JP2007011063A - Organic electroluminescence display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescence display device having each pixel of at least red (R), green (G) and blue (B), wherein green chromaticity is enhanced to improve the green reproducibility. <P>SOLUTION: The organic electroluminescence display device is equipped with an organic EL light emitting layer 9 which emits white light, a hole injection electrode 2, an electron injection electrode 8, color filter layers CFR and CFB of the red and the blue disposed on the photoirradiation side of the organic EL light emitting layer, wherein the organic EL light emitting layer 9 is placed between the hole injection electrode 2 and the electron injection electrode 8, and the organic EL light emitting layer 9 has such a structure that a blue light emitting layer 6 containing a host material and arranged on the electron injection electrode side, and an orange light emitting layer 4 containing a host material and arranged on the hole injection electrode side, are laminated, and a green light emitting layer 5 containing the host material is disposed between the blue light emitting layer 6 and the orange light emitting layer 4 in a region of a green pixel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence display device having at least red (R), green (G) and blue (B) pixels.

  In recent years, with the diversification of information equipment, there is an increasing demand for thin display devices capable of thin and full color display. As one of them, an organic electroluminescence element (organic EL element) having features such as high efficiency, thinness, light weight, and low viewing angle dependency has attracted attention.

Such an organic EL element has an advantage that high emission luminance of 100 to 100,000 cd / m ² or more can be obtained at a low voltage of about 10V. For this reason, the application to the full color display of an organic EL element is anticipated.

  As a full color technology for a display device using an organic EL element, a filter system that uses a white organic EL element as a light source (backlight) and emits light through three primary color RGB (red, green and blue) color filters. A blue organic EL element is used as a light source, and a color conversion layer (CCM) converts blue into red and green, thereby displaying each of RGB, and three primary color organic EL elements are arranged in parallel on the substrate. Accordingly, a method of emitting light independently of RGB is proposed.

  Patent Document 1 discloses an organic electroluminescence (organic EL) display device in which a blue light emitting layer and a green light emitting layer are sequentially laminated, a red light emitting dopant is contained in the green light emitting layer, and white light is emitted. In such an organic EL display device, full-color display is possible by providing red, green, and blue (RGB) color filters.

  In Patent Document 2, there is an organic EL display device in which elements that emit light of each color of RGB are stacked, an electrode is provided on each element, and power is individually supplied to each element so that each color is individually emitted and displayed. It is disclosed. Such an organic EL display device has a problem that a wiring circuit becomes complicated because it is necessary to individually supply power to each element.

  Patent Document 3 discloses an organic EL display device that emphasizes light emitted from an organic EL layer that emits white light so as to correspond to each color of RGB by multiple resonance, and emits light of three peaks, respectively. . Such a method has a problem that the color resolution is poor and a clear full color display cannot be performed.

In the organic EL display device of Patent Document 1, a blue light-emitting layer and a green light-emitting layer containing a red light-emitting dopant are laminated to emit white light, but the color temperature currently required in the market is high. As a method of lighting white (about 6500K), a method of lighting white light due to a complementary color relationship between blue light and orange light has been proposed. In the case of such a white light emitting element, the light of the blue component is emphasized and white having a high color temperature can be lit, but there is a problem that the green light emission intensity becomes insufficient.
JP-A-7-142169 Japanese National Patent Publication No. 10-503878 JP 2004-127588 A

  An object of the present invention is to provide an organic electroluminescence display device capable of improving green color reproducibility by increasing green chromaticity in an organic electroluminescence display device having at least RGB pixels.

  The organic EL display device according to the first aspect of the present invention is an organic electroluminescence display device having at least red (R), green (G) and blue (B) pixels, and emits white light. A light emitting layer, a hole injection electrode for supplying holes to the organic EL light emitting layer, an electron injection electrode for supplying electrons to the organic EL light emitting layer, and an organic EL light emitting layer corresponding to each of red and blue pixels And an organic EL light emitting layer is disposed between the hole injection electrode and the electron injection electrode, and the organic EL light emitting layer is made of an electron transporting material. A blue light emitting layer containing a host material and disposed on the electron injection electrode side, and an orange light emitting layer containing a host material made of a hole transporting material and disposed on the hole injection electrode side In the green pixel region, a green light emitting layer containing a host material made of an electron transporting material or a hole transporting material is provided between the blue light emitting layer and the orange light emitting layer. It is characterized by having.

