135 may be formed on the semiconductor layer 1131. The source electrode 1133 and the drain electrode 1135 may be made of a single layer or multiple layers, and may include molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), and nickel (Ni). ), neodymium (Nd), and copper (Cu), or an alloy thereof.

The protective layer 1140 is formed on the source electrode 1133 and the drain electrode 1135, and may be formed of a silicon oxide film (SiOx), a silicon nitride film (SiNx), or multiple layers thereof. Alternatively, it may be formed of acryl resin, polyimide resin, etc., but is not limited thereto.

The first electrode 202 is formed on the protective layer 1140 and is made of gold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), magnesium (Mg), or an alloy thereof. It may be formed as, but is not necessarily limited to this. Alternatively, it may be formed of ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), etc., but is not necessarily limited thereto. Additionally, a reflective electrode may be additionally configured below the first electrode 202.

The first electrode 202 is electrically connected to the drain electrode 1135 through a contact hole (CH) in a predetermined area of the protective layer 1140. In FIG. 9, the drain electrode 1135 and the first electrode 202 are shown to be electrically connected, but the source electrode 1133 and the first electrode are connected through a contact hole (CH) in a predetermined area of the protective layer 1140. It is also possible for (202) to be electrically connected.

The bank layer 1170 is formed on the first electrode 202 and defines the pixel area. That is, the bank layer 1170 is formed in a matrix structure in the boundary area between a plurality of pixels, so that the pixel area is defined by the bank layer 1170. The bank layer 1170 may be formed of an organic material such as benzocyclobutene (BCB)-based resin, acryl-based resin, or polyimide resin. Alternatively, the bank layer 1170 can be formed of a photoresist containing a black pigment, and in this case, the bank layer 1170 functions as a light blocking member.

The light emitting part 1180 is formed on the bank layer 1170. As shown in FIG. 4, the light emitting unit 1180 includes a first light emitting unit 210, a second light emitting unit 220, and a third light emitting unit 230 formed on the first electrode 202.

The second electrode 204 is formed on the light emitting part 1180 and is made of transparent conductive materials such as TCO (Transparent Conductive Oxide), ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and IGZO (Indium Gallium Zinc Oxide). ), etc., but is not necessarily limited thereto. Additionally, a buffer layer may be additionally formed under the second electrode 204.

An encapsulation layer 1190 is formed on the second electrode 204. The encapsulation layer 1190 serves to prevent moisture from penetrating into the light emitting unit 1180. The encapsulation layer 1190 may be composed of a plurality of layers in which different inorganic materials are laminated, or it may be composed of a plurality of layers in which inorganic materials and organic materials are alternately laminated. The encapsulation substrate 301 may be bonded to the first substrate 201 by the encapsulation layer 1190. The encapsulation substrate 301 may be made of glass or plastic, or may be made of metal. Additionally, a color filter 302 and a black matrix 303 are disposed on the encapsulation substrate 301. The light emitted from the light emitting unit 1180 travels toward the encapsulation substrate 301 and displays an image through the color filter 302.

As described above, according to the present specification, two light-emitting layers are formed in at least two of the three light-emitting parts, and the two light-emitting layers are made of dopants having the same light-emitting characteristics, so that exciton movement between the two light-emitting layers is easy. Therefore, there is an effect of improving efficiency and device lifespan.

Additionally, by forming a blue light-emitting layer and a green light-emitting layer within one light-emitting part, green efficiency and color gamut can be improved.

In addition, by forming a green light-emitting layer and a red light-emitting layer in one light-emitting part, green efficiency and red efficiency can be improved, and color reproduction rate can be improved.

In addition, by forming a blue light-emitting layer in the two light-emitting parts, there is an effect of improving color gamut.

In addition, by forming two light-emitting layers in at least two of the three light-emitting parts and configuring a structure with three peak wavelengths, it is possible to provide an organic light-emitting display device with improved efficiency and color gamut.

In addition, since there is no need to use a polarizer, it is possible to provide an organic light emitting display device with improved aperture ratio and luminance.

