WO2007111192A1

WO2007111192A1 - Organic electroluminescent element, and organic electroluminescent display

Info

Publication number: WO2007111192A1
Application number: PCT/JP2007/055610
Authority: WO
Inventors: Hiroshi Kashiwagi; Hiroyuki Hashimoto
Original assignee: Konica Minolta Holdings, Inc.
Priority date: 2006-03-24
Filing date: 2007-03-20
Publication date: 2007-10-04
Also published as: JP5381098B2; JPWO2007111192A1

Abstract

This invention provides an organic electroluminescent element, which can realize high brightness and high luminescence efficiency, has excellent power consumption and continuous drive service life and can take out white light, and a white backlight capable of realizing excellent color reproduction in use of the element in combination with a color filter. The organic electroluminescent element comprises a substrate, and an anode and at least one organic layer and a cathode provided on the substrate. The organic electroluminescent element is characterized in that at least one layer constituting the organic layer contains an electron donor, the volume concentration (%) of the electron donor in the organic layer is 5 to 95%, and an electron donor concentration region, which is different by not less than 5% in concentration, is present. The white backlight comprises the element in combination with a color filter.

Description

Specification

Organic Elect Mouth Luminescence Device and Organic Elect Mouth Luminescence Display

Technical field

TECHNICAL FIELD [0001] The present invention relates to an organic electoluminescence device and an organic electroluminescence device.

Background art

As a light-emitting electronic display device, there is an electoluminescence display (EL D). Examples of ELD constituent elements include inorganic electoluminescence devices (inorganic EL devices) and organic electroluminescence devices (hereinafter also referred to as organic EL devices). Inorganic electoric luminescence elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

[0003] An organic electoluminescence device has a structure in which a light-emitting layer containing a light-emitting compound is sandwiched between a cathode and an anode, and is excited by injecting electrons and holes into the light-emitting layer and recombining them. This is an element that emits light by utilizing the emission of light (fluorescence 'phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts.

Furthermore, since it is a self-luminous type, it has a wide viewing angle, and since it is a thin-film type completely solid element with high visibility, it is attracting attention from the viewpoint of space saving and portability.

[0004] Since there is a high demand for reduction in power consumption, methods for reducing drive voltage have been disclosed. For example, if the organic layer is made thin, the driving voltage for allowing a constant current to flow can be further reduced. The outflow of carriers increases, and the luminous efficiency decreases. In view of this, an electron transporting organic compound is doped with an alkali metal or an alkaline earth metal as an electron transporting layer (see, for example, Patent Document 1). This is the design and utilization of a so-called n-type semiconductor layer. Furthermore, an improved approach from an electron transporting organic compound has been made (see, for example, Patent Document 2). Metal Cs, in particular, has a small work function and a high dopant effect, but it is unstable in the air and is dangerous to handle, and has a drawback that the device deteriorates with time. Therefore, improvements have been made by changing to specific Cs and Rb compounds (for example, see Patent Document 3). [0005] However, there is a great need for a drastic improvement in power consumption, which has great expectations for the organic electroluminescence panel luminescence panel. That is, it is a performance improvement with a low driving voltage and a high luminous efficiency and a small performance with time. In the above document, the concentration of electron donors is all constant, and there is no description or suggestion that it is locally changed.

Patent Document 1: Japanese Patent Laid-Open No. 10-270172

Patent Document 2: JP 2004-193011 A

Patent Document 3: Japanese Patent Laid-Open No. 2004-335137

Disclosure of the invention

Problems to be solved by the invention

[0006] An object of the present invention is to provide an organic-electric-mouth luminescence device capable of extracting white light with high brightness, high luminous efficiency, excellent continuous drive life, and color reproduction in combination with a color filter using the device. Is to provide an excellent white backlight

Means for solving the problem

[0007] The above object of the present invention is achieved by the following configurations.

[0008] 1. In an organic electret nominence device comprising an anode, at least one organic layer and a cathode on a substrate, at least one of the organic layers contains an electron donor, and the organic layer of the electron donor An organic electoresistive element having an electron donor concentration region having a volume concentration (%) in the range of 5 to 95% and a difference of 5% or more.

[0009] 2. The organic electroluminescent device according to 1 above, wherein the difference between the maximum concentration and the minimum concentration of the volume concentration (Q / o) containing the electron donor is ¾0 to 90%. .

[0010] 3. Each film thickness of the region containing the maximum concentration or the minimum concentration of the electron donor is 1/100 to 1/4 with respect to the film thickness of the organic layer containing the electron donor. The organic electoluminescence device according to 1 or 2 above.

[0011] 4. A layer interface adjacent on the anode side in the organic layer containing the electron donor; The electron donor volume concentration (%) is 10% or less in a region within 1/3 of the thickness of the organic layer containing the electron donor.

The organic electoluminescence device according to any one of 1 to 3,

[0012] 5. The organic electroluminescent device according to any one of items 1 to 4, characterized in that there are at least three electron donor concentration regions different from each other by 5% or more.

[0013] 6. The organic layer containing an electron donor is in contact with a cathode.

The organic electoluminescence device according to any one of -5.

[0014] 7. The power according to any one of 1 to 6, wherein the organic layer has a light-emitting layer containing a light-emitting dopant (phosphorescent compound) that emits at least one phosphorescence. Organic electoluminescence element.

[0015] 8. The organic electoscope according to any one of the above:! To 6, wherein the organic layer includes a light emitting layer containing a phosphorescent compound and a light emitting layer containing a fluorescent compound. Nominescence element.

[0016] 9. The organic electroluminescence device according to 8 above, wherein the light emitting layer containing the fluorescent compound emits blue light.

[0017] 10. The organic electroluminescent element as described in any one of 1 to 9 above, which emits white light.

[0018] 11. Blue light, green light, and red light are obtained from white light extracted from the organic-electric-luminescence device described in 10 above through a blue filter, a green filter, and a red filter. Organic-elect luminescence display.

The invention's effect

[0019] According to the present invention, an organic electoluminescence device capable of extracting white light with high brightness, high luminous efficiency, excellent continuous drive life, and color reproducibility in combination with a color filter using the device. An excellent white backlight could be provided.

Brief Description of Drawings

FIG. 1 is a view showing CsF volume concentration in an electron injection / transport layer of an organic EL device 101 according to a film thickness from a cathode toward a hole blocking layer. 2] It is a diagram showing the CsF volume concentration in the electron injection / transport layer of the organic EL element 102 according to the film thickness from the cathode toward the hole blocking layer.

3] It is a diagram showing the CsF volume concentration in the electron injection / transport layer of the organic EL device 103 according to the film thickness from the cathode toward the hole blocking layer.

4] A diagram showing the volume concentration of CsF in the electron injection / transport layer of the organic EL element 104 according to the film thickness from the cathode toward the hole blocking layer.

FIG. 5 is a graph showing CsF volume concentration in the electron injection 'transport layer of the organic EL element 105 according to the film thickness from the cathode toward the hole blocking layer.

6] A graph showing the CsF volume concentration in the electron injection 'transport layer of the organic EL element 106 according to the film thickness from the cathode toward the hole blocking layer.

7] A graph showing the volume concentration of CsF in the electron injection 'transport layer of the organic EL element 107 according to the film thickness from the cathode toward the hole blocking layer.

FIG. 8 is a schematic diagram showing an example of the layer structure of the barrier film and its density profile. FIG. 9] A schematic view showing an example of an atmospheric pressure plasma discharge treatment apparatus for treating a substrate.

FIG. 10 is a schematic view of a lighting device.

FIG. 11 is a cross-sectional view of the lighting device.

Explanation of symbols

11 Glass substrate

12 Glass case

15 Cathode

16 OLED layer

17 Transparent electrode

18 Nitrogen gas

19 Water catcher

201 Noria membrane

202 Base material

203 Low density layer

204 Medium density layer 205 Low density layer

230 Plasma discharge treatment equipment

231 Plasma discharge treatment vessel

235 roll rotating electrode

236 Square tube type fixed electrode group

240 Electric field application means

250 Gas supply means

251 Gas generator

253 Exhaust port

260 Electrode temperature control means

F Substrate

P liquid pump

261 piping

266 Nip roll

267 Guide roll

268, 269 divider

BEST MODE FOR CARRYING OUT THE INVENTION

[0022] Hereinafter, details of each component according to the present invention will be sequentially described.

[0023] << Organic Elect Mouth Luminescence Element >>

The organic electoluminescence device of the present invention will be described. The organic electroluminescent element of the present invention is composed of a substrate, an electrode and an organic layer, and the organic layer is composed of at least a light emitting layer and an organic layer containing the electron donor according to the present invention (also simply referred to as a donor).

[0024] << Emission, Front Luminance, Chromaticity of Organic Electric Luminescence Element >>

The emission color of the organic electoluminescence device of the present invention is shown in Fig. 4.16 on page 108 of "New Color Science Handbook" (edited by the Japan Society for Color Science, The University of Tokyo Press, 1985). It is determined by the color when the result measured with the luminance meter CS-1000 (Konica Minolta Sensing) is applied to the CIE chromaticity coordinates. Organic organic of the present invention The white color in the Recto-Luminescence device means the chromaticity of the CIE1931 color system ½ = 0.33 ± 0.07, y = 0.33 ± 0 when the front luminance at 2 ° C viewing angle is measured by the above method. It is characterized by being in the 07 area.

[0025] << layer structure >>

In order to extract white light, the light-emitting layer, which is a constituent layer of the organic electoluminescence device according to the present invention, has different emission spectra with emission maximum wavelengths in the range of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm, respectively. It contains at least two layers, and preferably has three or more layers.

[0026] Preferred specific examples of the layer structure in the present invention are shown below, but the present invention is not limited thereto.