  In the first aspect of the present invention, the organic EL light emitting layer has a structure in which a blue light emitting layer disposed on the electron injection electrode side and an orange light emitting layer disposed on the hole injection electrode side are laminated. The blue light emitting layer contains a host material made of an electron transporting material and a blue light emitting dopant, and the orange light emitting layer contains a host material made of a hole transporting material and an orange light emitting dopant. In the pixel region, a green light emitting layer containing a host material made of an electron transporting material or a hole transporting material and a green light emitting dopant is provided between the blue light emitting layer and the orange light emitting layer. Generally, in an organic EL element, it is known that electrons and holes recombine near the interface where the electron transporting material and the hole transporting material are in contact with each other to emit light.

  Since the green light emitting layer in the first aspect of the present invention contains a host material made of an electron transporting material or a hole transporting material and a green light emitting dopant, the host material of the green light emitting layer is an electron transporting material. In some cases, light emission occurs near the interface between the orange light-emitting layer and the green light-emitting layer whose host material is a hole transporting material. Further, when the host material of the green light emitting layer is a hole transporting material, light emission occurs in the vicinity of the interface between the blue light emitting layer and the green light emitting layer whose host material is an electron transporting material.

  Therefore, according to the first aspect of the present invention, light can be emitted in the vicinity of the interface between the green light emitting layer and the blue light emitting layer or in the vicinity of the interface between the green light emitting layer and the orange light emitting layer in the green pixel region. . Accordingly, since light emission including a green component can be obtained in the green pixel region, the green chromaticity can be increased and the green color reproducibility can be improved.

  In the first aspect of the present invention, red and blue color filter layers are provided on the light irradiation side of the organic EL light emitting layer corresponding to the red and blue pixels. In the green pixel region, a green light-emitting layer is provided between the blue light-emitting layer and the orange light-emitting layer. Since light is emitted from the green light-emitting layer, light containing a green component is emitted. For this reason, it is not necessary to provide a color filter in the green pixel. However, in order to increase the purity of green, a green color filter layer may be provided on the light irradiation side of the organic EL light emitting layer corresponding to the green pixel.

  In the first aspect of the present invention, the host material of the green light emitting layer may be the same material as the host material of the blue light emitting layer. In this case, the host material of the green light emitting layer is an electron transporting material.

  In the first aspect of the present invention, the host material of the green light emitting layer may be the same material as the host material of the orange light emitting layer. In this case, the host material of the green light emitting layer is a hole transporting material.

  The electron transporting material in the present invention is an organic material whose electron mobility is higher than that of holes. For example, oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its Derivatives, anthraquinone and derivatives thereof, tetracyanoanthraquinodimethane and derivatives thereof, fluorene and derivatives thereof, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, 8-hydroxyquinoline and derivatives thereof, metal complexes, anthracene derivatives, distyryl derivatives, Examples thereof include phenanthroline derivatives. Specifically, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, 2-tertiary-butyl-9,10-di (2 -Naphthyl) anthracene (TBADN), anthraquinone, tris (8-quinolinol) aluminum, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and the like are preferable.

  The hole transporting material in the present invention is an organic material having a hole mobility higher than the electron mobility, and examples thereof include a pyrazoline derivative, an arylamine derivative, a stilpene derivative, and a triphenyldiamine derivative. Specifically, N, N′-di (naphthacene-1-yl) -N, N′-diphenylbenzidine (NPB) and the like are preferable.

  In the first aspect of the present invention, when the host material of the green light emitting layer is an electron transporting material, a hole transporting material layer may be provided between the green light emitting layer and the orange light emitting layer. By providing the hole transporting material layer, light can be emitted in the vicinity of the interface between the hole transporting material layer and the green light emitting layer.

  In the first aspect of the present invention, when the host material of the green light emitting layer is a hole transporting material, an electron transporting material layer may be provided between the green light emitting layer and the blue light emitting layer. By providing the electron transporting material layer, light can be emitted in the vicinity of the interface between the electron transporting material layer and the green light emitting layer.

  In the first aspect of the present invention, the green light emitting layer may be formed by laminating a plurality of light emitting layers. For example, a host material made of an electron transporting material and a first green light emitting dopant, a first green light emitting layer disposed on the blue light emitting layer side, a host material made of a hole transporting material, and a second green light It may contain a light emitting dopant and may have a structure laminated with a second green light emitting layer disposed on the orange light emitting layer side. In such a laminated structure, light can be emitted in the vicinity of the interface between the first green light emitting layer and the second green light emitting layer, and green light emission with higher color purity can be obtained.

