JP2003203771A - Organic light emitting element, display device, and illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an organic electroluminescence element and a display device and an illumination device using the element from being deteriorated due to moisture absorption and oxidation. <P>SOLUTION: In this organic electroluminescence element, at least a reflective layer, a light emitting area including an organic material, and a transparent or semi-transparent electrode are sequentially formed on a substrate. A translucent protective film is formed on the transparent or semi-transparent electrode. The protective film comprises a multi-layer film formed by laminating multiple layers of at least two or more types of thin films having different refractive indexes. The refractive indexes of the thin films sequentially laminated on the upper electrode are set to N1, N2, N3...Nn, and the ratios N(n-1)/Nn and Nn/N(n+1) of the sequentially laminated adjacent refractive indexes of the thin films are set to 0.8 to 1.1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various display devices, light sources or backlights of display devices, or organic light emitting devices used in optical communication equipment.

[0002]

2. Description of the Related Art Organic light emitting devices, especially organic electroluminescent devices, are light emitting devices that utilize the electroluminescence of solid fluorescent substances, and currently inorganic electroluminescent devices using inorganic materials as light emitters are in practical use. Was converted into
The development of applications for liquid crystal display backlights, flat displays, etc. has been partially pursued. However, the inorganic electroluminescence element requires a high voltage of 100 V or more for emitting light, and it is difficult to emit blue light, so that it is difficult to achieve full-color by the three primary colors of RGB.

On the other hand, research on electroluminescent elements using organic materials has been attracting attention for a long time, and various studies have been made. However, since the luminous efficiency is extremely poor, full-scale practical research progresses. There wasn't.

However, in 1987, Kodak C.I.
W. Tang et al. Proposed an organic electroluminescence device having a function-separated laminated structure in which an organic material is divided into two layers, a hole transport layer and a light-emitting layer, and the organic electroluminescence device has a low voltage of 10 V or less and 1000 cd / m ² It was revealed that the above high emission brightness can be obtained [C. W. Tang
and S. A. Vanslyke: Appl. Phy
s. Lett, 51 (1987) 913, etc.]. Since then, the light-emitting element has begun to receive a lot of attention, and even now, much research is being done on an organic electroluminescent element having a similar function-separated laminated structure.

Here, a conventional organic electroluminescent device will be described with reference to the drawings. FIG. 4 is a cross-sectional view of a main part of a conventional organic electroluminescence element. Figure 4
As shown in FIG. 1, the conventional organic electroluminescence device includes a transparent or semi-transparent substrate 1 such as glass and a transparent conductive material such as ITO formed on the substrate 1 by a sputtering method or a resistance heating vapor deposition method. A lower electrode 2 as a hole injection electrode made of a film, and N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1, formed on the lower electrode 2 by a resistance heating vapor deposition method, 1'-diphenyl-4,
A hole transport layer 4 made of 4′-diamine (hereinafter abbreviated as TPD) or the like, and 8-Hydroxyquinoline formed on the hole transport layer 4 by a resistance heating vapor deposition method or the like.
Aluminum (hereinafter abbreviated as Alq ₃ ) or the like, a light emitting layer 5, an upper electrode 6 as an electron injecting electrode made of a metal film formed on the light emitting layer 5 by a resistance heating vapor deposition method, and the like. And a protective film formed on.

In the organic electroluminescence device shown in FIG. 4, the organic layer 3 is composed of the hole transport layer 4 and the light emitting layer 5.

When a DC voltage or a DC current is applied with the lower electrode 2 as a hole injecting electrode and the upper electrode 6 as an electron injecting electrode of the light emitting element having the above structure as a positive electrode and a negative electrode, respectively, a DC voltage or a DC current is applied, Holes are injected into the light emitting layer 5 through the hole transport layer 4, and electrons are injected into the light emitting layer 5 from the upper electrode 6. Recombination of holes and electrons occurs in the light emitting layer 5, and a light emission phenomenon occurs when excitons generated accompanying this transition from the excited state to the ground state. Also,
The emission wavelength can be changed by changing the layer structure of the organic layer 3 and the material used for the light emitting layer 5.

In order to improve the light emission characteristics of such a light emitting device, heretofore, (1) the constitution of an organic layer such as a light emitting layer and a hole transport layer and the improvement of an organic material used therefor, or (2) a hole Improvements in materials used for injection electrodes and electron injection electrodes have been studied.

For example, with respect to (2), US Pat. No. 4,885,521 aims to lower the barrier between the electron injecting electrode and the light emitting layer so that electrons can be easily injected into the light emitting layer.
1 and the Mg-Ag alloy described in JP-A-5-1211.
A material having a small work function and high electric conductivity, such as an Al-Li alloy described in Japanese Patent Laid-Open No. 72, has been proposed, and such a material is widely used even now. In addition, recently, device design for efficiently extracting emitted light has also attracted attention as an important development factor. When the emitted light generated in the EL element is emitted to the outside through the glass substrate 1 (under-light extraction configuration), the emission rate is about 20%, and the remaining 80% is the emission layer 5 or the glass substrate 1.
Waves are guided to be absorbed by the metal surface or emitted from the edge of the substrate. Further, when the organic EL display is controlled using a switching element such as a thin film transistor, there is a problem that the switching element formed on the substrate lowers the aperture ratio of the pixel. In other words, if the light is extracted from the substrate side, it is very difficult to improve the total luminous efficiency because some light is confined in the substrate.

Therefore, FIG. 5 shows the structure of an EL element proposed in order to efficiently take out the emitted light generated inside the element to the outside of the element to improve the luminous efficiency.

As shown in FIG. 5, the upper electrode 6 is not made of an opaque metallic material such as Al but is made of ITO, SnO ₂ , In.
A transparent or semitransparent electrode made of O ₃ , ZnO, a complex of these oxides, or a combination of a metal thin film such as Mg—Ag and a transparent conductive film is used.

By using a transparent conductive film material for the upper electrode 6, the light emitting layer 5 is formed from the side of the cathode electrode which becomes the upper electrode of the light emitting element.
It becomes possible to take out the light emitted by. As shown in FIG. 5, the light emitted from the light emitting layer 5 passes through the transparent upper electrode 6 and goes out. When the lower electrode 2 is an opaque metal material (reflection electrode), the light that has traveled to the lower electrode 2 side is reflected by the lower electrode 2 and thus travels to the upper electrode 6 side and goes out through the upper electrode 6 to the outside. . When the electrodes are made of a transparent conductive film material, the light emitting layer 5 is formed by combining a reflective layer (scattering layer, not shown) on the glass substrate 1, for example.
The light that has been emitted by and has traveled to the lower electrode 2 side is reflected by the reflective layer,
As a result, it goes to the upper electrode 6 side and goes out through the upper electrode 6.

