JP2002260846A - Organic el element display panel and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make membrane sealing having no pinholes to the fine structure part without giving damages to the body structure of the organic EL element and realize a long life in the organic EL display panel of element separate type. SOLUTION: Membrane sealing is performed to cover uniformly the structure by a polyparaxylylene system protection membrane that is formed by CVD method in room temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL display panel and a method of manufacturing the same, and more particularly, to an organic EL display panel having a polyparaxylylene-based protective film suitable for a coating protective film of the organic EL display panel. It relates to the manufacturing method.

[0002]

2. Description of the Related Art In recent years, organic EL devices have been actively studied. This is tin-doped indium oxide (ITO)
A hole transport material such as tetraphenyldiamine (TPD) is formed into a thin film by vapor deposition or the like on a transparent electrode (anode: hole injection electrode) such as an aluminum quinolinol complex (A).
1q ₃ ) as a light-emitting layer, and a metal electrode having a small work function such as Mg (cathode: electron injection electrode). Attention has been paid to the extremely high luminance of / m ² .

As a material used as a cathode of such an organic EL device, a material that injects a large amount of electrons into a light emitting layer, an electron injection / transport layer or the like is considered to be effective. In other words, it can be said that a material having a smaller work function is more suitable as a cathode. Although there are various materials having a low work function, the metal having the lowest work function is an alkali metal. However, alkali metals are unstable in air,
It is difficult to use it for an electrode of an organic EL element, and there is a problem in terms of storage life and operation life.

[0004] In order to cope with such a problem, first, studies have been made on the material side of the cathode. For example, JP-A-2-15595 proposes a cathode in which a low work function metal and a stable metal are combined.
It is described that an alloy such as InMg is used. On the other hand, alloys such as AlLi are known as a combination of an alkali metal and a metal having a large work function.

[0005] However, the above materials are still very easily oxidized, so that dark spots are generated and the luminance is significantly deteriorated.

From such a viewpoint, Japanese Patent Application Laid-Open No. H10-125
No. 473 proposes a cathode in which an intermetallic compound selected from ZrAl ₃ , Zr ₅ Al ₈ , NbAl ₃ and TaAl _{3 is} formed by DC sputtering.

However, no matter which cathode is used, it is necessary to use a metal or alloy having a low work function.
There is a problem in terms of the storage life and the operation life of the organic EL element itself, and simple glass sealing at a low cost is insufficient.

[0008] For this reason, various proposals have been made to provide a protective film (protective layer) or a sealing film on the cathode.

For example, Japanese Patent No. 2813495 discloses that a protective layer made of an electronically insulating polymer compound is provided on the outer surface of a laminated structure of an organic EL element, and thereafter, an electrically insulating glass is provided outside the protective layer. It is disclosed to provide a shield layer selected from an electric insulating polymer compound and an electric insulating airtight fluid. As the protective layer, a film formed of a fluorine-based polymer compound such as polyethylene or Teflon (registered trademark) by a PVD method or a CVD method, or a film formed of a fluorine-based polymer compound by a cast method or a spin coating method And the like. On the other hand, as a shield layer, a glass substrate provided with a moisture absorbing layer of polyvinyl alcohol or the like is used, an epoxy adhesive is applied to the moisture absorbing layer side, and this surface is brought into contact with the protective layer, so that the glass substrate and the element can be used. Are laminated and cured, or a glass plate and an element are bonded at a predetermined position, and then, the space is filled with an airtight fluid such as silicone oil in which a hygroscopic material such as silica gel is dispersed. In form,
And the like.

Japanese Patent Application Laid-Open No. 2000-133440 discloses that amorphous silicon is used as a base film on a cathode.
It is disclosed that a DLC protective film having a two-layer structure is provided.

WO 98/24273 discloses oxides and nitrides of constituent materials of an electron injection electrode or an auxiliary electrode on an electron injection electrode or on an auxiliary electrode when an auxiliary electrode is provided on the electron injection electrode. And providing a sealing film containing a compound selected from carbides.

