KR20090059488A - White organic electroluminiscent device - Google Patents

Abstract

A white organic electroluminescent device is provided to improve lifetime of a full color display device by reducing contribution of a blue light about a white light. A white organic electroluminescent device includes an anode(110), a hole injection layer(120), a hole transport layer(130), a blue light emitting layer(140), a red light emitting layer(145), and a cathode(200). The blue light emitting layer is made of two light emitting materials. An energy band gap of each light emitting material is 2.8eV~3.2eV. A HOMO(Highest Occupied Molecular Orbital) level difference of two light emitting materials is less than 0.5eV. A LUMO(Lowest Occupied Molecular Orbital) level difference of two light emitting materials is less than 0.5eV. A light emitting intensity less than 400nm of a light emitting spectrum is less than 5/100 of a light emitting intensity of a maximum peak.

Description

White Organic Electroluminescent Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white organic electroluminescent device that can be used in a backlight light source, a full-color light emitting device, a luminaire, a signal and a novel display of a liquid crystal display, and more particularly, to form an image band. The present invention relates to a white organic light emitting display device that realizes simple white light emission using a blue light emitting material.

The most widely used liquid crystal display (LCD) is a non-light-emitting display device, which consumes little power and is light in weight, but has a complicated device driving system and does not reach satisfactory characteristics such as response time and contrast. Therefore, research on organic electroluminescence devices (organic electroluminescence devices), which are recently attracting attention as next-generation flat panel displays, is being actively conducted. An organic light emitting display device is a self-light emitting device, and has advantages such as brightness, driving voltage, and response speed, and no viewing angle dependency, compared to a liquid crystal display device.

The organic light emitting diode has a wide viewing angle, high speed response, and high contrast, and thus can be used as a pixel of a television image display or a surface light source, and has been spotlighted as a next-generation display because of its thin, light, and good color. In addition, when the plastic substrate is adopted, a curved element may be manufactured, and the element emitting white light may be used as a backlight of an organic light emitting diode or a backlight of a liquid crystal display device.

The light emitting mechanism of the organic light emitting diode is as follows. Holes injected from the anode into the valence band or highest occupied molecular orbital (HOMO) of the hole injection layer (HIL) proceed to the emitting layer through the hole transporting layer (HTL). At the same time, electrons move from the cathode to the emission layer through the electron injection layer to combine with holes to form excitons. The exciton falls to the ground and emits light. In this case, the light emitting layer is generally composed of an energy donor (host material) and an energy acceptor (dopant material). According to the known theory, energy transfer is only performed when a band gap of an energy donor forms a band larger than the band gap of an energy acceptor. This remained smooth, and a band of energy donors large enough to emit blue light was needed. The use of existing materials in accordance with these results may result in disturbance of electron / hole movement and ultraviolet light emission, which may shorten the lifespan and defects of the panel.

The structure of a conventional white organic light emitting display device is an anode layer 110 formed by vacuum deposition of indium tin oxide (ITO) on the transparent substrate 100, as shown in Figure 1, and the anode layer ( The hole injection layer 120, the hole transport layer 130, the light emitting layers 140, 150, and 160, the hole block layer 170, the electron transport layer 180, the electron injection layer 190, and the cathode layer 200 are disposed on the 110. It has a structure which vacuum-deposited in order (published patent 10-2005-0028564).

Another common white organic light emitting device uses a hetero multilayer structure including two light emitting layers using complementary relations of cyan, red, blue and orange, or a mixture of hetero multilayer structures including three primary light emitting layers of blue, green, and red. Is being manufactured.

However, white organic light emitting diodes using three wavelengths are difficult to realize stable three wavelengths by energy transfer from blue to green or green to red, and white organic electroluminescent devices using two wavelengths of complementary colors are called LCD BLU ( It is difficult to obtain an even distribution of red, green, and blue for the white light required by the Back Light Unit, and the range of color coordinates is short and it is difficult to satisfy the high efficiency full color display application white light source.