  The organic EL display device according to the second aspect of the present invention is an organic EL display device having at least each pixel of red (R), green (G), and blue (B), and emits white light. A hole injection electrode for supplying holes to the organic EL light emitting layer, an electron injection electrode for supplying electrons to the organic EL light emitting layer, and an organic EL light emitting layer corresponding to each pixel of red and blue A red and blue color filter layer provided on the light irradiation side, the organic EL light-emitting layer contains a host material made of an electron transporting material, a blue light-emitting dopant, an orange light-emitting dopant, and a hole injection electrode A white light emitting layer disposed between the electron injection electrode and the electron injection electrode. In the green pixel region, an electron transporting material or a hole transport material is interposed between the hole injection electrode and the organic EL light emitting layer. It is characterized in that the green emitting layer is provided containing a host material composed of sexual material.

  In the second aspect of the present invention, a single white light-emitting layer containing a blue light-emitting dopant and an orange light-emitting dopant in one layer is used as the organic EL light-emitting layer that emits white light. This white light emitting layer contains a host material made of an electron transporting material. In the second aspect of the present invention, a green light emitting layer containing a host material made of an electron transporting material or a hole transporting material and a green light emitting dopant is interposed between the hole injection electrode and the white light emitting layer in the green pixel region. Is provided. Since the green light emitting layer contains a host material made of an electron transporting material or a hole transporting material, light can be emitted in the vicinity of the interface between the green light emitting layer and a layer adjacent thereto, and light emission including a green component can be emitted. Obtainable. For this reason, the green chromaticity can be increased in the green pixel, and the green color reproducibility can be improved.

  In the second aspect of the present invention, red and blue color filter layers are provided on the light irradiation side of the organic EL light emitting layer corresponding to the red and blue pixels. In the green pixel region, light emission including a green component from the green light emitting layer can be obtained as described above. Therefore, a color filter layer is not necessary. However, for the purpose of increasing color purity, the green pixel is used. Corresponding to the above, a green color filter layer may be provided on the light irradiation side of the organic EL light emitting layer.

  In the second aspect of the present invention, when the host material of the green light emitting layer is made of an electron transporting material and the green light emitting layer is in contact with the hole injection electrode or the hole injection layer provided on the hole injection electrode Light emission can be obtained in the vicinity of the hole injection electrode or the interface between the hole injection layer and the green light emitting layer. When the host material of the green light emitting layer is made of a hole transporting material and the green light emitting layer is in contact with the organic EL light emitting layer (white light emitting layer), light emission can be obtained from the vicinity of the interface with the organic EL light emitting layer. Therefore, light emission with high green chromaticity can be obtained.

  In the second aspect of the present invention, the host material of the green light emitting layer may be the same material as the host material of the organic EL light emitting layer. In this case, the host material of the green light emitting layer is an electron transporting material.

  In the second aspect of the present invention, when a hole injection layer is provided between the hole injection electrode and the green light emitting layer, the host material of the green light emitting layer is the same material as the host material of the hole injection layer. There may be. In this case, the host material of the green light emitting layer is a hole transporting material.

  In the second aspect of the present invention, when the host material of the green light emitting layer is a hole transporting material, an electron transporting material layer may be provided between the green light emitting layer and the organic EL light emitting layer. Such a layer of an electron transporting material may be formed, for example, from a host material of an organic EL light emitting layer. When a green light emitting layer having a hole transporting material as a host material and an electron transporting material layer are provided in contact with each other, green light emission is obtained in the vicinity of these interfaces.

  Also in the second aspect of the present invention, the green light emitting layer may be a laminate of a plurality of light emitting layers. For example, a host material made of an electron transporting material and a first green light emitting dopant, a first green light emitting layer disposed on the organic EL light emitting layer side, a host material made of a hole transporting material, and a second It may have a structure in which a green light emitting dopant is contained and a second green light emitting layer disposed on the hole injection electrode side is laminated. In this case, since light is emitted in the vicinity of the interface between the first green light emitting layer and the second green light emitting layer, light emission with higher green chromaticity can be obtained.

  When a hole injection layer is provided between the hole injection electrode and the green light emitting layer, the host material of the second green light emitting layer may be the same material as that for forming the hole injection layer. The host material of the first green light emitting layer may be the same material as the host material of the organic EL light emitting layer.

  In the present invention, the emission peak wavelength of the blue emission layer or the blue emission dopant is preferably in the range of 430 to 490 nm, and the emission peak wavelength of the orange emission layer or the orange emission dopant is in the range of 550 to 640 nm. Preferably there is.

