JP5168762B2 - Method for manufacturing organic electroluminescence element - Google Patents

Description

  The present invention relates to a method for manufacturing an organic electroluminescence element (hereinafter also referred to as an organic EL element). In detail, it is related with the washing | cleaning method of the board | substrate which forms an organic EL element.

  In recent years, the use of organic EL elements for light sources such as display devices such as flat displays, electrophotographic copying machines, and printers has been studied.

  This organic EL element is a current-driven light-emitting element that emits light by flowing a very thin thin film of a fluorescent organic substance between a first electrode (hereinafter also referred to as an anode) and a second electrode (hereinafter also referred to as a cathode). is there. Usually, the organic substance is an insulator, but by making the film thickness of the organic layer very thin, current can be injected and it can be driven as an organic EL element. It can be driven at a low voltage of 10 V or less, and it is possible to obtain highly efficient light emission.

  In particular, phosphorescent organic EL devices using excited triplets that far exceed the efficiency of conventional organic EL devices using excited singlets have been disclosed by S.C. R. Forrest et al. (Appl. Phys. Lett. (1999), 75 (1), 4-6). Furthermore, C.I. As reported by Adachi et al. (J. Appl. Phys., 90, 5048 (2001)), such an element is used not only for a display but also for illumination. Application to is expected.

  In organic EL elements, the organic layer is very thin, so it is easily affected by the smoothness of the substrate (hereinafter also referred to as support, substrate, substrate, and support substrate), and dust (fine dust) adhering to the electrode surface It is affected by the roughness of the electrode surface due to foreign matters such as.

  The roughness of the electrode surface due to the foreign matter causes the leakage of current between the first electrode and the second electrode. If there is a current in the reverse direction, that is, a leakage current, display of organic EL elements such as crosstalk and luminance unevenness. This leads to a decrease in quality, and further energy consumption that does not contribute to light emission such as heat generation of defective elements occurs, resulting in a decrease in light emission efficiency.

  Furthermore, in the formation of the organic layer, the electrode short-circuit is caused by the non-deposited portion or the thin film portion which is shadowed by the protrusion due to the roughness of the electrode surface due to the foreign matter, and the dielectric breakdown due to the current short circuit of the electrode short or thinned portion. There is a problem that occurs.

  The following techniques are disclosed regarding the above problems.

  The surface roughness of the hole injection electrode on the side in contact with the organic compound layer is defined as 5.0 nm or less, the maximum roughness is defined as 55 nm or less, and the diameter of the foreign matter adhering to the surface is defined as 3 μm or less (for example, see Patent Document 1). ).

In the support substrate for an organic EL element, the total number of defects such as foreign matters, projections, holes, holes and the like of 1 μm or more in the film, the interface between the film and the electrode, and the electrode surface is 100 or less in terms of conversion value per 1 m ^2. (See, for example, Patent Document 2).

  The film thickness from the surface of the first electrode to the outer surface of the protective film in the portion where the foreign matter on the first electrode corresponding to the organic EL layer does not exist is larger than the size of the foreign matter present on the first electrode ( For example, see Patent Document 3).

  By providing a leak prevention layer that increases in resistance as the temperature rises in one layer of the organic layer, current concentration to a certain place in the organic layer is prevented and destruction of the organic EL element is prevented (see, for example, Patent Document 4). ).

  A single-layer or multi-layer organic layer constituting the element is formed on the surface of the transparent conductive film of the transparent conductive substrate that has been cleaned so that the contact angle of water is less than 25 ° (for example, Patent Documents) 5).

After forming the wiring electrode on the substrate, the substrate is cleaned by spraying dry ice particles on the substrate together with the high-speed fluid in any process until the organic layer is formed, and spraying the dry ice particles on the EL substrate. Fine particles adhering to the top are removed (for example, see Patent Document 6).
JP 2002-75660 A JP-A-6-124785 JP 2004-362912 A JP 2004-95388 A JP 7-220873 A JP 2003-31362 A

  As described above, the organic EL element is affected by the roughness of the electrode surface, and if a leakage current due to the roughness of the electrode surface is generated, the display quality of the organic EL element is degraded. Therefore, it is necessary to remove foreign matter and suppress the roughness of the electrode surface. Known methods for removing foreign matter on the electrode surface include dry cleaning and wet cleaning.

  On the other hand, Patent Documents 1 and 2 define the surface roughness of the electrode and the surface-attached foreign matter, but do not mention means for achieving it. A board that satisfies the conditions is sampled to determine whether it is good or bad, but many boards may be defective. Moreover, it becomes a factor which reduces production efficiency, such as wash | cleaning or removing a defective board | substrate again.

  In Patent Document 3, it is possible to eliminate pinholes in the protective layer by forming the film thickness from the surface of the first electrode to the outer surface of the protective film larger than the size of the foreign matter existing on the first electrode. Although it is possible to prevent moisture and oxygen from entering the organic layer, it is difficult to suppress leakage due to a short circuit between the electrodes. In addition, no measures have been taken to remove foreign matter.

  In Patent Document 4, the leakage current is suppressed, but the high resistance portion does not emit light, and the light emitting area is reduced. In addition, since the leak prevention layer is provided, the production process increases and becomes complicated, resulting in a decrease in productivity.

  In Patent Document 5, it is difficult to detect the presence or absence of foreign matter by the method of detecting the contamination state of the substrate surface with the contact angle of water.