Recently, a combination method of a white organic light emitting display device and a color filter has been proposed. These methods have been published based on CIE 1931 through a simple comparison of color reproducibility. In comparison, very low color reproducibility is shown, and this is because the excellent blue light emission described above cannot be obtained.

In order to solve this problem, layers such as a hole block layer / buffer layer are additionally formed, but the results are not satisfactory, causing a dysfunction that complicates the structure.

In addition, the conventional white organic light emitting display device is designed in consideration of the wide band gap between the energy donor layer and the energy receiving layer in order to obtain excellent blue light emission, causing disturbance of electron / hole movement and ultraviolet light emission, thereby The stability of the membrane is lowered, which can result in shortened life and defects in the panel.

The present invention uses two or more blue light emitting materials capable of forming an image band, and thus the movement of electrons and holes is not impeded by the blue light emitting materials, thereby preventing light emission such as ultraviolet rays. An object of the present invention is to provide a white organic electroluminescent device that can realize brightening.

The present invention for achieving the above object,

A white organic light emitting device comprising an anode, a blue light emitting layer, a red light emitting layer, and a cathode, wherein the blue light emitting layer is composed of two or more light emitting materials, and each energy band gap is 2.8 eV to 3.2. Provided is a white organic electroluminescent device which is eV.

In addition, the light emitting material is a white organic electroluminescent device, characterized in that the use of two light emitting materials having a difference in the HOMO level is 0.5 eV or less, the difference in the LUMO level is 0.5 eV or less is used. to provide.

The present invention also provides a white organic electroluminescent device comprising an anode, a blue light emitting layer, a red light emitting layer, and a cathode, and provides a white organic electroluminescent device having an image band gap of 2.9 eV to 3.1 eV of the blue light emitting layer.

In addition, the light emission intensity (EL intensity) of 400nm or less in the emission spectrum provides a white organic light emitting device, characterized in that 5/100 or less than the maximum intensity of the light emission.

Hereinafter, the present invention will be described in detail.

The white organic light emitting diode device according to the embodiment of the present invention is a white organic light emitting diode including an anode, a blue light emitting layer, a red light emitting layer, and a cathode, wherein the blue light emitting layer is composed of two or more light emitting materials, respectively. The energy band gap is characterized in that 2.8eV ~ 3.2eV. If the above range is exceeded, the flow of holes and electrons may be disturbed. In this case, efficiency may be reduced, and in the case of luminescence, light may be emitted in the ultraviolet region, causing deterioration of various organic layers constituting the organic light emitting diode. It is easy to cause shortening of life and defect generation, and it becomes difficult to pure blue light emission below the said range.

Conventionally, a host material having a large energy band gap and a dopant having a smaller energy band gap are used together to realize blue light emission through dopant emission. In the present invention, two or more light emitting materials emit light in a different manner. The band gap is formed to emit light through the image band gap.

That is, as shown in FIGS. 3 and 4, a virtual band (called an image band) is formed through co-deposition between two or more light emitting materials, rather than a generally known process of transferring energy between host and dopants. The light emission by means provides light emission in a new area different from the light emission area of the previous material.

The image bandgap can be defined as the gap between the homogeneous (HOMO) and the lumo (LUMO) of a new band formed through the interaction between molecules having different bandgap, and the image bandgap can be measured by the following equation. Suggest to get.

As a method of obtaining the image bandgap, a general spectrum (EL or PL) can be measured by an optical system, and the wavelength of λmax can be calculated by applying the following equation.

The following equation is a formula derived from the experimental statistics as a relation between the band gap and the wavelength.

In the case of multi-peak emission, by applying λ max indicated by each peak, the dopant contribution and the image band contribution of the emission portion can be confirmed by the following equation.

<Equation 1>

 Y = -3.1235Ln (x) + 22.24

Where Y = Image band gap (eV), X = λmax (nm)

In order to achieve excellent blue light emission, it is preferable that an image band gap is formed within a range of 2.9 eV to 3.1 eV. In order to realize such an image band gap, a difference in the HOMO level is 0.5 eV or less, and a difference in the LUMO level is achieved. It is preferable that two light emitting materials having 0.5 eV or less are used together. If not within the above range, light emission through the image band gap may not occur.

