KR102551866B1 - White organic light emitting diode and display device using the same - Google Patents

Abstract

The present invention relates to a white organic light emitting device having an n-stack structure capable of increasing luminous efficiency, color reproducibility, and lifetime of a light emitting layer, and a display device using the same. The white organic light emitting device according to the present invention includes a first electrode and A first light emitting unit including a first blue light emitting layer and a second light emitting unit including first and second red light emitting layers and a yellow-green light emitting layer are included between the second electrodes, and between the first and second light emitting units It has the feature that the first charge generation layer is located.

Description

White organic light emitting device and display device using the same

The present invention relates to a white organic light emitting device and a display device using the same, and more particularly, to a white organic light emitting device having an n (n is a natural number equal to or greater than 2) stack structure having a red light emitting layer and a display device using the same.

Recently, as interest in information displays has increased and demands for using portable information media have increased, research and commercialization of lightweight thin display devices have been focused.

Among them, the organic light emitting display device uses a self-luminous organic light emitting element, and thus has an excellent viewing angle and contrast ratio compared to a liquid crystal display device. In addition, since the organic light emitting display device does not require a separate light source, it is easy to implement a lightweight thin display device with low power consumption, and a flexible display device can be implemented.

Such an organic light emitting display device has a structure in which a white organic light emitting element emits white light and the white light passes through a color filter to convert it into red, green, and blue light to display an image, or By arranging organic light emitting devices generating light of , in each sub-pixel, it is possible to have a structure capable of displaying an image without a separate color filter. Among them, in an organic light emitting display device using a white organic light emitting device, it is an important task to develop a white organic light emitting device with high efficiency and long lifespan.

In order to manufacture a white organic light emitting device having high efficiency, lifespan, and color, a white organic light emitting device having a multi-stack structure is being applied. A white organic light emitting diode having a multi-stack structure may have a structure including a plurality of light emitting layers having a complementary color relationship.

For example, the white organic light emitting device having the multi-stack structure may have a structure including a blue light emitting layer and a yellow-green light emitting layer. In this case, white light is emitted with emission peak wavelengths formed in the blue wavelength region and the yellow-green wavelength region. When such white light passes through a red color filter to display red, the efficiency and color reproduction decrease, resulting in a decrease in color reproducibility. A problem occurred.

The present invention has been made to solve the above problems, and it is a task to solve the problem of providing an n-stack structure white organic light emitting device and a display device using the same that can increase the luminous efficiency, color reproduction rate and lifespan of the light emitting layer. do.

In order to solve the above problems, a white organic electroluminescent device according to the present invention includes a first light emitting unit including a first blue light emitting layer between a first electrode and a second electrode, first and second red light emitting layers and yellow- A second light emitting unit including a green light emitting layer is included, and a first charge generation layer is positioned between the first and second light emitting units.

The white organic light emitting device may further include a second charge generation layer positioned on the second light emitting part and a third light emitting part positioned on the second charge generating layer.

Here, the first red light emitting layer serves to generate charge together with the first charge generation layer and has hole transport characteristics, and has a hole mobility of 5.0×10 ^-5 cm/Vs to 9.0 ^× 10 ^-4 cm.Vs. have To this end, the first red light-emitting layer may be made of a host selected from the group α-NPD, TCTA, TPD, TPB, TPAC, m-TPEE, FTPD, (NDA)PP, TRP, PPD, and OPT1, Typically, it may be formed based on the following materials.

The second red light-emitting layer includes a carbazole group, and may be typically formed based on a host as described below.

The second light emitting unit may further include a second electron transport layer between the second red light emitting layer and the second charge generation layer, and the first light emitting unit includes first and second hole transport layers, a first blue light emitting layer, and a first electron transport layer. can do. Here, the second hole transport layer may include a host having a higher triplet energy level than that of the first hole transport layer.

The third light emitting unit may include a third hole transport layer positioned on the second charge generation layer, a second blue light emitting layer positioned thereon, and a third electron transport layer positioned on the second blue light emitting layer.