  In Patent Document 6, since cleaning is performed by spraying dry ice particles on a substrate together with a high-speed fluid, damage to the substrate electrode such as electrode peeling due to collision of dry ice particles is large, and cleaning equipment is complicated and expensive, resulting in a low cleaning cost. Incurs an increase.

  The present invention has been made in view of the above situation, and in the substrate cleaning step after electrode formation in the organic EL element, the dry cleaning and the wet cleaning are combined, and the foreign cleaning is effectively performed by performing the wet cleaning after the dry cleaning. An object of the present invention is to provide a method of manufacturing an organic EL element capable of suppressing leakage current due to a short circuit between electrodes by improving the cleaning performance of the substrate electrode surface.

  Moreover, it aims at providing the manufacturing method of the organic EL element which has the washing | cleaning process suitable for organic EL element manufacture by a roll-to-roll system.

The above object is achieved by the following configuration.
(Claim 1)
In the method for producing an organic electroluminescent element, wherein at least a first electrode and a light emitting layer composed of an organic substance and a second electrode are formed on a substrate.
A cleaning process comprising a dry cleaning process and a wet cleaning process for cleaning the first electrode of a substrate formed by forming a first electrode on the substrate; and the cleaning process includes the dry cleaning process, the wet cleaning process, and the dry cleaning process the have rows successively in this order, the method of manufacturing the organic electroluminescent device solvent used for the wet cleaning, characterized in that ultrapure water.
(Claim 2)
The method for producing an organic electroluminescent element according to claim 1, wherein the wet cleaning is performed by setting the contact angle of water on the surface of the substrate electrode to 45 ° or less in the dry cleaning.
(Claim 3)
3. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the dry cleaning method is at least one of ultraviolet ozone cleaning and plasma cleaning.
(Claim 4)
The wet cleaning method is at least one of cleaning bath immersion, ultrasonic cleaning bath immersion, flowing water cleaning bath immersion, flowing water ultrasonic cleaning bath immersion, flowing water shower, and flowing water ultrasonic shower method. The manufacturing method of the organic electroluminescent element of any one of Claims 1 thru | or 3 characterized by these .
( Claim 5 )
The washing step, the organic electroluminescent device according to any one of claims 1 to 4, characterized in that washing the continuous sheet-like substrate while web transport the continuous sheet-like substrate in a roll-to-roll method Production method.
(Claim 6 )
An organic layer film forming step on the same web conveyance line as the washing step, and after washing in the washing step, at least one organic layer on the continuous sheet-like substrate electrode in the same web conveyance line The method of manufacturing an organic electroluminescence element according to claim 5 , wherein the film is formed.

  With the above configuration, in the cleaning of the substrate electrode surface in the manufacture of the organic EL element, by performing dry cleaning before wet cleaning, organic contamination of the substrate electrode surface is removed, and the contact angle of water is set to 45 ° or less. The foreign particles embedded in the organic contamination can be efficiently removed by the next wet cleaning. In addition, stable foreign substance removal performance can be ensured and the cleaning process can be shortened.

  In addition, as described above, organic contamination is removed by dry cleaning, and the contact angle of water is set to 45 ° or less, so that the solvent used for wet cleaning can be efficiently removed only with an aqueous solvent, and continuously. It is possible to shorten the continuous cleaning process line in the roll-to-roll method in which the sheet-like substrate is conveyed on the web to manufacture the organic EL element.

  According to the above, it becomes possible to manufacture an organic EL element having a stable quality with no leakage current during driving and high production efficiency, and it is possible to improve the light emission efficiency and life of the organic EL element.

  The constituent layers and general configuration of the organic EL panel according to the present invention and the mode of the method for manufacturing the organic EL panel will be sequentially described below.

  In addition, in FIG. 5, as an example of the organic EL panel according to the present invention, the layer configuration of the passive matrix type full-color organic EL element (FIG. 5A) and the direction of arrow A in FIG. Although the front view (FIG. 5B) is shown, the organic EL panel according to the present invention is not limited to this.

  In the full color organic EL panel 900, an anode 902, a hole transport layer 903, a light emitting layer 904, an electron transport layer 905, and a cathode 906 are formed in a pattern on the support 1, respectively, and the support 1, the barrier film 907, and the adhesion are formed. A layer 908 encloses each of these layers.

<Structure layers and general structure of organic EL elements>
Although the preferable specific example of the laminated constitution of the organic electroluminescent panel which concerns on this invention is shown below, it is not limited to the following forms.
(1) Anode / light emitting layer unit / electron transport layer / cathode (2) Anode / hole transport layer / light emitting layer unit / electron transport layer / cathode (3) Anode / hole transport layer / light emitting layer unit / hole blocking Layer / electron transport layer / cathode (4) anode / hole transport layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer (hereinafter also referred to as electron injection layer) / cathode (5) anode / Anode buffer layer (hereinafter also referred to as hole injection layer) / hole transport layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode Here, the light emitting layer unit has a light emission maximum. At least one of the light emitting layers having wavelengths of 430 nm to 480 nm, 510 nm to 550 nm, and 600 nm to 640 nm, respectively.

  In the case of a white backlight (hereinafter also referred to as white BL), the light emitting layer unit patterns each color in the case of a full color by using a laminate of each color light emitting layer or a mixed material of each color light emitting material. Is achieved.