The blue light emitting layer may be formed by co-depositing two or more light emitting materials satisfying the above conditions.

As a material used for the implementation of the blue light emitting layer 140, generally known (4,4'-bis (2,2-diphenyl-ethen-1-yl) diphenyl (DPVBi), bis (styryl ) Amine (DSA) system, bis (2-methyl-8-quinolinolato) (triphenylsiloxy) aluminum (III) (SAlq), bis (2-methyl-8-quinolinolato) (para- Phenolato) aluminum (III) (BAlq), bis (salen) zin (II), 1,3-bis [4- (N, N-dimethylamino) phenyl-1,3,4-oxadiazolyl] benzene ( OXD8), 3- (biphenyl-4-yl) -5- (4-dimethylamino) 4- (4-ethylphenyl) -1,2,4-triazole (p-EtTAZ), 3- (4- Biphenyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (TAZ), 2,2 ', 7,7'-tetrakis (non-phenyl-4 -Yl) -9,9'-spirofluorene (Spiro-DPVBI), tris (para-ter-phenyl-4-yl) amine (p-TTA), 5,5-bis (dimethylbutylboryl) -2 In, 2-bithiophene (BMB-2T) and perylene, a material satisfying the above conditions can be selected and used.

In Formula 1, l is an integer of 1 to 3, m is an integer of 1 to 4, n is an integer of 0 to 3, R ₁ , R ₂ , R ₃ are each independently hydrogen, aromatic of 6 to 24 carbon atoms And it is selected from the group consisting of aromatics having 6 to 30 carbon atoms containing unsaturated aliphatic,

In the formula (2), n is an integer of 1 to 4, Ar is independently a group consisting of an aromatic having 6 to 24 carbon atoms, an aromatic having 6 to 30 carbon atoms including unsaturated aliphatic, and an unsaturated heterocyclic compound having 2 to 24 carbon atoms R ₁ and R ₂ are each independently selected from the group consisting of aromatics having 6 to 24 carbon atoms and aromatics having 6 to 30 carbon atoms including unsaturated aliphatic groups,

In the formula (3), n is an integer of 1 to 4, Ar is independently a group consisting of a C6-C24 aromatic, a C6-C30 aromatic containing unsaturated aliphatic, and a C2-C24 unsaturated heterocyclic compound R ₁ and R ₂ are each independently selected from the group consisting of hydrogen, aromatics having 6 to 24 carbon atoms, and aromatics having 6 to 30 carbon atoms including unsaturated aliphatic groups,

In formula (4), n is an integer of 1 to 4, Ar ₁ in the group consisting of an aromatic of 6 to 24 carbon atoms, an aromatic of 6 to 30 carbon atoms including unsaturated aliphatic, and an unsaturated heterocyclic compound of 2 to 24 carbon atoms Selected from Ar ₂ , Ar ₃ Are each independently selected from the group consisting of hydrogen, aromatics having 6 to 24 carbon atoms, and aromatics having 6 to 30 carbon atoms including unsaturated aliphatic,

In formula (5), R ₁ is selected from the group consisting of hydrogen, phenyl, and Ar 1 is each independently hydrogen, an aryl group having 6 to 30 carbon atoms, with or without a substituent, and an unsaturated hetero ring having 2 to 24 carbon atoms. Selected from the group consisting of compounds,

In Formula 6, n is an integer of 1 to 4, Ar is selected from the group consisting of an aryl group having 6 to 30 carbon atoms with or without a substituent, and an unsaturated heterocyclic compound with or without a substituent having 2 to 24 carbon atoms;

In formula (7), n is an integer of 1 to 4, Ar1 is each independently selected from the group consisting of an aryl group having 6 to 30 carbon atoms with or without a substituent, and an unsaturated heterocyclic compound with or without substituents having 2 to 24 carbon atoms. R1 and R2 are each independently selected from the group consisting of hydrogen, aromatics having 6 to 24 carbon atoms, and aromatics having 6 to 30 carbon atoms including unsaturated aliphatic, and X is selected from the group consisting of carbon, silane, oxygen and sulfur Is selected.