(I) Anode Z hole transport layer Z electron blocking layer Z light emitting layer unit Z hole blocking layer Z electron transport layer / cathode

(ii) Anode / hole transport layer / electron blocking layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode

(m) Anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode

(iv) Anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode

Here, the light-emitting layer unit is a light-emitting layer unit that has at least two light-emitting layers whose emission maximum wavelengths are in the range of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm, respectively. Further, the unit preferably has a non-light emitting intermediate layer between the light emitting layers.

[0028] 《Electron Donor》

The electron donor according to the present invention refers to an electron donating compound. An organic layer is formed by mixing with a host as a single pant. The presence of the host reduced by the electron donor in the state of an anion radical reduces the electron barrier near the layer interface on the cathode side, increases the electron supply density, and the effect of lowering the voltage is recognized. That is, the dopant according to the present invention has a higher LUMO level than the organic material to be mixed. It is essential that the thing function is small. The layer containing the electron donor may be a light emitting layer. In this case, the dopant contains the carrier donor and the light emitting source of the present invention. The emission source may be fluorescence or phosphorescence. The electron donor according to the present invention is preferably contained in the electron transport layer.

[0029] << Electron Transport Layer >>

The electron transport layer used in the present invention has an effect on the driving voltage, and the electron density is increased by doping the carrier donor, and the electron mobility by hopping is increased by forming a shallow level and LUMO level. It is interpreted because. Regarding the concentration of impurities to be doped, only a uniform concentration has been studied in the electron transport layer.

[0030] As a result of the inventor's detailed study on the impurity concentration dependence, the present invention has been achieved. That is, when the impurity concentration is locally changed rather than uniformly, in addition to the conventional low driving voltage, surprisingly, the effect of improving the luminous efficiency was recognized. In particular, when a high concentration region was provided locally above the average donor concentration, a remarkable effect was observed. Although there was a slight tendency to increase the driving voltage, it is advantageous in terms of power efficiency. The reason is not clear, but when the donor concentration is locally increased, the number of fixed holes increases and the hole barrier is increased, so that excitons are contained in the light-emitting layer. The power of The electron transport layer according to the present invention can be provided as a single layer or a plurality of layers.

[0031] As the electron transport material, known materials can be used. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carpositimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxazazomonore derivatives and the like can be mentioned. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which an oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

[0032] In addition, metal complexes of 8_quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-1-8-quinolinol) aluminum, tris (5,7-dibu) Lomo 1_Quinolinol) Aluminum, Tris (2-Methyl _8 _Quinolinol) Aluminum Yu , Tris (5-methyl 8-quinolinol) aluminum, bis (8-quinolinol) zinc (Zn q), etc., and the central metal of these metal complexes are placed in In, Mg, Cu, Ca, Sn, Ga or Pb. Alternative metal complexes can also be used as electron transport materials.

In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. Further, the distyrylpyrazine derivatives exemplified as the material for the light emitting layer can also be used as the electron transporting material. In addition, a compound represented by the general formula (1) described in the host section can be preferably applied.

[0034] As the carrier donor material according to the present invention, a known material can be used. For example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Appl. Phys., 95, 5773 (2004), etc. Those listed are listed. Further, general formulas (8) to (: 10) in JP-A-2006-41020 are also preferably used. In the present invention, by using such an electron transport layer having a high n property together with the P property semiconductor layer of the present invention, it is possible to produce a low power consumption element.

[0035] The electron transport material and the carrier donor are formed by thinning by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Power S can be.

[0036] Although not specified by the type of material, the donor-containing average volume concentration according to the present invention is 5 to 95%, and there is a region where the difference between at least the maximum concentration and the minimum concentration is 5% or more. . 0% is out of the gist of the present invention, and 100% is close to an insulator.

Rena, The difference between the highest and lowest concentrations is 20-90%, but the preferred highest concentration is 15-95%. More preferably, it is 25 to 90%. The film thickness ratio of the highest concentration region in the electron transport layer is 1 to 50%, more preferably 2. / ₀ force 45%. The film thickness is usually from In m to about lxm, preferably from 5 to 200 nm. In the region from the interface of the organic layer adjacent to the anode side to 1/3 of the thickness of the electron transport layer of the present invention, the carrier donor concentration is lower from the viewpoint of continuous driving life as the conductivity is not impaired. Masle. [0037] In the present invention, if there are 3 or more regions where the donor volume concentration differs by 5% or more, the light emission efficiency may be further improved, and one example is a case where it changes continuously. Depending on the material, it is often 5 or less. The term “local” as used in the present invention refers to, for example, a case where film thickness configurations of 1 nm or more having different donor volume concentrations are arbitrarily combined. Even in this case, the difference between the maximum and minimum donor volume concentrations is more than 5%.

[0038] << Hole Transport Layer >>

The hole transport layer can be provided as a single layer or a plurality of layers. The hole transport material has either hole injection or transport or electron barrier properties, and may be either organic or inorganic. For example, a triazole derivative, an oxadiazole derivative, an imidazole derivative, a polyarylalkane derivative, a pyrazoline derivative and a pyrazolone derivative, a vinylene diamine derivative, an arylamine derivative, an amino-substituted chalcone derivative, an oxazole derivative, a styrylanthracene derivative, a fluorenone derivative, Examples thereof include hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers. The above-mentioned materials can be used as the hole transport material, but it is preferable to use porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds, particularly aromatic tertiary amine compounds.

[0039] Representative examples of the aromatic tertiary amine compound and styrylamine compound include N, N, N ', N'-tetraphenyl 4, Α'-diaminophenyl; Ν, N'-diphenylol Ν, Ν '— Bis (3-methylphenyl) 1 [1, 1' — Biphenyl] 1, 4, 4 '— Diamine (TPD); 2, 2-bis (4-di 1 ρ-tolylaminophenyl) Propane; 1, 1-bis (4-di-ρ-triraminophenyl) cyclohexane; Ν, Ν, Ν ', N' — tetra-ρ-tolyl-1,4,4'-diaminobiphenyl; 1, 1— Bis (4-di-1-ρ-tolylaminophenyl) 1-phenyl hexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-ρ-tolylaminophenyl) phenylmethane Ν, N '— Diphenylenol N, N ′ — Di (4-methoxyphenyl) 1, 4 ′ — Diaminobihue N, N, N ′, N ′ —tetraphenyl —4, 1-diaminodiphenyl ether; 4, 1-bis (diphenylamino) quadryl ヱ nyl; Ν, Ν, Ν-tri (ρ-tolyl) amine; 4 _ (Di-ρ-tolylamino) _4 '_ [4- (di_ρ-tolylamino) styryl] stilbene; 4 _ Ν, Ν-diphenylaminomino (2-diphenyl) Norevininole) benzene; 3-methoxy-1-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and further described in US Pat. No. 5,061,569. In the molecule, for example, 4,4'-bis- (1-naphthyl) _N_phenylamino] biphenyl (NPD), a triphenylamine unit described in JP-A-4-308688 4, 4 ', "— Tris [^^ _ (3 _methylphenyl) _ N _phenylamino] triphenylamine (MTD ATA), etc. Polymer materials introduced into polymer chains or using these materials as the main chain of the polymer can also be used, and inorganic compounds such as p-type _Si and p-type single SiC can also be used as hole injection materials. Can be used as a hole transport material.

[0040] Also, the so-called p-type hole described in JP-A-11-251067 and J. Huang et. Al. (Applied Physics Letters 80 (2002), p. 139). Transport materials can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained. The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. The thickness of the hole transport layer is not particularly limited, but is usually about 1 nm to l / im, preferably 5 to 200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials. In addition, it is a hole transport layer having a high p property doped with impurities. Examples thereof include those described in JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Appl. Phys., 95, 5773 (2004), etc. Can be mentioned. Further, general formulas (1) to (7) in JP-A No. 2006-41020 are also preferably used. In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

[0041] << Injection layer: electron injection layer, hole injection layer >>

The injection layer is provided as necessary, and includes an electron injection layer and a hole injection layer, and as described above, exists between the anode and the light emitting layer or hole transport layer and between the cathode and the light emitting layer or electron transport layer. May be. The injection layer is a layer that is provided between the electrode and the organic layer in order to reduce the drive voltage and improve the luminance of the light emission. “The organic EL element and its forefront of industrialization (January 30, 1998) 2) Chapter 2 “Electrode Materials” (pages 123-166) of “NTS, Inc.”) is described in detail. The hole injection layer (anode buffer layer) and the electron injection layer (cathode) Buffer one layer)

[0042] The details of the anode buffer layer (hole injection layer) are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. One layer of phthalocyanine buffer typified by copper phthalocyanine, one layer of oxide buffer typified by vanadium oxide, one layer of amorphous carbon buffer, one layer of polymer buffer using a conductive polymer such as polyaniline (emeraldine) or polythiophene, etc. Can be mentioned

[0043] The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Metal buffer layer typified by aluminum or titanium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer typified by aluminum oxide One layer and so on. The buffer layer (injection layer) is preferably a very thin film, although the film thickness is preferably in the range of 0.1 nm to 5 / im.

[0044] << Blocking layer: hole blocking layer, electron blocking layer >>

The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, see pages 237 of JP-A-11-204258, JP-A-11-204359, and “OLEDs and the Forefront of Industrialization (issued by NTT S. Co., Ltd., November 30, 1998)”. There is a hole blocking layer.

