JP2007273229A - Deposition method of organic thin membrane layer of organic electroluminescent (el) element, deposition device of organic thin-film layer of organic el element and organic el element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deposition method, or the like, of an organic thin-film layer of a polymer organic EL element which has high reliability since a dark spot is hard to occur due to ageing. <P>SOLUTION: The deposition method of an organic thin-film layer of an organic EL element includes a process in which an organic thin-film solution containing a high molecular polymer and an organic solvent is coated in a shape of a solid membrane and the organic solvent is vaporized to obtain a deposition of an organic thin-film layer such as a light-emitting layer and a hole transfer layer or the like. Prior to deposition, an atmosphere to deposit the organic thin-film layer is adjusted to an atmosphere which has a low dew point and contains an organic steam, the organic thin-film layer is deposited in this atmosphere. A deposition device to achieve the deposition method in a simple structure is composed of a coater (51) to deposit an organic thin-film layer, a deposition box 71 housing the coater (51) inside, a dehumidifier 81 to adjust an inner space of the deposition box 71 to a low dew point atmosphere and an organic steam generating unit (91) to adjust the inner space of the deposition box 71 to an atmosphere containing organic steam. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic thin film layer forming method for an organic EL element, an organic thin film layer forming apparatus for an organic EL element, and an organic EL element, each of which includes a polymer in an organic thin film layer such as a light emitting layer or a hole transport layer.

  The phenomenon of emitting light of a wavelength corresponding to the electronic band structure when an electric field is applied to a substance is called electroluminescence. A light-emitting element utilizing this phenomenon is an electroluminescence light-emitting element (hereinafter referred to as an EL element).

  As this EL element, a so-called inorganic EL element using an inorganic substance as a light emitting material has been known for a long time. In this inorganic EL element, a light emitting layer containing an inorganic light emitting material such as ZnS is provided between a pair of opposed electrodes, and electrons (hot electrons) accelerated by a high electric field collide with a base lattice of the inorganic light emitting material to emit light. It is an element that emits light by emitting light having a wavelength corresponding to the prohibited body width of the inorganic light emitting material when the center is collisionally excited and relaxed. However, since high voltage is required for driving and there are problems in colorization, the current situation is that it is limited to commercialization in limited fields.

On the other hand, as an EL element, there is a so-called organic EL element using an organic material as a light emitting material. The organic EL element, a light emitting layer containing an organic luminescent material such as Alq ₃ or PPV between a pair of opposing electrodes provided to inject holes and electrons from the respective pair of electrodes to the light-emitting layer, the light-emitting layer within the An element that recombines to generate excitons and emits light having a wavelength corresponding to the HOMO-LUMO gap of the organic light-emitting material.

  A lot of research has been done for a long time, but at the beginning, its luminous efficiency was low and it was far from being applied to practical light emitting devices. However, it has been considerably improved recently, taking advantage of the excellent features such as low voltage drive, low power consumption, and easy colorization compared to inorganic EL elements, liquid crystal paper backlight, electronic paper, surface emitting lighting, A wide range of applications such as flat-screen TVs are expected.

  Here, the element structure of the organic EL element will be outlined with reference to FIGS. FIG. 8 shows a simple structure of the organic EL element 1. The organic EL element 1 shown in the figure includes a transparent substrate 10 such as a glass substrate or a PET film, an anode 20 made of a transparent electrode such as ITO, a light emitting layer 30 containing an organic light emitting material, and a metal electrode such as Mg / Ag. The cathodes 40 are sequentially stacked. Holes are injected from the anode 20 and electrons are injected from the cathode 40 into the light emitting layer 30 sandwiched between the anode 20 and the cathode 40. As a result of the hopping movement of the injected holes and electrons and recombination in the light emitting layer 30, excitons are generated, and EL light emission occurs in the process in which the electrons in the organic light emitting material excited thereby return to the ground state. To do. This EL light emission is extracted outside through the anode 20 which is a transparent electrode and the transparent substrate 10.

  For such a structure, there is also an organic EL element 1 as shown in FIG. This is because a hole injection layer 25 and a hole transport layer 26 are sequentially laminated between the anode 20 and the light emitting layer 30, and an electron transport layer 46 and an electron injection layer 45 are disposed between the light emitting layer 30 and the cathode 40. Are sequentially laminated.

  The hole transport layer 26 and the electron transport layer 46 are for the purpose of balancing the holes and electrons injected into the light emitting layer 30, and by confining carriers and excitons in the light emitting layer 30, to improve the light emission intensity and light emission efficiency. It is provided for purposes. In addition, the hole injection layer 25 reduces the hole injection barrier from the anode 20 and matches the electronic properties with the interface of the hole transport layer 26 (or the light emitting layer 30 interface), thereby improving the luminous efficiency. It is provided for the purpose of improving, for the purpose of realizing driving at a low voltage, and the like. Similarly, the electron injection layer 45 is intended to improve the luminous efficiency by reducing the electron injection barrier from the cathode 40 and matching the electronic properties with the interface of the electron transport layer 46 (or the interface of the light emitting layer 30). It is provided for the purpose of realizing driving at a low voltage.

  There are organic EL elements having various structures other than those shown in FIGS. For example, in FIG. 9, when the hole transport layer 26 and the electron transport layer 46 have a bipolar property and have a strong light emitting property, a structure that also serves as the light emitting layer 30 is used. 25 and the electron transport layer 46 may be composed of two or more layers. There is also a so-called top emission type structure in which EL light is extracted from the cathode 40 side using the anode 20 as a non-translucent metal electrode and the cathode 40 as a translucent transparent electrode. As described above, various organic EL elements have been studied based on the structures shown in FIGS.

  Regarding such an organic EL element, conventionally, a so-called low molecular organic EL element in which a light emitting layer is made of a low molecular organic light emitting material has been the mainstream of research and development. However, since it takes time to deposit the organic light emitting material, there are problems such that the man-hours are bulky and cannot be provided at low cost, and the coating strength is weak. Therefore, in recent years, in order to solve these problems, so-called polymer organic EL elements using a polymer polymer in an organic thin film layer such as a light emitting layer have been actively developed. The polymer organic EL device has an inactive polymer polymer as a binder as a light emitting layer, a carrier transporting low molecular weight organic compound or a light emitting organic compound dispersed in the binder, or a carrier transporting low molecular weight organic compound. There have been proposed polymers that have been polymerized by introducing a vinyl group into the polymer, and the feature is high productivity.

  That is, the organic thin film layer can be formed by a wet process (wet process) by dissolving the polymer constituting the organic thin film layer in a solvent such as an organic solvent, so that the spin coating method, screen printing method, gravure printing method, die coating method can be used. Various coating techniques such as the method can be used, and the organic thin film layer can be formed in a short time compared with the vapor deposition process. In addition, a film can be easily formed on a large-area substrate by utilizing a die coating method or a screen printing method. In addition, since the coating apparatus used for these various coating techniques is less expensive than the vapor deposition apparatus, capital investment can be kept low. In this way, a polymer organic EL element that can be applied in a wet manner is considered to be significantly advantageous in terms of production speed and production cost compared to a low molecular organic EL element, and low-cost mass production of organic EL elements is expected. It is what makes it possible.

  However, there is a problem because it is wet. That is, the wet film formation tends to be in a state in which impurities such as trace moisture are contained in the organic thin film layer or the like. Then, due to the influence of the impurities, there is a problem that a non-light emitting point called “dark spot” is generated in the light emitting surface and is enlarged with time and the light emission efficiency is lowered. Various methods have been studied to solve this problem. Many of them relate to a sealing structure, a sealing material, a sealing method, or a desiccant provided inside the sealing structure of an organic EL element. However, there are few things regarding the film-forming process which is the basis of an organic EL element manufacturing process like this invention mentioned later. Here, the inventions disclosed in the following Patent Document 1 and Patent Document 2 have been studied for the film forming process.