  According to the present invention, in an organic electroluminescence display device having at least RGB pixels such as RGBW, green chromaticity can be increased and green color reproducibility can be improved.

  FIG. 1 is a cross-sectional view showing an organic electroluminescence (organic EL) display device of one embodiment according to the first aspect of the present invention. As shown in FIG. 1, the organic EL display device of this embodiment is divided into R (red), G (green), B (blue), and W (white) pixel regions. A full color display can be performed by emitting a predetermined color in each pixel.

  A red color filter layer CFR, a green color filter layer CFG, and a blue color filter layer CFB are provided on the substrate 1 so as to correspond to the R, G, and B regions. These color filter layers are covered with a planarizing layer 1 '. As shown in FIG. 1, the color filter layer is not provided in the W region, and the white light from the organic EL light emitting layer 9 is emitted to the outside as it is.

  On the planarizing layer 1 ′, a hole injection electrode 2 capable of supplying power individually is provided so as to correspond to the R, G, B, and W regions. A hole transport layer 3 is provided between the upper and adjacent hole injection electrodes.

  An orange light emitting layer 4 is provided on the hole transport layer 3, and a blue light emitting layer 6 is provided on the orange light emitting layer 4 in the R, B, and W pixel regions. In the G pixel region, a green light emitting layer 5 is provided on the orange light emitting layer 4, and a blue light emitting layer 6 is provided on the green light emitting layer 5. Therefore, the green light emitting layer 5 is disposed between the orange light emitting layer 4 and the blue light emitting layer 6.

  In the organic EL display device of this example, the blue light emitting layer 6 is laminated on the orange light emitting layer 4 to constitute an organic EL light emitting layer 9 that emits white light.

  An electron transport layer 7 is provided on the blue light emitting layer 6, and an electron injection electrode 8 is provided on the electron transport layer 7.

  In the present embodiment, the green light emitting layer 5 is provided between the orange light emitting layer 4 and the blue light emitting layer 6 in the G pixel region, and in the other regions, the orange light emitting layer 4 and the blue light emitting layer are emitted. Layer 6 is directly laminated. The host material of the orange light emitting layer 4 is a hole transporting material, and the host material of the blue light emitting layer 6 is an electron transporting material. Accordingly, in the R, B, and W pixel regions, light is emitted near the interface between the orange light-emitting layer 4 and the blue light-emitting layer 6 to emit white light. In the G region, when the host material of the green light emitting layer 5 is an electron transporting material, light is emitted near the interface between the orange light emitting layer 4 and the green light emitting layer 5. Further, when the host material of the green light emitting layer 5 is a hole transporting material, light is emitted in the vicinity of the interface between the green light emitting layer 5 and the blue light emitting layer 6. Therefore, in any case, light emission including a green component can be obtained in the G pixel region, so that the green chromaticity can be increased.

  In the R pixel region, white light from the organic EL light emitting layer 9 is emitted to the outside through the red color filter layer CFR. Therefore, red light is emitted.

  In the G pixel region, the light containing the green component from the organic EL light emitting layer 9 including the green light emitting layer 5 is emitted to the outside through the green color filter layer CFG. Accordingly, green light is emitted.

  In the B pixel region, white light from the organic EL light emitting layer 9 is emitted through the blue color filter layer CFB. Accordingly, blue light is emitted.

  In the W pixel region, white light from the organic EL light emitting layer 9 is emitted to the outside as it is. Accordingly, white light is emitted.

  As described above, in this embodiment, since the green light emitting layer 5 is provided in the G pixel region, light containing a green component is emitted. Therefore, the chromaticity of green can be increased and the color reproducibility of green can be improved.

  FIG. 2 is a cross-sectional view showing an organic EL display device of another embodiment according to the first aspect of the present invention. In the organic EL display device shown in FIG. 2, the green color filter layer CFG is not provided in the G pixel region. Other configurations are the same as those of the embodiment shown in FIG. In the G pixel region, the green light emitting layer 5 is provided, and the light containing the green component is emitted. Therefore, the green color filter layer can be omitted.

  FIG. 3 is a cross-sectional view showing an organic EL display device of one embodiment according to the second aspect of the present invention. In the present embodiment, a single white light emitting layer (organic EL light emitting layer) 10 containing a blue dopant and an orange dopant is provided on the hole transport layer 3, and on the white light emitting layer 10. An electron transport layer 7 is provided. In the G pixel region, a green light emitting layer 5 is provided on the hole transport layer 3, and a white light emitting layer (organic EL light emitting layer) 10 is provided on the green light emitting layer 5. Other configurations are the same as those of the embodiment shown in FIG.