"anode"
As the anode in the organic EL element, 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, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by photolithography, or the pattern accuracy is not so required. (About 100 μm or more), the 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 electroconductivity compound, wet film forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"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 / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. 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, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. 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 / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

  Next, an injection layer, a blocking layer, an electron transport layer, and the like used as a constituent layer of the organic EL element of the present invention will be described.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to lower drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (November 30, 1998, NTS Corporation) Issue) ”, Chapter 2,“ Electrode Materials ”(pages 123 to 166) in detail, and a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer) are is there.

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, and the like. Specific examples thereof include copper phthalocyanine. Phthalocyanine buffer layer typified by, oxide buffer layer typified by vanadium oxide, amorphous carbon buffer layer, polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene Etc.

  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. Specifically, strontium or aluminum Metal buffer layer represented by lithium fluoride, alkali metal compound buffer layer represented by lithium fluoride, alkaline earth metal compound buffer layer represented by magnesium fluoride, oxide buffer represented by aluminum oxide Layer and the like. The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm, although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
As described above, the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film. For example, as described in JP-A Nos. 11-204258 and 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT Corporation on November 30, 1998). There is a hole blocking layer that is applied.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer as needed.

  In general, the hole blocking layer of the organic EL device is preferably provided adjacent to the light emitting layer.

  In the case of having a plurality of light emitting layers having different emission colors, 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. It is preferable to additionally provide a hole blocking layer between the light emitting layer and the light emitting layer next to the anode next to the shortest wave light emitting layer. Furthermore, 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 0.3 eV or more higher than the host compound of the shortest wave emitting layer.

The ionization potential is defined by the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by the following method, for example.
(1) Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), which is molecular orbital calculation software manufactured by Gaussian, USA -The ionization potential can be obtained as a value obtained by rounding off the second decimal place of a value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G * as a word. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.
(2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. Examples of the measurement method using photoelectron spectroscopy include a method using a low energy electron spectrometer “Model AC-1” (manufactured by Riken Keiki Co., Ltd.). It is also possible to use a measurement method by ultraviolet photoelectron spectroscopy.

  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 having a function of transporting holes while having a very small ability to transport electrons, and transporting electrons while transporting holes. By blocking, the recombination probability 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 nm to 100 nm, and more preferably 5 nm to 30 nm.

<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 in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

(Host compound)
The light emitting layer of the organic EL device of the present invention preferably contains the following host compound and phosphorescent compound (also referred to as phosphorescent compound).

  Here, in the present invention, the host compound is a compound contained in the light emitting layer, the mass ratio in the layer is 20% or more, and phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.). A rate is defined as a compound of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. In addition, by using a plurality of phosphorescent compounds, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to illumination and backlight.

  As these known host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing the emission of longer wavelengths, and having a high Tg (glass transition temperature) are preferable.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  In the present invention, it has a plurality of light emitting layers, but it is preferable that 50% by mass or more of the host compound in each layer is the same compound because it is easy to obtain a uniform film property over the entire organic layer. It is preferable that the phosphorescence emission energy of the compound is 2.9 eV or more because it is advantageous for efficiently suppressing energy transfer from the dopant and obtaining high luminance.

(Phosphorescent compound (phosphorescent compound))
The material used for the light emitting layer (hereinafter referred to as the light emitting material) preferably contains a phosphorescent compound at the same time as the host compound. Thereby, it can be set as an organic EL element with higher luminous efficiency.

  The phosphorescent compound according to the present invention is a compound in which light emission from an excited triplet is observed, is a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 0.2 at 25 ° C. 01 or more compounds. The phosphorescence quantum yield is preferably 0.1 or more. The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield used in the present invention only needs to achieve the above phosphorescence quantum yield in any solvent.

  There are two types of light emission of the phosphorescent compound in principle. One is the recombination of the carrier on the host compound to which the carrier is transported and the excited state of the host compound is generated, and this energy is phosphorescent. An energy transfer type in which light emission from the phosphorescent compound is obtained by transferring to the compound, and another is that the phosphorescent compound becomes a carrier trap, and carrier recombination occurs on the phosphorescent compound and the phosphorescent compound In any case, the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of the organic EL device.

  The phosphorescent compound used in the present invention is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex). System compounds), rare earth complexes, and most preferred are iridium compounds.

  Although the specific example of a phosphorescent compound is shown below, this invention is not limited to these. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  In the present invention, the phosphorescence emission maximum wavelength of the phosphorescent compound is not particularly limited, and can be obtained in principle by selecting a central metal, a ligand, a ligand substituent, and the like. The emission wavelength can be changed.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates.

The white element referred to in the present invention means that the chromaticity in the CIE 1931 color system at 1000 Cd / m ² is X = 0.33 ± 0.77 when the front luminance at 2 ° viewing angle is measured by the above method. It is in the region of Y = 0.33 ± 0.77.

  The light emitting layer can be formed by forming the above compound by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, and an ink jet method.

  In the white panel, it is preferable that the light emitting layer includes at least three layers having different emission spectra having emission maximum wavelengths in the range of 430 nm to 480 nm, 510 nm to 550 nm, and 600 nm to 640 nm, respectively. If it is three or more layers, there will be no restriction | limiting in particular. When there are more than four layers, there may be a plurality of layers having the same emission spectrum. A layer having an emission maximum wavelength in the range of 430 nm to 480 nm is referred to as a blue light emitting layer, a layer in the range of 510 nm to 550 nm is referred to as a green light emitting layer, and a layer in the range of 600 nm to 640 nm is referred to as a red light emitting layer.