However, none of these methods has a sufficient element life.

On the other hand, the use of an organic EL device as a thin flat panel display has been studied, and the device has been reduced in size and size. For example, JP-A-9
No. 330792 discloses an insulating film or an insulating film and a spacer provided on or between transparent electrodes (anodes) or an insulating film and a spacer and an overhanging body (a spacer may also serve as an insulating film. )). In particular, when an organic EL element is used as such a display panel, a sufficient life is hardly obtained because the structure is complicated by element separation.

Japanese Patent Application Laid-Open No. 11-111452 discloses that
In an organic electroluminescent device in which at least a transparent electrode, a light emitting layer, and a back electrode (cathode) are sequentially laminated on a transparent substrate, two or more kinds of polyparaxylylenes whose outer surfaces on the back electrode side are laminated by a thermal CVD method. Coated with a ren-based polymer coating, or further, or the outer surface of this laminated coating is coated with a coating made of a gas and a moisture-impermeable material such as a metal, and the organic layer and Although it is disclosed that the back electrode is reliably shielded from moisture and gas to extend the life, it does not correspond to the element isolation structure as described above.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to perform film sealing without pinholes in a fine structure portion without damaging an organic EL element body structure.
An object of the present invention is to provide an organic EL display panel capable of dramatically improving the life, and a method for manufacturing the same.

[0016]

Means for Solving the Problems A resin film having no pinhole defect is formed by a CVD film forming method under a condition in which a structure such as an organic EL element which is element-isolated is not damaged by heat. After studying the formation of a film, it was found that the formation of a polyparaxylylene-based polymer was particularly effective, and the present invention was accomplished.

That is, the present invention is as follows. (1) An organic EL element body structure in which an anode, a light emitting layer, and a cathode are stacked in this order on a substrate, and a spacer structure for separating the organic EL element body structure,
Further, an organic EL display panel having a polyparaxylylene-based protective film uniformly covering these structures. (2) The organic EL display panel according to (1), wherein the spacer structure has a spacer member provided on a substrate and an overhang member having a width larger than the spacer member provided thereon. (3) In manufacturing the organic EL display panel of the above (1) or (2), the organic E is formed by forming the polyparaxylylene-based protective film at room temperature by a CVD (chemical vapor deposition) method.
A method for manufacturing an L display panel.

Japanese Patent No. 2813495 discloses that CV
It discloses that a protective film is formed by Method D, and describes that a gaseous monomer such as ethylene or propylene is polymerized by plasma. It is also described that general thermal decomposition CVD is not suitable because the substrate temperature is high. However, what is specifically disclosed in the examples is only film formation by the PVD method.

Japanese Patent Application Laid-Open No. 11-111452 discloses that
Although it is disclosed that the outer surface on the cathode side is coated with two or more kinds of polyparaxylylene-based polymer coating laminates by a thermal CVD method, it does not correspond to an element isolation structure.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The organic EL display of the present invention has an organic EL device main body structure in which an organic material layer including an anode, a light emitting layer, and a cathode are laminated in this order on a substrate. Having a spacer structure. That is, the organic EL display panel of the present invention is one in which elements are separated.

The spacer structure in the present invention is usually a member for element isolation which is provided on the anode and has at least the same height as the organic EL element main body structure. 0.5 μm or more, preferably 4 μm
μm or more, usually about 5 μm. The upper limit of the height is not particularly limited, but is practically about 10 μm. Therefore, the present invention includes an insulating film (0.1 μm
This does not include an aspect in which the element is separated only by the thickness (about the thickness).

The organic EL display panel of the present invention comprises:
A polyparaxylylene-based protective film is provided, and the polyparaxylylene-based protective film is formed so as to uniformly cover the structure on the substrate. That is, a polyparaxylylene-based protective film having a uniform and uniform thickness is formed on all portions of the structure except for a contact portion between the substrate and the structure. In this case, when there is a portion where no structure exists on the substrate, a polyparaxylylene-based protective film similar to the above may be formed on that portion of the substrate.