  In Patent Document 1, “in an organic electroluminescent element manufacturing method having an organic layer including a light emitting layer made of at least an organic light emitting material between a pair of opposed electrodes, the organic layer material is applied in an inert gas atmosphere. Thereafter, “a method for producing an organic EL device, wherein drying is performed at a temperature lower by 10 ° C. or more than the glass transition temperature Tg in an inert gas atmosphere or in vacuum” is disclosed. As a result, “when producing an organic EL element, after applying an organic layer material in an inert gas atmosphere, and heating and drying in an inert gas atmosphere or in a vacuum, oxygen in the air, moisture, organic It is possible to isolate the organic layer from contaminants and prevent oxidation, hydrolysis, contamination and the like of the organic layer caused by them, and to produce a high performance organic EL device.

  Patent Document 2 states that “in an organic electroluminescence device manufacturing apparatus in which an organic layer including a light emitting layer and a metal electrode are sequentially formed on a substrate provided with a transparent electrode, the organic layer formed on the transparent electrode” In addition, each processing chamber is hermetically connected so that the metal layer formed on the organic layer is not exposed to the atmosphere, and at least the processing chamber for forming the organic layer is formed of a glove box. An organic electroluminescent device manufacturing apparatus characterized by the above is disclosed. As a result, “At least the processing chamber for forming the organic layer is composed of a glove box, so that maintenance can be performed without destroying the control atmosphere. Therefore, replenishment of materials such as coating liquids is also isolated from the outside. It is possible to prevent the organic material from scattering to the outside, and to prevent contamination of impurities such as dust from the outside. " Also, paragraph 0011 disclosing the prior art states, “When applying, the processing atmosphere is a dry atmosphere with as little moisture as possible, and is performed in an inert gas. This is because the organic EL layer has a moisture content. This is because it is necessary to eliminate such a factor as much as possible when it is formed.

  Thus, a method for improving the reliability of an organic EL element by forming an organic thin film layer in a dry atmosphere (low humidity atmosphere) or an inert gas atmosphere is known.

  On the other hand, an organic thin film layer film forming method of an organic EL element focusing on an atmosphere containing organic vapor (organic solvent vapor) at the time of coating or drying (that is, film formation) is that an organic thin film solution is applied to a minute dot. Although it is related to the so-called ink jet coating method of coating, it is disclosed in the following Patent Document 3 and Patent Document 4.

  In Patent Document 3, “in an organic EL material coating apparatus including an ink coating unit that applies ink to an R, G, B3 color dot that is formed on a substrate and corresponds to R, G, and B colors constituting a pixel. An organic EL material application comprising a solvent application means for applying a solvent to the display area of the substrate or the outer periphery of the display area in advance before applying the ink to the predetermined dots by the ink application means. An apparatus "is disclosed. As a result, it is described that “the luminance unevenness due to the difference in the drying time of the ink that has occurred in the past can be reduced and a high-quality organic EL display device can be provided”.

  Further, Patent Document 4 relates to an inkjet coating method (droplet ejection method), which is “a method of applying droplets by ejecting droplets onto a substrate by a droplet ejection method. Discharging a droplet to a position corresponding to one end of the droplet; and (b) discharging a droplet to a position corresponding to the other end of the applied droplet opposite to the one end. And (c) a droplet applying method including a step of discharging droplets to a position corresponding to the one end portion of the applied droplets. " Then, in paragraph 0101, “a solvent atmosphere on the substrate becomes uniform, so that coating unevenness is eliminated, and a substrate free from factors causing luminance unevenness, display unevenness, and exposure unevenness is obtained. As a result of the uniform atmosphere, the state of the droplets on the substrate is also made uniform. "

  As described above, in an inkjet coating method in which an organic thin film solution is applied to a minute dot, it is also known to provide an organic EL element with less luminance unevenness by utilizing an atmosphere containing organic vapor to prevent coating unevenness. is there.

Japanese Patent Laying-Open No. 2005-310639 (Claim 1, paragraph 0008) JP 2003-173871 A (claim 1, paragraph 0011, paragraph 0066) JP 2004-31070 A (Claim 1, paragraph 0039) JP 2004-298844 A (Claim 1, paragraph 0101)

  Thus, a method for improving the reliability of an organic EL element by forming a film in a low-humidity atmosphere or an inert gas atmosphere is known. However, the formation of dark spots could not be sufficiently suppressed by simply forming a film in a low humidity atmosphere or an inert gas atmosphere. It is also known to prevent coating unevenness by utilizing an atmosphere containing organic vapor in an ink jet coating method. However, the problem in the above-mentioned patent document is that the “coating” is caused by the difference in drying time between the micro dots, which is inherent to the ink jet coating method in which an organic thin film solution is applied to a large number of micro dots little by little. It is “unevenness” or “brightness unevenness”. Moreover, even if these “application unevenness” and “brightness unevenness” can be improved, it is difficult to suppress the generation of dark spots over time.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and it is difficult to generate dark spots with time and has high reliability, an organic thin film layer forming method for an organic EL element, an organic thin film layer forming apparatus for an organic EL element, and an organic An EL element is provided.

  In order to solve the above problems, an organic thin film layer forming method of an organic EL device of the present invention is a light emitting layer in which an organic thin film solution containing a polymer and an organic solvent is applied in a solid film shape and the organic solvent is volatilized. Organic thin film layer forming method for organic EL elements that form organic thin film layers such as a hole transport layer and the like, prior to film formation, the atmosphere in which the organic thin film layer is formed has a low dew point and contains organic vapor The organic thin film layer is formed in this atmosphere by adjusting the atmosphere. Here, the “organic solvent” is included in the organic thin film solution applied to form the organic thin film layer. On the other hand, “organic vapor” is contained in an atmosphere for forming an organic thin film layer.

  The inventor of the present application has been trial manufacture of an organic EL element in which an organic thin film solution is applied in a solid film form to form a uniform organic thin film layer and the entire surface emits light in a single color (same color). In the trial production, an organic thin film layer such as a light emitting layer was formed in a low humidity and inert atmosphere as described above. However, when a film is formed in an atmosphere with a low dew point (low humidity) and organic vapor, it is surprising that the generation of dark spots over time is remarkably suppressed, and the reliability of the organic EL element is remarkably reduced. I found that the sex is greatly improved. As a result of intensive studies based on this discovery, the present invention has been achieved. That is, the greatest point of the present invention is to break the existing concept of film formation in a low dew point and in an inert atmosphere in order to suppress the occurrence of dark spots. By forming a film-forming atmosphere including the film, and forming the film in this atmosphere, both conditions act synergistically, and generation of dark spots over time of the organic EL element can be remarkably suppressed.

  At this time, the atmosphere having a low dew point and containing an organic vapor can be an organic thin film layer forming method of an organic EL element having a dew point of −40 ° C. or lower and an organic vapor concentration of 50 ppm or higher.

  The lower the dew point for forming the organic thin film layer and the atmosphere containing the organic vapor, the better the lower the dew point. When the dew point exceeds −40 ° C., the effect of the present invention is hardly obtained. The dew point is preferably −60 ° C. or lower, more preferably −70 ° C. or lower, and most preferably −80 ° C. or lower. The lower limit of the dew point is determined by the equipment capacity. Further, in an atmosphere having a low dew point and containing an organic vapor, the effect of the present invention is hardly obtained if the concentration of the organic vapor is less than 50 ppm. The concentration of the organic vapor is preferably 80 ppm or more, more preferably 120 ppm or more, and most preferably 150 ppm or more. The upper limit of the concentration of the organic vapor is not particularly limited as long as the organic solvent in the applied organic thin film solution is volatilized from the coating film so that the organic thin film layer can be formed. The following is preferred. The upper limit of the concentration of the organic vapor is more preferably 800 ppm or less, and most preferably 500 ppm or less. The atmosphere in which the organic thin film layer is formed is adjusted to these predetermined atmospheres prior to film formation, but the organic thin film layer can be formed while being controlled to these predetermined atmospheres during film formation. preferable.