The first red light-emitting layer should include 0.5 wt% or more of the red dopant, and should include at least 0.5 wt% or less of the red dopant of the second red light-emitting layer.

The white organic light emitting device as described above is connected to a drain electrode of a thin film transistor positioned on a substrate through a contact hole, and is converted into R/G/B colors through a color filter layer and emitted, thereby displaying an image.

The red light emitting layer of the present invention serves as a light emitting layer and simultaneously generates charge and transports holes to the yellow-green light emitting layer 23, and the red light emitting layer adds light in a wavelength range of 600 to 650 nm corresponding to the red region to emit light. , and thus has a characteristic capable of improving red luminance and color gamut. In particular, the white organic light emitting device according to the present invention due to the red light emitting layer of the present invention has an effect of improving the luminance of the entire device by increasing the efficiency of red light.

In particular, the red light emitting layer of the present invention may include a first red light emitting layer and a second red light emitting layer. At this time, the first red light emitting layer of the white organic light emitting device according to the present invention generates charges and transports holes and contributes to red light emission, thereby increasing the thickness of the entire red light emitting layer. Life expectancy is greatly increased. In particular, when the first red light emitting layer and the second red light emitting layer are formed of a single host different from each other, the scattering problem that occurs when co-depositing different types of hosts does not occur, thereby maximizing the lifespan and efficiency of the red light emitting layer. have an effect

In addition, the white organic light emitting device according to the present invention has an effect of further increasing the lifespan and efficiency of the red light emitting layer by increasing the thickness of the red light emitting layer without changing the thickness for the optimum cavity.

At this time, as the sum of the thicknesses of the first red light emitting layer and the second red light emitting layer becomes thinner, the viewing angle of the white organic light emitting device is improved, and accordingly, when the thicknesses of the first and second red light emitting layers are optimized, the red light emitting layer It is possible to improve the viewing angle characteristics as well as to improve the lifespan and efficiency of the.

Also, the doping concentration of the red dopant of the first red light emitting layer is lower than that of the red dopant of the second red light emitting layer. Accordingly, by reducing the number of holes trapped in the red light emitting layer and supplying a sufficient amount of holes to the yellow-green light emitting layer, the driving voltage of the organic light emitting device does not increase even when the thickness of the red light emitting layer increases.

1 is a schematic diagram for explaining a white organic light emitting device according to the present invention.
Figure 2 shows an experimental example for testing the lifespan, spectrum and viewing angle characteristics of the white organic light emitting device according to the present invention.
3 is a graph showing the lifespan of white organic light emitting diodes according to Comparative Example, First Experimental Example, and Second Experimental Example.
4 is a graph showing wavelength distributions of white organic light emitting diodes according to Comparative Example, First Experimental Example, and Second Experimental Example.
5 is a graph showing changes in color coordinates (Δu', v') according to viewing angles of white organic light emitting diodes according to Comparative Example, First Experimental Example, and Second Experimental Example.
6 is an exemplary diagram for explaining an organic light emitting display device according to the present invention.
7 is a cross-sectional view illustrating a schematic structure of each pixel included in the display panel according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Like reference numbers throughout the specification indicate substantially the same elements. In the following description, if it is determined that a detailed description of a technique or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, the component names used in the following description are selected in consideration of the ease of writing the specification, and may be different from the part names of the actual product.

When an element or layer is referred to as being “on” or “on” another element, it includes both a case where another element layer or another element is interposed therebetween as well as directly on another element layer. On the other hand, when an element or layer is referred to as "adjacent" to another element, it indicates that another element or layer is not intervened.

1 is a schematic diagram for explaining a white organic light emitting device according to the present invention.

As shown in FIG. 1, the white organic light emitting device according to the present invention includes a first light emitting unit 10 disposed on a first electrode 1 and including a first blue light emitting layer 13; 1 the first charge generating layer 40 positioned on the light emitting part 10, the second light emitting part 20 positioned on the first charge generating layer 40, and the second light emitting part 20 a second charge generation layer 50 located on the upper side, a third light emitting unit 30 located on the second charge generation layer 50 and including a second blue light emitting layer 32; It includes a second electrode (2) located on the portion (30).