  The total thickness of the light emitting layer is not particularly limited, but is usually 2 nm to 5 μm, preferably 2 nm to 200 nm. In the present invention, it is preferably in the range of 10 nm to 20 nm. If it is too thin, it is difficult to obtain film uniformity. If it is thicker than this, a high voltage is required to obtain light emission, which is not preferable. A film thickness of 20 nm or less is preferable because it has the effect of improving the stability of the emission color with respect to the driving current as well as the voltage surface.

  The film thickness of each light emitting layer is preferably selected in the range of 2 nm to 100 nm, and more preferably in the range of 2 nm to 20 nm. Although there is no restriction | limiting in particular about the film thickness relationship of each light emitting layer of blue, green, and red, It is preferable that the blue light emitting layer (the sum total when there are multiple layers) is the thickest among three light emitting layers.

  Moreover, in the range which maintains the said maximum wavelength, you may mix a several luminescent compound in each light emitting layer. For example, the blue light emitting layer may be used by mixing a blue light emitting compound having a maximum wavelength of 430 nm to 480 nm and a green light emitting compound having the same wavelength of 510 nm to 550 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazol derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives Fluorenone derivatives, 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 a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) qua -Dryphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N- Diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and further described in US Pat. No. 5,061,569 Having two condensed aromatic rings in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] trimethyl triphenylamine unit described in Japanese Patent No. 8 is linked in three starburst types. Phenylamine (MTDATA) etc. are mentioned.

  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. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) 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 is 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. Can do. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazol derivatives, and the like. Further, in the above oxadiazol derivative, a thiadiazol derivative in which the oxygen atom of the oxadiazol 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. it can. 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.

  Also, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo). -8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc. , And metal complexes in which the central metal of these metal complexes is replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as the electron transport material. 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 transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC can be used. A semiconductor can also be used as an electron transport material.

  The electron transport layer can be formed by thinning the electron 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. . Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, an electron transport layer having high n property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

<Support>
In general, the support that can be used in the organic EL element is not particularly limited in the type of glass, plastic, and the like, and may be transparent or opaque. Examples of the support include glass plates, polymer plates and films. The shape of the support may be a single sheet or a continuous strip.

  In the case where light is extracted from the support side, the support is preferably transparent. Examples of the transparent support preferably used include glass, quartz, and a transparent resin film.

  Examples of the glass plate include soda lime glass, barium strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz glass.

  Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone.

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulosic triacetate, and cellulose acetate. Cellulose esters such as tobutyrate, cellulose acetate propionate (CAP), cellulose acetate phthalate (TAC), and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol Polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyethersulfone (PES), polyphenylene sulfide, polysulfones, Lier Terimide, Polyether Ketoneimide, Polyamide, Fluororesin, Nylon, Polymethylmethacrylate, Acrylic or Polyarylate, Aton (trade name, manufactured by JSR) or Apel (trade name, manufactured by Mitsui Chemicals) ) And the like. An inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film, and it is preferably a barrier film having a water vapor permeability of 0.01 g / m ² / day / atm or less. Furthermore, a high barrier film having an oxygen permeability of 10 ⁻³ ml / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing intrusion of an element such as moisture or oxygen that causes deterioration of the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, 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.

  The method for forming the barrier film is not particularly limited. For example, a vacuum deposition method, a sputtering method, a reactive sputtering method, a molecular beam epitaxy method, a cluster ion beam method, an ion plating method, a plasma polymerization method, a large size, and the like. An atmospheric pressure plasma polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma weight as described in JP-A-2004-68143 is used. A legal method is particularly preferred.

  Examples of the opaque support include metal plates / films such as aluminum and stainless steel, opaque resin substrates, and the like.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support body with an adhesive agent can be mentioned, for example.

  Generally, the sealing member may be disposed so as to cover the display area of the organic EL element, and may be a concave plate shape or a flat plate shape. Further, 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 soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum. In the present invention, a polymer film and a metal film can be preferably used because the support has flexibility and the device can be thinned. Furthermore, the polymer film preferably has an oxygen permeability of 10 ⁻³ ml / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less.

  Specific examples of adhesives include photocuring and thermosetting adhesives having reactive vinyl groups of acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. Can be mentioned. Moreover, the heat | fever and chemical curing types (two-component mixing), such as an 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, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use a commercially available dispenser, and may print it like screen printing.

  In addition, it is also preferable to coat the electrode and the organic layer on the outside of the electrode facing the support with the organic layer interposed therebetween, and form an inorganic or organic layer in contact with the support to form a sealing film. it can. 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, or the like is used. it can. Furthermore, 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. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, An atmospheric pressure plasma polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil is injected in the gas phase and the liquid phase. Is also possible. A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (eg, 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, barium perchlorate, In particular, anhydrous salts are preferably used in sulfates, metal halides and perchloric acids.

《Light extraction processing》
An organic electroluminescence element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1), and only 15% to 20% of the light generated in the light emitting layer. It is generally said that it cannot be taken out. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the side surface of the device.

  As a technique for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (for example, US Pat. No. 4,774,435). A method for improving efficiency by providing a substrate with a light condensing property (for example, JP-A-63-314795). A method of forming a reflective surface on the side surface of the element (for example, Japanese Patent Laid-Open No. 1-220394). A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between a substrate and a light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691). A method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter (for example, JP-A-2001-202827). There is a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside) (for example, JP-A-11-283951).

  These methods can be used in combination with the organic electroluminescence device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, a transparent electrode layer, and light emission A method of forming a diffraction grating between any of the layers (including between the substrate and the outside) can be suitably used.