  The organic vapor contained in the adjusted atmosphere is also preferably an organic thin film layer forming method for an organic EL element, which is chloroform vapor, benzene vapor, toluene vapor, or a mixed vapor thereof. These organic solvent vapors generally having a low boiling point have a high saturated vapor pressure and tend to emit high-concentration vapors in the atmosphere.

  The organic solvent contained in the organic thin film solution is preferably a chloroform solvent, a benzene solvent, a toluene solvent, or an organic thin film layer forming method for an organic EL element, which is a mixed solvent thereof. A chloroform solvent and a benzene solvent are so-called low boiling solvents, and a toluene solvent is a so-called medium boiling solvent. Since these organic solvents having a low boiling point generally have a high saturated vapor pressure and are likely to volatilize, it is easy to form an organic thin film layer.

  Moreover, it is also preferable to set it as the organic thin film layer film-forming method of the organic EL element which used the die coating method for application | coating of an organic thin film solution. By using the die coating method, it is possible to form a film with a rapid and uniform thickness over a large area.

  An organic thin film layer forming apparatus for forming an organic thin film layer of an organic EL element by such a film forming method applies an organic thin film solution containing a polymer polymer and an organic solvent such as chloroform solvent in a solid film shape. A low dew point is formed in the film forming unit for evaporating the organic solvent to form an organic thin film layer such as a light emitting layer and a hole transport layer, the film forming chamber in which the film forming unit is installed, and the internal space of the film forming chamber. What is necessary is just to set it as the organic thin film layer film-forming apparatus of the organic EL element which consists of a dehumidifier which adjusts to atmosphere, and the organic vapor generator which adjusts the internal space of a film-forming chamber to the atmosphere containing organic vapor | steam. With this film forming apparatus, the internal space of the film forming chamber can be adjusted to a predetermined atmosphere containing a low dew point and containing organic vapor.

  Moreover, as an organic thin film layer deposition apparatus suitable for mass production, a substrate supply unit for sequentially supplying a substrate material such as glass or film, and an organic material including a polymer polymer and an organic solvent such as chloroform solvent in the supplied substrate material A sequential film forming unit that sequentially deposits a thin film solution in the form of a solid film and volatilizes the organic solvent to form an organic thin film layer, and a deposition substrate recovery unit that sequentially collects the film forming substrate material on which the organic thin film layer is formed And a deposition unit installation chamber in which a substrate supply unit, a sequential deposition unit, and a deposition substrate recovery unit are installed, and are provided in the deposition unit installation chamber so as to cover only the deposition unit sequentially. A film forming unit covering body, and a substrate material supply window opened in the film forming unit covering body for supplying the substrate material from the substrate supplying unit to the film forming unit sequentially covered by the film forming unit covering body, The film formation substrate material is sequentially formed from the film formation unit covered by the film formation unit covering body. In order to adjust the internal space of the film formation unit cover and the internal space of the film formation unit cover to a low dew point atmosphere, it is taken in from the outside of the film formation unit installation chamber. The outside air is dehumidified to form a low dew point outside air, and the low dew point outside air is continuously supplied into the film forming unit installation chamber, so that the supplied low dew point outside air is passed through the substrate material supply window and the film forming substrate recovery window. A dehumidifying device that flows into the film forming unit covering body and a low dew point that flows into the film forming unit covering body in order to adjust the internal space of the film forming unit covering body to an atmosphere containing organic vapor. An organic vapor generator that releases organic vapor to the outside air to generate low dew point solvent inside air, and an exhaust duct that exhausts the low dew point solvent inside air present inside the film forming unit cover to the outside of the film forming unit installation chamber. By providing, the internal space of the film forming unit covering body has a low dew point and contains organic vapor May be an organic thin film layer forming apparatus of an organic EL device was adjustable to a constant atmosphere.

  By using such a film forming apparatus, it is possible to form a film stably in a mass production apparatus in an atmosphere having a low dew point and containing organic vapor. Further, only the internal space of the film forming unit covering body can be made into an atmosphere containing organic vapor, and the work in the atmosphere containing organic vapor can be reduced, and the organic thin film layer film forming apparatus which is gentle to the operator Become.

  According to the present invention, it is possible to provide a method for forming an organic thin film layer of a polymer organic EL element that is less likely to cause dark spots over time and has high reliability.

  Hereinafter, embodiments of the organic thin film layer forming apparatus and the like of the present invention will be described with reference to the drawings. 1 to 4 are diagrams illustrating embodiments of an "organic thin film layer deposition apparatus for organic EL elements" according to the present invention, FIG. 1 is a diagram illustrating the first embodiment, and FIG. 2 is a second embodiment. The figure which showed the form, FIG. 3 is the figure which showed 3rd embodiment, FIG. 4 is the figure which showed 4th embodiment. The film forming apparatus of FIG. 1 corresponds to claim 7, and the film forming apparatus of FIGS. 2 to 4 corresponds to claim 8. First, the first embodiment of the “organic thin film layer forming apparatus for organic EL elements” of the present invention will be described with reference to FIG. 1 and the “organic thin film layer forming method for organic EL elements” of the present invention will also be described. An example will be described.

[First embodiment]
The film forming apparatus shown in the first embodiment of FIG. 1 corresponds to claim 7, and includes a spin coater 51 (film forming unit) for forming an organic thin film layer and a spin coater 51 installed therein. The film forming box 71 (film forming chamber), the dehumidifier 81 that adjusts the internal space of the film forming box 71 to a low dew point atmosphere prior to film formation, and the internal space of the film forming box 71 prior to film formation. A chloroform vapor generator 91 (organic vapor generator) that adjusts to a predetermined chloroform vapor concentration.

  As the spin coater 51 (deposition unit), a commercially available one can be used. However, as will be described later, in the film forming apparatus of the present embodiment, it is necessary to form a film with the opening / closing door 711 of the film forming box 71 closed, so that the film formation control (sample table) is provided from the outside of the film forming box 71. It is necessary to configure so that 512 rotation ON-OFF and dropping of the organic thin film solution are possible. Moreover, since it coats in the atmosphere containing chloroform vapor | steam, it is preferable that it is an explosion-proof specification.

  The film formation box 71 (film formation chamber) is provided with an opening / closing door 711 from which the spin coater 51 can be taken in and out. The film formation box 71 preferably has a temperature adjustment function.

  The dehumidifier 81 is provided to circulate the gas present in the inner space of the film forming box 71 between the dehumidifier 81 and adjust the inner space of the film forming box 71 to a low dew point atmosphere. The dehumidifier 81 has a capability of dehumidifying the atmosphere of the internal capacity of the film forming box 71 to a dew point of −40 ° C. or lower. The dehumidifying capacity is preferably a dew point of −60 ° C. or lower, more preferably a dew point of −70 ° C. or lower. A dew point of -80 ° C or less is satisfactory. The suction port 811 and the supply port 813 of the dehumidifier 81 are individually communicated with the inside of the film formation box 71 by the suction hose 812 and the supply hose 814, respectively. The gas sucked into the dehumidifier 81 from 811 and dehumidified inside the dehumidifier 81 returns to the inside of the film formation box 71 from the supply port 813 through the supply hose 814. The dew point inside the film forming box 71 is measured by a dew point sensor (not shown), and the dehumidifier 81 is feedback controlled so as to have a predetermined value. In the present embodiment, a capacitive sensor is used as the dew point sensor.