The first electrode 1 is an anode and may be formed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO) having a relatively high work function.

The first charge generation layer 40 includes a first N-type charge generation layer 41 and a first P-type charge generation layer 42 . The first charge generation layer 40 may have a laminated structure in which the first P-type electrolysis generation layer 42 is positioned on the first N-type charge generation layer 41, but is not necessarily limited thereto. The first N-type charge generation layer 41 serves to inject electrons into the adjacent first light emitting part 10, and the first P-type charge generation layer 42 injects holes into the adjacent second light emitting part 20. It serves as an injector.

The second charge generation layer 50 includes a second N-type charge generation layer 51 and a second P-type charge generation layer 52 . The structure of the second charge generation layer 50 may also be formed identically to the structure of the first charge generation layer 40, but is not necessarily limited thereto. The second N-type charge generation layer 51 serves to inject electrons into the second light emitting unit 20, and the second P-type charge generation layer 42 injects holes into the third light emitting unit 30. play a role

The charge generation layers 40 and 50 may be formed using various organic materials having electron donor and acceptor characteristics.

For example, the P-type charge generation layers 42 and 52 are hexaazatriphenylene-hexacarbonitrile (HAT-CN) (Dipyrazino [2, 3-f: 2', 3'-h] quinoxaline = 2 , 3, 6, 7, 10, 11-hexacar bonitrile) or P-doped structure. Also, the charge generation layers 40 and 50 may be composed of a single layer such as the HAT-CN.

The first charge generation layer 40 adjusts the balance of charges between the first light emitting unit 10 and the second light emitting unit 20, and the second charge generation layer 50 controls the balance of charges between the second light emitting unit 20 ) and the third light emitting unit 30 to adjust the balance of charges.

The first light emitting unit 10 includes a first hole transport layer 11, a second hole transport layer 12 located on the first hole transport layer 11, and a first hole transport layer 12 located on the second hole transport layer 12. It includes a blue light emitting layer 13 and a first electron transport layer 14 positioned on the first blue light emitting layer 13 . The first hole transport layer 11, the second hole transport layer 12, the first blue light emitting layer 13, and the electron transport layer 14 may have a sequentially stacked structure, but are not limited thereto. For example, the first and second hole transport layers and the first electron transport layer 14 may be formed as a single layer or a multi-layer structure.

Here, the first hole transport layer 11 is formed to include a material having high mobility, and the second hole transport layer 12 includes a material having a higher triplet energy level T1 than the first hole transport layer 11. It is desirable to form Meanwhile, depending on the design, the first and second hole transport layers 11 and 12 may be formed as a single layer.

The third light emitting unit 30 includes a third hole transport layer 31, a second blue light emitting layer 32 positioned on the third hole transport layer 31, and a third light emitting layer positioned on the second blue light emitting layer 32. An electron transport layer 33 is included. The third hole transport layer 31, the second blue light emitting layer 32, and the third electron transport layer 33 may have a sequentially stacked structure, but are not necessarily limited thereto.

The first and second blue light emitting layers 13 and 32 are light emitting layers including a blue dopant and a host, and emit blue light. In this case, the first and second blue light emitting layers 13 and 32 may be composed of a deep blue light emitting layer or a sky blue light emitting layer. The peak wavelength region of the blue light emitting layer is determined within a range of about 440 nm to 480 nm. The first and second blue light-emitting layers 13 and 32 may emit fluorescence or phosphorescence, and include at least one mixed host and at least one dopant. Specifically, at least one host material selected from the group consisting of anthracene derivatives, pyrene derivatives, and perylene derivatives may be doped with a blue dopant, but is not necessarily limited thereto.