[0045] In a broad sense, the hole blocking layer has a function of an electron transport layer, and is composed of a hole blocking material having a function of transporting electrons and having a remarkably small ability to transport holes, and transports electrons. By blocking holes, the recombination probability of electrons and holes can be improved. In addition, the structure of the electron transport layer described later can be used as a hole blocking layer according to the present invention as required. The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

[0046] In the present invention, a plurality of light emitting layers having different emission colors are provided. In this case, it is preferable that the light emitting layer whose emission maximum wavelength is the shortest wave is closest to the anode among all the light emitting layers. In such a case, the light emitting layer closest to the anode next to the shortest wave layer and the layer is used. It is preferable to additionally provide a hole blocking layer therebetween. Further, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.2 eV or more larger than the host compound of the shortest wave emitting layer. Les.

[0047] The ionization potential is defined by the energy required to emit an electron at the HM0 (highest occupied molecular orbital) level of the compound to the vacuum level. For example, the ionization potential can be obtained by the following method. it can.

[0048] (1) Gaussian98 (Gaussian98, Revision A. 11.4, MJ Frisch, et ai, Gaussian, Inc., Pitts Durg h PA, 2002.) Structural optimization using B3LYP / 6-31G * as keywords

The ionic potential can be obtained by rounding off the second decimal place of the value calculated in (eV unit conversion value). The reason why this calculated value is effective is that there is a high correlation between the calculated value obtained by this method and the experimental value.

[0049] (2) The ionization potential can also be obtained by a method of direct measurement by photoelectron spectroscopy. For example, a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd. or a method known as ultraviolet photoelectron spectroscopy can be suitably used.

[0050] On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports holes. However, by blocking electrons, the probability of recombination of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

[0051] <Light emitting layer>

The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is within the layer of the light emitting layer. Alternatively, it may be the interface between the light emitting layer and the adjacent layer. The light emitting layer according to the present invention has at least three colors of a blue light emitting layer having a light emission maximum wavelength in the range of 430 to 480 nm, a green light emitting layer in the range of 510 to 550 nm, and a red light emitting layer in the range of 600 to 640 nm. Although it is preferable to have a light emitting layer, a two-color configuration may be used. For example, even if two colors are selected from the three categories, the color reproducibility is inferior to that of the three-color configuration, but white is obtained.

[0052] When there are more light emitting layers than several power layers, there may be a plurality of layers having an emission spectrum or emission maximum wavelength in the same section. There is no restriction | limiting in particular as a lamination order of a light emitting layer. It is preferable to have a non-light emitting intermediate layer between each light emitting layer.

[0053] The total film thickness of the light emitting layer is not particularly limited, but it is possible to prevent film homogeneity, application of unnecessary high voltage during light emission, and improvement of stability of emitted color with respect to driving current. Therefore, it is preferable to adjust to the range of 2 to 30 nm, and more preferably in the range of 5 to 25 nm.

[0054] For the production of the light emitting layer, a light emitting dopant or a host compound described later is formed by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink jet method. can do. The film thickness of each light emitting layer may be arbitrary as long as it is within the above-mentioned range. There are no particular restrictions on the relationship between the thicknesses of the blue, green, and red light emitting layers, but in order to obtain white light, the thickness of the light emitting layer with the lowest recombination probability is the largest. In addition, a plurality of light emitting compounds may be mixed in each light emitting layer within a range in which the maximum wavelength is maintained. For example, a blue light emitting compound having a maximum wavelength of 430 to 480 nm and a green light emitting compound having a maximum wavelength of 510 to 550 nm may be mixed and used in the blue light emitting layer.

[0055] Next, a host compound and a light emitting dopant contained in the light emitting layer will be described.

[0056] (Host compound)

The host compound contained in the light emitting layer of the organic EL device of the present invention is defined as a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1. Preferably, the phosphorous photon yield is less than 0.01. Further, among the compounds contained in the light emitting layer, the mass ratio in the layer is preferably 20% or more. As the host compound, known host compounds may be used alone or in combination of two or more. By using multiple types of host compounds, it is possible to adjust the charge transfer, which increases the efficiency of organic EL devices. Ability to do S. Further, by using a plurality of phosphorescent compounds used as light-emitting dopants, which will be described later, it becomes possible to mix different light emissions, thereby obtaining an arbitrary emission color. It is possible to adjust the kind of phosphorescent compound and the amount of doping, and it can be applied to illumination and backlight.

As the host compound according to the present invention, an example of a compound that is preferably used is a compound represented by the following general formula (1). The compound is also preferably used in a layer adjacent to the light emitting layer (for example, a hole blocking layer).

[0058] [Chemical 1]

-General

[0059] In the formula, Z represents an aromatic heterocyclic ring which may have a substituent, and each Z has a substituent.

1 2 represents an aromatic heterocycle or aromatic hydrocarbon ring that may be substituted, and Z represents a divalent linking group.

Three

Or just a bond. R represents a hydrogen atom or a substituent.

101

In the general formula (1), examples of the aromatic heterocycle represented by Z and Z include a furan ring,

1 2

Fen ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, benzoimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole And a ring in which the carbon atom of the hydrocarbon ring constituting the ring, quinoxaline ring, quinazoline ring, phthalazine ring, force rubazole ring, carboline ring or carboline ring is further substituted with a nitrogen atom. Further, the aromatic heterocycle is a substituent represented by R described later.

101

It may have a group.

[0061] Examples of the aromatic hydrocarbon ring represented by Z include a benzene ring, a biphenyl ring, and a naphthalene ring.

2

, Azulene ring, anthracene ring, phenanthrene ring, pyrene ring, talycene ring, naphthacene ring, triphenylene ring, o_terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluorene ring Olanthrene ring, naphthacene ring, penta Examples include a cene ring, a perylene ring, a pentaphen ring, a picene ring, a pyrene ring, a pyranthrene ring, and an anthanthrene ring. Further, the aromatic hydrocarbon ring is represented by R described later.

101 may have a substituent.

Examples of the substituent represented by R 1 include an alkyl group (eg, methinole group, ethyl group, propyl group).

101

Group, isopropyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecinole group, tetradecinole group, pentadecinole group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group etc.), An alkenyl group (for example, a buyl group, a aryl group, etc.), an alkynyl group (for example, an ethul group, a propargyl group, etc.), an aryl group (for example, a phenyl group, a naphthyl group, etc.), an aromatic heterocyclic group (for example, a furyl group, Chenyl group, pyridinole group, pyridazinyl group, pyrimidinyl group, pyriduryl group, triazinyl group, imidazolinole group, pyrazolyl group, thiazolyl group, quinazolinyl group, phthaladyl group, etc.), heterocyclic group (for example, pyrrolidyl group, imidazolidyl group, morpholyl) Group, oxazolidyl group, etc.), alkoxy group (for example, Methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecinoleoxy group, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, phenoxy group) Group, naphthyloxy group, etc.), alkylthio group (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, docythio group, etc.), cycloalkylthio group (for example, cyclopentylthio group, cyclo Hexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butoxycarbonyl group, Cutylical Bonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenylcarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, etc.) , Dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2_ Pyridylaminosulfonyl group, etc.), acyl groups (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylene group). A carbonyl group, an octylcarbonyl group, a 2-ethylhexylcarbonyl group, a dodecylcarbonyl group, a phenylcarbonyl group, a naphthylcarbonyl group, a pyridylcarbonyl group, etc.), an acyloxy group (for example, an acetylyloxy group, an ethylcarbonyloxy group, Butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methenorecanoleponinoreamino group, ethylcarbonylamino group, Dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, Phenylcarbonylamino group, naphth Rucarbonylamino groups, etc.), strong ruberamoyl groups (for example, aminocarbonyl groups, methylaminocarbonyl groups, dimethylaminocarbonyl groups, pylaminocarbonyl groups, pentylaminocarbonyl groups, cyclohexylamino groups). Carbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc. ), Ureido group (eg, methinoureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecinoureido group, phenylureido group, naphthylureido group, 2-pyridinoreaminoureido group), sulfier group (For example, methylsulfier Ethylsulfinyl group, butylsulfiel group, cyclohexylsulfiel group, 2-ethylhexylsulfiel group, dodecylsulfiel group, phenylsulfiel group, naphthylsulfiel group, 2-pyridylsulfiel group, etc.) Alkylsulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group (eg, phenylsulfonyl) Group, naphthylsulfonyl, 2_pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethynolehexinoremino group, dodecinoreamino group, dilino group , Naftino Amino group, 2_pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom, etc.), fluorinated hydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl) Group), cyano group, nitro group, hydroxy group, mel Examples thereof include a capto group and a silyl group (for example, a trimethylsilyl group, a triisopropyl silyl group, a triphenylsilyl group, a phenyljetylsilyl group, etc.). These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring. Preferred substituents are an alkyl group, a cycloalkyl group, a fluorinated hydrocarbon group, an aryl group, and an aromatic heterocyclic group.

[0063] Examples of the divalent linking group include hydrocarbon groups such as alkylene, alkenylene, alkynylene, and arylene, as well as those containing heteroatoms, and thiophene-2,5-diyl groups, It may be a divalent linking group derived from a compound having an aromatic heterocycle such as a 2,3-diyl group (also referred to as a heteroaromatic compound) or a chalcogen atom such as oxygen or sulfur. Anyway. In addition, it may be a group that joins and connects heteroatoms such as an anolequinolemino group, a dialkylsilane diyl group, and a diarylgermandyl group. A simple bond is a bond that directly connects the linking substituents together.

In the present invention, the Z-membered ring represented by the general formula (1) is preferable. This

1

, The luminous efficiency can be further increased. Furthermore, the lifetime can be further increased. In the present invention, the z-membered ring represented by the general formula (1) is preferable. to this

2

Thus, the luminous efficiency can be further increased. Furthermore, the life can be further extended. Furthermore, by making Z and Z in the general formula (1) both 6-membered rings, the luminous efficiency can be further increased.