  The chloroform vapor generator 91 (organic vapor generator) circulates the gas existing in the inner space of the film forming box 71 between the chloroform vapor generator 91 and the inner space of the film forming box 71 contains chloroform vapor. Provided to adjust to atmosphere. The chloroform vapor generator 91 has the ability to adjust the atmosphere of about the internal capacity of the film forming box 71 to an atmosphere containing chloroform vapor having a concentration of 50 ppm or more. It is even better if it has an ability to adjust to an atmosphere containing chloroform vapor having a concentration of preferably 80 ppm or more, more preferably 120 ppm or more. If it has the ability to adjust to an atmosphere containing chloroform vapor with a concentration of 150 ppm or more, it is satisfactory. Similar to the dehumidifier 81 described above, the suction port 911 and the supply port 913 of the chloroform vapor generator 91 are individually communicated with the inside of the film formation box 71 by the suction hose 912 and the supply hose 914, respectively. Gas is sucked into the chloroform vapor generator 91 from the suction port 911 through the suction hose 912, and the gas containing the chloroform vapor inside the chloroform vapor generator 91 enters the film formation box 71 through the supply hose 914 from the supply port 913. Return. As the chloroform vapor generator 91, an apparatus using an appropriate method such as an apparatus that generates chloroform vapor by bubbling gas in chloroform or an apparatus that generates chloroform vapor using ultrasonic waves may be used. . Further, when the concentration of chloroform vapor is precisely adjusted and controlled, a chloroform vapor generator 91 having an adsorption / recovery function of chloroform vapor may be used. In the present embodiment, a steam generator is used in which chloroform is heated with a heater and mixed with the gas sucked from the film formation box 71. The chloroform used for the chloroform vapor generator 91 is a high-purity product that has been repeatedly purified. The higher the purity, the better. The concentration of the chloroform vapor in the film forming box 71 is measured by a sensor (not shown), and the heater temperature of the chloroform vapor generator 91 and the like are feedback controlled so as to have a predetermined value.

  The method and procedure for forming an organic thin film layer using this film forming apparatus are generally as follows, for example. First, the spin coater 51 is taken out of the film formation box 71 and an organic thin film solution for forming an organic thin film layer is injected into the solution reservoir 511. The organic thin film solution contains a polymer and a chloroform solvent. On the sample table 512 of the spin coater 51, the substrate 10 to be deposited is placed and fixed. Next, the spin coater 51 is returned to the inside of the film formation box 71, and the door 711 is closed to make the film formation box 71 airtight. Thereafter, the dehumidifier 81 is operated to adjust the internal space of the film forming box 71 to a dew point of −40 ° C. or lower. When the dew point becomes −40 ° C. or lower, the chloroform vapor generator 91 is operated to adjust the internal space of the film formation box 71 to a concentration of chloroform vapor of 50 ppm or more. By doing so, the atmosphere in the inner space of the film forming box 71 is set to a concentration of chloroform vapor having a dew point of −40 ° C. or lower and 50 ppm or higher. In this state, the spin coater control switch (not shown) provided outside the film formation box 71 is operated to drop the organic thin film solution onto the substrate 10 while rotating the sample table 512 of the spin coater 51. An organic thin film solution is applied on top. Thereafter, the rotation of the sample table 512 is stopped and the spin coater 51 is left in the film formation box 71 for several minutes in order to volatilize the chloroform solvent. During this period, that is, during film formation, the dehumidifier 81 and the chloroform vapor generator 91 can be controlled so as to have a predetermined atmosphere (in this embodiment, the dew point is -40 ° C. or lower and the chloroform vapor concentration is 50 ppm or higher). preferable. Finally, the opening / closing door 711 is opened, the spin coater 51 is taken out from the film formation box 71, and the substrate 10 on which the organic thin film layer is formed is removed from the sample table 512.

  In the present embodiment, the chloroform vapor generator 91 is used as the organic vapor generator. However, the present invention is not limited to this, and a benzene vapor generator, a toluene vapor generator, or a mixed vapor generator thereof may be used. Moreover, although the thing containing a high molecular polymer and a chloroform solvent (organic solvent) was used for the organic thin film solution, it may replace with a chloroform solvent and may use a benzene solvent, a toluene solvent, or these mixed solvents. However, considering the case where the film is formed while being controlled to an atmosphere having a predetermined organic vapor concentration, it is preferable to use the same kind of organic substance for the organic vapor and the organic solvent as in this embodiment. “Organic thin film layer formation” refers to forming an organic thin film layer by applying an organic thin film solution containing a polymer and an organic solvent such as a chloroform solvent in the form of a solid film and volatilizing the organic solvent. Say.

  The organic thin film layer forming apparatus exemplified in the first embodiment may have a simple configuration. However, mass productivity is poor. Therefore, for example, the spin coater 51 is replaced with a film forming line using screen printing excellent in mass productivity, the film forming box 71 is regarded as a film forming room, and the entire film forming room has a low dew point and organic vapor is removed. It is conceivable to adjust the atmosphere. However, it is difficult to stably keep the entire wide film formation room in a predetermined atmosphere containing organic vapor, and it is not preferable in terms of work hygiene. This problem is solved by an organic thin film layer forming apparatus exemplified in the second embodiment.

[Second Embodiment]
FIG. 2 shows a second embodiment of the “organic thin film layer deposition apparatus for organic EL elements” of the present invention. The film forming apparatus shown here corresponds to claim 8 and is roughly divided into a single-wafer substrate supply device 61 (substrate supply unit), a sequential film formation device 52 (sequential film formation unit), and a film formation substrate. A film forming unit comprising a recovery device 65 (film forming substrate recovery unit), a unit room 72 (film forming unit installation chamber) in which the film forming unit is installed, and a film forming provided in the unit room 72 An apparatus partition chamber 73 (film forming unit covering body), a dehumidifier 82 that dehumidifies the inside of the unit room 72 to adjust the inside of the film forming apparatus partition chamber 73 to a predetermined dew point, and a film forming apparatus partition chamber 73 It comprises a benzene vapor generator 92 (organic vapor generator) that adjusts the interior to a predetermined benzene vapor concentration.

  First, each component of the film forming unit including the single substrate supply device 61, the film forming device 52, and the film forming substrate collecting device 65 will be described. This embodiment is an example of a case where a glass substrate or a substrate cut from an original fabric roll film is used as a substrate, and a screen printing method is adopted as a coating method.

  The single substrate supply device 61 (substrate supply unit) sequentially supplies the glass substrate 11 cut into a rectangle to the film formation device 52 sequentially. In this example, the glass substrates 11 stocked in a stacked state on the supply rack 611 are adsorbed one by one from the top to a suction cup 613 provided on the lower side of the conveyance unit 612, and then the conveyance unit 612 is supplied to the supply conveyor 614. In this state, the suction of the glass substrate 11 is released and placed on the supply conveyor 614. By repeating this operation, the glass substrate 11 is sequentially supplied to the screen printing device 521. Yes.

  The sequential film forming device 52 (sequential film forming unit) includes a screen printing device 521 and a transfer conveyor 524, and sequentially applies an organic thin film solution containing a polymer and a benzene solvent to the supplied glass substrate 11 to apply a solvent. The organic thin film layer is formed by volatilization. In this example, the screen printing apparatus 521 is used, and the organic thin film solution supplied on the printing mask 522 is applied onto the glass substrate 11 by the squeegee 523. The glass substrate 11 on which the organic thin film solution has been applied is transferred by the transfer conveyor 524, and the benzene solvent is volatilized and the organic thin film layer is formed until the film is recovered by the film formation substrate recovery device 65. Although not shown in FIG. 2, a drying heater such as a panel heater may be installed in the vicinity of the conveyor 524 in order to facilitate the evaporation of the benzene solvent from the applied organic thin film solution.

  The film formation substrate recovery device 65 (film formation substrate recovery unit) sequentially recovers the deposited glass substrates 11 and stocks them in a stacked state on the recovery rack 651. The single substrate supply device 61, the film formation device 52, and the film formation substrate recovery device 65 sequentially constitute a film formation unit.

  The film forming unit is installed in a unit room 72 (film forming unit installation chamber). Further, inside the unit room 72, a film forming apparatus partition chamber 73 (film forming part covering body) is provided. In this film forming apparatus partition chamber 73, only the film forming apparatus 52, that is, the screen printing apparatus 521 and the transfer conveyor 524 are sequentially covered among the film forming units. Further, a substrate material supply window 731 and a film formation substrate recovery window 732 are opened on the left and right side walls of the film formation apparatus partition chamber 73, and the single substrate supply apparatus 61 sequentially transfers the glass to the screen printing apparatus 521 of the film formation apparatus 52. The substrate 11 is supplied, and the film formation substrate collecting device 65 can sequentially collect the film-formed glass substrate 11 from the transfer conveyor 524 of the film formation device 52.