Since the emitted light generated in such an organic electroluminescence device is not emitted to the outside through the glass substrate 1, the emission ratio to the outside is increased as compared with the configuration of FIG.

However, since the alloy material forming the organic electroluminescence element as described above has high activity and is chemically unstable, corrosion or oxidation occurs due to the reaction with moisture or oxygen in the air. Corrosion and oxidation of such an electron injecting electrode significantly grows a non-light emitting portion called a dark spot existing in the light emitting layer, or lowers the light emission brightness of the entire light emitting layer. This is a cause of characteristic deterioration over time.

Further, not only the electron injecting electrode but also the organic material used for the organic layer such as the light emitting layer and the hole transporting layer,
In general, the structure changes due to the reaction with water or oxygen, which similarly causes the growth of dark spots and the reduction of the emission brightness.

Therefore, in order to improve the durability and reliability of the organic electroluminescent element, in order to prevent the reaction between the material used for the electron injecting electrode and the organic layer and moisture and oxygen, the whole organic electroluminescent element is Must be sealed.

Regarding the encapsulation of the organic electroluminescent element, two methods have been mainly studied so far. One is to form a protective film on the outer surface of the organic electroluminescent element by using a vacuum film forming technique such as vapor deposition, and the other is to seal a glass cap or the like to the light emitting element. is there.

A method for forming a protective film and sealing a light emitting element is described in, for example, Japanese Patent Application Laid-Open No. 6-96858, Ge.
A method of forming O, SiO, AlF ₃ or the like on the outer surface of a light emitting element by using an ion plating method is disclosed. Further, Japanese Patent Application Laid-Open No. 7-212455 discloses a method of forming a protective film composed of a water-absorbing substance having a water absorption rate of 1% or more and a moisture-proof substance having a water absorption rate of 0.1% or less.

As a method for sealing a light emitting element by sealing a glass cap or the like, a glass plate is provided outside the back electrode and the back electrode is used, as has already been used in inorganic electroluminescence elements. There is a method of enclosing silicone oil between the glass plate and the glass plate. In addition to this, JP-A-5-089959 discloses a method of forming a protective film made of an insulating inorganic compound and then shielding it with an electrically insulating glass or an electrically insulating hermetic fluid.

[0020]

As a result of studying the growth of dark spots from various viewpoints, for example, 133 ×
It was confirmed that even a trace amount of water existing in a vacuum of about 10 ⁻⁴ Pa (10 ⁻⁴ Torr) promotes the growth of dark spots.

Therefore, in order to completely eliminate the growth of dark spots, it is necessary to almost completely block the ingress of water and oxygen into the materials used for the electron injection electrode and the organic thin film layer.

By the way, regarding the organic material used for the organic electroluminescent element, the upper limit of the heating temperature allowed in the manufacturing process is about 100 ° C. due to its characteristics. Therefore, this temperature cannot be exceeded even when the protective film is formed by the vapor deposition method, but oxides such as GeO, SiO, and SiO ₂ used as the protective film are generally sufficiently dense at a low temperature of about 100 ° C. It is difficult to form such a film, and under such film formation conditions, many defects and pinholes exist in the film, and a single layer cannot completely block moisture and oxygen. Even if an attempt is made to solve these problems by increasing the film thickness, the internal stress of the protective film increases as the film thickness increases, damaging the electron injecting electrode and the organic thin film layer and decreasing the emission brightness. Or a short circuit of the light emitting element may occur.

On the other hand, the cause of the dark spot is mainly due to dirt on the hole injecting electrode such as an ITO film or dust adhering to the substrate. In the case of an ITO film, stains on the surface can be almost solved by devising a cleaning method, but it is difficult to completely eliminate dust adhering to the substrate. For example, even if a light emitting element is manufactured in a clean room, even if it is a class 100 clean room,
1/10 liters of dust with a particle size of about m are present. Further, a large amount of dust also exists in the vapor deposition apparatus used in the manufacturing process, and the dust often adheres to the substrate during film formation. Therefore, even when working in a clean room with a high degree of cleanliness, dust is present at a considerably high rate on the substrate, and it is extremely difficult to completely prevent the generation of dark spots.

Further, since the dark spots are caused by dusts of about several μm existing on the substrate, an organic layer of about 0.1 μm, an upper electrode of about 0.2 μm, as in a conventional light emitting device, With the protective film of about 0.5 μm formed on these, the dust cannot be completely covered because the total film thickness is about 1 μm. Therefore, even if the protective film itself has a property of not permeating oxygen or moisture, if the dust cannot be completely covered by the protective film, oxygen and moisture will eventually be removed from the peripheral portion of the dust. The dark spots grow by entering the organic thin film layer and the electron injection electrode.

Furthermore, the sealing with a glass cap, which has been tried so far, has not yet completely suppressed the growth of dark spots.

The epoxy resin used for sealing the electrically insulating glass and the substrate described in JP-A-5-089959 mentioned above is generally 3 to 5 (g / m ² · 24 h /
mm), and even with polyimide resin 2 (g / m ² · 24h)
/ Mm) of water vapor permeability, it is impossible to completely suppress the ingress of water from the sealed portion.

As described above, it is impossible to completely suppress the growth of dark spots by sealing with a protective film or a glass cap that has been used in conventional light emitting devices.

Therefore, Japanese Patent Laid-Open No. 10-41067 discloses a method of completely covering the above dust with a protective film. At least 2 having an insulating compound as the lowermost layer on the outer surface of the organic electroluminescent device.
A method for forming a protective film having a film thickness of 3 μm to 30 μm, which includes a laminated film having at least layers, is disclosed.

However, when the above method is used for the above-mentioned light extraction structure which is considered to have good light extraction efficiency,
The emitted light passes through the upper electrode on the light extraction side and the protective film,
Light will be emitted to the outside. As a result, the emission ratio of the emitted light due to the interface reflection of the upper electrode and each protective film, absorption, multilayer film interference, etc. is reduced, and further, the transmittance is reduced and the emission characteristic is deteriorated due to the viewing angle dependency. Problem has occurred. In this case, the effect of the light extraction structure is not exhibited.