  By combining these means, it is possible to obtain an element having higher luminance or durability.

  When a low refractive index medium 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 aerogel, porous silica, magnesium fluoride, fluorine polymer, and the like. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method is generated from the light emitting layer by utilizing 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 or second-order diffraction. Of the light, light that cannot go out due to total reflection between layers, etc., is diffracted by introducing a diffraction grating in any layer or medium (in the transparent substrate or transparent electrode) It tries to take out light.

  The introduced diffraction grating desirably 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 is diffracted. The light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic 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 of light in the medium.

  The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condensation sheet>
When the organic electroluminescence device of the present invention is used for a surface light source, it is processed so as to provide, for example, a structure on a microlens array on the light extraction side of the substrate, or combined with a so-called condensing sheet. Thus, by focusing light in a specific direction, for example, in the front direction with respect to the element light emitting surface, the luminance in the specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, an LED backlight of a liquid crystal display device that is put into practical use can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Ltd. can be used. As the shape of the prism sheet, for example, the base material may be formed with a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or the apex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use a light diffusing plate and a film together with a condensing sheet. For example, a diffusion film “light up” (manufactured by Kimoto Co., Ltd.) can be used.

<Embodiment of the manufacturing method of the organic EL element which concerns on this invention>
Next, an embodiment of a method for producing an organic EL panel according to the present invention will be described. The present invention is not limited to the following embodiments.

  Although the example of the layer structure of the organic EL panel is described in the preferred specific example of the layer structure of the organic EL panel described above, in this embodiment, an electrode material such as ITO (indium tin oxide) is formed on the substrate according to the present invention. The electrode layer cleaning step and the organic layer forming step from the cleaning step where the first electrode (anode) is formed by patterning by photoetching and the like will be described.

(Embodiment 1)
FIG. 1 is a schematic diagram of Embodiment 1 of a cleaning process in which dry cleaning and wet cleaning are combined.

  As shown in FIG. 1, the substrate 1 on which the first electrode is formed is dry-cleaned by a dry-cleaning device 21 to remove organic contaminants so that the contact angle of water on the substrate electrode is 45 ° or less. When dry cleaning is not sufficient and organic contamination residue is generated, the contact angle of water on the substrate electrode exceeds 45 °, which reduces the efficiency of the next wet cleaning.

  The dry cleaning is performed by at least one of ultraviolet ozone cleaning and plasma cleaning. Ultraviolet ozone cleaning is a method of generating active oxygen using ultraviolet rays and simultaneously decomposing, oxidizing and volatilizing and removing organic substances adhering to the substrate surface. There are a method using an excimer lamp, a method using a low-pressure mercury lamp, and the like. Plasma cleaning is a method in which a high frequency is applied to oxygen gas or argon gas to generate plasma, and the substrate surface is irradiated and cleaned by a chemical reaction.

  FIG. 2 is an example of a dry cleaning apparatus for the single wafer sheet substrate 1 using ultraviolet ozone cleaning. The substrate 1 is placed on the transport means C1 such as a conveyor, transported to the ultraviolet ozone cleaning device 21, and dry cleaning is performed while transporting. The substrate may be placed on a fixed table or the like and cleaned without transporting the substrate. In this embodiment, a 200 W low-pressure mercury lamp (manufactured by Sen Special Light Source Co., Ltd.) is used to perform a cleaning process with an irradiation distance of 10 mm and an irradiation time of 1 minute, and the contact angle of water on the substrate electrode surface is set to 45 ° or less. Yes.

  Since the contact angle of water on the surface of the substrate electrode is difficult to measure while washing, cleaning and measurement are separately performed on the sample substrate, and the cleaning condition is set such that the contact angle of water is 45 ° or less. Do.

  The contact angle of water is measured with a contact angle meter (DropMaster 700 manufactured by Kyowa Interface Science Co., Ltd.) based on the test method of JIS R 3257 standard.

  The substrate 1 that has been dry-cleaned by the dry-cleaning device 21 is wet-cleaned by the wet-cleaning device 22. Foreign particles embedded in organic contamination should be removed efficiently by wet cleaning because organic contamination is removed by dry cleaning as described above and the contact angle of water on the substrate electrode is 45 ° or less. Can do. Moreover, the solvent used for washing | cleaning can be performed only with an aqueous solvent.

  The wet cleaning is performed by at least one of an ultrasonic cleaning bath immersion, a flowing water cleaning bath immersion, a flowing ultrasonic cleaning bath immersion, a flowing shower, and a flowing ultrasonic shower method.

  The ultrasonic cleaning bath immersion method is a method of cleaning by immersing the substrate 1 in an ultrasonic cleaning bath in which a solvent is stored. The flowing water type washing bath immersion method is a method in which the substrate 1 is immersed and washed in a flowing washing bath. The flowing water type ultrasonic cleaning bath immersion method is a method in which ultrasonic vibration is applied to the solvent in the cleaning bath by the ultrasonic wave generating means to perform cleaning in the flowing water type cleaning bath immersion method. The flowing water shower method is a method in which a solvent is sprayed onto the substrate 1 from a shower nozzle for cleaning. The flowing water type ultrasonic shower method is a method of cleaning by adding ultrasonic vibration to the solvent sprayed in the flowing water type shower method by ultrasonic generating means.