The second light emitting unit 20 includes a red light emitting layer and a yellow-green light emitting layer 23 . In particular, the red light emitting layer is preferably formed of two layers in which a first red light emitting layer 21 and a second red light emitting layer 22 are sequentially stacked. In other words, the second red light emitting layer 22 is positioned in contact with the first red light emitting layer 21 on the first red light emitting layer 21, and the yellow-green light emitting layer 23 is positioned on the second red light emitting layer 22. 2 positioned in contact with the red light emitting layer 23.

Here, the yellow-green light emitting layer 23 may be replaced with a green light emitting layer. In addition, a second electron transport layer 24 may be further positioned on the yellow-green light emitting layer 23 . The second electron transport layer 24 may be formed to contact the yellow-green light emitting layer 23 and the second charge generation layer 50, but is not necessarily limited thereto.

The yellow-green light emitting layer 23 may include a mixed host in which at least one host is co-deposited and at least one dopant. Specifically, a phosphorescent yellow-green dopant may be doped into a phosphorescent host material made of a carbazole-based compound or a metal complex. Carbazole-based compounds may include CBP (4, 4' -bis (carbazol-9-yl) -biphenyl), CBP derivatives, mCP (N, N'-dicarbazolyl-3, 5-benzene) or mCP derivatives, , The metal complex may include a znPBO (phenyloxazole) metal complex or a ZnPBT (phenylthiazole) metal complex.

The wavelength region of the red emission layer may be in the range of 600 to 650 nm, and the peak wavelength region corresponding to the yellow-green emission layer 23 may be in the range of 510 nm to 590 nm including the yellow to green region.

The first red light emitting layer 21 is positioned in contact with the first P-type charge generation layer 42 . The first red light emitting layer 21 may include at least one host having excellent charge generation characteristics and hole transport characteristics, and it is preferable to improve the scattering characteristics by using a single host. Specifically, the host of the first red light-emitting layer 21 is preferably an organic material having a hole mobility in the range of 5.0 × 10 ^-5 cm/Vs to 9.0 × 10 ^-4 cm/Vs, for example, α-NPD. , TCTA, TPD, TPB, TAC, m-TPEE, FTPD, (NDA)PP, TRP, PPD, and OPT1. Examples of representative materials that can be used as a host of the first red light emitting layer 21 are as follows.

A second red light emitting layer 22 is positioned on the first red light emitting layer 21 to contact the first red light emitting layer 21 . The second red light emitting layer 22 includes a host having an excellent ability to form excitons and an excellent ability to transfer energy to a red dopant. For example, the host of the second red light emitting layer 22 may be an organic material containing a carbazole group, and is also preferably formed of a single host. Examples of representative materials are as follows.

The first and second red light-emitting layers 21 and 22 may emit fluorescence or phosphorescence.

A phosphorescent dopant material that can be used as a dopant of the first and second red light-emitting layers 21 and 22 may be formed of a metal compound that forms a tricoordinate with NN or NO, OO, with iridium (Ir) metal as the center. there is. Specifically, the phosphorescent dopant is Ir(Piq) ₃ (Tris(1-phenylisoquinoline)iridium(III)), Ir(piq) ₂ (acac)(Bis(1-phenylisoquinoline)(acetylacetonate)iridiumIII)), Ir(btp) ) ₂ (acac)(Bis)2-benzo[b]thiophen-2-yl-pyridine)(acetylacetonate)iridiumIII)), Ir(BT) ₂ (acac)(Bis(2-phenylbenzothazolato)(acetylacetonate)iridiumIII)) etc., but is not necessarily limited thereto.

Fluorescent dopants usable as dopants for the first and second red light emitting layers 21 and 22 include Rubrene (5, 6, 11, 12-tetraphenylnaphthacene), DCJTB (4-(dicyanomethylene)-2-tert-butyl-6 -(1,1,7,7-tetramethyl juloidin-4-yl-vinyl)-4H pyran), etc., but is not necessarily limited thereto.