  The dehumidifier 82 sucks outside air from the outside of the unit room 72 through the inlet 821, dehumidifies inside the dehumidifier 82 to form low dew point outside air, and continuously supplies this low dew point outside air to the inside of the unit room 72. The interior is made to have a low dew point atmosphere adjusted to a predetermined dew point of −40 ° C. or lower. The supply port 823 of the dehumidifier 82 and the inside of the unit room 72 are connected to each other via a supply pipe 824 so that the low dew point outside air dehumidified by the dehumidifier 82 falls from the upper part of the unit room 72 via the supply pipe 824. Continuously supplied. The low dew point outside air continuously supplied into the unit room 72 flows into the film forming apparatus partition chamber 73 through the substrate material supply window 731 and the film forming substrate recovery window 732 opened in the film forming apparatus partition chamber 73. As a result, the internal space of the film forming apparatus partition chamber 73 is also adjusted to a low dew point atmosphere. A dew point sensor (not shown) is attached to the inside of the film forming apparatus partition chamber 73, and this data is fed back to the dehumidifying apparatus 82, so that the dehumidifying apparatus 82 has a predetermined dew point inside the film forming apparatus partition chamber 73. Is driving.

  The benzene vapor generator 92 (organic vapor generator) continuously or intermittently releases benzene vapor to the low dew point outside air that has flowed into the film forming apparatus partition chamber 73 to form low dew point benzene internal air, thereby forming a film. The internal space of the apparatus partition chamber 73 is adjusted to an atmosphere containing a predetermined benzene vapor having a concentration of 50 ppm or more. In the present embodiment, as the benzene vapor generation device 92, an apparatus of a type in which benzene is heated by a heater inside the apparatus and the benzene vapor is released to the low dew point outside air inside the film forming apparatus partition chamber 73 is used. The concentration of benzene vapor in the film forming apparatus partition chamber 73 is measured by a sensor (not shown), and the heater temperature of the benzene vapor generator 92 and the like are feedback controlled so as to have a predetermined value. The benzene vapor generator 92 has a discharge duct extending from the apparatus main body to the periphery of the substrate material supply window 731 and the film formation substrate recovery window 732, and the substrate material from the discharge port provided at the tip of the discharge duct. Benzene vapor may be emitted to the periphery of the supply window 731 and the film formation substrate recovery window 732.

  The upper part of the film forming apparatus partition chamber 73 communicates the inside of the film forming apparatus partition room 73 and the outside of the unit room 72 to unite the low dew point benzene air present inside the film forming apparatus partition room 73. An exhaust duct 74 that naturally discharges outside the room 72 is provided. Depending on the amount of low dew point outside air supplied continuously into the unit room 72 by the dehumidifier 82 described above, the low dew point benzene inside air inside the film forming apparatus partition room 73 is naturally discharged to the outside of the unit room 72. Will be.

  By forming a film forming apparatus having such a configuration, even in a mass production apparatus, it is possible to stably realize an atmosphere containing low vapor and organic vapor, and stably form an organic thin film layer having excellent reliability. It becomes possible. During film formation, the dehumidifier 82 and the benzene vapor generator 92 are controlled so as to be in a predetermined atmosphere (in this embodiment, the dew point is −40 ° C. or lower and the organic vapor concentration is 50 ppm or higher).

  In the second embodiment, the benzene vapor generator 92 is used as the organic vapor generator, but the present invention is not limited to this, and a chloroform vapor generator, a toluene vapor generator, or a mixed vapor generator thereof may be used. In addition, the organic thin film solution includes a polymer polymer and a benzene solvent (organic solvent), but a chloroform solvent, a toluene solvent, or a mixed solvent thereof may be used instead of the benzene solvent. However, in the same manner as in Example 1, in consideration of the case where the film is formed while being controlled in an atmosphere having a predetermined organic vapor concentration, it is preferable to use the same kind of organic substance for the organic vapor and the organic solvent. In particular, in the second embodiment, the organic thin film layer is continuously formed by the sequential film forming apparatus 52. Therefore, it is conceivable that the organic solvent in the organic thin film solution is volatilized in a large amount in the film formation atmosphere during continuous film formation and becomes a part of the organic vapor component, thereby increasing the organic vapor concentration in the atmosphere. Even in such a case, it is only necessary to measure the organic vapor concentration in the atmosphere and control the organic vapor generator as necessary, but the organic vapor composed of a single organic substance, that is, the organic vapor and the organic solvent By using the same kind of organic matter, it becomes easy to measure the organic vapor concentration in the atmosphere.

  In the second embodiment, focusing on the flow of the low dew point outside air, the low dew point outside air supplied from the dehumidifier 82 to the inside of the unit room 72 is formed through the substrate material supply window 731 and the film formation substrate recovery window 732. The benzene vapor generator 92 discharges benzene vapor into the low dew point outside air into the low dew point benzene air, and thereby the inside space of the film formation unit partition room 73 is predetermined. A low dew point benzene atmosphere is formed, and the low dew point benzene air is naturally discharged to the outside of the unit room 72 through the exhaust duct 74. As a result, not only the entire unit room 72 but only the internal space of the film forming apparatus partition chamber 73 where the film forming apparatuses 52 sequentially exist can be selectively made into a benzene atmosphere. Further, due to the flow of the low dew point outside air, the low dew point benzene internal air existing in the inner space of the film forming apparatus partition chamber 73 flows back to the work space outside the film forming apparatus partition chamber 73 and inside the unit room 72. Therefore, the organic thin film layer forming apparatus is easy on the operator when the formed glass substrate 11 is unloaded.

  In order to further increase the mass productivity of the film forming apparatus illustrated in the second embodiment, the film forming apparatus illustrated in the following third embodiment may be used.

[Third embodiment]
FIG. 3 shows a third embodiment of the “organic thin film layer deposition apparatus for organic EL elements” of the present invention. The film forming apparatus shown here also corresponds to claim 8 as in the second embodiment described above. However, the configuration of the film forming unit is different from that of the second embodiment.

  The film forming unit of this embodiment is a case where a roll-shaped film substrate 13 is used, and a film is formed by a so-called roll-to-roll method. The film forming unit includes a roll film unwinding device 62 (substrate supply unit), a roll film film forming device 53 (sequential film forming unit), and a roll film winding device 66 (film forming substrate collecting unit). The die coating method is illustrated as a film forming method. The configuration and roles of the unit room 72, the film forming apparatus partition room 73, the dehumidifying apparatus 82, the benzene vapor generating apparatus 92, the exhaust duct 74, and the like are the same as those described above in the second embodiment, and thus the description thereof is omitted. To do.

  The roll film unwinding device 62 (substrate supply unit) places the roll film substrate 13 wound around the unwinding bobbin 621 on the unwinding stand 622 together with the unwinding bobbin 621, and the roll film substrate 13 from the end. The paper is unwound and continuously supplied to a roll film deposition apparatus 53 described later.

  The roll film deposition device 53 (sequential deposition unit) continuously applies an organic thin film solution containing a polymer and a benzene solvent to a roll-shaped film substrate 13 that is continuously supplied, and volatilizes the benzene solvent. A thin film layer is continuously formed. In this example, a die coat applicator 531 is used as the applicator. The roll-shaped film substrate 13 supplied to the roll film forming apparatus 53 is placed on the film forming conveyor 532, moves with the progress of the film forming conveyor 532, and is wound around a roll film winding apparatus 66 described later. . In the meantime, first, the organic thin film solution is applied by the die coat application device 531, and thereafter the benzene solvent in the applied organic thin film solution is volatilized and dried until it is wound on the roll film winding device 66. An organic thin film layer is formed. As in this embodiment, when the die coat applicator 531 is used, it can be applied in a short time. However, if the coating speed is increased too much, the benzene solvent is not easily volatilized from the coated organic thin film solution and may be wound around the roll film winder 66 in a wet state. For this reason, in this embodiment, a panel heater 533 is provided on the lower side of the die coat coating device 531 and in the vicinity of the film forming conveyor 532, and the surface temperature is set to 60 ° C., and the benzene solvent is easily volatilized from the applied organic thin film solution. is doing. Thereby, the film can be sufficiently formed even if the coating speed is increased.