  The foreign particle size and the number of particles in the solvent are preferably 1500 particles / ml or less with a foreign particle size of 0.5 μm or more. The foreign particle size of less than 0.5 μm is difficult to manage and can be omitted by managing the number of particles having a foreign particle size of 0.5 μm or more. When the number of particles having a foreign particle size of 0.5 μm or more exceeds 1500 / ml, a leak current is likely to occur when the organic EL element is driven.

  FIG. 3 shows an example of wet cleaning using a flowing water type ultrasonic shower.

  The substrate 1 is held by a substrate holding means (not shown) of the cleaning tank 221, and the aqueous solvent B 1 is supplied from the solvent storage container 224 to the cleaning surface of the substrate 1 through the shower nozzle 222 by the supply pump P 1 by the flowing water shower method. Wash 1 Ultrasonic vibration is applied to the shower of the solvent B1 by the ultrasonic generator 223. The substrate 1 is always held above the uppermost liquid surface of the cleaning tank 221 so as not to contact the solvent B1 stored in the cleaning tank 221.

  The solvent B1 that has been subjected to substrate cleaning by the flowing water shower method is dropped and stored in the cleaning tank 221. The accumulated solvent B1 is transferred by the pump P2, returned to the solvent storage container 224 through the filter 225, and circulated. The circulating solvent B1 may be returned directly to the supply path as shown by the broken line in FIG.

  The number of foreign particles of the solvent B1 in the cleaning tank 221 is measured every predetermined time by an LPC (particle number measuring means) 51. The interval of the predetermined time can be appropriately set according to the specifications of the cleaning process. In this embodiment, it is every 10 seconds. Based on the measured data, the analysis unit 52, which is a particle number analysis means, analyzes the number of particles per unit volume. The analysis data is sent to the calculation unit 53, and a predetermined determination method, for example, the analysis data is determined in advance. The substrate cleanliness is determined based on whether the analysis data is changed over time or the like.

  The substrate 1 that has been wet-cleaned by the wet-cleaning device 22 is dried by the drying device 23. As a drying method, a known spin drying method, hot air drying method, or air knife drying method can be used.

  The substrate 1 that has been dried by the dry-drying device 23 is dry-cleaned by the dry-cleaning device 24. The mode of the dry cleaning device 24 is in accordance with the dry cleaning device 21.

  On the substrate 1 that has been dry-cleaned by the dry-cleaning device 24, an organic layer is formed by an organic layer film-forming device that forms an organic layer (not shown). The organic layer can be formed by a known method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink jet method.

(Embodiment 2)
FIG. 4 shows a process of cleaning the continuous sheet substrate in a roll-to-roll manner while transporting the web by a roll-to-roll method in a cleaning process combining dry cleaning and wet cleaning, and forming an organic layer on the same web transport line. It is a schematic diagram of Embodiment 2 which performs.

  As shown in FIG. 4, a dry cleaning device 21, a first wet cleaning device 22 </ b> A, a second wet cleaning device 22 </ b> B, a drying device 23, a dry process are provided on the web conveyance line of the continuous sheet-like substrate 1 </ b> A on which the first electrode is formed. A cleaning device 24 and an organic layer film forming device 3 are provided. In the present embodiment, the wet cleaning process has two stages of the first wet cleaning apparatus 22A and the second wet cleaning apparatus 22B, but is not limited thereto. Similarly, the number of apparatus stages of other apparatuses disposed on the web conveyance line of the continuous sheet substrate 1A is not limited to this embodiment.

  The continuous sheet-like substrate 1A fed from the feed roll 1A1 is dry-cleaned by the dry-cleaning device 21 to remove organic contaminants so that the contact angle of water on the substrate electrode is 45 ° or less. When dry cleaning is not sufficient and organic contamination residue is generated, the contact angle of water on the substrate electrode exceeds 45 °, which reduces the efficiency of the next wet cleaning.

  The dry cleaning is performed by at least one of ultraviolet ozone cleaning and plasma cleaning. Ultraviolet ozone cleaning is a method of generating active oxygen using ultraviolet rays and simultaneously decomposing, oxidizing and volatilizing and removing organic substances adhering to the substrate surface. There are a method using an excimer lamp, a method using a low-pressure mercury lamp, and the like. Plasma cleaning is a method in which a high frequency is applied to oxygen gas or argon gas to generate plasma, and the substrate surface is irradiated and cleaned by a chemical reaction.

  In the present embodiment, ultraviolet ozone cleaning is used for the dry cleaning device 21. The continuous sheet-like substrate 1A fed from the feed roll 1A1 is cleaned by the ultraviolet ozone cleaning device 21 while carrying the web.

  In this embodiment, a 200 W low-pressure mercury lamp (manufactured by Sen Special Light Source Co., Ltd.) is used to perform a cleaning process with an irradiation distance of 10 mm and an irradiation time of 1 minute, and the contact angle of water on the substrate electrode surface is set to 45 ° or less. Yes.

  Since the contact angle of water on the surface of the substrate electrode is difficult to measure while washing, cleaning and measurement are separately performed on the sample substrate, and the cleaning condition is set such that the contact angle of water is 45 ° or less. Do.

  The contact angle of water is measured with a contact angle meter (DropMaster 700 manufactured by Kyowa Interface Science Co., Ltd.) based on the test method of JIS R 3257 standard.

  The continuous sheet substrate 1A that has been dry-cleaned by the dry-cleaning device 21 is wet-cleaned by the wet-cleaning devices 22A and 22B. Foreign particles embedded in organic contamination should be removed efficiently by wet cleaning because organic contamination is removed by dry cleaning as described above and the contact angle of water on the substrate electrode is 45 ° or less. Can do. Moreover, the solvent used for washing | cleaning can be only an aqueous solvent.