However, as described above, the organic electroluminescent element has low heat resistance, and it is extremely difficult to form a high quality single layer film having both barrier property and transparency at a substrate temperature of 100 ° C. or less. Is.

The present invention solves the above problems by completely blocking the ingress of moisture and oxygen into the upper electrode and the organic layer, preventing the growth of dark spots in the light emitting layer, and emitting light. It is an object of the present invention to provide a light emitting element capable of suppressing a decrease in luminance with time and an element having a light extraction efficiency improved by extracting light from the element side.

[0032]

In order to solve this problem, the present invention firstly provides, in an organic light emitting device, a substrate, a light emitting region comprising a reflective layer and an organic thin film layer laminated on the substrate, A laminated structure including a transparent or semi-transparent upper electrode, the protective film having a light-transmitting property formed on an outer surface of the laminated structure, wherein the protective film is made of at least 2 different materials. A multi-layered film formed by laminating a plurality of translucent films of a kind or more, and the refractive index of the film group sequentially laminated on the upper electrode is N1, N2, N3 ... Nn,
The refractive index ratio N (n-
1) / Nn and Nn / N (n + 1) are 0.8 or more and 1.1 or less.

Secondly, in the organic light emitting device, the difference between the maximum value and the minimum value of the relative transmittance of light having a wavelength of 400 nm to 780 nm which is transmitted through the protective film is 15% or less.

Thirdly, in the organic light emitting device, the protective film is composed of a multi-layered film in which a plurality of translucent films of at least two different materials are laminated, and the multi-layered film has a moisture permeability. It is characterized in that it is 1 × 10 ⁻² g / m ² / day / atm or less.

Fourth, in the organic light emitting device, the protection
The film stress is 500 MPa (5 x 10 ⁸Pa) or less
It is characterized by

Fifth, in the organic light emitting device, the protective film is composed of a multi-layered film in which a plurality of translucent films of at least two different materials are laminated, and the protective film of the translucent film is formed. It is characterized in that the number of layers is two or more and 50 or less.

Sixth, in the organic light emitting device, the protective film is a multi-layered film formed by laminating a plurality of translucent films of at least two different materials, and the multi-layered film is made of an organic material. It is characterized in that a buffer layer and a barrier film made of an inorganic material are alternately laminated.

Seventh, the organic light emitting device is characterized in that the barrier film group made of the inorganic material is in an amorphous state.

Eighth, the organic light emitting device is characterized in that the barrier film group made of the inorganic material is a metal, a metal oxide, a metal nitride or a metal oxynitride.

Ninth, in the light emitting element, the moisture permeability (or water permeability) of the barrier film group made of the inorganic material is 10 g /
It is characterized in that it is not more than m ² / day / atm.

Tenth, in the organic light emitting device, the barrier film group made of the inorganic material is formed by the sputtering method, and the moisture permeability (or water permeability) is 1 g / m ² / day / atm.
It is characterized by the following.

Eleventh, in the organic light emitting device, the film thickness of the barrier film group made of the inorganic material is 2 nm or more and 50 n or more.
It is characterized by being m or less.

Twelfth, in the organic light emitting device, the saturated water absorption of the buffer layer group made of the organic material is 1% (23%).
℃) or less.

Thirteenth, in the organic light emitting device, the Young's modulus of the buffer layer group made of the organic material is 5 × 10 5.
^{It is characterized by being 8} (N / m ² ) or more and 9 × 10 ⁹ (N / m ² ) or less.

Fourteenth, in the organic light emitting device, the coefficient of thermal expansion of the buffer layer group made of the organic material is 8 × 10 ^5.
It is characterized by being (K ⁻¹ ) or less.

Fifteenth, in the organic light emitting device, the organic material is a polymerizable functional group containing at least one of an acrylate group and a methacrylate group, and at least one of an aromatic group, an alicyclic group and a thioether group. It is characterized by comprising a skeletal structure containing.

Sixteenth, in the organic light emitting device, the thickness dn of the buffer layer group made of the organic material is 0.4 × λ.
/Nn<dn<0.6×λ/Nn.

Seventeenth, in the organic light emitting device, the central wavelength of the emitted light emitted from the light emitting region is λ, the refractive index of the outermost layer of the protective film is N (n + 1), and the outermost layer of the protective film is the film. The thickness d (n + 1) is 0.4 × λ / N (n +
1) <d (n + 1) <0.6 × λ / N (n + 1).

Eighteenth, in the organic light emitting device, the central wavelength λ is 550 nm.

The nineteenth feature is that, in the organic light emitting device, the film thickness of the buffer layer group made of the organic material is 0.2 μm or more and 30 μm or less.

20th, in the organic electroluminescent element, the lowermost layer of the protective film is made of an organic material.

Twenty-first, in the organic light emitting device, the lowermost layer of the protective film is made of an organic material and has a film thickness which is 2 times or more and 10 times or less than the maximum unevenness of the surface of the substrate having the laminated structure. Characterize.

Twenty-second, in the organic light emitting device, the protective film has a plurality of film thicknesses so that emitted light emitted from the light emitting region can be efficiently extracted through the protective film. .

Twenty-third, in the organic light emitting device, the film thickness of the outermost layer of the protective film is 50 nm or more and 250 nm or less.

Twenty-fourth, the organic light emitting device is characterized in that the outermost layer of the protective film has a refractive index smaller than that of the upper electrode.

Twenty-fifth, in the organic light emitting device, the outermost layer of the protective film is made of a thin film having the smallest refractive index among two or more kinds of translucent film groups made of different materials. .

Twenty-sixth, in the method for manufacturing an organic light emitting device, a laminated structure comprising a substrate, a light emitting region comprising a reflective layer and an organic thin film layer laminated on the substrate, and a transparent or semitransparent upper electrode. A step of forming a body, and a step of alternately and repeatedly laminating a buffer layer made of an organic material and a barrier film made of an inorganic material on the outer surface of the laminated structure, wherein the step is performed in the atmosphere even once. It is characterized in that it is continuously formed in a vacuum without being taken out, and then heat treatment is performed.

Twenty-seventh, in the method for manufacturing an organic light emitting device, all of the above steps are performed at a substrate temperature of 100 ° C. or lower.

Twenty-eighthly, in the method of manufacturing an organic light emitting device, the buffer layer group made of the organic material is characterized in that after being deposited by a vapor deposition method, it is cured by electron beam irradiation.