  In this embodiment, the green light emitting layer 5 is provided in the region of G pixels. The host material of the organic EL light emitting layer 10 is an electron transporting material, and the host material of the green light emitting layer 5 is an electron transporting material or a hole transporting material. When the host material of the green light emitting layer 5 is an electron transporting material, light is emitted near the interface between the hole transport layer 3 and the green light emitting layer 5. Further, when the host material of the green light emitting layer 5 is a hole transporting material, light is emitted near the interface between the organic EL light emitting layer 10 and the green light emitting layer 5. Therefore, in the G pixel region, light emission including a green component can be obtained, and the green color reproducibility can be improved by increasing the green chromaticity.

  FIG. 4 is a sectional view showing an organic EL display device of another embodiment according to the second aspect of the present invention. The embodiment shown in FIG. 4 has the same configuration as that of the embodiment shown in FIG. 3 except that the green color filter layer is not provided in the G pixel region.

  As in the embodiment shown in FIG. 4, the green light emitting layer 5 is provided in the G pixel region, and light emission including a green component can be obtained, so that no green color filter layer is provided. Is possible.

  FIG. 5 is a cross-sectional view showing an organic EL display device including a thin film transistor (TFT) for driving the organic EL light emitting layer of each pixel.

As shown in FIG. 5, a laminated film 11 of a layer made of silicon oxide (SiO ₂ ) and a layer made of silicon nitride (SiNx) is formed on a substrate 1 such as a glass substrate. A TFT 20 is provided on each pixel.

  The TFT 20 is configured by forming a source electrode 13 s on the source region of the polycrystalline silicon layer 12, a drain electrode 13 d on the drain region, and providing a gate electrode 15 on the channel region via a gate oxide film 14. Has been.

A first interlayer insulating film 16 is formed on the gate oxide film 14 so as to cover the gate electrode 15. A second interlayer insulating film 17 is provided on the first interlayer insulating film 16 so as to cover the drain electrode 13d and the source electrode 13s. The first interlayer insulating film 16 and the second interlayer insulating film 17 are made of, for example, SiO ₂ or SiNx.

  On the second interlayer insulating film 17, a first planarization layer 18 is formed from, for example, an acrylic resin. A hole injection electrode 2 is formed on each pixel region of the first planarization layer 18. The hole injection electrode 2 is formed of a transparent conductive film such as indium tin oxide (ITO). The hole injection electrode 2 passes through via holes formed in the first planarization layer 18 and the second planarization layer 17 and is electrically connected to the drain electrode 13d of the TFT 20.

  A second planarization layer 19 is provided so as to cover the hole injection electrode 2 in a portion other than the area of each pixel. Therefore, the second planarizing layer 19 is not provided in each pixel portion.

  On the hole injection electrode 2 and the second planarization layer 19, as in the embodiment shown in FIG. 1, the hole injection layer 3, the orange light emitting layer 4, the blue light emitting layer 6, the electron injection layer 7, and the electrons An injection electrode 8 is formed. In the G pixel region, a green light emitting layer 5 is formed between the orange light emitting layer 4 and the blue light emitting layer 6.

  The color filter layers CFR, CFG, and CFB are formed on the second interlayer insulating film 17 in the same manner as the embodiment shown in FIG. 1, and the first planarizing layer 18 is formed thereon. ing.

  In the organic EL display device shown in this embodiment, each pixel can be driven to emit light in accordance with a video signal by being driven by the TFT 20 of each pixel, and full color display is possible.

  In this embodiment, since the green light emitting layer 5 is provided in the G pixel region, light containing a green component can be emitted, the green chromaticity is increased, and the green color reproducibility is improved. Can be improved.

(Examples 1-6 and Comparative Example 1)
As an organic EL element structure of a green pixel, an organic EL element having a structure as shown in Table 1 was produced. The composition of each layer is as shown in Table 2. In Table 2, () indicates the thickness of each layer, and the unit is nm.

  A substrate in which indium tin oxide (ITO) was formed on a glass substrate was used, and this ITO film was used as a hole injection electrode.

  As shown in Table 2, the hole transport layer was formed from NPB. NPB is N, N′-di (naphthasen-1-yl) -N, N′-diphenylbenzidine and has the following structure.