The red dopant of the second red light emitting layer 22 is formed to have a doping concentration of 1.0 to 10.0 wt%. In addition, the red dopant of the first red light emitting layer 21 is formed to have a doping concentration lower than that of the red dopant of the second red light emitting layer 22 . In this case, the doping concentration of the red dopant of the first red light-emitting layer 21 is lower than that of the red dopant of the second red light-emitting layer 22 by at least 0.5 wt% or more. For example, if the doping concentration of the red dopant of the second red light emitting layer 22 is set within the range of 1.0 to 10.0 wt%, the doping concentration of the red dopant of the first red light emitting layer 21 is 0.5 wt% to 9.5 wt%. It can be set within the range.

The red light emitting layer of the present invention serves as a light emitting layer and simultaneously generates charge and transports holes to the yellow-green light emitting layer 23, and the red light emitting layer adds light in a wavelength range of 600 to 650 nm corresponding to the red region to emit light. , and thus has a characteristic capable of improving red luminance and color gamut. In particular, due to the red light emitting layer of the present invention, the white organic light emitting device according to the present invention has an effect of improving the luminance of the entire device by increasing the efficiency of red light.

In the first and second red light emitting layers 21 and 22 formed of the two-layer stack structure of the present invention, the first red light emitting layer 21 and the first hole exnihilation layer 42 may not have a hole transport layer interposed therebetween. At this time, the first red light emitting layer 21 contributes to red light emission and is formed of a host having excellent charge generation characteristics and hole transport characteristics, so that a large amount of holes can be transferred to the second red light emitting layer 22 without a separate hole transport layer. ) and can transport holes to the yellow-green light emitting layer 23.

On the other hand, when the thickness of the red light emitting layer increases, including the first and second red light emitting layers 21 and 22 as described above, the number of holes trapped in the red light emitting layer increases, and accordingly, the yellow-green light emitting layer ( 23), there is a problem that the driving voltage of the white organic light emitting device increases because a sufficient amount of holes does not reach. In order to solve this problem, the doping concentration of the red dopant of the first red light emitting layer 21 is lower than that of the red dopant of the second red light emitting layer 22 . Therefore, the number of holes required for light emission in the first red light emitting layer 21 is only small compared to the total number of holes generated in the first charge generating layer 40 and the first red light emitting layer 21, so that the second red light emitting layer 22 and a sufficient amount of holes can be supplied to the yellow-green light emitting layer 23 . Accordingly, when the dopant doping concentrations of the first and second red light-emitting layers 21 and 22 are formed differently as described above, an increase in driving voltage is prevented and the thickness of the entire red light-emitting layer can be increased.

The first red light emitting layer 21 generates charge and transports holes and contributes to red light emission, so that the thickness of the entire red light emitting layer increases, and thus the lifespan of the red light emitting layer greatly increases. In particular, when the first red light emitting layer 21 and the second red light emitting layer 22 are formed of a single host different from each other, since the distribution problem that occurs when co-depositing different types of hosts does not occur, the lifespan of the red light emitting layer and It has the effect of maximizing efficiency.

In particular, the thickness of the red light emitting layer is increased without changing the thickness for the optimum cavity in the all-white organic light emitting device, thereby further increasing the lifespan and efficiency of the red light emitting layer.

On the other hand, when the sum of the thicknesses of the first red light emitting layer 21 and the second red light emitting layer 22 is small, viewing angle characteristics are improved. When the thickness of the light emitting layer 22 is optimized, the lifetime and efficiency of the red light emitting layer can be improved and viewing angle characteristics can be improved.

In this embodiment, the white organic light emitting display device having the first light emitting unit 10, the second light emitting unit 20, and the third light emitting unit 30 has been described, but according to the design, the third light emitting unit 30 ) and the second charge generation layer 50 may be omitted. Even in this case, the first light emitting unit 10 includes a blue light emitting layer, and the second light emitting unit 20 includes the first and second red light emitting layers 21 and 22 .

Figure 2 shows an experimental example for testing the lifespan, spectrum and viewing angle characteristics of the white organic light emitting device according to the present invention.