Twenty-ninth, in the method for manufacturing an organic light emitting device, the barrier film group made of the inorganic material is laminated by a sputtering method, and the moisture permeability of the barrier film group is 1 g / m ² / d.
It is characterized in that it is adjusted to be not more than ay / atm.

Thirtieth, in the method for manufacturing an organic light emitting device, the barrier film group made of the inorganic material is formed by vapor deposition, and the moisture permeability of the barrier film group is 7 g / m ² / day /
It is characterized in that it is adjusted to be equal to or less than atm.

Thirty-first, the organic light emitting device is characterized in that a film having a light control function is attached to the outer surface of the protective film.

[0063]

BEST MODE FOR CARRYING OUT THE INVENTION As the substrate used in the present invention, transparent or translucent glass, PET (polyethylene terephthalate), polycarbonate, amorphous polyolefin or the like is used. Further, the substrate may be a flexible substrate in which these materials are thin films or a flexible substrate.

As the lower electrode, ITO or ATO is used.
(Sb-doped SnO ₂ ), AZO (Al-doped ZnO), or the like is used.

In addition to the single-layer structure of the light-emitting layer, the organic layer includes a hole-transporting layer and a light-emitting layer or a light-emitting layer and an electron-transporting layer.
Any of a layer structure and a three-layer structure of a hole transport layer, a light emitting layer and an electron transport layer may be used. However, in the case of such a two-layer structure or a three-layer structure, the hole transport layer and the hole injection electrode are
Alternatively, the electron-transporting layer and the electron-injecting electrode are stacked so that they are in contact with each other.

The light emitting layer is preferably made of a phosphor having a fluorescent property in the visible region and having a good film-forming property, such as Alq ₃ or Be-benzoquinolinol (BeB).
In addition to the q _2), 2,5-bis (5,7-di -t- pentyl-2-benzoxazolyl) -1,3,4-thiadiazole, 4,4'-bis (5,7 Pentyl-2-benzoxazolyl) stilbene, 4,4′-bis [5,7
-Di- (2-methyl-2-butyl) -2-benzoxazolyl] stilbene, 2,5-bis (5,7-di-t-
Bentyl-2-benzoxazolyl) thiophene, 2,
5-bis ([5-α, α-dimethylbenzyl] -2-benzoxazolyl) thiophene, 2,5-bis [5,7
-Di- (2-methyl-2-butyl) -2-benzoxazolyl] -3,4-diphenylthiophene, 2,5-bis (5-methyl-2-benzoxazolyl) thiophene, 4,4 '-Bis (2-benzoxazolyl) biphenyl, 5-methyl-2- [2- [4- (5-methyl-
2-benzoxazolyl) phenyl] vinyl] benzoxazolyl, benzoxazoles such as 2- [2- (4-chlorophenyl) vinyl] naphtho [1,2-d] oxazole, 2,2 ′-(p -Phenylenedivinylene) -benzothiazoles such as bisbenzothiazole,
Fluorescent brighteners such as 2- [2- [4- (2-benzimidazolyl) phenyl] vinyl] benzimidazole and 2- [2- (4-carboxyphenyl) vinyl] benzimidazole based benzimidazoles and tris ( 8-quinolinol) aluminum, bis (8-quinolinol)
Magnesium, bis (benzo [f] -8-quinolinol) zinc, bis (2-methyl-8-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, 8- 8 such as lithium quinolinol, tris (5-chloro-8-quinolinol) gallium, bis (5-chloro-8-quinolinol) calcium, poly [zinc-bis (8-hydroxy-5-quinolinol) methane]
-A metal chelated oxinoid compound such as a hydroxyquinoline-based metal complex or dilithium epindridione,
1,4-bis (2-methylstyryl) benzene, 1,4
-(3-Methylstyryl) benzene, 1,4-bis (4
-Methylstyryl) benzene, distyrylbenzene,
1,4-bis (2-ethylstyryl) benzene, 1,4
-Styrylbenzene compounds such as bis (3-ethylstyryl) benzene and 1,4-bis (2-methylstyryl) 2-methylbenzene, 2,5-bis (4-methylstyryl) pyrazine, 2,5- Bis (4-ethylstyryl)
Pyrazine, 2,5-bis [2- (1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxystyryl)
Distilpyrazine derivatives such as pyrazine, 2,5-bis [2- (4-biphenyl) vinyl] pyrazine, and 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine, naphthalimide derivatives, and perylene derivatives Further, an oxadiazole derivative, an aldazine derivative, a cyclopentadiene derivative, a styrylamine derivative, a coumarin derivative, an aromatic dimethylidin derivative, etc. are used. Further, anthracene, salicylate, pyrene, coronene and the like are also used.

The hole transporting layer is preferably one having a high hole mobility, being transparent and having a good film-forming property. In addition to TPD, porphine, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine, titanium phthalocyanine oxide is preferable. Such as porphyrin compounds, 1,1-bis {4- (di-P-tolylamino) phenyl} cyclohexane, 4,4 ′, 4 ″ -trimethyltriphenylamine, N, N, N ′, N′-tetrakis (P-tolyl)-
P-phenylenediamine, 1- (N, N-di-P-tolylamino) naphthalene, 4,4'-bis (dimethylamino) -2-2'-dimethyltriphenylmethane, N,
N, N ', N'-tetraphenyl-4,4'-diaminobiphenyl, N, N'-diphenyl-N, N'-di-m
-Aryl such as tolyl-4, N, N-diphenyl-N, N'-bis (3-methylphenyl) -1,1'-4,4'-diamine, 4'-diaminobiphenyl, N-phenylcarbazole Tertiary amine, 4-di-P-tolylaminostilbene, 4- (di-P-tolylamino) -4 '
-[4- (di-P-tolylamino) styryl] stilbene and other stilbene compounds, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, and phenylenediamines Derivatives, annealed amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, polysilane-based aniline-based copolymers, polymer oligomers, styryl An amine compound, an aromatic dimethylidene compound, or an organic material such as poly-3-methylthiophene is used. Further, a polymer-dispersed hole transport layer in which a low molecular weight organic material for a hole transport layer is dispersed in a polymer such as polycarbonate is also used.

As the electron transport layer, 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7) and other joxadiazole derivatives and anthraquinodimethane derivatives are used. , Diphenylquinone derivatives and the like are used.

As the upper electrode, ITO or SnO is used.
₂ , InO ₃ , ZnO, or a complex of these oxides,
Alternatively, a transparent or semitransparent electrode made of a combination of a metal alloy such as Mg-Ag or other metal thin film and a transparent conductive film is used.