In the case where a spacer structure for element isolation is provided as in the present invention, the spacer structure is preferably a spacer member (as described in Japanese Patent Application Laid-Open No. 9-330792). The polyparaxylylene-based protective film of the present invention is effective when a spacer structure having an overhang member wider than the spacer member is used.

Examples of the polyparaxylylene-based polymer constituting the polyparaxylylene-based protective film include polyparaxylylene and its derivatives. As derivatives, p-xylene-α, which is a structural unit of polyparaxylylene,
There is a polymer having a substituted unit of α'-diyl (paraxylylene) as a constituent unit. Examples thereof include polymonochloroparaxylylene, polydichloroparaxylylene, polymonobromoparaxylylene, polycyanoparaxylylene, and polymethylparaxylylene. Xylylene, polyethylparaxylylene, poly-
α, α-difluoro-p-xylene-α, α′-diyl and the like. In the present invention, homopolymers composed of the same structural units are generally used. However, the homopolymers are composed of two or more of these structural units, p-xylene-α, α′-diyl and substituted products thereof. It may be a copolymer, furthermore p-xylene-α, α′-diyl and / or
Alternatively, the copolymer may contain a constituent unit different from the constituent unit of the substituted product. Particularly preferred are polyparaxylylene, polymonochloroparaxylylene, polydichloroparaxylylene, polymonobromoparaxylylene and the like.

The polyparaxylylene-based protective film is formed by a CVD method. As a result, it is possible to form a pinhole-free and dense film up to a fine structure portion with a uniform and constant film thickness as compared with the vapor deposition method and the sputtering method. Further, the polyparaxylylene-based protective film is characterized in that it can be formed at room temperature (normally, a temperature of about 15 ° C. to about 30 ° C.) by polymerization by a CVD method. For this reason, there is no fear of heat damage to the structure to be adhered.

Therefore, in the organic EL display panel of the present invention, after forming the cathode, a protective film of polyparaxylylene and / or a derivative thereof is formed at room temperature by the CVD method, so that the organic EL element body structure is formed. The film can be sealed without pinholes in the fine structure portion of the device without causing damage, and the life can be dramatically improved. That is, the presence of such a polyparaxylylene-based protective film can prevent the structure from being deteriorated by a gas such as moisture or oxygen. In the element separation type organic EL display panel as in the present invention, not only the protection by blocking the gas such as moisture and oxygen by the polyparaxylylene-based protective film, but also the moisture and gas contained in the spacer structure However, there is a problem that causes specific device deterioration such as emission due to temperature rise, but due to the presence of the polyparaxylylene-based protective film,
Such internal release is prevented.

One example of the organic EL display panel of the present invention has the structure shown in FIG. As shown in FIG. 1, the organic EL display panel has an organic EL element main body structure 1A and a spacer structure 1B for separating a cathode on a substrate 1 made of a transparent material.

The organic EL element main body structure 1A comprises an anode (hole injection electrode) 2, which is a transparent electrode, and a hole injection and / or transport layer (hereinafter referred to as "hole injection and transport" for convenience) provided on the substrate 1. Layer)), a light-emitting layer 4 and a cathode (electron injection electrode) 5, which are stacked in this order, and on the cathode 5, an auxiliary electrode 6 for protecting the cathode is provided. Further, a polyparaxylylene-based protective film 7 is preferably provided on the auxiliary electrode 6. At this time, the light emitting layer 4 also has a function as an electron injection and / or transport layer (hereinafter, for convenience, an “electron injection and transport layer”).

On the other hand, the spacer structure 1B is provided on the insulating film 81 provided on the substrate 1, has a spacer member 8 and an overhang member 9, and has an overhang wider than the spacer member 8. On the member 9, a laminated structure excluding the anode 2 of the organic EL element main body structure 1A (that is, the hole injection / transport layer 3, the light emitting layer 4, the cathode 5, the auxiliary electrode 6, and the polyparaxylylene-based protective film 7). Having.