  The roll film take-up device 66 (deposition substrate recovery unit) receives the formed roll-shaped film substrate 13 from the film formation conveyor 532 of the roll film formation device 53 and is provided at the leading end of the take-up stand 662 It will be wound around 661. The winding bobbin 661 is configured to wind a film substrate formed by rotating in a winding direction by a winding motor (not shown).

  The “organic thin film layer film forming apparatus for organic EL elements” of the third embodiment employs a roll-to-roll method, so that the film forming unit is simpler than the film forming apparatus of the second embodiment. Configuration is enough. Further, by using the die coat coating device 531, the coating can be performed in a short time.

  Note that the anode formed on the roll-shaped film substrate 13 can also be formed using this film forming apparatus. In this case, an ITO thin film solution in which ITO powder is uniformly dispersed in a solution obtained by dissolving a polymer in an organic solvent is applied on a roll film substrate 13 and dried to form an anode. Good.

[Fourth embodiment]
In the “organic thin film layer deposition apparatus for organic EL elements” of the third embodiment, a panel heater 533 is provided in the vicinity of the deposition conveyor 532 so that sufficient film deposition can be achieved even when the coating speed is increased. . However, providing a panel heater 533 as a heat source in an atmosphere containing chloroform vapor or benzene vapor is not preferable from the viewpoint of safety. Therefore, FIG. 4 illustrates a fourth embodiment of an organic thin film layer film forming apparatus configured to be able to form a film sufficiently without providing the panel heater 533. In addition, the film-forming apparatus shown here also respond | corresponds to Claim 8 like 2nd embodiment and 3rd embodiment mentioned above.

  In this embodiment, instead of removing the panel heater 533 (see FIG. 3) in the third embodiment from the configuration, a buffer mechanism is provided after the film forming conveyor 534 using a short film forming conveyor 534 (see FIG. 4). Is. This buffer mechanism suspends and holds the roll-shaped film substrate 13 coated with the organic thin film solution on two drooping rolls 535 and 536 in a state of being bent substantially vertically, and these two drooping rolls 535 and 536 are moved in the film feeding direction. And the roll film winder 66 is sequentially fed. The three curved lower end points 537, 538, 539 of the suspended roll-shaped film substrate 13 are respectively detected by position sensors (not shown), and two drooping points are applied depending on the coating speed so that the curved lower end points 537, 538, 539 exist in a predetermined height range. The rotational speed of the rolls 535 and 536 and the rotational speed of a winding motor (not shown) of the roll film winding device 66 are controlled.

  By adopting such a configuration, the time from coating by the die coat coating device 531 to winding on the roll film winding device 66 becomes longer. Therefore, the applied organic thin film solution can be sufficiently formed without providing a panel heater. The benzene vapor generator 92 is preferably an apparatus that generates benzene vapor by bubbling a gas in benzene, or an apparatus that generates benzene vapor using ultrasonic waves.

  Hereinafter, the “organic EL element” produced by using the “organic thin film layer forming method for organic EL element” of the present invention will be described in detail with reference to examples. FIG. 5 is a diagram for explaining Example 1 of the “organic EL element” of the present invention, and FIG. 6 is a diagram for explaining Example 2 of the “organic EL element” of the present invention. On the other hand, FIG. 7 is a diagram for explaining a comparative example 1 of a conventional “organic EL element”.

Example 1
The organic EL element 1 of Example 1 has the configuration shown in FIG. 5, and includes an anode 201, a hole injection layer 251, a light emitting layer 301, an electron injection layer 451, and a cathode 401 on a glass substrate 11. Although the hole transport layer 26 and the electron transport layer 46 are omitted from the structure of FIG. 9 described above, a material having a high hole mobility is used for the light emitting layer 301 in Example 1 shown in FIG. In use, the light emitting layer 30 in FIG. 9 is configured to function as the hole transport layer 26. In this embodiment, only the light emitting layer 301 is formed by using the “organic thin film layer forming method of an organic EL element” of the present invention.

  First, on a glass substrate 11 (t = 0.5 mm) made of soda glass, an indium tin oxide (ITO) transparent conductive thin film as an anode 201 was formed to a thickness of 150 nm by a sputtering method. Thereafter, this glass substrate was cut into a 10 mm square, subjected to ultrasonic cleaning in the order of acetone and IPA (isopropyl alcohol), then dried with vapor, and finally the surface of the ITO anode 201 was cleaned by plasma treatment to be cleaned. Next, a hole injection layer 251 was formed on the cleaned ITO anode 201. The hole injection layer 251 is formed by spin coating with a mixed suspension (0.3 mol / L) of PEDT (poly (3,4) ethylenedioxythiophene) which is a polythiofin derivative and PSS (polysulfonic acid) as a dopant. And 400 nm on the ITO anode. Application was performed in a water vapor atmosphere with a humidity of 40%. After coating, the film was dried by heating in an oven set at 200 ° C. for 30 minutes to obtain a hole injection layer 251 having a film thickness of 50 nm and an area resistance value of 100Ω / □. Next, a light emitting layer 301 was formed on the hole injection layer 251. The light-emitting layer 301 is prepared by dissolving 100 mg of polyfluorene, which is a π-conjugated polymer, as a light-emitting material in 1 L of purified chloroform to form an organic thin film solution. The organic thin film solution has a dew point of −70 ° C. and a chloroform vapor concentration. In a film formation chamber set to an atmosphere of 100 ppm, 100 nm was applied by spin coating. Thereafter, the film was left to dry in the film formation chamber for about 3 minutes to form a light emitting layer 301 having a thickness of 20 nm, and then heat treatment was performed in an oven set at 80 ° C. for 30 minutes. Next, an electron injection layer 451 was formed over the heat-treated light emitting layer 301. As the electron injection layer 451, Ca, which is an alkaline earth metal, was vacuum-deposited on the light emitting layer 301 to form an electron injection layer 451 having a thickness of 5 nm. Finally, Al was vacuum-deposited on the formed electron injection layer 451 to form a cathode 401 having a thickness of 100 nm.

When DC10V to DC30V were applied between both electrodes of the organic EL device 1 thus produced, blue light with a peak wavelength of 420 nm was emitted, and a maximum luminance of 4000 cd / m ² was obtained. The efficiency was 10 lm / W (10 lumens per watt). In this state, the sample was left in a room temperature and normal room atmosphere for 1000 hours, but dark spots were hardly generated. In Example 1, in place of the chloroform solvent used in the organic thin film solution for forming the light-emitting layer 301, a prototype evaluation was also made for one using a benzene solvent and one using a toluene solvent. And the same result as in Example 1 was obtained.

(Example 2)
The organic EL element 1 of Example 2 has the configuration shown in FIG. 6, and includes an anode 201, a hole transport layer 262, a light emitting layer 302, an electron transport layer 462, an electron injection layer 452, and a cathode 401 on the film substrate 12. Become. The hole injection layer 25 is omitted from the structure shown in FIG. In this embodiment, the hole transport layer 262, the light emitting layer 302, and the electron transport layer 462 are formed by using the “organic thin film layer forming method of an organic EL element” of the present invention.