Further, as the protective layer, GeO, SiO
x, SiO ₂ , MgO ₃ , Al ₂ O _{3 and} other oxides, Al
A nitride such as N or Si ₃ N ₄ , a thermoplastic organic polymer such as PET, or a curable organic polymer such as polyacrylate or polymethacrylate is used.

Further, Ag, In, Cu, Al, Cr, F
An organic material containing metal particles such as e and Ti is used.

Specific examples in the embodiments of the present invention will be described below.

(Embodiment 1) FIG. 1 is a sectional view of a main part of a light emitting device according to an embodiment of the present invention. After forming an ITO film having a thickness of 160 nm as the lower electrode 102 on the glass substrate 101 by a sputtering method, a resist material (OFPR-800 manufactured by Tokyo Ohka Co., Ltd.) is applied on the ITO film by a spin coating method to form a film. A resist film having a thickness of 10 μm was formed, and the resist film was patterned into a predetermined shape by masking, exposing and developing. Next, this glass substrate 6
After immersing in 50% hydrochloric acid at 0 ° C. to etch the ITO film in the portion where the resist film is not formed, the resist film is also removed to form a hole injection electrode made of the ITO film having a predetermined pattern. A glass substrate was obtained.

Next, this glass substrate was ultrasonically cleaned with a detergent (Semicoclean, manufactured by Furuuchi Chemical Co., Ltd.) for 5 minutes, ultrasonically cleaned with pure water for 10 minutes, aqueous ammonia 1
After ultrasonic cleaning for 5 minutes with a solution of hydrogen peroxide water 1 and water 5 mixed (volume ratio) and ultrasonic cleaning for 5 minutes with pure water at 70 ° C., the glass was cleaned with a nitrogen blower. Water adhering to the substrate was removed, and the substrate was further heated to 250 ° C. and dried.

On the surface of the dried glass substrate on the side of the hole injection electrode, the hole transport layer was placed in a resistance heating vapor deposition apparatus depressurized to a vacuum degree of 266 × 10 ⁻⁶ Pa (2 × 10 ⁻⁶ Torr) or less. As 103, TPD was formed with a film thickness of about 50 nm.

Next, in the same manner as above, in the resistance heating vapor deposition device, Alq ₃ as a light emitting layer 104 was formed on the hole transport layer to a thickness of about 75 nm.
It was formed with a film thickness of. The vapor deposition rates of TPD and Alq ₃ were both 0.2 nm / s.

Next, similarly, in the resistance heating vapor deposition apparatus, Mg-Ag having a film thickness of 5 nm was formed on the light emitting layer, and then the Mg-
Indium tin oxide (ITO) was formed on Ag by ion beam sputtering to have a film thickness of 130 nm to form the upper electrode 105.

The refractive index of the ITO film according to the first embodiment was 1.9.

By the above method, a plurality of glass substrates having the lower electrode 102, the hole transport layer 103, the light emitting layer 104, and the upper electrode 105 laminated thereon were prepared, and at least the hole transport layer and the light emitting layer were formed on these glass substrates. After evaporating the acrylic monomer onto the substrate so that the organic thin film layer consisting of and the electron injecting electrode are sealed, the electron beam is irradiated to polymerize on the substrate to form a buffer layer having a refractive index of 1.65. The thickness was about 3 μm, and the surface roughness was 50 nm or less. The lowermost layer of the protective film is an organic electroluminescence element (hereinafter referred to as an organic EL).
2 times or more the surface roughness of the laminated structure on which elements are formed 1
The thickness is preferably 0 times or less. This has the effect of flattening the surface irregularities, preventing cracks in the barrier film to be laminated, and improving reliability. Next, the refractive index is 1.66 by the ion beam sputtering method.
Al ₂ O ₃ film having a thickness of 15 nm is formed, and thereafter,
A buffer layer having a thickness of 0.3 μm was formed in the same manner as the lowermost layer. By repeating this operation, 10 layers each of a film made of an acrylic resin and Al ₂ O ₃ were formed alternately. After that, the outermost layer made of SiO _{2 is formed} by ion beam sputtering to 180
It was formed with a film thickness of nm. After that, heat treatment is performed at 80 ° C. for 3 hours. All of the above steps were performed without ever being taken out into the atmosphere. Refractive index of the SiO ₂ film N (Si
O ₂ ) is 1.45, which is smaller than the refractive index of the upper electrode 105. Further, SiO ₂ film having a thickness d (SiO _2), as emitted light is extracted through the efficient protective film, with respect to the central wavelength _{λ = 550nm, d (SiO 2} ) = 0.47
It is formed of λ / N (SiO ₂ ).

In the first embodiment, the ratio of the refractive indexes of the acrylic resin layer and the Al ₂ O ₃ layer is 1.65 / 1.66 =
It is 0.99. In the present invention, the refractive index ratio of the adjacent thin films is preferably 0.8 or more and 1.1 or less, and more preferably 0.95 or more and 1.05 or less.

Still more preferably, the ratio of the refractive index of the buffer layer to the barrier film is 0.95 or more and 0.97 or less, or 0.
It is preferably 98 or more and 1 or less and 1.02 or less, and 1.03 or more and 1.05 or less.

In the first embodiment, the thickness of the Al ₂ O ₃ layer is 15 nm, but in the present invention, the thickness of the thin film is preferably 50 nm or less. This is because the light more remarkably exhibits the characteristics of particles as waves.

Further, it is preferable that the thin film has a thickness of 2 nm or more. This is because the thin film is necessary for having a sufficient barrier property.

The moisture permeability of the Al ₂ O ₃ film is 0.5 g / m.
^It has a water vapor barrier property of ² / day / atm or less.

The moisture permeability of the SiO ₂ film is 1 g / m ² / d.
It has a water vapor barrier property of not more than ay / atm.

The moisture permeability of the protective film is 10 ^-6 g / m ² / day
It was about / atm.

(Embodiment 2) A light emitting device according to a second embodiment of the present invention will be described. The method of forming the light emitting element according to the second embodiment is the same as that of the first embodiment, and thus the description thereof is omitted.

The refractive index of the ITO film in the second embodiment was 1.9.