It is preferable that the polyparaxylylene-based protective film 7 uniformly covers portions of the above-mentioned structures 1A and 1B other than those in contact with the substrate 1 or the insulating film 81, as shown in the figure. Further, when there is a portion where the above structures 1A and 1B do not exist on the substrate 1 or the insulating film 81, it is preferable to provide the polyparaxylylene-based protective film 7 between the above structures 1A and 1B. .

The above structures 1A and 1B are
And a space formed by the transparent material sealing plate 10, and the space is filled with an inert gas or the like.

As shown in the illustrated example, preferably, the polyparaxylylene-based protective film 7 is formed uniformly, so that the life can be drastically improved.

Such an organic EL display panel is obtained as follows. The anode 2 is patterned on the substrate 1 by a photolithography method, an insulating film 81 is formed at a predetermined position between the patterned anodes 2, and a spacer film made of an insulating resin material is applied thereon. Baking, further applying a positive resist, exposing and developing to form a desired photo pattern, and forming an overhang member 9. In this case, the spacer film in the intermediate stage is also formed in the shape of the spacer member 8.
Then, on the anode 2, a hole injection transport layer 3, a light emitting layer 4,
The cathode 5 and the auxiliary electrode 6 are formed in this order. In this case, at the same time, the anode 2 was also removed on the overhang member 9,
The same laminated structure is formed.

After the cathode 5 and the auxiliary electrode 6 are formed, a polyparaxylylene-based protective film 7 is formed by CVD at room temperature.
It is formed by a method. In this case, the polyparaxylylene-based protective film 7 is formed uniformly as shown in the figure.

Thereafter, these structures 1A and 1B are sealed using the sealing plate 10 in an inert gas atmosphere.

Although the above has been described with reference to the illustrated example, the present invention is not limited to this. For example, the layer structure of the organic material layer of the organic EL element body structure can be appropriately changed within a range not to impair its function. , Can be changed.

In order to obtain the effect of the present invention, the thickness of the polyparaxylylene-based protective film in the organic EL display panel is 0.5 to 3.0 μm, more preferably 1.0 to 3.0 μm.
It is preferably 2.0 μm. If the thickness is reduced, the effect of the present invention cannot be obtained, and if the thickness is increased, it becomes difficult to radiate heat generated during light emission.

Next, an organic material layer and the like provided in the organic EL element body structure will be described.

The organic layer includes a light emitting layer. The light emitting layer is composed of a single layer or a multilayer of at least one kind or two or more kinds of organic compound thin films involved in the light emitting function.

The light emitting layer has a function of injecting holes (holes) and electrons, a function of transporting them, and a function of generating excitons by recombination of holes and electrons. By using a relatively electronically neutral compound for the light emitting layer, electrons and holes can be easily injected and transported in a well-balanced manner.

When the light emitting layer means a so-called light emitting layer in a narrow sense, the light emitting layer may have, in addition to the light emitting layer in a narrow sense, a hole injection transport layer, an electron injection transport layer, and the like, if necessary.

The hole injection transport layer has a function of facilitating injection of holes from the hole injection electrode, a function of stably transporting holes, and a function of preventing electrons.
The electron injection transport layer has a function of facilitating injection of electrons from the electron injection electrode, a function of stably transporting electrons, and a function of preventing holes. These layers increase and confine holes and electrons injected into the light emitting layer, optimize the recombination region, and improve luminous efficiency.

The thickness of the light emitting layer, the thickness of the hole injecting and transporting layer, and the thickness of the electron injecting and transporting layer are not particularly limited, and vary depending on the forming method.
It is preferable that the thickness be in the range of 10 to 300 nm.

The thickness of the hole injecting and transporting layer and the thickness of the electron injecting and transporting layer depend on the design of the recombination / light emitting region, but may be about the same as the thickness of the light emitting layer or about 1/10 to 10 times. When the hole injection / transport layer or the electron injection / transport layer is divided into an injection layer and a transport layer, the thickness of the injection layer is preferably 1 nm or more, and the thickness of the transport layer is preferably 1 nm or more. At this time, the upper limit of the thickness of the injection layer and the transport layer is usually about 500 nm for the injection layer and about 500 nm for the transport layer. Such a film thickness is the same when two injection / transport layers are provided.