1 2

This is preferable. Furthermore, it is preferable because the lifetime can be further increased. Specific examples of the compound represented by the general formula (1) according to the present invention are shown below, but the present invention is not limited thereto.

[0065] [Chemical 2]

[S ^] [9900]

The light emitting host used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a bur group or an epoxy group (deposition). Polymerizable light-emitting host). Known host compounds include hole transport ability and electron transport ability, while preventing the emission of longer wavelengths and high Tg.

A compound having a (glass transition temperature) is preferred. Specific examples of known host compounds include compounds described in the following documents. For example, JP 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-88. No. 60, No. 2002-334787, No. 2002-15871, No. 2002-334 788, No. 2002-43056, No. 2002-334789, No. 2002-75 645, No. 2002-75 645, No. 2002 -338579, 2002-105445, 2002-3 43568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002 — No. 231453, No. 20 03-3165, No. 2002-234888, No. 2003-27048, No. 200 2-255934, No. 2002-260861, No. 2002-280183, No. 2 002-299060, 2002-302516, 2002-305083, No. 2002-305084 and No. 2002-308837.

[0068] In the present invention, the light emitting layer having a light emission maximum wavelength in the range of 430 to 480 nm,

The light emitting layer has a light emitting layer in the range of 550 nm and the light emitting layer in the range of 600 to 640 nm. The light emitting layer has at least three light emitting layers. Compounds each having 2.9 eV or more and Tg (glass transition point) of 90 ° C or more are preferred, and compounds having 100 ° C or more are more preferred. Among these, from the viewpoint of improving the storage stability of the organic EL device (also referred to as durability improvement) and reducing the uneven distribution of the compound at the light emitting layer interface, the molecular structures of the compounds are particularly preferably the same. Here, it is preferable that the physicochemical characteristics of the host compound are the same or the molecular structure is the same. For this reason, the details will be described in the non-light emitting intermediate layer described later. .

[0069] (Tg (glass transition point))

The organic compound of each layer constituting the organic electoluminescence device of the present invention is characterized by containing a material having a Tg of 100 ° C. or more at least 80% by mass or more of each layer.

Here, the glass transition point (Tg) is a value determined by a method based on JIS-K 7121 using DSC (Differential Scanning Colorimetry). By using a host compound having the same physical characteristics as described above, and more preferably using a host compound having the same molecular structure, an organic compound layer (both organic layer and organic layer) of the organic EL element is used. Homogeneous film properties can be obtained throughout, and the phosphorescence emission energy of the host compound can be adjusted to be 2.9 eV or more, effectively suppressing energy transfer from the dopant, High brightness can be obtained.

[0071] (Phosphorescence energy)

The phosphorescent energy according to the present invention will be described. The phosphorescent energy according to the present invention is the peak energy of the 0-0 band of the phosphorescence obtained when the photoluminescence of the deposited film of lOOnm is measured on a support substrate (which may be simply a substrate). Say.

First, a method for measuring a phosphorescence spectrum will be described. The luminescent host compound to be measured Dissolve in a well-deoxygenated ethanol / methanol = 4/1 (volume / volume) mixed solvent, put in a phosphorescence measurement cell, and then irradiate excitation light at a liquid nitrogen temperature of 77 ° K. Measure the emission spectrum at 100ms after irradiation. Since phosphorescence has a longer emission lifetime than fluorescence, it can be considered that the light remaining after 100 ms is almost phosphorescent.

[0073] For compounds with a phosphorescence lifetime shorter than 100 ms, the delay time may be shortened, but if the delay time is set so short that it cannot be distinguished from fluorescence, phosphorescence and fluorescence cannot be separated. Therefore, it is necessary to select a delay time that can be separated. In addition, for a compound that cannot be dissolved in the solvent system, any solvent that can dissolve the compound may be used (substantially no problem is caused by the solvent effect of the phosphorescence wavelength in the measurement method described above).

[0074] Next, the force that is a method for obtaining the 0_0 band In the present invention, the emission maximum wavelength that appears on the shortest wavelength side in the phosphorescence spectrum chart obtained by the above-described measurement method is expressed as 0-0 band. Define. Since the phosphorescence spectrum is usually weak in intensity, it may be difficult to distinguish between noise and peak when enlarged. In such a case, the emission spectrum during irradiation with excitation light (for convenience, this is called the steady light spectrum) is enlarged and superimposed with the emission spectrum after 100 ms after irradiation with excitation light (for convenience, this is called the phosphorescence spectrum). It can be determined by reading the peak wavelength of the phosphorescence spectrum from the portion of the steady light spectrum derived from the spectrum. In addition, by smoothing the phosphorescence spectrum, noise and peak can be separated and peak wavelength can be read. As the smoothing process, a smoothing method such as Savititzky & Golay can be applied.

[0075] (Luminescent dopant)

The light emitting dopant according to the present invention will be described. As the light-emitting dopant according to the present invention, a fluorescent compound or a phosphorescent compound can be used. From the viewpoint of obtaining an organic EL element with higher luminous efficiency, the light-emitting layer and the light-emitting layer of the organic EL element of the present invention can be used. The light-emitting dopant used in the unit (sometimes simply referred to as a light-emitting material) contains the above host compound and at least one phosphorescent compound. When a fluorescent compound is used in combination, it is preferable to select blue.

[0076] (phosphorescent compound) The phosphorescent compound according to the present invention is a compound in which light emission from an excited triplet is observed.

Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C), and is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C. Is greater than or equal to 0.1. The phosphorescence quantum yield can be measured by the method described in Spectra II, page 398 (1992 edition, Maruzen) of 4th edition, Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescent compound according to the present invention can be measured in any one of the above-mentioned phosphorescence quantum yields (0.01 or more). If it is achieved,

[0077] The light emission of the phosphorescent compound includes two types of principles. One is that the recombination of carriers occurs on the host compound to which carriers are transported, and an excited state of the host compound is generated. This energy is transferred to the phosphorescent compound to obtain light emission from the phosphorescent compound. The other is that the phosphorescent compound becomes a carrier trap, and carrier recombination occurs on the phosphorescent compound, causing phosphorescence. In all cases, the excited state energy of the phosphorescent compound is lower than the excited state energy of the phosphine compound. is there.

[0078] The phosphorescent compound can be appropriately selected and used as a known compound used for the light emitting layer of the organic EL device. The phosphorescent compound according to the present invention is preferably a complex compound containing a group 8 to 10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum). Complex-based compounds) and rare earth complexes, and most preferred are iridium compounds. Specific examples of the compound used as the phosphorescent compound are shown below, but the present invention is not limited thereto. These compounds are synthesized from ί, 列免, Inorg. Chem. 40 卷, 1704-1711 11, etc.

[0079] Specific examples of the compound used as the phosphorescent compound include compounds described in paragraphs [0106] to [0109] of JP-A-2004-311410. The present invention is not limited to these.

[0080] (Fluorescent compound)

Representative examples of fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorine dyes. Examples include cein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

Conventionally known dopants can also be used in the present invention. For example, WO 00/70655, Pamphlet, JP 2002-280178, JP 2001-181616, JP 2002 — 280179, JP 2001-181617, JP 2002-280 180, JP 2001-247859, JP 2002-299060, JP 20 01-313178, JP 2002 — 302671, JP 2001-345183, 2002-324679, WO 02/15645, JP 2002-332291, JP 2002-50484, JP No. 2002-332292, No. 2002-83684, No. 2002-540572, No. 2002-117978, No. 2002-338588, No. 2002-170684, No. 2002 — 3 52960, International Publication No. 01Z93642, JP 2002-50483, JP 2002-100476, JP 2002— JP 173674, JP 2002-359 082, JP 2002-175884, JP 2002-363552, JP 20 02-184582, JP 2003-7469, JP 2002- JP 525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-2 35076 No., JP 2002-241751, JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-100474, JP 2002-203679. JP-A-2002-343572, JP-A-2002-203678, and the like.

[0082] Non-light emitting intermediate layer

The non-light emitting intermediate layer according to the present invention will be described. The non-light emitting intermediate layer according to the present invention refers to the above light emitting layer unit having at least three light emitting layers each having a light emission maximum wavelength force S in the range of 430 to 480 nm, 510 to 550 nm, and 600 to 640 nm, respectively. It is provided between each light emitting layer.

[0083] The film thickness of the non-light emitting intermediate layer is preferably in the range of 1 to 15 nm, and more preferably in the range of 3 to 10 nm to suppress interactions such as energy transfer between adjacent light emitting layers. Moreover, it is preferable from the viewpoint of not giving a large load to the current-voltage characteristics of the element.

[0084] The material used for the non-light emitting intermediate layer may be the same as or different from the host compound of the light emitting layer, but is the same as the host material of at least one of the adjacent light emitting layers. It is preferable that

[0085] The non-emissive intermediate layer may contain a common compound (for example, a host ion compound) with each non-emission light emitting layer, and each common host material (where a common host material is used). Indicates the case where the physicochemical characteristics such as phosphorescence emission energy and glass transition point are the same, or the case where the molecular structure of the host compound is the same.) As a result, the injection barrier of holes and electrons can be easily maintained even when the voltage (current) is changed. It was also found that the effect of improving color shift when voltage (current) was applied was obtained. Furthermore, the host compound contained in each light-emitting layer in the undoped light-emitting layer uses a host material having the same physical characteristics or the same molecular structure. The complexity of manufacturing a certain device can also be eliminated.