A plurality of glass substrates in which the lower electrode 102, the hole transport layer 103, the light emitting layer 104, and the upper electrode 105 are laminated are manufactured by the above method, and at least the hole transport layer and the light emitting layer are formed on these glass substrates. After evaporating the acrylic monomer onto the substrate so that the organic thin film layer consisting of and the electron injecting electrode are sealed, the electron beam is irradiated to polymerize on the substrate to form a buffer layer having a refractive index of 1.65. About 0.3 μm
Formed. Then, an Al ₂ O ₃ film having a refractive index of 1.66 was formed with a film thickness of 15 nm by an ion beam sputtering method. Repeating this operation, acrylic resin and Al ₂
Ten layers of O ₃ films were alternately formed. Then 7
Heat treatment is performed at 0 ° C. for 5 hours. All of the above steps were performed without ever being taken out into the atmosphere. Then, a light control film having a light condensing and diffusing function is attached.

In the second embodiment, the ratio of the refractive indexes of the acrylic resin layer and the Al ₂ O ₃ layer is 1.65 / 1.66 =
It is 0.99. In the present invention, the refractive index ratio of the adjacent thin films is preferably 0.8 or more and 1.1 or less, and more preferably 0.95 or more and 1.05 or less.

More preferably, the ratio of the refractive index of the buffer layer to the barrier film is 0.95 or more and 0.97 or less, or 0.
It is preferably 98 or more and 1 or less and 1.02 or less, and 1.03 or more and 1.05 or less.

In the second embodiment, the thickness of the Al ₂ O ₃ layer is 15 nm, but in the present invention, the thickness of the thin film is preferably 50 nm or less. This is because the light more remarkably exhibits the characteristics of particles as waves.

Further, the thickness of the thin film is preferably 2 nm or more. This is because the thin film is necessary for having a sufficient barrier property.

The water permeability of the Al ₂ O ₃ film is 0.5 g / m.
^It has a water vapor barrier property of ² · day or less.

The water permeability of the protective film is 10 ⁻⁵ g / m ² · day.
It was about.

(Embodiment 3) A third embodiment of the present invention will be described. The method of forming the light emitting element according to the third embodiment is the same as that of the first and second embodiments up to the process of forming the light emitting layer, and thus the description thereof is omitted.

Alq as a light emitting layer 104 on the hole transport layer.
After forming ₃ , the Mg-Ag was formed in a thickness of 5 nm on the light emitting layer in the same manner in the resistance heating vapor deposition apparatus, and indium tin oxide (ITO) was formed on the Mg-Ag by ion beam sputtering to a thickness of 120 nm. The upper electrode 105 was formed with a film thickness.

The refractive index of the ITO film in the third embodiment was 2.1.

A plurality of glass substrates in which the lower electrode 102, the hole transport layer 103, the light emitting layer 104, and the upper electrode 105 are laminated are manufactured by the above method, and at least the hole transport layer and the light emitting layer are formed on these glass substrates. The lowest layer having a refractive index of 1.46 after evaporating an epoxy-based monomer onto a substrate so as to seal the organic thin film layer consisting of About 3 buffer layers
μm, and the surface unevenness was set to 30 nm or less. Then
A SiO ₂ film having a refractive index of 1.45 is formed to a thickness of about 20 nm by an ion beam sputtering method, and then a buffer layer is formed to a thickness of about 0.3 μm in the same manner as the lowermost layer. By repeating the same operation, epoxy resin and SiO ₂
10 layers each of which consisted of The refractive index N (SiO ₂ ) of the SiO ₂ film is 1.45, and the upper electrode 105
Has a refractive index smaller than that of the protective film. Further, a light control film having a light converging and diffusing effect is attached on the protective film via an adhesive layer (not shown).

In the third embodiment, the refractive index ratio between the epoxy resin layer and the SiO ₂ layer is 1.46 / 1.45 =
It is 1.01 (rounded to two decimal places), but in the present invention, the ratio of the refractive index of adjacent thin films is 0.8 or more and 1.1.
It is preferably not more than 0.95, more preferably not less than 0.95 and not more than 1.05.

Further, more preferably, the ratio of the refractive index of the buffer layer to the barrier film is 0.95 or more and 0.97 or less, or 0.
It is preferably 98 or more and 1 or less and 1.02 or less, and 1.03 or more and 1.05 or less.

It is preferable that a buffer layer made of an organic material and a barrier layer made of an inorganic material are alternately and repeatedly laminated. The third embodiment by using the buffer layer
In the above, the thickness of the SiO ₂ layer is 20 nm, but in the present invention, the thickness of the thin film is preferably 50 nm or less. This is because the light more remarkably exhibits the characteristics of particles as waves.

Further, it is preferable that the thin film has a thickness of 2 nm or more. This is because the thin film is necessary for having a sufficient barrier property.

The water permeability of the SiO ₂ film is 1 g / m ² / d.
It has a water vapor barrier property of not more than ay / atm.

The water permeability of the protective film is 10 ⁻⁴ g / m ² / day.
It was about / atm.

When the number of laminated barrier films is increased, the barrier properties against water and oxygen are improved. However, when the number of laminated layers is increased, a large amount of multilayer film interference is caused by light reflection and absorption at the interface of the laminated films of materials having different refractive indexes. Become. That is, the wavelength dependency of the transmitted light becomes large, and the display characteristics deteriorate.
Further, when the number of stacked layers increases, there is a problem that the organic EL element deteriorates due to the film stress of the protective film.

FIG. 2 shows a schematic diagram of the incidence of light when the light enters from the medium 1 having a different refractive index to the medium 2, ..., The medium n. Total reflection occurs when the refractive index of the medium 1 is smaller than that of the medium 2, and the critical angle is determined by the refractive indices of the media 1 and 2.

FIG. 3 shows the wavelength dependence of transmitted light (400 nm
The relationship between the limit of the number of stacked layers and the ratio of the refractive index of the barrier film to the buffer layer at which the difference between the maximum value and the minimum value of each relative transmittance of light having a wavelength of 780 nm or less is 15% or less is shown.

Accordingly, when the refractive index ratio of the adjacent laminated films having different refractive indexes is 0.8 or more and 1.1 or less, the wavelength dependence of the transmitted light is 15 even if two or more layers of different materials are laminated.
%, Good transmitted light can be obtained. Further, the ratio of adjacent laminated films having different refractive indexes is 0.95 or more and 1.05 or more.
The following is more preferable. As a result, even if the number of layers is further increased, the wavelength dependence of the transmitted light is small, and it is possible to obtain excellent transmitted light, and it is possible to obtain an organic EL element with good light extraction efficiency.