2(a) is a comparative example, and the second light emitting unit 20 includes a structure in which a hole transport layer, a single-layer red light emitting layer, and a yellow-green light emitting layer are sequentially stacked, and the rest is formed in the same manner as in FIG. 1 . It shows an organic electroluminescent device. At this time, the red light emitting layer includes a dopant having a doping concentration of 3wt%, and at this time, the sum of the thicknesses of the hole transport layer and the single-layer red light emitting layer was formed to be 120 Å. In the comparative example, the red light emitting layer includes a red dopant doped at a concentration of 3wt%.

2(b) shows a first experimental example, in which the second light emitting unit 20 has a structure in which a first red light emitting layer 21, a second red light emitting layer 22, and a yellow-green light emitting layer 23 are sequentially stacked. It shows a white organic electroluminescent device shown in FIG. 1 including a. At this time, the sum of the thicknesses of the first and second red light emitting layers 21 and 22 was formed to be 120 Å.

2(c) is a second experimental example, in which the second light emitting unit 20 has a structure in which a first red light emitting layer 21, a second red light emitting layer 22, and a yellow-green light emitting layer 23 are sequentially stacked. Including, the rest shows a white organic light emitting device formed in the same way as in FIG. Here, the sum of the thicknesses of the first and second red light emitting layers 21 and 22 was formed to be 100 Å.

In the first and second experimental examples, the doping concentration of the red dopant of the first red light emitting layer 21 was 1wt%, and the doping concentration of the red dopant of the second red light emitting layer 22 was 3wt%.

The light emitting efficiency, lifetime, and viewing angle characteristics of the white organic light emitting device according to the Comparative Example and the first and second experimental examples are compared using Table 1 and FIGS. 3, 4, and 5 below.

Table 1 shows the lifetime, luminous efficiency and viewing angle-color change relationship of the white organic light emitting device according to Comparative Example set to 1.0, and the life, luminous efficiency and viewing angle of the white organic light emitting device according to the first and second experimental examples. It shows the relative value of the color change according to . 3 is a graph showing the lifetime of white organic light emitting devices according to Comparative Example, Experimental Example 1, and Experimental Example 2, and FIG. 5 is a graph showing the wavelength distribution of the electroluminescent device, and FIG. 5 shows changes in color coordinates (Δu', v') according to the viewing angle of the white organic electroluminescent device according to the comparative example, the first experimental example, and the second experimental example. is the graph shown.

comparative example 1st experimental example 2nd experimental example life span 1.00 1.13 1.08 R luminous efficiency (cd/A) 1.0 1.0 1.0 G luminous efficiency (cd/A) 1.0 1.0 1.0 B luminous efficiency (cd/A) 1.0 1.0 1.0 W luminous efficiency (cd/A) 1.0 1.0 1.0 viewing angle - color change 1.0 1.0 0.81

First, referring to FIG. 4 and Table 1, the wavelength distribution and luminous efficiency of the white organic light emitting device according to the comparative example and the first and second experimental examples are almost the same. However, according to Table 1 and FIG. 3, the white organic light emitting device according to the first experimental example has a lifespan increased by about 13% compared to the comparative example, and the white organic light emitting device according to the second experimental example has a lifespan compared to that of the comparative example. An increase of about 8% can be seen.

That is, compared to the comparative example, the white organic light emitting device according to the present invention has an effect of greatly improving its lifespan while maintaining luminous efficiency and wavelength distribution.

Meanwhile, referring to Table 1 and FIG. 5 , the white organic light emitting diode according to the second experimental example has the smallest change in color coordinates (Δu', v') when the viewing angle increases. That is, the display device using the white organic light emitting device according to the second experimental example has a wider viewing angle than the comparative example and the first experimental example.

Hereinafter, an organic light emitting display device to which the white organic light emitting device according to the present invention is applied will be described.

6 is an exemplary diagram for explaining an organic light emitting display device according to the present invention.

An organic light emitting display device according to the present invention includes a display panel 5 including a plurality of pixels positioned in an area defined by crossing a plurality of gate lines GL and a plurality of data lines DL, and a plurality of gates. A gate driver 6 that drives the line GL, a data driver 7 that drives a plurality of data lines DL, and various types of data that align image data input from the outside and control the operation timing of each pixel. and a timing controller 8 outputting signals to the gate driver 6 and the data driver 7.