  First, on the PET (polyethylene terephthalate) film substrate 12 (t = 0.2 mm), an ITO transparent conductive thin film as an anode 201 was formed to a thickness of 150 nm as in Example 1, and this substrate was formed into a 10 mm square. Then, the surface of the ITO anode 201 was cleaned. Next, a hole transport layer 262 was formed on the cleaned ITO anode 201. The hole transport layer 262 has 15 g of CuPc (copper phthalocyanine) having a hole injection function added to a solution obtained by dissolving 10 g of PVK (polyvinylcarbazole), which is a polymer having a conjugated system in the side chain, in 1 L of purified chloroform. The organic thin film solution is uniformly dispersed to form an organic thin film solution, and the organic thin film solution is applied by about 400 nm by a spin coating method in a film forming chamber set in an atmosphere having a dew point of −70 ° C. and a chloroform vapor concentration of 100 ppm. A hole transport layer 262 having a thickness of 100 nm was formed by leaving it in the film formation chamber for 3 minutes to dry. Next, a light emitting layer 302 was formed on the hole transport layer 262. The light-emitting layer 302 is obtained by adding 2.5 g of perylene as a dope dye to a solution obtained by dissolving 100 mg of PVK in 1 L of purified chloroform, and uniformly dispersing it to obtain an organic thin film solution. The organic thin film solution has a dew point of −70 ° C. and chloroform. In a film formation chamber set to an atmosphere with a vapor concentration of 100 ppm, coating was performed with a thickness of about 100 nm by a spin coating method, followed by drying in a film formation chamber for about 3 minutes to form a light emitting layer 302 with a thickness of 20 nm. Thereafter, heat treatment was performed for 30 minutes in an oven set at 80 ° C. Next, an electron transport layer 462 was formed on the light emitting layer 302. In the electron transport layer 462, 150 mg of PBD (2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxyazole) as an electron transport material was dissolved in 1 L of purified chloroform. The organic thin film solution was applied at about 400 nm by a spin coating method in a film forming chamber set to an atmosphere with a dew point of −70 ° C. and a chloroform vapor concentration of 100 ppm, and then left to dry in the film forming chamber for about 3 minutes. An electron transport layer 462 having a thickness of 100 nm was formed. Next, Ba was vacuum-deposited on the electron transport layer 462 to form an electron injection layer 452 having a thickness of 1 nm. Finally, Al was vacuum-deposited on the formed electron injection layer 452 to form a cathode 401 having a thickness of 100 nm.

When 10 V DC to 30 V DC was applied between both electrodes of the organic EL element 1 thus prepared, blue light with a peak wavelength of 505 nm was emitted, and a maximum luminance of 4000 cd / m ² was obtained. The efficiency was 15 lm / W. In this state, the sample was left in a room temperature and normal room atmosphere for 1000 hours, but dark spots were hardly generated.

In addition, instead of the PET film substrate 12 of Example 2 above, prototype evaluation was also conducted for those using a PEN (polyethylene naphthalate) film substrate and those using a PES (polyethersulfone) film substrate. Similar results to Example 2 were obtained. In addition, instead of CuPc used for the hole transport layer 262 of Example 2 above, trial evaluation was performed for those using carbazole, and the same results as in Example 2 were obtained. Further, instead of Ba used for the electron injection layer 452 of Example 2, trial production evaluation was performed for those using Ca, Mg, and Sr, and the same results as those of Example 2 were obtained. In addition, an iridium organometallic compound (Ir (ppy) ₃ ), which is a phosphorescent material, was used for the purpose of obtaining light emission from a triple light excited state in place of the perylene used in the light emitting layer 302 of Example 2 above. The prototype was also evaluated. When DC 10 V to DC 30 V were applied, green light emission was obtained. In this state, the sample was left in a room temperature and normal room atmosphere for 1000 hours, but almost no dark spots were generated.

(Example 3)
In Example 2 described above, the hole transport layer 262, the light emitting layer 302, and the electron transport layer 462 are formed in a film formation chamber set in an atmosphere having a dew point of −70 ° C. and a concentration of “benzene vapor” of 100 ppm. Produced an organic EL device under the same conditions. When DC 10 V to DC 30 V were applied between both electrodes of the obtained organic EL element, light was emitted with the same peak wavelength, maximum luminance and efficiency as in Example 2, and left in a room temperature and normal room atmosphere as in Example 2 for 1000 hours. However, almost no dark spots were generated.

Example 4
In Example 2 described above, the hole transport layer 262, the light emitting layer 302, and the electron transport layer 462 are formed in a film formation chamber set in an atmosphere having a dew point of −70 ° C. and a concentration of “toluene vapor” of 100 ppm. Produced an organic EL device under the same conditions. When DC 10 V to DC 30 V were applied between both electrodes of the obtained organic EL element, light was emitted with the same peak wavelength, maximum luminance and efficiency as in Example 2, and left in a room temperature and normal room atmosphere as in Example 2 for 1000 hours. However, almost no dark spots were generated.

(Comparative Example 1)
The organic EL element 1 of Comparative Example 1 has the configuration shown in FIG. 7 and comprises an anode 201, a hole transport layer 263, a light emitting layer 303, and a cathode 402 on a glass substrate 11. The hole transport layer 263 is added to the structure of FIG. 1 described above. In this comparative example, in the formation of the hole transport layer 263 and the light emitting layer 303, it was possible to use the “organic thin film layer formation method of an organic EL element” of the present invention, but an argon gas having a dew point of −70 ° C. The film was formed in the middle (low dew point inert atmosphere).

  First, in the same manner as in Example 1, an indium tin oxide (ITO) transparent conductive thin film as an anode 201 was formed to a thickness of 150 nm on a glass substrate 11 (t = 0.5 mm). A corner was cut out and the surface of the ITO anode 201 was cleaned. Next, a hole transport layer 263 was formed on the cleaned ITO anode 201. The hole transport layer 263 is uniformly dispersed by adding 5 g of carbazole having a hole transport function to a solution obtained by dissolving 10 g of PVK in 1 L of purified chloroform, and the organic thin film solution is placed in an argon gas atmosphere having a dew point of −70 ° C. After applying about 400 nm by spin coating in the set film formation chamber, the film was left to dry in the film formation chamber for about 3 minutes to form a hole transport layer 263 having a thickness of 50 nm. Next, a light emitting layer 303 was formed on the hole transport layer 263. The light emitting layer 303 uses the same organic thin film solution as in Example 2, that is, an organic thin film solution in which 2.5 g of perylene as a dope dye is added and uniformly dispersed in a solution obtained by dissolving 100 mg of PVK in 1 L of purified chloroform. . However, like the hole transport layer 263, the organic thin film solution is formed in a film formation chamber set in an argon gas atmosphere having a dew point of −70 ° C., which is different from Example 2. In this atmosphere, about 100 nm was applied by a spin coating method, and then left to dry in the film formation chamber for about 3 minutes to form a light emitting layer 303 having a thickness of 20 nm. Thereafter, heat treatment was performed for 30 minutes in an oven set at 80 ° C. Finally, Mg · Ag (magnesium silver alloy) was vacuum-deposited on the formed light-emitting layer 303 to form a cathode 402 having a thickness of 100 nm.

When DC 10 V to DC 30 V were applied between both electrodes of the organic EL device 1 thus prepared, blue light with a peak wavelength of 510 nm was emitted, and a maximum luminance of 3000 cd / m ² was obtained. The efficiency was 1 lm / W. In this state, the sample was left in a room temperature and normal room atmosphere for 1000 hours. When 100 hours passed, a clear black spot was generated. After 1000 hours, the light emitting part almost disappeared and dark spots were generated throughout. It was.

In addition, it replaced with the perylene used for the light emitting layer 303 of the said comparative example 1, and trial manufacture evaluation was also performed about what used the iridium organometallic compound (Ir (ppy) ₃ ) which is a phosphorescent material. When DC 10 V to DC 30 V were applied, green light emission was obtained. When left in a normal temperature room atmosphere for 1000 hours in this state, a black spot was clearly generated after 100 hours as in Comparative Example 1, and 1000 hours. After the lapse of time, dark spots were generated over the entire area so that the light emitting portion almost disappeared. In addition, a trial evaluation was performed on a product using BND of an oxadiazole derivative instead of the perylene used in the light emitting layer 303 of Comparative Example 1, and the same result was obtained.