[0086] Further, as described above, by using a material in which the lowest excited triplet energy level T1 of the common host material is higher than the lowest excited triplet energy level T2 of the phosphorescent compound, It has been found that a highly efficient device can be obtained because the triplet excitons of the light emitting layer are effectively confined in the light emitting layer. In addition, in the organic EL device of three colors of blue 'green' and red, when a phosphorescent compound is used for each light emitting material, the excited triplet energy of the blue phosphorescent compound is the largest, but the blue A host material having an excited triplet energy larger than that of the phosphorescent compound may be included in the light-emitting layer and the non-light-emitting intermediate layer as a common host material.

[0087] In the organic EL device of the present invention, since the host material is responsible for carrier transport, a material having carrier transport capability is preferred. Although carrier mobility is used as a physical property representing carrier transport ability, the carrier mobility of organic materials generally depends on electric field strength. Since a material with high electric field strength dependency easily breaks the hole-electron injection / transport balance, it is preferable to use a material whose mobility is less dependent on electric field strength for the intermediate layer material and the host material. On the other hand, in order to optimally adjust the injection balance of holes and electrons, It is also preferable that the optical intermediate layer functions as a blocking layer, that is, a hole blocking layer and an electron blocking layer.

[0088] The carrier transport layer and the carrier blocking layer according to the present invention will be described below. The carrier means an electron or a hole. In general, the hole transport layer is made of a material having the ability to transport holes, and includes a hole injection layer and an electron blocking layer in a broad sense. Similarly, the electron transport layer is made of a material having the ability to transport electrons, and includes an electron injection layer and a hole blocking layer in a broad sense.

[0089] 《Support base》

The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) according to the organic EL device of the present invention is not particularly limited in the type of glass, plastic and the like, and is transparent or opaque. There may be. In the case where light is extracted from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and transparent resin film. A particularly preferable support base is a resin film capable of imparting flexibility to the organic EL element.

[0090] Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellose diacetate, cenorelose triacetate, ce / relose acetate butyrate, and cenole mouth. Cellulose acetates such as cellulose acetate propionate (CAP), cellulose acetate phthalate (TAC), cellulose nitrate or their derivatives, polyvinylidene chloride, polybutyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, Polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyethersulfone (PES), polyphenylene sulfide, polysulfones, polyether Cycloolefins such as imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethylmethalylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Abel (trade name, manufactured by Mitsui Chemicals) Resin etc. are mentioned.

[0091] On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of the both may be formed. Water vapor permeability measured by a method based on JIS K 7129-1992 is 0. A barrier film of Olg / m ² 'day atm or less is preferred , Even JIS K 7126- oxygen permeability measured in compliance with the method 1992 is 10- ³ g / m ² / day or less, high barrier water vapor permeability of less than 10- ³ g / m ² / day Film preferably Dearuko and is fitting the water vapor permeability, oxygen permeability to be both less than or equal ^{^{10- 5 g / m 2 / d}} ay, further preferable.

[0092] As a material for forming a barrier film formed on the surface of the resin film in order to obtain a high barrier film, any material may be used as long as it has a function of suppressing intrusion of elements such as moisture and oxygen that cause deterioration of the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Furthermore, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

<< Method for Forming Barrier Film >>

The barrier film formation method is not particularly limited, for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method The ability to use a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, etc. A method using an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferred. . Examples of the opaque support base include metal plates such as aluminum and stainless steel, film opaque resin substrates, and ceramic substrates.

[0094] The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, and is preferably S, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL device / the number of electrons sent to the organic EL device × 100. In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor may be used in combination.

Here, an example of the layer structure of the transparent barrier film used for the support substrate according to the present invention will be described with reference to FIG. 8, and an example of an atmospheric pressure plasma discharge treatment apparatus preferably used for forming the barrier layer will be described. This will be described with reference to FIG.

FIG. 8 is a schematic diagram showing an example of the layer structure of a barrier film (also referred to as a gas barrier film) and its density profile. Barrier film 201 (which may be transparent or opaque) is densely placed on substrate 202. A structure in which layers of different degrees are laminated is adopted. In the present invention, a medium density layer 204 is provided between the low density layer 203 and the high density layer 205, and further, a medium density layer 204 is provided on the high density layer 205. A configuration composed of a density layer, a high-density layer, and a medium-density layer is one unit, and FIG. 8 shows an example in which two units are stacked. At this time, the density distribution in each density layer is uniform, and the density change between the P-contacting layers is stepped. In FIG. 8, the force shown with the medium density layer 204 as one layer may be configured with two or more layers as required. In addition, as a layer structure of the barrier film (gas barrier film) according to the present invention, at least one of three layers having different densities (a high density layer, a medium density layer, and a low density layer) is provided. It is preferable to have 2 or 3 layers of different density, preferably

Here, an atmospheric pressure plasma discharge treatment apparatus as shown in FIG. 9 below is used as an example for forming the high-density layer, the medium-density layer, and the low-density layer. Examples of density setting values for high-density layers, medium-density layers, and low-density layers, materials used for forming each layer (for example, silicon oxide, silicon oxynitride, alumina oxide, etc.) and formation conditions are shown in Examples. Will be described in detail.

FIG. 9 is a schematic view showing an example of an atmospheric pressure plasma discharge treatment apparatus for treating a substrate.

The atmospheric pressure plasma discharge processing apparatus is an apparatus having at least a plasma discharge processing apparatus 230, an electric field applying means 240 having two power supplies, a gas supply means 250, and an electrode temperature adjusting means 260. Fig. 9 shows the distance between the counter electrode (discharge space) between the roll rotating electrode (first electrode) 235 and the square tube type fixed electrode group (second electrode) 236 (each electrode is also called the square tube type fixed electrode 236). Thus, the substrate F is subjected to plasma discharge treatment to form a thin film. In FIG. 9, one pair of rectangular tube type fixed electrode group (second electrode) 236 and roll rotating electrode (first electrode) 235 form one electric field. Form. Figure 9 shows an example of a configuration with a total of five units with such a configuration, and by arbitrarily independently controlling the types of raw materials and output voltage supplied by each unit, A type of noria film (also referred to as a transparent gas nolia layer) can be formed continuously.

[0099] In the discharge space (between the counter electrodes) 232 between the roll rotating electrode (first electrode) 235 and the rectangular tube-shaped fixed electrode group (second electrode) 236, the roll rotating electrode (first electrode) 235 Around 1st power supply 241 The first high-frequency electric field of wave number ω 1, electric field strength VI, current II, and rectangular tube-shaped fixed electrode group (second electrode) 236 has a frequency ω 2 and electric field strength V2 from the corresponding second power source 242. A second high frequency electric field with a current of 12 is applied. A first filter 243 is installed between the roll rotating electrode (first electrode) 235 and the first power source 241. The first filter 243 can easily pass current from the first power source 241 to the first electrode. In addition, the current from the second power source 242 is grounded so that the current from the second power source 242 to the first power source is difficult to pass. In addition, a second filter 244 is installed between the square tube type fixed electrode group (second electrode) 236 and the second power source 242 respectively, and the second filter 244 is connected to the second electrode from the second power source 242. It is designed to facilitate the passage of current, ground the current from the first power supply 241 and make it difficult to pass the current from the first power supply 241 to the second power supply. The roll rotating electrode 235 may be the second electrode, and the square tube fixed electrode group 236 may be the first electrode. In any case, the first power source is connected to the first electrode, and the second power source is connected to the second electrode.

[0100] It is preferable that the first power supply applies higher high-frequency electric field strength (VI> V2) than the second power supply. In addition, the frequency has the ability to be ω ΐ ω 2. Also, the current should be II to 12. Current II of the first high-frequency electric field is preferably 0. 3~20mA / cm ^2, further rather preferably is 1. 0~20mA / cm ^2. The current 12 of the second high-frequency electric field is preferably 10 to 100 mA / cm ² , more preferably 20 to 100 mA / cm ² .

[0101] The gas G generated by the gas generator 251 of the gas supply means 250 is introduced into the plasma discharge treatment vessel 231 through the supply port while controlling the flow rate. Air that is transported by unwinding the base material F from the unillustrated base or front process force Air that is transported and entrained on the base material by the nip roll 265 via the guide roll 264, etc. , And while being in contact with the roll rotating electrode 235, it is transported between the square tube fixed electrode group 236 and the roll rotating electrode (first electrode) 235 and the square tube fixed electrode group (second electrode). Electrode is applied from both of the electrode 236 and discharge plasma is generated between the opposing electrodes (discharge space) 232. Substrate F forms a thin film with a gas in a plasma state while being rolled while being in contact with roll rotating electrode 235. The base material F is transferred to the next process through a nip roll 266 and a guide roll 267, and the force to be scraped off by a scraper (not shown). Discharged treated exhaust gas G 'is discharged from the exhaust port 25 3. During thin film formation, roll rotating electrode (first electrode) 235 and square tube fixed electrode To heat or cool the group (second electrode) 236, the medium whose temperature is adjusted by the electrode temperature adjusting means 260 is sent to both electrodes via the pipe 261 by the liquid feed pump P, and the temperature is adjusted from the inside of the electrode. . Reference numerals 268 and 269 denote partition plates that partition the plasma discharge processing vessel 231 and the outside.

[0102] 《Sealing》

Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support base with an adhesive. The sealing member can be either concave or flat as long as it is arranged to cover the display area of the organic EL element. Also, transparency and electrical insulation are not particularly limited. Specific examples include a glass plate, a polymer plate 'film, and a metal plate' film. Examples of the glass plate include sodalite ash glass, norium strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, norium borosilicate glass, and quartz.

[0103] Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. The metal plate is made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, anorium, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum. Can be mentioned. In the present invention, a polymer film and a metal film can be preferably used because the device can be formed into a thin film.