More specifically, in Formula 1, l is an integer of 1 to 3, m is an integer of 1 to 4, n is an integer of 0 to 3,

In Formula 2, n is an integer of 1 to 4, Ar is selected from the group consisting of phenyl, biphenyl, naphthalene, anthracene, thiophene, pyridine and the like, and R ₁ , R ₂ are each phenyl, stilbene , Phenylstilbene, diphenylstilbene and the like,

In the formula (3), n is an integer of 1 to 4, Ar is selected from the group consisting of phenyl, biphenyl, naphthalene, anthracene, thiophene, pyridine and the like, R ₁ , R ₂ is stilbene, phenylstilbene, Diphenylstilbene and the like, but when R ₁ or R ₂ is hydrogen, the other is selected from groups other than hydrogen,

In Formula 4, n is an integer of 1 to 4, Ar ₁ is selected from the group consisting of phenyl, naphthalene, anthracene, thiophene, pyridine, fluorene, spyrrole and the like, Ar ₂ , Ar ₃ are each Selected from the group consisting of hydrogen, phenyl, and the like,

In Formula 5, R ₁ is selected from the group consisting of hydrogen, phenyl, and Ar ₁ is each independently hydrogen, an aryl group having 6 to 30 carbon atoms with or without a substituent, and an unsaturated hetero group having 2 to 24 carbon atoms with or without substituents. Selected from the group consisting of cyclic compounds,

In formula (6), n is an integer of 1 to 4, Ar is each selected from the group consisting of naphthalene, anthracene, pyrene, dimethylphenylamine, triphenylamine, diphenylnaphthylamine, diphenylstilbenamine, and the like.

In formula (7), n is an integer of 1 to 4, and Ar ₁ is each independently a group consisting of an aryl group having 6 to 30 carbon atoms with or without a substituent, and an unsaturated heterocyclic compound having or without carbon atoms at 2 to 24 substituents. R ₁ and R ₂ are each independently selected from the group consisting of hydrogen, aromatics having 6 to 24 carbon atoms, and aromatics having 6 to 30 carbon atoms including unsaturated aliphatic, X is carbon, silane, oxygen, sulfur It is selected from the group consisting of.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

Materials used for the implementation of the red light emitting layer 145 are generally known as DCM1 (4-dicyanomethylene-2-methyl-6- (para-dimethylaminostyryl) -4H-pyran), DCM2 (4-dicyano) Methylene-2-methyl-6- (zulolidin-4-yl-vinyl) -4H-pyran), DCJT (4- (dicyanomethylene) -2-methyl-6- (1,1,7,7- TetramethylJulolidyl-9-enyl) -4H-pyran), DCJTB (4- (dicyanomethylene) -2-terrybutylbutyl-6- (1,1,7,7-tetramethylzololidyl-9 -Enyl) -4H-pyran), DCJTI (4-dicyanomethylene) -2-isopropyl-6- (1,1,7,7-tetramethylzololidyl-9-enyl) -4H-pyran) and Nile red, Rubrene, and the like can be used, and DCJTB (4- (dicyanomethylene) -2-tert-butyl-6- (1,1,7,7-tetramethyljulolidil) -9-enyl) -4H-pyran), Rubrene are preferred.

In the white organic light emitting device that satisfies the above characteristics, the EL intensity of 400 nm or less in the emission spectrum is 5/100 or less of the maximum intensity of the maximum peak, and almost no light emission in the ultraviolet region exists.