Each pixel of the display panel 5 includes an organic light emitting diode (OLED) composed of an organic light emitting layer between an anode and a cathode, and a pixel circuit independently driving the organic light emitting diode (OLED).

The pixel circuit includes at least one switching transistor TR1, at least one capacitor Cst, and a driving transistor TR2. In FIG. 1 , a pixel circuit having a 2T1C structure is illustrated, but is not necessarily limited thereto, and the pixel circuit may be variously configured such as a 3T1C, 4T2C, or 5T2C structure. The plurality of switching transistors TR1 charges the capacitor Cst with data signals in response to scan signals generated in units of horizontal periods. Also, the driving transistor TR2 supplies current to the organic light emitting device according to the data voltage charged in the capacitor Cst to drive the organic light emitting device OLED.

7 is a cross-sectional view illustrating a schematic structure of each pixel included in the display panel according to the present invention.

As shown in FIG. 7 , the driving transistor TR2 is formed on the substrate 100 and the buffer layer 101 and includes a semiconductor layer 104 including a source region 109a and a drain region 109b on both sides and , A substrate including a gate insulating film 106 covering the semiconductor layer 104, a gate electrode 102 positioned above the gate insulating film 106 corresponding to the semiconductor layer 104, and the gate electrode 102 ( 100) and through the first protective layer 112 including contact holes 113 exposing the source/drain regions 109a and 109b located on both sides of the semiconductor layer 104, and the contact hole. It includes a source electrode 110 and a drain electrode 108 connected to the source/drain regions 109a and 109b.

A second passivation layer 114 and a third passivation layer 116 are positioned on the driving transistor TR2. On the third protective layer 116, the organic electroluminescent device according to the present invention is located. The organic light emitting device includes a first electrode 1, a bank insulating film 124 having an opening 133 exposing the first electrode 1, a spacer 126 positioned on the bank insulating film 124, and , an organic layer 118 including a light emitting layer formed on the first electrode 1 exposed through the opening 133, and a second electrode 2 formed on the organic layer 118.

At this time, the first protective layer 112 includes a contact hole exposing the drain electrode 108, and the first electrode 1 is connected to the drain electrode 108 of the thin film transistor through the contact hole.

In this case, the substrate 100 is a flexible glass or polymer substrate, and the light emitting display panel according to the present invention can be manufactured as a flexible display or a foldable display. In this case, the light emitting display panel according to the present invention includes at least one folding area within the display area, and the entire display area may be bent.

The organic layer 118 is positioned between the first to third light emitting units 10, 20 and 30 of the white organic light emitting device according to the present invention and between the first light emitting unit 10 and the second light emitting unit 20 It may be configured to include a first charge generation layer 40 and a second charge generation layer 50 positioned between the second light emitting part 20 and the third light emitting part 30 . Meanwhile, as described above, the organic layer 118 may include the first and second light emitting parts 10 and 20 and the first charge generation layer 40 .

A barrier layer 130 is positioned on the second electrode 2 . The barrier layer 130 has a structure in which at least one inorganic layer 127 and an organic layer 129 are crossed and stacked.

A color filter 135 is positioned in an area corresponding to the opening 133 on the second organic layer 114 . The color filter 135 converts white light emitted from the white organic light emitting device into red, green, and blue light.

In this way, the organic light emitting display device using the white organic light emitting element and the color filter 135 does not independently deposit red, green, and blue organic light emitting elements on each pixel, and the first to white light emitting elements are used. It is formed by depositing the third light emitting units 10, 20, and 30 on all pixels. Accordingly, the organic light emitting display device using the white organic light emitting element can form the organic layer 118 without a mask, but has effects of increasing size, improving lifespan, and reducing power consumption.