  The wet cleaning is performed by at least one of an ultrasonic cleaning bath immersion, a flowing water cleaning bath immersion, a flowing ultrasonic cleaning bath immersion, a flowing shower, and a flowing ultrasonic shower method. In order to perform continuous and uniform cleaning on the continuous sheet-like substrate 1A, any of a flowing water type cleaning bath immersion, a flowing water type ultrasonic cleaning bath immersion, a flowing water type shower and a flowing water type ultrasonic shower method is preferable. About the aspect of each said washing | cleaning method and a solvent, it applies to the content of Embodiment 1.

  The continuous sheet-like substrate 1A that has been cleaned by the dry cleaning device 21 is cleaned by the wet cleaning devices 22A and 22B while being conveyed on the web. In this embodiment, a flowing water type ultrasonic shower system is used for wet cleaning. About the aspect of the wet-cleaning apparatus using a flowing water type ultrasonic shower system, it applies to the content of Embodiment 1.

  The continuous sheet substrate 1A that has been wet-cleaned by the wet-cleaning devices 22A and 22B is dried by the drying device 2C. As the drying method, a known hot air drying method or air knife drying method can be used.

  The substrate 1 that has been dried by the dry-drying device 23 is dry-cleaned by the dry-cleaning device 24. The mode of the dry cleaning device 24 is in accordance with the dry cleaning device 21.

  On the substrate 1 that has been dry-cleaned by the dry-cleaning device 24, an organic layer is formed by the organic layer film-forming device 3 that forms an organic layer. The organic layer can be formed by a known method such as a vacuum deposition method, a casting method, an LB method, or an ink jet method.

  The continuous sheet-like substrate 1A on which the organic layer is formed is wound around a winding roll.

  In order to maintain the cleanliness after cleaning the substrate, it is preferable to transfer the continuous sheet-like substrate electrode surface in a non-contact state in the transfer of the continuous sheet-like substrate 1A on the same web transfer line after the cleaning.

  Hereinafter, although an example is given and the concrete effect of the present invention is shown, the mode of the present invention is not limited to this.

  An organic EL element having a size of one dot of 2.0 mm × 2.0 mm and a total of 9 dots (light emitting region) of 3 dots × 3 dots was manufactured by the method described below.

<Preparation of substrate>
As a substrate, a soda-lime glass plate having a thickness of 1.1 mm and 30 mm × 30 mm was prepared. The entire surface of the soda-lime glass plate was silica-coated to protect from acid and alkali.

<Formation of the first electrode>
On the prepared substrate, ITO was deposited on the entire surface of the glass plate with a thickness of 150 nm by a sputtering vapor deposition method, and then patterned to form a first electrode made of vertically striped ITO.

A resist is applied on the entire surface of the patterned ITO film. After pre-baking, a predetermined pattern is exposed to light, and after the phenomenon, post-baking is performed, followed by immersion in a ferric chloride solution and etching. The film was patterned to form a first electrode made of vertically striped ITO on a glass plate. After the etching is completed, the resist is removed. The formed first electrodes had a width of 2.0 mm, an interval of 1.0 mm, and three.

<Cleaning the first electrode forming substrate>
The substrate on which the first electrode was formed was dry-cleaned to produce a substrate in which the contact angle of water on the surface of the substrate electrode was changed. 1-1 to 1-12.

Ultraviolet ozone cleaning was performed using a dry cleaning 200 W low pressure mercury lamp (manufactured by Sen Special Light Source Co., Ltd.). As shown in Table 1, by adjusting the irradiation distance and irradiation time, a first electrode forming substrate was prepared by changing the contact angle of water on the substrate electrode surface. 1-1 to 1-12. In addition, the contact angle of water on the surface of the substrate electrode was separately cleaned and measured with a sample substrate to determine cleaning conditions, and cleaning was performed under those conditions.

  The contact angle of water was measured with a contact angle meter (DropMaster 700 manufactured by Kyowa Interface Science Co., Ltd.) based on the test method of JIS R 3257 standard.

  Each of the first electrode forming substrates No. 1 subjected to the dry cleaning. 1-1 to 1-12 were wet cleaned. Thereafter, drying treatment was performed, and dry cleaning was performed again.

Wet cleaning Using a flowing water type high frequency ultrasonic cleaning machine (W-357-P25 manufactured by Honda Electronics Co., Ltd.), cleaning was performed by flowing water type shower cleaning. The oscillation frequency was 1 MHz, the high frequency output was 60 W, the amount of water was 1.5 liters / minute, and the electrode surface was sprayed for 5 minutes. The solvent used for washing was ultrapure water.

Drying treatment The substrate after wet cleaning was held on a rotary table, and spin drying was performed at a rotation speed of 3000 r / min and a rotation time of 30 seconds.

Dry cleaning The substrate after the drying treatment was subjected to ultraviolet ozone cleaning using a 200 W low-pressure mercury lamp (manufactured by Sen Special Light Source Co., Ltd.) at an irradiation distance of 10 mm and an irradiation time of 60 seconds.

<Production of organic EL element>
Each cleaned first electrode forming substrate No. A hole transport layer, a light emitting layer, an electron injection layer, a second electrode, and a sealing film are sequentially formed on the 1-1 to 1-12 by the method described below to produce an organic EL element, and sample NO. 101-112.