2 is a schematic cross-sectional view of a white organic light emitting display device according to an exemplary embodiment of the present invention. As shown, the anode 110, the hole injection layer 120, the hole transport layer 130, the blue light emitting layer 140, the red light emitting layer 145, which consists of two or more materials to emit light through the image bandgap, The electron transport layer 180, the electron injection layer 190, and the cathode 200 have a structure. In the above configuration, at least one or more of the hole injection layer 120, the hole transport layer 130, the electron transport layer 180, and the electron injection layer 190 may be omitted as necessary. In addition, other components may be further included and are not limited. The blue light emitting layer 140 and the red light emitting layer 145 have been described above and thus will be omitted. Here, the dotted line represents the image band gap.

Examples of the anode 110 material include metal oxides or metal nitrides such as ITO, IZO, tin oxide, zinc oxide, zinc aluminum oxide, and titanium nitride; Metals such as gold, platinum, silver, copper, aluminum, nickel, cobalt, lead, molybdenum, tungsten, tantalum and niobium; Alloys of these metals or alloys of copper iodides; Conductive polymers such as polyaniline, polythiopine, polypyrrole, polyphenylenevinylene, poly (3-methylthiopine), and polyphenylenesulfagard. The anode may be formed of only one type of the above materials or may be formed of a mixture of a plurality of materials. In addition, a multilayered structure composed of a plurality of layers of the same composition or different composition may be formed.

The hole injection layer 120 of the present invention may use a material known in the art, but is not limited to PEDOT / PSS or copper phthalocyanine (CuPc), 4,4 ', 4 "-tris (3-methylphenylphenylamino) A material such as triphenylamine (m-MTDATA) is formed to a thickness of 5 nm to 40 nm.

The hole transport layer 130 may be 4,4'-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (NPD) or N, N'-diphenyl-N, N'-bis Substances such as (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (TPD) can be used.

The electron transport layer 180 may include an aryl-substituted oxadiazole, aryl-substituted triazole, aryl-substituted phenanthroline, benzoxazole, or benzoxazole compound, for example, 1, 3-bis (N, Nt-butyl-phenyl) -1,3,4-oxadiazole (OXD-7); 3-phenyl-4- (1'-naphthyl) -5-phenyl-1,2,4-triazole (TAZ); 2,9-dimethyl-4,7-diphenyl-phenanthroline (vasocuproin or BCP); Bis (2- (2-hydroxyphenyl) -benzoxazolate) zinc; Or bis (2- (2-hydroxyphenyl) -benziazolate) zinc; As the electron transporting material, (4-biphenyl) (4-t-butylphenyl) oxydiazole (PDB) and tris (8-quinolinato) aluminum (III) (Alq3) can be used, preferably Tris ( Preference is given to 8-quinolinato) aluminum (III) (Alq3).

The electron injection layer 190 and the cathode 200 may be made of a material known in the art, and are not limited. LiF may be used as the electron injection layer and a metal having a low work function such as Al, Ca, Mg, Ag, or the like may be used. It is possible to use, preferably Al is preferred.

The white organic electroluminescent device of the present invention, even with a simple configuration, improves the problem of the blue light emitting layer, lowers the contribution of blue to white in the fabrication of a full color display device, and reduces the lifetime of the entire display device. By improving more than two times, it is possible to create a foundation that can be commercialized using an organic light emitting device.

In addition, when using a material having a minimum bandgap to have an image bandgap, it is possible to suppress the interference of electrons, hole movements and ultraviolet light emission due to the use of the existing material, which can shorten the lifespan and defects of the panel Can be prevented.

As shown in FIG. 5, when compared through CIE 1976 considering the area of color coordinates, it can be seen that the color reproduction range currently applied to the broadcasting system can be almost covered.

Furthermore, the light emitting device using the image bandgap is not limited to blue light emission, but is applied to all colors of green, red, and white in consideration of the difference in the bandgap and the compatibility between the light emitting materials, and has various colors. It can be helpful for device implementation of the purpose.

Embodiments of the present invention are only specific examples, and are not intended to limit or limit the protection scope of the present invention.