The light emitting layer of the organic EL element contains a fluorescent substance which is a compound having a light emitting function. Examples of such a fluorescent substance include, for example, JP-A-63-26469.
No. 2 discloses at least one compound selected from compounds such as quinacridone, rubrene, and styryl dyes. Also, Tris (8
Quinolinol derivatives such as metal complex dyes having 8-quinolinol or a derivative thereof as a ligand, such as (quinolinolato) aluminum; tetraphenylbutadiene, anthracene, perylene, coronene, and 12-phthaloperinone derivatives. Further, phenylanthracene derivatives described in JP-A-8-12600, JP-A-8-1600
For example, a tetraarylethene derivative described in JP-A-2969 can be used.

Also, it is preferable to use in combination with a host substance capable of emitting light by itself, and it is also preferable to use it as a dopant. In such a case, the content of the compound in the light emitting layer is preferably 0.01 to 10% by volume, more preferably 0.1 to 5% by volume. Particularly, in the case of a rubrene-based material, the content is preferably 0.01 to 20% by volume. When used in combination with a host substance, the emission wavelength characteristics of the host substance can be changed, light emission shifted to a longer wavelength becomes possible, and the luminous efficiency and stability of the device are improved.

The host substance is preferably a quinolinolato complex, and more preferably an aluminum complex having 8-quinolinol or a derivative thereof as a ligand. Such an aluminum complex is disclosed in JP-A-63-26469.
No. 2, JP-A-3-255190, JP-A-5-7707
3, JP-A-5-258859, JP-A-6-2158
No. 74 and the like.

Specifically, first, tris (8-quinolinolato) aluminum, bis (8-quinolinolato) magnesium, bis (benzo {f} -8-quinolinolato) zinc, bis (2-methyl-8-quinolinolato) aluminum Oxide, tris (8-quinolinolato) indium,
Tris (5-methyl-8-quinolinolato) aluminum, 8-quinolinolatolithium, tris (5-chloro-
8-quinolinolato) gallium, bis (5-chloro-8-
Quinolinolato) calcium, 5,7-dichloro-8-quinolinolatoaluminum, tris (5,7-dibromo-
8-hydroxyquinolinolato) aluminum and poly [zinc (II) -bis (8-hydroxy-5-quinolinyl) methane].

In addition to 8-quinolinol or a derivative thereof, an aluminum complex having another ligand may be used, such as bis (2-methyl-
8-quinolinolato) (phenolato) aluminum (III)
, Bis (2-methyl-8-quinolinolato) (ortho-
Cresolato) aluminum (III), bis (2-methyl-
8-quinolinolato) (meth-cresolate) aluminum
(III), bis (2-methyl-8-quinolinolato) (para-cresolato) aluminum (III), bis (2-methyl-8-quinolinolato) (ortho-phenylphenolate)
Aluminum (III), bis (2-methyl-8-quinolinolato) (meth-phenylphenolato) aluminum (II
I), bis (2-methyl-8-quinolinolato) (para-
Phenylphenolato) aluminum (III), bis (2-
Methyl-8-quinolinolato) (2,3-dimethylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (2,6-dimethylphenolato) aluminum (III), bis (2-methyl- 8-quinolinolato)
(3,4-dimethylphenolato) aluminum (III),
Bis (2-methyl-8-quinolinolato) (3,5-dimethylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (3,5-di-tert-butylphenolato) aluminum (III) ), Bis (2-methyl-8)
-Quinolinolato) (2,6-diphenylphenolato) aluminum (III), bis (2-methyl-8-quinolinolato) (2,4,6-triphenylphenolato) aluminum (III), bis (2-methyl- 8-quinolinolato)
(2,3,6-trimethylphenolato) aluminum (I
II), bis (2-methyl-8-quinolinolato) (2,
3,5,6-tetramethylphenolato) aluminum (I
II), bis (2-methyl-8-quinolinolato) (1-naphthrat) aluminum (III), bis (2-methyl-8
-Quinolinolato) (2-naphthrat) aluminum (II
I), bis (2,4-dimethyl-8-quinolinolato)
(Ortho-phenylphenolato) aluminum (III),
Bis (2,4-dimethyl-8-quinolinolato) (para-
Phenylphenolato) aluminum (III), bis (2,
4-dimethyl-8-quinolinolato) (meta-phenylphenolato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) (3,5-dimethylphenolato) aluminum (III), bis (2 4-dimethyl-8
-Quinolinolato) (3,5-di-tert-butylphenolato) aluminum (III), bis (2-methyl-4-ethyl-8-quinolinolato) (para-cresolato) aluminum (III), bis (2-methyl) -4-methoxy-8-quinolinolato) (para-phenylphenolato) aluminum (III), bis (2-methyl-5-cyano-8-quinolinolato) (ortho-cresolato) aluminum (III),
Bis (2-methyl-6-trifluoromethyl-8-quinolinolato) (2-naphthrat) aluminum (III);