More preferably, the ratio of the refractive index of the buffer layer to that of the barrier film is 0.95 or more and 0.97 or less, or 0.
It is preferably 98 or more and 1 or less and 1.02 or less, and 1.03 or more and 1.05 or less. This makes it possible to achieve both a sufficient barrier property and high transmittance characteristics, and to obtain an organic EL element having a good light extraction efficiency.

Table 1 shows a characteristic comparison table in the first, second and third embodiments.

[0112]

[Table 1]

In order to examine the change over time of dark spots in this light emitting device, a test was conducted in which the unit was left to stand in a constant temperature and humidity chamber at a temperature of 40 ° C. and a humidity of 90% for 500 hours. The number of dark spots per hit was measured by microscopic observation.

When a display device was manufactured using this light emitting element, a very thin display device was obtained.

Furthermore, in the first and second embodiments, when a lighting device was manufactured using this light emitting element, a very thin lighting device was obtained.

Incidentally, the Al ₂ O ₃ film and the SiO ₂ film which will be the protective film.
For forming an oxide such as a film, it is preferable to use an ion beam sputtering method as in this embodiment mode.
The material is not particularly limited to this, and it may be formed by another film forming method such as a resistance heating vapor deposition method. Also,
Protective film with low water vapor transmission rate, preferably 1 g / m ² / d
It is preferable to use those having ay / atm or less.

Further, the method of forming the upper electrode is not particularly limited, and other than the resistance heating evaporation method ion beam sputtering method shown in the present embodiment, magnetron sputtering method, electron beam evaporation method, CVD method. However, it is necessary to form the film so that the temperature does not rise until the heat resistance of the organic material is exceeded during film formation.

In the present embodiment, the case where the organic thin film layer has a two-layer structure composed of the hole transport layer and the light emitting layer has been described, but the structure is not particularly limited to this as described above. is not.

A laminated structure formed on the substrate,
It is preferable that the protective film formed on the outer surface of the laminated structure is continuously formed in a vacuum without being taken out into the atmosphere even once. This makes it possible to form an organic EL element without adsorbing or absorbing water in the atmosphere.

Further, in the first and second embodiments, the heat treatment has the effect of improving the adhesion at the interface of the laminated film and improving the reliability.

The outermost layer of the protective film preferably has a refractive index smaller than that of the upper electrode. Further, it is preferable that the outermost layer of the protective film is a thin film having the smallest refractive index in the two or more kinds of thin film groups having different refractive indices.

The refractive index of the protective film is preferably 1.1 or more and 1.8 or less. This is because the reduction of emitted light (transmitted light) due to interface reflection between the protective film and the atmosphere is improved.

The protective film has a plurality of film thicknesses so that the light emitted from the light emitting region can be efficiently extracted through the protective film. The film thickness of the outermost layer of the protective film is
It is preferably 50 nm or more and 250 nm or less. This improves the scratch resistance of the organic EL element and makes it possible to obtain an organic EL element having excellent barrier properties and optical characteristics.

Further, the central wavelength of the emitted light emitted from the light emitting region is λ, the refractive index of at least one of the protective films is Nn, and the film thickness dn of at least one layer of the protective film is dn.
Is preferably 0.4 × λ / Nn <dn <0.6 × λ / Nn.

The central wavelength of the emitted light emitted from the light emitting region is λ, and the refractive index of the outermost layer of the protective film is N (n
+1), and the film thickness d (n + 1) of the outermost layer of the protective film.
Is 0.4 × λ / N (n + 1) <d (n + 1) <0.6
It is preferably × λ / N (n + 1).

As a result, the adjacent thin film interface and the protective film /
Interference due to interface reflection and absorption such as the atmosphere interface is reduced, and low wavelength dependence of emitted light (transmitted light) is reduced.

Further, the protective film is composed of a multi-layered film in which a plurality of thin films of at least two kinds having different refractive indexes are laminated, and the number of laminated thin films is preferably 2 or more and 50 or less. As a result, it is possible to provide an organic electroluminescence device having a small film stress, an excellent barrier property, and a high yield.

As described above, according to the first, second, and third embodiments, the substrate, the lower electrode laminated on the substrate, the light emitting region including the organic thin film layer, and the transparent or semitransparent upper electrode are provided. A laminated structure comprising: a light-transmitting protective film formed on an outer surface of the laminated structure, wherein the protective film is formed by laminating at least two kinds of thin films having different refractive indexes. Nn, N2, N3 ... Nn of the thin films sequentially formed on the upper electrode.
And the ratio N of the refractive indexes of the adjacent thin films sequentially stacked.
(N-1) / Nn and Nn / N (n + 1) are 0.8
By setting the ratio to 1.1 or less, it is possible to prevent the growth of dark spots in the light emitting layer, the light extraction efficiency is improved, and the optical characteristics that are independent of the wavelength of the transmitted light and the viewing angle are obtained. It is possible to obtain a good organic electroluminescent element, display device and lighting device.

[0129]

As described above, according to the organic electroluminescence device of the present invention, it is possible to provide an organic electroluminescence device having good transmittance characteristics without interfacial reflection of a laminated film, multilayer film interference, and the like. It is possible to prevent corrosion and oxidation of the transparent electrode and moisture absorption and deterioration of the organic light emitting layer, and obtain a long-life and highly reliable organic electroluminescent element, display device and lighting device. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view showing first to third embodiments of an organic electroluminescent element according to the present invention.

FIG. 2 is a schematic diagram of light incidence when light enters from a medium 1 having a different refractive index to a medium 2, ... Medium n.

FIG. 3 is a diagram showing a ratio of refractive indexes of a buffer layer and a barrier film and a limit on the number of stacked barrier films.

FIG. 4 is a cross-sectional view of a main part of a conventional organic electroluminescence device.

FIG. 5 is a sectional view of a main part of a conventional organic electroluminescence device.