[ Example  One]

Fabrication of White Organic Light Emitting Diode Having Image Band (WOLED 1)

A substrate (manufactured by Asahi Corporation) on which a positive electrode material was deposited on a glass substrate was produced using lithography as a unit device. The lithographic finished unit substrate was washed with acetone, detergent, distilled water and isopropyl alcohol. The cleaned unit substrate was transferred to an organic chamber after UV / O ₃ cleaning and plasma treatment. Plasma was performed using oxygen (O ₂ ).

The surface-treated substrate was deposited in an organic chamber in a hole injection layer 120 to deposit 4,4 ', 4 "-tris (3-Methylphenylphenylamino) tri phenylamine (m-MTDATA) to a thickness of 500 Å. After depositing NPD (N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) benzidine) to the hole transport layer 130 to a thickness of 200130, the blue light emitting layer was represented by Chemical Formula 4-1. (141) and the chemical formula 2-1 (142) are each 100Å thick to have a thickness ratio of 95: 5, and the red light emitting layer has a thickness of 300 되도록 to give a thickness ratio of 98: 2 to Alq3, which is a host material, and rubrene, a dopant material. A light emitting layer was formed by vacuum deposition of Alq3 (tris- (8-hydroxyquinoline) aluminum (III)) on the electron transport layer 150 to a thickness of 200 .. Then, an Al: Li layer was vacuum deposited on the upper layer to obtain a thickness of 1500 의. The device was fabricated by forming an aluminum-lithium electrode. After the deposition of the organic light-emitting device constituent layer, the cap was encapsulated in a glove box. It was carried out to complete the device manufacture.

[Formula 4-1]

[Formula 2-1]

[ Example  2]

Fabrication of White Organic Light Emitting Diode Having Image Band (WOELD 2)

In forming the blue light-emitting layer, the formulas 4-1 (141) and 6-1 (142) were manufactured in the same manner as in Example 1 except that the devices were manufactured so as to have a thickness ratio of 95: 5.

 [Formula 6-1]

[ Comparative example  One]

Fabrication of deep blue or pure blue organic light emitting diode (WOLED)

In the formation of the blue light emitting layer, DPVBi 141 and Chemical Formula 2 142 were carried out in the same manner as in Example 1 except for fabricating a device such that the thickness ratio was 95: 5.

[ Comparative example  2]

In Example 1, instead of the blue light emitting layer and the red light emitting layer, except that 28 nm light emitting layer comprising a mixture of NPB and 27.5% rubrene (yellow dopant) and 0.5% periplanthene (red dopant) was vacuum deposited. The same was done.

[Production of color filter]

On a supporting substrate (transparent substrate) of 50 mm x 50 mm x 0.7 mm, BK0800H (Cheil Industries) is spin-coated as a material of the black matrix (BM), ultraviolet-exposed through a photomask which becomes the pattern of FIG. 5A, and 0.043 After developing with% aqueous alkali metal hydroxide solution, the solution was baked at 220 ° C. to form a pattern of a black matrix (film thickness of 1.5 μm).

Next, as a material of a blue color filter, YB-766 (Dongwoo Fine Chem) containing copper phthalocyanine-based pigment is spin-coated and positioned on BM through a photo mask capable of obtaining four square (18 mm X 18 mm) patterns. The film was exposed to ultraviolet light, developed with a 2.38% TMAH aqueous solution, and baked at 220 ° C. to form a pattern of a blue color filter (film thickness of 1.5 μm).

Next, YG-766 (product of Dongwoo Fine Chem) containing brominated phthalocyanine azo pigment was spin-coated as a material of the green color filter, and 4 square patterns (18mmX18mm) were obtained to the BM through a photo mask. Position matching was carried out to ultraviolet exposure, development with a 2.38% TMAH aqueous solution, followed by baking at 220 ° C. to form a pattern of a green color filter (film thickness of 1.5 μm) next to the blue color filter.