(Comparative Example 2)
In Example 1 described above, the organic EL element is formed under the same conditions except that the light-emitting layer 301 (see FIG. 5) is formed in a film formation chamber set in an argon gas atmosphere (low dew point inert atmosphere) with a dew point of −70 ° C. Prototyped. When DC10V to DC30V were applied between both electrodes, as in Example 1, blue light having a peak wavelength of 420 nm was emitted, and a maximum luminance of 4000 cd / m ² was obtained. The efficiency was 10 lm / W as in Example 1. However, when left in a normal temperature and normal room atmosphere in this state for 1000 hours, unlike the result of Example 1, a black spot is clearly generated when 100 hours have passed, and the light emitting part almost disappears after 1000 hours. A dark spot was generated throughout.

  Table 1 below shows a list of evaluation results of the organic EL elements of Examples 1 to 4, Comparative Example 1 and Comparative Example 2. The elements using the film forming method of the present invention (Examples 1 to 4) generated dark spots over time as compared with the elements using the conventional film forming method (Comparative Examples 1 and 2). It is obvious that it is suppressed. In all examples and comparative examples, the organic solvent for the organic thin film solution for forming the organic thin film layer is a chloroform solvent. In addition, as described above, instead of the chloroform solvent of Example 1, a benzene solvent and a toluene solvent were used for trial production evaluation, and the same results as Example 1 were obtained. In all the examples and comparative examples, the dew point in the organic thin film layer deposition atmosphere is −70 ° C.

  The evaluation of the occurrence of dark spots was made visually. In the light emitting part (10 mm square), less than 6 dot-like dark spots are marked with ◎, and more than 6 and less than 16 are marked with ◯, and more than 16 and less than 41 are marked with △, and 41 or more. Further, the case where the proportion of the light emitting portion occupies less than 90% of the light emitting portion area was evaluated as x, and the case where the number of the light emitting portion was 41 or more and the proportion of the light emitting portion occupied 90% or more of the light emitting portion area was evaluated as xx.

  The present invention has been described above with reference to specific embodiments and examples. However, the present invention is not limited to the above-described embodiments, and is attached to the application for this application by those skilled in the art. Various changes and modifications can be made without departing from the scope of the appended claims.

It is the figure which showed 1st embodiment of the "organic thin film layer film-forming apparatus of an organic EL element" of this invention corresponding to Claim 7. FIG. 9 is a view showing a second embodiment of an “organic thin film layer film forming apparatus for organic EL elements” according to an eighth aspect of the present invention. FIG. 10 is a view showing a third embodiment of an “organic thin film layer film forming apparatus for organic EL elements” according to an eighth aspect of the present invention. FIG. 10 is a view showing a fourth embodiment of an “organic thin film layer forming apparatus for organic EL elements” according to an eighth aspect of the present invention. It is a figure for demonstrating Example 1 of the "organic EL element" of this invention. It is a figure for demonstrating Example 2 of the "organic EL element" of this invention. It is a figure for demonstrating the comparative example 1 of the conventional "organic EL element". It is a figure for demonstrating the element structure of an "organic EL element." It is a figure for demonstrating the element structure of an "organic EL element."

Explanation of symbols

1 Organic EL device
10 Board
11 Glass substrate
12 PET film substrate
13 Roll film substrate
20,201 anode
25,251 hole injection layer
26,262,263 hole transport layer
30,301,302,303 Light emitting layer
40,401,402 cathode
46,462 Electron transport layer
45,451,452 Electron injection layer

51 Spin coater
71 Deposition box (deposition chamber)
81 Dehumidifier
91 Chloroform vapor generator (organic vapor generator)

61 Single substrate supply equipment (substrate supply part)
52 Sequential deposition system (sequential deposition unit)
65 Deposition substrate recovery equipment (deposition substrate recovery section)
72 Unit room (deposition unit installation room)
73 Deposition unit partition room (Deposition unit cover)
731 Substrate material supply window
732 Deposition substrate recovery window
82 Dehumidifier
92 Benzene vapor generator (organic vapor generator)
74 Exhaust duct

62 Roll film unwinding device (substrate supply unit)
53 Roll film deposition system (sequential deposition unit)
66 Roll film take-up device (deposition substrate recovery unit)

Claims (8)

An organic thin film layer of an organic EL device that forms an organic thin film layer such as a light-emitting layer or a hole transport layer by coating an organic thin film solution containing a polymer and an organic solvent into a solid film and volatilizing the organic solvent. In the method
Prior to film formation, the organic thin film layer is formed by adjusting the atmosphere for forming the organic thin film layer to an atmosphere containing a low dew point and containing organic vapor, and forming the organic thin film layer in the atmosphere. Thin film layer deposition method.   The organic thin film layer forming method for an organic EL element according to claim 1, wherein the atmosphere having a low dew point and containing organic vapor has a dew point of -40 ° C or lower and an organic vapor concentration of 50 ppm or higher.   The organic thin film layer forming method for an organic EL element according to claim 1 or 2, wherein the organic vapor contained in the adjusted atmosphere is chloroform vapor, benzene vapor, toluene vapor, or a mixed vapor thereof.   The organic solvent contained in the organic thin film solution is a chloroform solvent, a benzene solvent, a toluene solvent, or a mixed solvent thereof. The organic thin film layer forming method for an organic EL element according to any one of claims 1 to 3.   The organic thin film layer film-forming method of the organic EL element according to any one of claims 1 to 4, wherein a die coating method is used for applying the organic thin film solution.   The organic EL element containing the organic thin film layer formed into a film by the film-forming method in any one of Claims 1-5. An organic thin film layer film forming apparatus for carrying out the organic thin film layer film forming method for an organic EL element according to claim 1,
A film forming unit for applying an organic thin film solution containing a polymer and an organic solvent into a solid film and volatilizing the organic solvent to form an organic thin film layer such as a light emitting layer or a hole transport layer;
A film forming chamber in which the film forming unit is installed, and a dehumidifier that adjusts the internal space of the film forming chamber to a low dew point atmosphere;
An organic thin film layer film forming apparatus for an organic EL element, comprising an organic vapor generator for adjusting an internal space of the film forming chamber to an atmosphere containing organic vapor. An organic thin film layer film forming apparatus for carrying out the organic thin film layer film forming method for an organic EL element according to claim 1,
A substrate supply unit for sequentially supplying substrate materials;
A sequential film forming unit that sequentially applies an organic thin film solution containing a polymer and an organic solvent to the supplied substrate material in a solid film form, volatilizes the organic solvent, and forms an organic thin film layer;
A film formation substrate recovery unit for sequentially recovering the film formation substrate material on which the organic thin film layer is formed;
The substrate supply unit, the sequential film formation unit and the film formation substrate collection unit is provided with a film formation unit installation chamber,
A film forming unit covering body provided inside the film forming unit installation chamber and covering only the film forming unit sequentially;
A substrate material supply window opened in the film formation unit covering body to supply substrate material from the substrate supply unit to the sequential film formation unit;
A film formation substrate recovery window opened in the film formation unit covering body so that the film formation substrate recovery unit recovers the film formation substrate material from the sequential film formation unit;
The dew point outside air taken in from the outside of the film forming unit installation chamber is dehumidified to a low dew point outside air, and the low dew point outside air is continuously supplied to the inside of the film forming unit installation chamber, thereby supplying the supplied low dew point outside air. A dehumidifying device that flows into the inside of the previous film formation section covering body through the substrate material supply window and the film formation substrate recovery window;
An organic vapor generator that discharges organic vapor into the low dew point outside air that has flowed into the film forming unit covering body, and makes the low dew point solvent inside air;
An organic thin film layer film forming apparatus for an organic EL element, provided with an exhaust duct for exhausting a low dew point solvent inside air present inside the film forming unit covering body to the outside of the film forming unit installation chamber.

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