[0104] Furthermore, the polymer film oxygen permeability 10- ³ g / m ² / day or less, it is preferable that the following water vapor permeability ^{^{10- 5 g / m 2 / day}} . Further, the water vapor permeability, it is more preferable oxygen permeability excessively are both less ^{^{10- 5 g / m 2 / day}} . The sealing member is processed into a concave shape by sandblasting, chemical etching or the like.

[0105] Specific examples of adhesives include photocuring and thermosetting adhesives having reactive bully groups of acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanacrylic acid esters. Can be mentioned. In addition, heat- and chemical-curing types (two-component mixing) such as epoxy type can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned. In addition, organic EL elements are deteriorated by heat treatment Therefore, those that can be adhesively cured from room temperature to 80 ° C are preferable. Further, a desiccant may be dispersed in the adhesive. Application of the adhesive to the sealing portion may be performed using a commercially available dispenser, or may be printed like screen printing.

[0106] Alternatively, the electrode and the organic layer may be coated on the outer side of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer may be formed in contact with the support substrate to form a sealing film. It can be preferred. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of the element such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, etc. Can be used. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.

[0107] The method for forming these films is not particularly limited, for example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster one ion beam method, ion plating method, plasma polymerization method, Atmospheric pressure plasma polymerization, plasma CVD, laser CVD, thermal CVD, coating, etc. can be used. In the gap between the sealing material and the display area of the organic EL device, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil is injected in the gas and liquid phases. Is preferred. A vacuum can also be used.

[0108] In addition, a hygroscopic compound may be enclosed inside. Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, Cobalt sulfate, etc.), metal halides (eg, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (eg, perchloric acid) Barium chlorate, magnesium perchlorate, etc.), and anhydrous salts are preferably used in sulfates, metal halides and perchloric acids.

[0109] 《Protective film, protective plate》

In order to increase the mechanical strength of the device, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween, or the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not limited. However, it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate 'film, metal plate' film, and the like used for the sealing can be used. It is preferable to use a film.

[0110] Anode

As the anode in the organic EL device, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, conductive transparent materials such as Cul, indium tinoxide (IT 0), SnO, and ZnO. IDIXO (In O _Zn〇)

A material such as 2 2 3 that is amorphous and capable of producing a transparent conductive film may be used. For the anode, these electrode materials can be formed into a thin film by vapor deposition or sputtering, and a pattern of the desired shape can be formed by a single photolithography method. A pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. Or when using the substance which can be apply | coated like an organic electroconductive compound, wet film forming methods, such as a printing system and a coating system, can also be used. In the case of taking out light emission from this anode, it is desirable to increase the transmittance to more than 10%, and the sheet resistance as the anode is preferably several hundred Ω / mouth or less. Further, the film thickness is a force depending on the material, usually 10 to 1000 nm, preferably 10 to 200 nm.

[0111] 《Cathode》

On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium Z indium mixture, aluminum Z aluminum oxide (Al O) mixture, indium, lithium Z aluminum mixture, rare earth metal etc.

twenty three

Can be mentioned. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixture, magnesium / Indium mixture, aluminum / aluminum oxide (Al 2 O 3) mixture, lithium /

twenty three

Aluminum mixtures, aluminum and the like are preferred.

[0112] The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / mouth or less, and the preferred film thickness is usually 10 nm to 5 × m, preferably 50 to 200 nm. In order to transmit the emitted light, if either the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

[0113] In addition, after the metal is formed to a thickness of 1 to 20 nm on the cathode, the transparent conductive material described in the description of the anode is formed thereon, whereby a transparent or translucent cathode is manufactured. By applying this, it is possible to produce a device in which both the anode and the cathode are transparent.

[0114] << Light extraction and / or light collecting sheet >>

In particular, for organic EL devices for backlights, it is usually desirable that the light is emitted in all directions and the brightness does not change even if the viewing angle changes, but depending on the type of use, the front brightness is increased. It is desirable to reduce the brightness at large viewing angles (angles observed from an oblique direction). For this purpose, it is preferable to combine a diffuser plate, prism sheet, etc. to control the radiation angle on top of the organic EL element.

[0115] Normally, in an organic EL element that emits light from a substrate (glass substrate, resin substrate, etc.), part of the light emitted from the light emitting layer is totally reflected at the interface between the substrate and air. This causes the problem of loss of light. To solve this problem, the surface of the substrate is processed into a prism or lens, or a prism sheet or lens sheet is applied to the surface of the substrate to suppress total reflection and improve light extraction efficiency. Let

[0116] In the following, preferred forms of the light extraction and Z or condensing sheet will be described. However, in the present invention, the light extraction efficiency can be improved by using these as long as the objective effects are not impaired.

[0117] (1) Configuration in which a diffusion plate and a prism sheet are placed on a glass substrate

For example, in an organic EL device consisting of a glass substrate Z transparent conductive film Z light emitting layer Z electrode Z sealing layer, the first diffusion plate is in contact with the substrate surface opposite to the light emitting layer of the glass substrate. Put. Position the first lens sheet (for example, 3M BEF II) so that the lens surface faces away from the glass substrate so that it is in contact with the diffuser, and then place the second lens sheet on the first lens sheet. The lens is arranged so that it is orthogonal to the lens stripe and the lens surface faces away from the glass substrate. Next, a second diffusion plate is disposed so as to contact the second lens sheet. As the shape of the first and second lens sheets, an octagonal stripe having an apex angle of 90 degrees and a pitch of 50 111 is formed of acrylic resin on a PET base material. Shapes with rounded apex angles (3M RBEF), shapes with randomly changing pitch (3M BEF III), and other similar shapes may be used.

[0118] The first diffusion plate is a film in which beads that diffuse light are mixed on an approximately 100 μm PET substrate. The transmittance is approximately 85% and the haze value is approximately 75%. is there. The second diffusing plate is a film in which beads that diffuse light are mixed on a PET substrate of about 100 μm. The transmittance is about 90% and the haze value is about 30%. is there. The diffusion plate arranged in contact with the glass substrate may be bonded to the glass substrate via an optical adhesive. Further, a layer for diffusing light may be directly applied on the surface of the glass substrate, or a fine structure for diffusing light on the surface of the glass substrate may be provided. Although the glass substrate has been described above, the substrate may be a resin substrate.

[0119] (2) When forming a microlens array on the surface of a substrate

In an organic EL device consisting of a glass substrate / transparent conductive film / light emitting layer / electrode / sealing layer, a microlens array sheet is placed on the surface of the glass substrate opposite to the surface on which the light emitting layer is provided. Paste through. Each microlens array sheet has a 50 / m square shape (pyramid shape) and a microlens whose apex angle is 90 degrees.

[0120] As a sheet manufacturing method, a UV curable resin is injected between a metal mold which is a mother mold of a microlens array and a glass plate placed with a spacer of 0.5 mm. The resin is cured by UV exposure from a glass substrate to obtain a microlens array sheet. Here, as the shape of each microlens, a conical shape, a triangular pyramid shape, a convex lens shape, or the like is applicable. Although described as a structure in which the microlens array sheet is attached to the glass substrate, the microlens array sheet may be attached to the resin substrate. My A configuration in which a transparent electrode / light emitting layer / electrode / sealing layer is provided on the surface opposite to the surface on which the microlens array of the black lens array sheet is provided may be employed.

[0121] (3) Structure in which the microlens array sheet is bonded downward on the surface of the substrate

Glass substrate Z Transparent conductive film Z Light-emitting layer Z electrode In an organic EL device consisting of a Z sealing layer, a microlens array sheet is formed on the surface of the glass substrate opposite to the surface on which the light-emitting layer is provided. Affix with an optical adhesive so that the surface faces the glass substrate. The microlens array sheet has a shape in which microlenses having a structure in which the apexes of a quadrangular shape with a side of 50 x m are flattened are arranged 1J at a pitch of 50 μm. The flat apex is bonded to the surface of the glass substrate. Here, as the shape of each microlens, a conical shape, a triangular pyramid shape, a convex lens shape, or the like is applicable. Although the microlens array sheet has been described as being attached to the glass substrate, the microlens array sheet may be attached to the resin substrate.

[0122] In order to further increase the light extraction efficiency, it is preferable to insert a low refractive index layer between the transparent electrode and the transparent substrate. When a medium with a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower. . Examples of the low refractive index layer include air mouth gel, porous silica, magnesium fluoride, and fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to about 1.7, it is preferable that the low refractive index layer has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less. Also, it is desirable that the thickness of the low refractive index medium is longer than the wavelength in the light medium, preferably more than twice. This is because the effect of the low-refractive index layer is reduced when the thickness of the low-refractive index medium is about the wavelength of light and the electromagnetic wave exuded by evanescent enters the substrate.

[0123] Hereinafter, examples of the low refractive index layer according to the present invention will be described. However, the present invention does not impair the target effect, and is not limited thereto as long as it is within the range.

[0124] (a) When hollow silica is dispersed

A method for producing a glass substrate having a low refractive index layer in which hollow silica is dispersed by a sol-gel method will be described. A low refractive index layer can be formed on a glass substrate by the following procedure. The

[0125] Metal alkoxide (original tetraethyl silicate Si (OC H) [TEOS for short] as a raw material compound

2 5 4

), Ethanol as solvent, acetic acid as catalyst, and water required for hydrolysis, and low refractive index material (Catalyst Chemical Industries, silica particles (refractive index 1.35)) in isopropyl alcohol. Mix the added liquid and dozens. It is kept at C to cause hydrolysis and polycondensation reaction to produce a liquid sol. When the prepared sol is applied onto a glass substrate by spin coating and reacted, it solidifies as a gel. This is further dried in an atmosphere of 150 ° C. to obtain a dry genolet, and the conditions of solution preparation and spin coating are set so that the film thickness at that time becomes 0.5 m. As a result, a low refractive index layer having a film thickness of 0.5 × m and a refractive index of 1.37 is formed.