  The orange light-emitting layer uses 80% by weight of NPB, which is a hole transporting material, as a host material, 20% by weight of tBuDPN, which is a green light-emitting dopant, and DBzR, which is an orange light-emitting dopant, is 100% by weight in total of NPB and tBuDPN. 3% by weight is used. However, in this case, the green light emitting dopant tBuDPN does not emit light, and functions as an energy transfer assisting dopant that delivers excitation energy from the host material to the orange light emitting dopant DBzR. Here, the energy transfer assisting dopant is a material having a LUMO (lowest unoccupied molecular orbital) level and an energy gap between the host and the luminescent dopant, and efficiently converts the excitation energy from the host into the luminescent dopant. Indicates a dopant that plays a role of delivery.

  tBuDPN is 5,12-bis (4-tertiary-butylphenyl) naphthacene and has the following structure.

  DBzR is 5,12-bis {4- (6-methylbenzothiazol-2-yl) phenyl} -6,11-diphenylnaphthacene and has the following structure.

  The blue light emitting layer uses TBADN, which is an electron transporting material, as a host material, NPB as a carrier transfer assisting dopant, and TBP as a blue light emitting dopant. The content of TBADN is 80% by weight, the content of NPB is 20% by weight, and the content of TBP is 2.5% by weight with respect to the total of 100% by weight of TBADN and NPB. Here, the carrier transfer assisting dopant is a material having a higher mobility of carriers to be supported than the host material, promoting the injection of one carrier, and balancing both carrier densities in the light emitting layer. A dopant having a role of increasing luminous efficiency by increasing the recombination probability is shown. In this case, by including NPB having higher hole transport mobility than TBADN in TBADN which is an electron transporting material, NPB plays a role of assisting the movement of holes in the blue light emitting layer and increasing the light emission efficiency. I'm in charge.

  TBADN is 2-tertiary-butyl-9,10-di (2-naphthyl) anthracene and has the following structure.

  TBP is 2,5,8,11-tetra-tertiary-butylperylene and has the following structure.

  The electron transport layer is made of BCP. BCP is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline and has the following structure.

  The electron injection electrode is formed of a laminated film of LiF and Al.

  In Example 1, the green light emitting layer using the host material of the blue light emitting layer is formed between the blue light emitting layer and the orange light emitting layer. Specifically, 80% by weight of TBADN is used as a host material, 20% by weight of NPB is used as a carrier transfer assisting dopant, and C545T is used as a green light emitting dopant by using 5% by weight with respect to 100% by weight of TBADN and NPB in total. Is forming.

  C545T is 10- (2-benzothiazolyl) -2,3,6,7-tetrahydro-1,1,7,7-tetramethyl1-1H, 5H, 11H- [1] benzopyrano [6,7,8, ij] quinolinidin-11-one, which has the following structure.

  In Example 2, a green light emitting layer using NPB, which is a host material of an orange light emitting layer, as a host material is provided between the blue light emitting layer and the orange light emitting layer. As a green light emitting dopant, tBuDPN is contained so as to be 3% by weight with respect to 100% by weight of NPB.

  In Example 3, a green light emitting layer using TBADN, which is a host material of the blue light emitting layer, as a host material in an amount of 80% by weight is provided between the orange light emitting layer and the blue light emitting layer. A layer of hole transport material made of NPB is provided between the color light emitting layers. In the green light emitting layer, 20% by weight of NPB is used as in the case of the blue light emitting layer, and 5% by weight of C545T is contained as a green light emitting dopant with respect to a total of 100% by weight of TBADN and NPB.

  In Example 4, a green light emitting layer using NPB, which is a host material of an orange light emitting layer, as a host material is provided between the blue light emitting layer and the orange light emitting layer, and the green light emitting layer and the blue light emitting layer are provided. Between these layers, an electron transporting material layer made of TBADN which is a host material of the blue light emitting layer is provided. The green light emitting layer contains 3% by weight of tBuDPN as a green light emitting dopant with respect to 100% by weight of NPB.

  In Example 5, the same green light-emitting layer as in Example 4 is provided between the blue light-emitting layer and the orange light-emitting layer, and the material for the electron transport layer is provided between the green light-emitting layer and the blue light-emitting layer. A layer of an electron transporting material made of some BCP is provided.

  In Example 6, two light emitting layers of a first green light emitting layer and a second green light emitting layer are provided between a blue light emitting layer and an orange light emitting layer. The first green light-emitting layer provided on the blue light-emitting layer side uses TBADN, which is the host material of the blue light-emitting layer, as 80% by weight as a host material, NPB as 20% by weight as a carrier transfer auxiliary dopant, and C545T as a green light-emitting dopant. Is 5% by weight with respect to 100% by weight in total of TBADN and NPB. The second green light emitting layer provided on the orange light emitting layer side uses NPB as a host material of the orange light emitting layer as a host material, and contains 3% by weight of tBuDPN as a green light emitting dopant with respect to 100% by weight of NPB. is doing.