Although the embodiments of the present specification have been described in more detail with reference to the accompanying drawings, the present specification is not necessarily limited to these embodiments, and various modifications may be made without departing from the technical spirit of the present specification. . Accordingly, the embodiments disclosed in this specification are not intended to limit the technical idea of the present specification, but rather to explain it, and the scope of the technical idea of the present specification is not limited by these embodiments. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of protection of this specification should be interpreted in accordance with the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of this specification.

100, 200: Organic light emitting device
101, 201: substrate 102,202: first electrode
104, 204: second electrode 110, 210: first light emitting unit
120, 220: second light emitting unit 130, 230: third light emitting unit
140, 240: first charge generation layer 150, 250: second charge generation layer
112, 212: first hole transport layer 122, 222: second hole transport layer
132, 232: third hole transport layer 116, 216: first electron transport layer
126, 226: second electron transport layer 136, 236: third electron transport layer
114, 214: first emitting layer 215: second emitting layer
124, 224: third emitting layer 225: fourth emitting layer
134, 234: fifth light emitting layer

Claims (19)

first electrode and second electrode;
a first light emitting unit located on the first electrode;
a second light emitting unit located above the first light emitting unit; and
It includes a third light emitting unit located above the second light emitting unit,
The first light emitting unit, the second light emitting unit, and the third light emitting unit include at least one of a dark blue light emitting layer, a green light emitting layer, and a red light emitting layer. According to claim 1,
The organic light emitting display device wherein the dark blue light emitting layer is included in at least two light emitting parts of the first light emitting part, the second light emitting part, and the third light emitting part. According to claim 1,
The green light emitting layer is included in at least two light emitting parts of the first light emitting part, the second light emitting part, and the third light emitting part. According to claim 1,
Each of the dark blue light emitting layer and the green light emitting layer is included in at least two light emitting parts of the first light emitting part, the second light emitting part, and the third light emitting part. According to claim 1,
An organic light emitting display device, wherein at least one of the first light emitting unit, the second light emitting unit, and the third light emitting unit includes two light emitting layers. According to claim 5,
The two light emitting layers include at least one of the dark blue light emitting layer, the green light emitting layer, and the red light emitting layer. According to claim 5,
The two light emitting layers include the green light emitting layer and the dark blue light emitting layer. According to claim 5,
The two light emitting layers include the green light emitting layer and the red light emitting layer. According to claim 5,
An organic light emitting display device, wherein the two light emitting layers are composed of dopants having the same light emitting characteristics. According to clause 9,
The dopant included in the two light-emitting layers includes a phosphorescent dopant or a fluorescent dopant. According to claim 1,
Each of the first light emitting unit and the second light emitting unit includes two light emitting layers, and the third light emitting unit includes the dark blue light emitting layer. According to claim 11,
The two light emitting layers of the first light emitting unit include the dark blue light emitting layer and the green light emitting layer. According to claim 11,
The two light emitting layers of the second light emitting unit include the green light emitting layer and the red light emitting layer. According to claim 11,
An organic light emitting display device, wherein the first light emitting part and the second light emitting part are composed of dopants having different light emitting characteristics. According to claim 14,
The dopant included in the two light-emitting layers of the first light-emitting part is a fluorescent dopant,
The organic light emitting display device, wherein the dopant included in the two light emitting layers of the second light emitting part is a phosphorescent dopant. According to claim 1,
An organic light emitting display device, wherein at least one of the first light emitting unit, the second light emitting unit, and the third light emitting unit further includes a hole transport layer and an electron transport layer. According to claim 16,
The organic light emitting display device wherein the triplet energy of the hole transport layer and the electron transport layer is higher by 0.01 eV to 0.4 eV than the triplet energy of the dark blue light emitting layer. According to claim 1,
The organic light emitting display device wherein the first electrode is a reflective electrode and the second electrode is a transflective electrode. According to claim 1,
The first light emitting unit, the second light emitting unit, and the third light emitting unit have three emission peaks in the range of 440 nm to 480 nm, 530 nm to 580 nm, and 600 nm to 650 nm.