<Formation of hole transport layer>
The first electrode forming substrate is set in a vacuum vapor deposition machine, the inside of the vacuum chamber is evacuated to 1 × 10 ⁻⁴ Pa, and then N, N′-diphenyl-N, N′-m-tolyl 4,4′-diamino-1 1,1′-biphenyl (hereinafter, TPD) was vacuum-deposited to a thickness of 50 nm at a deposition rate of 0.3 nm / second to form a hole transport layer.

<Formation of light emitting layer>
The substrate on which the hole transport layer is formed is set in a vacuum vapor deposition machine, the inside of the vacuum chamber is evacuated to 1 × 10 ⁻⁴ Pa, Alq ₃ is used as a light emitting material, and the thickness is 50 nm at a vapor deposition rate of 0.3 nm / second. Was vacuum evaporated.

<Formation of electron injection layer>
The substrate on which the light emitting layer is formed is set in a vacuum vapor deposition machine, the inside of the vacuum chamber is evacuated to 1 × 10 ⁻⁴ Pa, LiF is used as an electron injection layer material, and the thickness is 1 nm at a vapor deposition rate of 0.03 nm / second. Vacuum deposited.

<Formation of second electrode>
The substrate on which the electron injection layer is formed is set in a vacuum vapor deposition machine, the inside of the vacuum chamber is evacuated to 1 × 10 ⁻⁴ Pa, Al is used as the second electrode material, and the first electrode is placed directly on the electron injection layer. In the direction where the first electrode was formed, vacuum deposition was performed to a thickness of 100 nm at a deposition rate of 0.3 nm / second to form a width of 2.0 mm, a spacing of 1.0 mm, and three second electrodes. .

<Formation of sealing film>
The substrate on which the second electrode is formed is set in a vacuum vapor deposition machine, evacuated to 1 × 10 ⁻⁴ Pa, and then SiOx is used as a sealing film material, except for the region that becomes the connection terminal of the first electrode and the second electrode. A sealing film was formed by sputtering to a thickness of 300 nm at a deposition rate of 0.3 nm / second.

(Evaluation)
Each prepared sample No. Table 2 shows the results of the leak current characteristics tested by the test method shown below and evaluated according to the evaluation rank shown below.

Test Method for Leakage Current Characteristics Using a constant voltage power source, a reverse voltage (reverse bias) was applied at 5 V for 5 seconds, and the current flowing through the device at that time was measured. Measurement was performed for all 9 dots (light emitting region), and the maximum current value was defined as a leakage current.
Evaluation rank of leakage current ◎: Less than 1 × 10 ⁻⁸ A ○: 1 × 10 ⁻⁸ A or more, less than 1 × 10 ⁻⁶ A △: 1 × 10 ⁻⁶ A or more, less than 1 × 10 ⁻⁴ A ×: 1 × 10 ^-4 A or more

  The effectiveness of the present invention was confirmed.

It is a schematic diagram of the cleaning process combining dry cleaning and wet cleaning. It is a schematic diagram of ultraviolet ozone dry cleaning of a single wafer sheet-like substrate. It is a schematic diagram of flowing water type ultrasonic shower wet cleaning. It is a schematic diagram of the process which cleans a continuous sheet-like board | substrate by a roll-to-roll system, and forms the organic layer into a film by the same web conveyance line. It is a schematic diagram which shows the layer structure of the full color organic EL element of a passive matrix.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 1A Continuous sheet-like substrate 21, 24 Dry cleaning device 22, 22A, 22B Wet cleaning device 211 Low-pressure mercury lamp light source 221 Cleaning tank 222 Shower nozzle 223 Ultrasonic generator 224 Solvent storage container 225 Filter 23 Drying device 3 Organic layer formation Membrane device 51 Particle number measuring means (LPC)
52 Analysis Unit 53 Calculation Unit 54 Control Unit C1 Conveyor B1 Solvent P1 Supply Pump P2 Circulation Pump

Claims (6)

In the method for producing an organic electroluminescent element, wherein at least a first electrode and a light emitting layer composed of an organic substance and a second electrode are formed on a substrate.
A cleaning process comprising a dry cleaning process and a wet cleaning process for cleaning the first electrode of a substrate formed by forming a first electrode on the substrate; and the cleaning process includes the dry cleaning process, the wet cleaning process, and the dry cleaning process the have rows successively in this order, the method of manufacturing the organic electroluminescent device solvent used for the wet cleaning, characterized in that ultrapure water. The method for producing an organic electroluminescent element according to claim 1, wherein the wet cleaning is performed by setting the contact angle of water on the surface of the substrate electrode to 45 ° or less in the dry cleaning.   3. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the dry cleaning method is at least one of ultraviolet ozone cleaning and plasma cleaning.   The wet cleaning method is at least one of cleaning bath immersion, ultrasonic cleaning bath immersion, flowing water cleaning bath immersion, flowing water ultrasonic cleaning bath immersion, flowing water shower, and flowing water ultrasonic shower method. The manufacturing method of the organic electroluminescent element of any one of Claims 1 thru | or 3 characterized by these. The washing step, the organic electroluminescent device according to any one of claims 1 to 4, characterized in that washing the continuous sheet-like substrate while web transport the continuous sheet-like substrate in a roll-to-roll method Production method. An organic layer film forming step on the same web conveyance line as the washing step, and after washing in the washing step, at least one organic layer on the continuous sheet-like substrate electrode in the same web conveyance line The method of manufacturing an organic electroluminescence element according to claim 5 , wherein the film is formed.

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