  In Comparative Example 1, a blue light emitting layer and an orange light emitting layer are directly laminated, and no green light emitting layer or the like is provided between them.

  As shown in Table 2, it can be seen that in the organic EL element structures of Examples 1 to 6 according to the present invention, light emission containing a green component was obtained as compared with the organic EL element structure of Comparative Example 1. Moreover, the luminous efficiency in Examples 1-6 is equivalent to or higher than that of Comparative Example 1.

(Examples 7 to 11 and Comparative Example 2)
As an organic EL element structure of a green pixel, an organic EL element having a structure as shown in Table 3 was produced. The composition of each layer is as shown in Table 4.

  Similar to Examples 1 to 6, a substrate having ITO formed on a glass substrate was used, and an ITO film was used as a hole injection electrode.

  As in Examples 1 to 6, the electron transport layer is made of BCP, and the electron injection electrode is made of a laminated film of LiF and Al.

  The blue light emitting layer contains 80% by weight of TBADN as a host material and 20% by weight of NPB as a carrier transfer assisting dopant. Further, as the light emitting dopant, 2.5 weight percent of TBP, which is a blue light emitting dopant, and 0.2 weight percent of DBzR, which is an orange light emitting dopant, are contained with respect to a total of 100 weight percent of TBADN and NPB. .

  In Example 7, 80% by weight of TBADN, which is a host material of the white light emitting layer, is used as a host material, and 20% by weight of NPB is used as an auxiliary dopant. Further, C545T is contained as a green light emitting dopant in an amount of 5% by weight with respect to 100% by weight of the total of TBADN and NPB.

  In Example 8, NPB, which is a material for the hole transport layer, is used as a host material, and 3% by weight of the green light-emitting dopant tBuDPN is contained with respect to 100% by weight of NPB.

  In Example 9, a green light-emitting layer containing NPB, which is a material of the hole transport layer, as a host material and containing 3% by weight of the green light-emitting dopant tBuDPN with respect to 100% by weight of NPB is formed between the hole transport layer and the white light-emitting layer. Is provided. Between the green light emitting layer and the white light emitting layer, an electron transporting material layer made of TBADN which is a host material of the white light emitting layer is provided.

  In Example 10, NPB, which is a material of the hole transport layer, is used as a host material, and a green light-emitting layer containing 3% by weight of a green light-emitting dopant tBuDPN with respect to 100% by weight of NPB is composed of a hole transport layer and a white light-emitting layer. It is provided in between. Between the green light emitting layer and the white light emitting layer, an electron transporting material layer made of BCP, which is an electron transporting layer material, is provided.

  In Example 11, the first green light emitting layer and the second green light emitting layer are provided between the hole transport layer and the white light emitting layer. The first green light emitting layer provided on the white light emitting layer side uses TBADN, which is a host material of the white light emitting layer, as a host material and NPB as an auxiliary dopant. 5% by weight of the green light emitting dopant C545T is contained with respect to 100% by weight of the total of 80% by weight of TBADN and 20% by weight of NPB. The second green light emitting layer provided on the hole transport layer side uses NPB, which is a material of the hole transport layer, as a host material, and contains 3% by weight of green light emitting dopant tBuDPN with respect to 100% by weight of NPB.

  As shown in Table 4, it can be seen that in the organic EL elements of Examples 7 to 11 according to the present invention, light emission containing a green component was obtained as compared with the organic EL element of Comparative Example 2. It can also be seen that the luminous efficiency is equal to or higher than that of Comparative Example 2.

1 is a cross-sectional view showing an organic EL display device of one embodiment according to the first aspect of the present invention. Sectional drawing which shows the organic electroluminescence display of the other Example according to the 1st aspect of this invention. Sectional drawing which shows the organic electroluminescence display of one Example according to the 2nd aspect of this invention. Sectional drawing which shows the organic electroluminescence display of the other Example according to the 2nd aspect of this invention. 1 is a cross-sectional view showing an organic EL display device according to a first aspect of the present invention that includes a TFT for driving an organic EL light emitting layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate 1 '... Planarization layer 2 ... Hole injection electrode 3 ... Hole transport layer 4 ... Orange light emitting layer 5 ... Green light emitting layer 6 ... Blue light emitting layer 7 ... Electron transport layer 8 ... Electron injection electrode 9 ... Organic EL light emission Layer 10: organic EL light emitting layer (white light emitting layer)
CFR, CFG, CFB ... Color filter layer