[0126] Here, as a solution coating method, a force dip coating described as spin coating may be used as long as a uniform film thickness can be obtained. Although an example of a glass substrate is shown as the substrate, since the process temperature is 150 ° C. or less, it can be applied directly on the resin substrate. Further effects can be expected by selecting a lower refractive index as a raw material compound or a low refractive index material and making the resulting low refractive index layer have a refractive index of 1.37 or less. The film thickness is preferably 0.5 μm or more, more preferably 1 μm or more.

[0127] The production of hollow silica is described in, for example, JP-A No. 2001-167637, JP-A No. 2001-233611, and JP-A No. 2002-79616.

[0128] (b) Silica air mouth gel

The transparent low refractive index layer is formed by a silica air mouth gel obtained by supercritical drying of a wet gel formed by a sol-gel reaction of silicon alkoxide. Siri-force air mouth gel is a light-transmitting porous material with a uniform ultra-fine structure. Liquid A was prepared by mixing tetramethoxysilane oligomer and methanol, and liquid B was prepared by mixing water, aqueous ammonia, and methanol. The alkoxysilane solution obtained by mixing the A and B solutions is applied onto the substrate 2. After the alkoxysilane is gelled, it is immersed in a curing solution of water, aqueous ammonia and methanol, and then cured at room temperature for one day and night. Next, the cured gel-like compound is immersed in an isopropanol solution of hexamethyldisilazane, hydrophobized, and then subjected to supercritical drying to form a silica air mouth gel.

[0129] (c) In the case of porous silica A film of low dielectric constant material containing water repellent hexamethyldisiloxane or hexamethyldisilazane as a low refractive index material is applied to a substrate. In addition to water-repellent materials such as hexamethyldisiloxane and hexamethyldisilazane, alcohol or butyl acetate may be added as an additive to the solution of the low dielectric constant material used here, if necessary. . Then, a low refractive index film made of a porous silica material is formed by evaporating the solvent, water, acid, alkali catalyst, surfactant or the like in the solution of the low relative dielectric constant material by a baking treatment or the like. This is washed to obtain a low refractive index film.

[0130] After forming the low refractive index film on the substrate in this way, an intermediate layer is formed on the low refractive index film directly or with a transparent insulating film made of a SiO film by, for example, RF sputtering, afterwards,

2

An IT ○ film is formed on the intermediate layer by DC sputtering to form a substrate with a transparent electrode.

[0131] Further, in order to further improve the light extraction efficiency, for example, as described in Japanese Laid-Open Patent Publication No. 11-283751, a diffraction grating is introduced into an interface or a medium that causes total reflection. It is preferable to use a combination of these methods. For example, a diffraction grating is formed on a glass substrate.

[0132] This method utilizes the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction, such as first-order diffraction and second-order diffraction. Of the light generated from the light, the light that cannot go out due to total reflection between layers is introduced by introducing a diffraction grating into any layer or medium (in the transparent substrate or transparent electrode). Is diffracted to extract light out.

[0133] It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction can be obtained. It is not diffracted, and the light extraction efficiency is greatly improved.

However, by making the refractive index distribution a two-dimensional distribution, the light traveling in all directions is diffracted, and the light extraction efficiency increases. The position where the diffraction grating is introduced may be in any one of the layers or in the medium (in the transparent substrate or transparent electrode) as described above, but is preferably in the vicinity of the light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength in the medium of the light to be amplified. Diffraction grating array is square It is preferable that the arrangement is repeated two-dimensionally, such as a lattice lattice shape, a triangular lattice shape, or a honeycomb lattice shape.

[0135] For example, in order to form a diffraction grating on a glass substrate, a glass-type resist is applied to the surface after washing the glass substrate. Next, two parallel lights of wavelength λ are applied to the resist so as to face each other at an angle of Θ degrees from the vertical direction of the substrate. At this time, interference fringes having a pitch d are formed in the resist. Here, d = / (2cos θ). Using an argon laser with a wavelength of 488 nm, when producing 300 nm as the pitch of the photonic crystal, if both light beams are exposed at an angle of 35.6 degrees from the direction perpendicular to the substrate, a first interference fringe with a pitch of 300 nm is formed. Is done.

[0136] Next, the substrate is rotated 90 degrees in the plane of the substrate to form second interference fringes so as to be orthogonal to the first interference fringes. If the light beam to be exposed is maintained as it is, second interference fringes are formed at a pitch of 300 nm. The resist is exposed with two interference fringes superimposed to form a grid-like exposure pattern. By appropriately setting the exposure power and development conditions, development is performed so that the resist is removed only in the areas where two interference fringes overlap and are strongly exposed. On the glass substrate, a pattern in which the resist is removed in a substantially circular shape is formed in the overlapping part of the lattices with vertical and horizontal pitches of 300 nm each. The diameter of the circle is, for example, 220ηm.

Next, by performing dry etching, a hole having a depth of 200 nm is formed in the portion from which the range has been removed. Thereafter, the resist is removed and the glass substrate is washed.

As described above, a glass substrate is formed in which holes having a depth of 200 nm and a diameter of 220 nm are arranged on the surface at the apexes of square lattices having a pitch of 300 nm. Next, an ITO film with a film thickness of about 300 nm measured from the bottom of the hole is formed by bias sputtering, and the surface irregularities can be flattened to 50 nm or less by appropriately controlling the bias sputtering conditions. it can.

[0139] By polishing the surface of the glass substrate with ITO produced as described above, a glass substrate with ITO for organic EL is formed. In addition to the method of coating and patterning a photoresist on a glass substrate and etching the glass substrate, a glass mold is formed by a similar method, and a UV-curable resist is transferred onto the glass substrate by a nanoimprint method. A method of etching the substrate is also possible. Also, the pattern formed on the glass substrate It is possible to carry out the present invention even on a resin substrate by using as a substrate a substrate that has been transferred to a mold by a method such as a luminaire and transferred to a resin by a nanoimprinting method.

[0140] In the organic EL element using the light extraction and / or condensing sheet as described above, the front luminance amplification factor is increased. The light extracted in this way has a chromaticity of CIE1931 color system of x = 0.33 ± 0.07, y = 0 when the 2 ° C viewing angle front luminance is measured by the above method. It is adjusted to be so-called white light in the region of 33 ± 0.07. Usually, the emission color is classified into blue light emission of 420 nm or more and less than 500 nm, blue light emission of 500 nm or more and less than 550 nm, and red light of 600 nm or more to less than 650 nm.

Accordingly, the front luminance peak value of the organic EL element when there is no light extraction and / or light collection sheet in the present invention is different depending on the material that emits light (substantially a dopant). On the other hand, qualitatively, blue is the smallest ratio.

[0142] In the lifetime in continuous driving or the like, generally, blue is rate-determined, and therefore, when such a light extraction and / or light collecting sheet is used, a longer lifetime can be achieved in the organic EL element. In addition, the driving voltage is limited by blue, which has the largest energy gap between HOMO and LUMO. Therefore, the organic EL element with improved light extraction is designed to require less blue front luminance and drive. The voltage can be lowered.

[0143] That is, since the blue light emitting layer can be made thin and the driving voltage can be lowered, it can have a longer life than when no light extraction and / or condensing sheet is provided. Can get to.

[0144] Here, the amplification factor of the front luminance by the light extraction and / or condensing sheet is measured from the front using a spectral radiance meter (for example, CS-1000 (manufactured by Konica Minolta Sensing)). The light emission brightness (2 ° C viewing angle front brightness) is adjusted so that the optical axis of the spectroradiometer matches the normal from the light emitting surface with and without light extraction and with Z or a light collecting sheet. Measure and integrate in the necessary visible light wavelength range and take the ratio.

[0145] <Method for manufacturing organic EL element>

As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode Z hole injection layer Z hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode will be described. . First, a desired electrode material such as an anode material is formed on a suitable support substrate. A thin film is formed by a method such as vapor deposition or sputtering so as to have a thickness of 1 μΐη or less, preferably 10 200 nm, to produce an anode.

Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, which are organic EL element materials, is formed thereon. As a method of thinning the organic compound thin film, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above. The vacuum deposition method, spin coating method, ink jet method, and printing method are particularly preferred because they are difficult to generate pinholes. Further, different film forming methods may be applied for each layer.

[0147] Film when adopting the deposition, the deposition conditions are different due to kinds of materials used, generally boat temperature 50 450 ° C, vacuum degree. 10 to: 10- ² Pa, deposition rate 0 01 50nmZ seconds, substrate temperature—50 300 C, film thickness 0.15 xm, preferably 5 200 nm, preferably selected appropriately.

[0148] After these layers are formed, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so that the film thickness is 1 μm or less, preferably 50 to 200 nm. The desired organic EL device can be obtained by forming the cathode and providing the cathode. The organic EL element is preferably manufactured from the hole injection layer to the cathode consistently by a single evacuation, but it may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere. Further, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 240 V with the anode as + and the cathode as one polarity. An alternating voltage may be applied. The applied AC waveform may be arbitrary.

[0149] << Application >>

The organic electoluminescence element of the present invention can be used as a display device, a display, or various light sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sensors. Light source, etc. Although not specified, it can be effectively used particularly as a backlight of a liquid crystal display device combined with a color filter and an illumination light source. In the organic electroluminescence element of the present invention, patterning may be performed by a metal mask or an ink jet printing method when forming a film, if necessary. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

[0150] <Display device>

The display device of the present invention will be described. The display device of the present invention is used for a multicolor or white display device. In the case of a multicolor or white display device, a shadow mask is provided only when the light emitting layer is formed, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like. In the case of patterning only the light emitting layer, the method is not limited, but the vapor deposition method, the ink jet method, and the printing method are preferable. When using the vapor deposition method, patterning using a shadow mask is preferable. In addition, the cathode, electron transport layer, hole blocking layer, and light emitting layer unit (having at least three light emitting layers and non-light emitting intermediate layers between the light emitting layers) It is also possible to produce the hole transport layer and the anode in this order.