[Explanation of symbols]

1 substrate 2 Lower electrode 3 organic layers 4 Hole transport layer 5 Light emitting layer 6 Upper electrode 101 glass substrate 102 lower electrode 103 hole transport layer 104 light emitting layer 105 upper electrode

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor, Jiro Sumita             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 3K007 AB03 AB08 AB12 AB13 AB18                       BB01 BB06 CB01 DB03 FA01                       FA02

Claims (33)

[Claims] 1. A laminated structure comprising a substrate, a light emitting region comprising a reflective layer and an organic thin film layer laminated on the substrate, and a transparent or semitransparent upper electrode, the laminated structure. Has a light-transmitting protective film formed on the outer surface thereof, and the protective film is a multi-layer film formed by laminating a plurality of light-transmitting films of at least two kinds of different materials,
The refractive index of the film group sequentially laminated on the upper electrode is N1,
N2, N3 ... Nn, the refractive index ratios N (n-1) / Nn and Nn / N of the adjacent films that are sequentially stacked.
(N + 1) is 0.8 or more and 1.1 or less, The organic light emitting element characterized by the above-mentioned. 2. 400 nm or more which is transmitted through the protective film 7
The organic light emitting device according to claim 1, wherein the difference between the maximum value and the minimum value of the relative transmittance of light having a wavelength of 80 nm or less is 15% or less. 3. The protective film is a multilayer film formed by laminating at least two kinds of translucent films made of different materials, and the moisture permeability of the multilayer film is 1 × 10 ⁻² g / m ² /
The organic light emitting device according to claim 1, wherein the organic light emitting device has a day / atm or less. 4. The organic light emitting device according to claim 1, wherein the stress of the protective film is 500 MPa or less. 5. The protective film is a multi-layer film formed by laminating a plurality of translucent films of at least two kinds of different materials, and the translucent film has two or more laminated layers.
The organic light emitting device according to claim 1, wherein the number of layers is 0 or less. 6. The protective film is a multilayer film formed by stacking at least two or more translucent films made of different materials, and the multilayer film is made of a buffer layer made of an organic material and an inorganic material. The organic light-emitting device according to claim 1, wherein the barrier films are alternately laminated. 7. The organic light emitting device according to claim 6, wherein the barrier film group made of the inorganic material is in an amorphous state. 8. The organic light emitting device according to claim 6, wherein the barrier film group made of the inorganic material is a metal, a metal oxide, a metal nitride or a metal oxynitride. 9. The organic light emitting device according to claim 1, wherein the barrier film group made of the inorganic material has a moisture permeability of 10 g / m ² / day / atm or less. . 10. The barrier film group made of the inorganic material is formed by a sputtering method and has a moisture permeability of 1 g / m ² / day.
It is below / atm, The organic light emitting element of Claim 6 characterized by the above-mentioned. 11. The organic light emitting device according to claim 6, wherein the barrier film group made of the inorganic material has a thickness of 2 nm or more and 50 nm or less. 12. The organic light emitting device according to claim 6, wherein the saturated water absorption of the buffer layer group made of the organic material is 1% (23 ° C.) or less. 13. The buffer layer group made of the organic material has a Young's modulus of 5 × 10 ⁸ (N / m ² ) or more and 9 × 10 ⁹ (N / m ² ).
The organic light emitting device according to claim 6, wherein the organic light emitting device is m ² ) or less. 14. A buffer layer group comprising the organic material
Thermal expansion coefficient is 8 × 10 ^Five(K^-1) Characterized by
The organic light emitting device according to claim 6. 15. The organic material comprises a polymerizable functional group containing at least one of an acrylate group and a methacrylate group, and a skeletal structure containing at least one of an aromatic group, an alicyclic group and a thioether group. 7. The organic light emitting device according to claim 6, wherein 16. The thickness dn of the buffer layer group made of the organic material is 0.4 × λ / Nn <dn <0.6 × λ / N
7. The organic light emitting device according to claim 6, wherein n is n. 17. The central wavelength of the emitted light emitted from the light emitting region is λ, and the refractive index of the outermost layer of the protective film is N (n +
1) and the film thickness d (n + 1) of the outermost layer of the protective film is
0.4 × λ / N (n + 1) <d (n + 1) <0.6 × λ
/ N (n + 1), The organic light emitting element of Claim 6 characterized by the above-mentioned. 18. The organic light emitting device according to claim 16, wherein the center wavelength λ is 550 nm. 19. The organic light emitting device according to claim 6, wherein the buffer layer group made of the organic material has a thickness of 0.2 μm or more and 30 μm or less. 20. The organic light emitting device according to claim 1, wherein the lowermost layer of the protective film is made of an organic material. 21. The lowermost layer of the protective film is made of an organic material, and has a film thickness of 2 times or more and 10 times or less of the maximum unevenness of the surface of the substrate having the laminated structure.
The organic light-emitting device described. 22. The organic light emitting diode according to claim 1, wherein the protective film has a plurality of film thicknesses so that emitted light emitted from the light emitting region can be efficiently extracted through the protective film. element. 23. The outermost layer of the protective film has a thickness of 50 n.
It is m or more and 250 nm or less, Claim 1 characterized by the above-mentioned.
The organic light-emitting device described. 24. The organic light emitting device according to claim 1, wherein the outermost layer of the protective film has a refractive index smaller than that of the upper electrode. 25. The outermost layer of the protective film is made of different materials.
The organic light emitting device according to claim 1, wherein the organic light emitting device comprises a thin film having the smallest refractive index in a film group having at least one kind of translucency. 26. A step of forming a laminated structure including a substrate, a light emitting region including a reflective layer and an organic thin film layer laminated on the substrate, and a transparent or semitransparent upper electrode,
On the outer surface of the laminated structure, there is a step of alternately stacking a buffer layer made of an organic material and a barrier film made of an inorganic material, and the step is performed in vacuum without taking out into the atmosphere even once. A method for manufacturing an organic light-emitting element, which comprises continuously forming and then performing heat treatment. 27. The method of manufacturing an organic light emitting device according to claim 26, wherein all the steps are performed at a substrate temperature of 100 ° C. or lower. 28. The method of manufacturing an organic light emitting device according to claim 26, wherein the buffer layer group made of the organic material is deposited by an evaporation method and then cured by electron beam irradiation. 29. The barrier film group made of the inorganic material is laminated by a sputtering method, and the moisture permeability of the barrier film group is 1
27. The method for producing an organic light-emitting device according to claim 26, wherein the adjustment is performed so that it is g / m ² / day / atm or less. 30. The barrier film group made of the inorganic material is formed by a vapor deposition method, and the moisture permeability of the barrier film group is 7 g / m.
27. The method for manufacturing an organic light emitting device according to claim 26, wherein the method is adjusted to be ² / day / atm or less. 31. The organic light emitting device according to claim 1, wherein a film having a light control function is attached to an outer surface of the protective film. 32. A display device using the organic light emitting device according to claim 1. 33. An illumination device using the organic light emitting device according to claim 1.