Claims (15)

An organic electroluminescent display device having at least each pixel of red (R), green (G), and blue (B),
An organic EL light emitting layer that emits white light;
A hole injection electrode for supplying holes to the organic EL light emitting layer;
An electron injection electrode for supplying electrons to the organic EL light emitting layer;
A red and blue color filter layer provided on the light irradiation side of the organic EL light emitting layer corresponding to the red and blue pixels,
The organic EL light emitting layer is disposed between the hole injection electrode and the electron injection electrode, and the organic EL light emitting layer contains a host material made of an electron transporting material and is disposed on the electron injection electrode side. A blue light emitting layer and a host material made of a hole transporting material, and having a structure in which an orange light emitting layer disposed on the hole injection electrode side is laminated,
A green light emitting layer containing a host material made of an electron transporting material or a hole transporting material is provided between the blue light emitting layer and the orange light emitting layer in the region of the green pixel. Organic electroluminescence display device.   The organic electroluminescence display device according to claim 1, further comprising a green color filter layer on a light irradiation side of the organic EL light emitting layer corresponding to the green pixel.   The organic electroluminescence display device according to claim 1, wherein the host material of the green light emitting layer is the same material as the host material of the blue light emitting layer.   The organic electroluminescence display device according to claim 1, wherein the host material of the green light emitting layer is the same material as the host material of the orange light emitting layer.   The host material of the green light emitting layer is an electron transporting material, and a layer of a hole transporting material is provided between the green light emitting layer and the orange light emitting layer. The organic electroluminescence display device according to any one of the above.   The host material of the green light emitting layer is a hole transporting material, and an electron transporting material layer is provided between the green light emitting layer and the blue light emitting layer. The organic electroluminescence display device described in 1.   The green light emitting layer contains a host material made of an electron transporting material, contains a first green light emitting layer disposed on the blue light emitting layer side, a host material made of a hole transporting material, and the orange color The organic electroluminescence display device according to claim 1, wherein the organic electroluminescence display device has a structure in which a second green light emitting layer disposed on the light emitting layer side is laminated. An organic electroluminescent display device having at least each pixel of red (R), green (G), and blue (B),
An organic EL light emitting layer that emits white light;
A hole injection electrode for supplying holes to the organic EL light emitting layer;
An electron injection electrode for supplying electrons to the organic EL light emitting layer;
A red and blue color filter layer provided on the light irradiation side of the organic EL light emitting layer corresponding to the red and blue pixels,
The organic EL light-emitting layer contains a host material made of an electron transporting material, a blue light-emitting dopant, and an orange light-emitting dopant, and is a single layer white disposed between the hole injection electrode and the electron injection electrode A light emitting layer,
In the green pixel region, a green light emitting layer containing a host material made of an electron transporting material or a hole transporting material is provided between the hole injection electrode and the organic EL light emitting layer. Organic electroluminescence display device.   The organic electroluminescence display device according to claim 8, further comprising a green color filter layer on the light irradiation side of the organic EL light emitting layer corresponding to the green pixel.   The organic electroluminescence display device according to claim 8, wherein a host material of the green light emitting layer is the same material as a host material of the organic EL light emitting layer.   The hole injection layer is provided between the hole injection electrode and the green light emitting layer, and the host material of the green light emitting layer is the same material as the host material of the hole injection layer. The organic electroluminescence display device according to 8 or 9.   The host material of the green light emitting layer is a hole transporting material, and an electron transporting material layer is provided between the green light emitting layer and the organic EL light emitting layer. The organic electroluminescence display device described.   The organic electroluminescence display device according to claim 12, wherein the layer of the electron transporting material is formed from a host material of the organic EL light emitting layer.   The green light emitting layer contains a host material made of an electron transporting material, contains a first green light emitting layer disposed on the organic EL light emitting layer side, a host material made of a hole transporting material, and the holes 10. The organic electroluminescence display device according to claim 8, wherein the organic electroluminescence display device has a structure in which a second green light emitting layer disposed on the injection electrode side is laminated. A hole injection layer is provided between the hole injection electrode and the green light emitting layer, a host material of the first green light emitting layer is the same material as a host material of the organic EL light emitting layer, and the second The organic electroluminescence display device according to claim 14, wherein a host material of the green light emitting layer is the same material as that forming the hole injection layer.

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