Next, as a material of the red color filter, YR-766 (Dongwoo Fine Chem), which contains a diketopyrrolopiat azo pigment, was spin-coated, and a photo mask capable of obtaining four square (18mmX18mm) patterns was obtained. Position matching was performed on the BM, followed by ultraviolet exposure, development with a 2.38% TMAH aqueous solution, and baking at 220 ° C. to form a pattern of a red color filter (film thickness of 1.5 μm) between the blue color filter and the green color filter.

[Evaluation of the device]

The characteristic of the device obtained through the said Example and the comparative example was measured as follows.

1) Driving voltage

The change of current density according to the voltage change was measured for the manufactured organic electroluminescent device. In the measurement, the current value flowing through the unit device was measured using a current-voltmeter (Kethely 237) while increasing the current density from 2.5 mA / cm 2 to 100 mA / cm 2.

2) color coordinates

The current density of the prepared organic electroluminescent device was measured using a luminance meter (PR650) while increasing the current density from 2.5 mA / cm 2 to 100 mA / cm 2.

3) luminance

Power was supplied from a current-voltmeter (Kethley SMU 236) and measured using a luminance meter (PR650).

4) efficiency

Luminous efficiency was calculated using the brightness and current density measured above, and the results are summarized at 10mA / cm2.

5) Life time measurement

While setting the initial luminance to 1000 nits while driving a constant current, the time at 50% of the initial luminance was measured and converted into the following equation.

The conversion life was measured by substituting the following equation from the fact that the life was generally different from the square ratio of luminance.

expression. T ₅₀₀ = (1000/500) ² XT ₁₀₀₀

The measurement results are shown in Table 1.

Table 1 Results of Examples 1 and 2 and Comparative Example 1

Luminous Efficiency (cd / A @ 10mA / ㎠) Color coordinates Color Reproducibility (With CF) Life expectancy (hr @ 500nit) Image emission (λmax) Image Bandgap (eV) Example 1 10.0 (0.243, 0.309) 63.9 928 470 3.06 Example 2 6.9 (0.273, 0.301) 56.6 992 475 3.03 Comparative Example 1 4.9 (0.271, 0.337) 54.0 624 - -

Table 2 Comparison between Example 1 and Comparative Example 2

Example 1 Comparative Example 2 x Y u v x y u v R 0.649 0.347 0.4426 0.5324 R 0.657 0.337 0.4586 0.5293 G 0.286 0.543 0.1279 0.5464 G 0.256 0.555 0.1119 0.5460 B 0.136 0.067 0.1540 0.1707 B 0.114 0.142 0.1019 0.2855 W 0.243 0.309 W 0.273 0.301 Color gamut 63.9% 79.2% Color gamut 62.1% 60.8%

1 is a structure of a conventional white organic light emitting display device,

2 is a structure of a white organic light emitting display device using an image band according to an embodiment of the present invention;

3 is a schematic view of the image band used in the present invention,

4 is a light emission schematic and spectrum according to the present invention;

5 is a photograph and CIE 1931/1976 color coordinates of a white organic electroluminescent device of the present invention combined with a color filter to emit light.

Claims (4)

A white organic light emitting display device comprising an anode, a blue light emitting layer, a red light emitting layer, and a cathode, The blue light emitting layer is composed of two or more light emitting materials, each energy band gap (energy band gap) is a white organic light emitting device having a 2.8eV ~ 3.2eV. The white organic material of claim 1, wherein the light emitting material includes two light emitting materials having a difference in homogeneity (HOMO) level of 0.5 eV or less and a difference in lumo (LUMO) level of 0.5 eV or less. Electroluminescent element. A white organic light emitting display device comprising an anode, a blue light emitting layer, a red light emitting layer, and a cathode, The white organic electroluminescent device having an image band gap of the blue light emitting layer is 2.9eV ~ 3.1eV. The white organic electroluminescent device according to any one of claims 1 to 3, wherein the emission intensity (EL intensity) of 400 nm or less in the emission spectrum is 5/100 or less of the emission intensity of the maximum peak.

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