The above description is merely illustrative of the present invention, and various modifications may be made by those skilled in the art without departing from the technical spirit of the present invention. Therefore, the embodiments disclosed in the specification of the present invention are not intended to limit the present invention. The scope of the present invention should be construed by the claims below, and all techniques within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Reference Signs List 1: first electrode 2: second electrode
5: display panel 6: gate driver
7: data driver 8: timing controller
10: first light emitting unit 11: first hole transport layer
12: second hole transport layer 13: first blue light emitting layer
14: first electron transport layer 20: second light emitting unit
21: first red light emitting layer 22: second red light emitting layer
23: yellow-green light emitting layer 24: second electron transport layer
30: third light emitting unit 31: third hole transport layer
32: second blue light emitting layer 33: third electron transport layer
100: substrate 101: buffer layer
102: gate electrode 104: semiconductor layer 109a, 109b: source/drain region 106: gate insulating film
108: drain electrode 110: drain electrode
114: second protective layer 116: third protective layer
133 opening 118 organic layer
135: color filter 130: barrier layer

Claims (13)

A first light emitting unit disposed on the first electrode and including a first blue light emitting layer;
A first charge generation layer positioned on the first light emitting part;
A second light emitting part located on the first charge generation layer, and
And a second electrode positioned on the second light emitting unit,
The second light emitting unit,
A first red light emitting layer positioned to be in contact with the first charge generation layer;
A second red light emitting layer positioned to be in contact with the first red light emitting layer and
A white organic light emitting device comprising a yellow-green light emitting layer positioned to be in contact with the second red light emitting layer. According to claim 1,
A white organic electroluminescent device further comprising a second charge generation layer and a third light emitting part between the second light emitting part and the second electrode, wherein the third light emitting part includes a second blue light emitting part. According to claim 1,
The first red light emitting layer has charge generation and hole transport characteristics, and a white organic electroluminescent device including an organic material having a hole mobility in the range of 5.0×10 ^-5 cm/Vs to 9.0×10 ^-4 cm.Vs. . According to claim 3,
The first red light-emitting layer is any one material selected from the group α-NPD, TCTA, TPD, TPB, TPAC, m-TPEE, FTPD, (NDA)PP, TRP, PPD, and OPT1 having charge generation characteristics and hole transport characteristics A white organic electroluminescent device comprising a phosphorus host. 5. The white organic light emitting device of claim 4, wherein the host of the first red light emitting layer is based on one of the following materials.

According to claim 1,
The host of the second red light emitting layer is a white organic light emitting device based on any one of materials containing a carbazole group. According to claim 6,
The host of the second red light emitting layer is a white organic light emitting device based on any one of the following materials.

According to claim 1,
The second light emitting unit further comprises a second electron transport layer positioned between the second red light emitting layer and the second charge generation layer. According to claim 1,
The first light emitting unit,
a first hole transport layer positioned on the first electrode;
a second hole transport layer positioned on the first hole transport layer;
A first blue light emitting layer positioned on the second hole transport layer, and
A white organic electroluminescent device comprising a first electron transport layer positioned on the first blue light emitting layer. According to claim 2,
The third light emitting unit,
A third hole transport layer located on the second charge generation layer;
A second blue light emitting layer positioned on the third hole transport layer and
A white organic light emitting device comprising a third electron transport layer positioned between the second blue light emitting layer and the second electrode. According to claim 1,
The first red light-emitting layer includes a red dopant of 0.5wt% or more, and the red dopant is at least 0.5wt% less than the second red light-emitting layer. According to claim 9,
The second hole transport layer includes a host having a triplet energy level higher than that of the first hole transport layer. A thin film transistor positioned on a substrate;
A first protective layer positioned to cover the thin film transistor;
a color filter layer positioned on the first protective layer;
a second protective layer positioned on the color filter layer;
a contact hole formed in the first passivation layer to expose a drain electrode of the thin film transistor; and
An organic light emitting display comprising the white organic light emitting device according to any one of claims 1 to 12 positioned on the second passivation layer and connected to a drain electrode of the thin film transistor through the contact hole. Device.

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