[0151] When a DC voltage is applied to the multicolor or white display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the anode as + and the cathode as one polarity. wear. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Furthermore, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the single state. The alternating current waveform to be applied may be arbitrary. Light emitting sources include household lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, optical storage media light sources, electrophotographic copying machine light sources, optical communication processor light sources, optical sensor light sources, etc. However, it is not limited to these.

[0152] 《Lighting device》

The lighting device of the present invention will be described. The organic EL device of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a type for directly viewing a still image or a moving image. As a display device (display) May be used. When used as a display device for video playback, either the simple matrix (passive matrix) method or the active matrix method can be used. In the white organic electroluminescence device used in the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned. The light emitting material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display device, the white metal complex according to the present invention is adapted so as to conform to the wavelength range corresponding to the CF (color filter) characteristics. In addition, any one of known light emitting materials may be selected and combined, or may be combined with the light extraction and / or light collecting sheet according to the present invention to be whitened.

As described above, the white organic EL element used in the present invention is combined with the CF (color filter), and the element and the driving transistor circuit are arranged in accordance with the CF (color filter) pattern. As described in claim 11, blue light, green light, and red light are obtained through a blue filter, a green filter, and a red filter using white light extracted from the organic electroluminescence element as a backlight. Thus, a long-life, full-color organic electoluminescence display can be obtained with a low driving voltage, which is preferable.

[0154] In addition to these displays, various light-emitting light sources and lighting devices are also useful for display devices such as backlights for liquid crystal display devices as household lighting, interior lighting, and a kind of lamp such as an exposure light source. Used for. In addition, backlights such as watches, signboard advertisements, traffic lights, light sources such as optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processing machines, light sources for optical sensors, etc. There are a wide range of uses such as household appliances.

Example

[0155] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto.

[0156] Example 1

<< Production of organic EL elements 101 and 102 >>

After patterning a substrate (also called a support substrate) with a 120 nm film of ΙΤΟ (indium oxide) on a glass substrate of 30 mm X 30 mm and a thickness of 0.4 mm as an anode, this I The transparent support substrate with a TO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaned for 5 minutes. This transparent support base was fixed to a substrate holder of a commercially available vacuum deposition apparatus.

[0157] Each of the deposition crucibles in the vacuum deposition apparatus was filled with F4_TCNQ, m_MTDATA, BCz VBi, DPVBi, CBP, phosphorescence G, phosphorescence R, HB, BCP, and CsF, respectively, in the optimum amounts for device fabrication. The crucible for vapor deposition was made of molybdenum or tungsten resistance heating material.

[0158] Then, the pressure was reduced to a vacuum degree 4 X 10- ⁴ Pa, heated by supplying an electric current to the evaporation crucible containing the m_MTDATA and F4_TCNQ, total as volume concentration of F4-TCNQ is 2% uniformly Vapor deposition was performed on the ITO electrode side of the transparent support substrate at a deposition rate of 0. InmZ seconds, and a 40 nm hole injection and transport layer containing an electron acceptor was provided.

[0159] Further, the vaporization crucible loaded with each material was energized so that each layer was formed in the materials and mixing ratios shown in Table 1, and then co-evaporated or vapor-deposited to produce the light-emitting layer 1 and the intermediate layer 1 A light emitting layer 2, an intermediate layer, a light emitting layer 3, a hole blocking layer, and an electron injecting / transporting layer were formed.

[0160] The electron injection / transport layer was deposited on the hole blocking layer at a total deposition rate of 0.1 nm / sec so that the volume concentration of CsF was uniformly 20%, and 30 nm electron injection containing an electron donor was performed. · A transport layer was provided.

[0161] Finally, aluminum lOnm was vapor-deposited to form a cathode, and an organic EL device 101 was produced.

[0162] The organic EL element 102 was produced in the same manner as the organic EL element 101 except that the volume concentration of CsF was uniformly 40%.

FIGS. 1 and 2 show that the CsF volume concentration in the electron injection / transport layer is 20% and 40%, respectively, depending on the film thickness from the cathode toward the hole blocking layer.

[0164] Finally, the vapor deposition surface side is covered with a glass case, and a glove box in a nitrogen atmosphere (with an atmosphere of high-purity nitrogen gas with a purity of 99.999% or higher is used without contacting the organic-electric luminescence element 101 with the atmosphere). (Below). 10 and 11 are schematic views and cross-sectional views of the lighting device. In FIG. 11, 15 indicates a cathode, 16 indicates an organic EL layer, and 17 indicates a glass substrate with a transparent electrode. The glass cover 12 is filled with nitrogen gas 18 and a water catching agent 19 is provided. ing.

[0165] << Production of organic EL elements 103 to 111 >>

As shown in Figs. 3-7, the organic EL devices 103-107 change the volume concentration of CsF in the electron injection / transport layer according to the film thickness in the direction from the cathode to the hole blocking layer. Each component in the injection / transport layer was fabricated in the same manner as the organic EL device 101. The organic EL element 108 was manufactured in the same manner as the organic EL element 107 except that Fir (pic) was used instead of BCzVBi in the light emitting layer 1.

[0166] Organic EL devices 109 to 111 were prepared in the same manner except that in the organic EL device 108, BCP in the electron injection and transport layer was replaced with H_3, H_7, and compound (1), respectively.

[0167] Specifically, for example, for the organic EL element 103, the CsF volume is 14 nm from the cathode side out of the total film thickness of 30 nm of the electron injection / transport layer under the condition of a total deposition rate of 0.1 nm / sec. The concentration was adjusted to 20%, then 2nm was reduced to 50%, and then back to 20% at 14nm. The organic EL elements 104 to 111 were produced in the same manner.

[0168] Further, sealing was performed in the same manner as the organic EL element 101, and a lighting device was manufactured.

[0169] [Chemical 4]

i VIVOSE I

Tomb [0

[0171] [Table 1]

[0172] The numbers in parentheses in Table 1 represent mass%. [0173] << Evaluation of organic EL elements >>

The front luminance of each element produced as described above was evaluated. Wherein all elements, 2 ° C Field of view angle front luminance chromaticity Χ = 0 · 33 ± in CIE1931 color system at ^{1000cd / m 2 0. 07,} Υ = 0. 33 range of ± 0. 07 And it was confirmed to be white. The light emission conditions of the device were measured at a constant luminance (lOOOOcdZcm ² ), and the obtained drive voltage results are shown in Table 2. In addition, the luminance half-life at the initial luminance (lOOOOcdZcm ² ) was evaluated, and the results are shown in Table 2.

[0174] [Table 2]

[0175] From Table 2, when the high-concentration region is locally provided in the organic EL elements 103 to 105 at 2 nm near the center with respect to the thickness of the electron injection and transport layer of 30 nm, the drive voltage tends to increase slightly. Is seen, but current efficiency is improved. When comparing the organic EL elements 104 and 106, the degree of power saving was almost the same, but an improvement over the uniform concentration was observed. In addition, when the CsF concentration on the anode side was lowered as in the case of the organic EL element 107, a power saving effect was observed, and an improvement in the driving life was recognized. This is a surprising effect that was unexpected. Furthermore, the organic EL elements 109 to 111 changed to H_3, H_7, and compound (1) in place of BCP showed an effect of improving the driving voltage life.

Claims

The scope of the claims

[1] In an organic electroluminescence device composed of an anode, at least one organic layer and a cathode on a substrate, at least one of the organic layers contains an electron donor, and the volume of the electron donor in the organic layer An organic electoluminescence device having an electron donor concentration region having a concentration (%) of 5 to 95% and a difference of 5% or more.

[2] The organic electoluminescence device according to claim 1, wherein the difference between the maximum concentration and the minimum concentration of the volume concentration (%) containing the electron donor is 20 to 90%. .

[3] The thickness of the region containing the maximum concentration or the minimum concentration of the electron donor is 1/100 to 1/4 of the thickness of the organic layer containing the electron donor. The organic electoluminescence device according to claim 1 or claim 2.

[4] The electron donor volume in a region where the distance between the organic layer containing the electron donor and the adjacent layer interface on the anode side is within 1/3 of the film thickness of the organic layer containing the electron donor. The organic electoluminescence device according to any one of claims 1 to 3, wherein the concentration (%) is 10% or less.

[5] The organic electoluminescence device according to any one of [1] to [4], wherein there are at least three electron donor concentration regions different by 5% or more.

[6] The organic electroluminescent device according to any one of [1] to [5], wherein the organic layer containing the electron donor is in contact with the cathode.

7. The power according to any one of claims 1 to 6, wherein the organic layer has a light emitting layer containing a light emitting dopant (phosphorescent compound) that emits at least one kind of phosphorescence. The organic-elect mouth luminescence element of description.

[8] The organic layer according to any one of claims 1 to 6, wherein the organic layer includes a light emitting layer containing a phosphorescent compound and a light emitting layer containing a fluorescent compound. Organic electoluminescence element.

[9] The light emitting layer containing the fluorescent compound emits blue light. 9. An organic electoluminescence device according to item 8.

[10] The organic electoluminescence device according to any one of [1] to [9], which emits white light.

[11] A blue light, a green light, and a red light are obtained from white light extracted from the organic electoluminescence device according to claim 10 through a blue filter, a green filter, and a red filter. Organic-elect luminescence display.