In addition, bis (2-methyl-8-quinolinolato) aluminum (III) -μ-oxo-bis (2-
Methyl-8-quinolinolato) aluminum (III), bis (2,4-dimethyl-8-quinolinolato) aluminum
(III) -μ-oxo-bis (2,4-dimethyl-8-quinolinolato) aluminum (III), bis (4-ethyl-
2-methyl-8-quinolinolato) aluminum (III)-
μ-oxo-bis (4-ethyl-2-methyl-8-quinolinolato) aluminum (III), bis (2-methyl-4
-Methoxyquinolinolato) aluminum (III) -μ-oxo-bis (2-methyl-4-methoxyquinolinolato)
Aluminum (III), bis (5-cyano-2-methyl-
8-quinolinolato) aluminum (III) -μ-oxo-
Bis (5-cyano-2-methyl-8-quinolinolato) aluminum (III), bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum (III) -μ
-Oxo-bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum (III) and the like.

Other host materials are disclosed in
Also preferred are phenylanthracene derivatives described in JP-A-12600 and tetraarylethene derivatives described in JP-A-8-12969.

The light emitting layer may also serve as an electron injection / transport layer. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like.

The light emitting layer is preferably a mixed layer of at least one kind of hole injecting and transporting compound and at least one kind of electron injecting and transporting compound, if necessary.
Further, it is preferable that a dopant is contained in the mixed layer. The content of the compound in such a mixed layer is 0.01 to 20% by volume, further 0.1 to 15% by volume.
% Is preferable.

In the mixed layer, a hopping conduction path of carriers is formed, so that each carrier moves in a material having a favorable polarity, and carrier injection of the opposite polarity is less likely to occur, so that the organic compound is less likely to be damaged. This has the advantage that the element life is extended. Further, by including the above-described dopant in such a mixed layer, the emission wavelength characteristics of the mixed layer itself can be changed, the emission wavelength can be shifted to a longer wavelength, and the emission intensity is increased, The stability of the device can be improved.

The hole injecting and transporting compound and the electron injecting and transporting compound used in the mixed layer may be selected from the hole injecting and transporting compound and the electron injecting and transporting compound described below, respectively.

As the compound capable of injecting and transporting electrons, it is preferable to use a quinoline derivative, furthermore a metal complex having 8-quinolinol or its derivative as a ligand, particularly tris (8-quinolinolato) aluminum (Alq ₃ ). It is also preferable to use the above-mentioned phenylanthracene derivatives and tetraarylethene derivatives.

As the compound for the hole injecting and transporting layer, it is preferable to use an amine derivative having strong fluorescence, for example, a triphenyldiamine derivative, a styrylamine derivative, or an amine derivative having an aromatic condensed ring.

The mixing ratio in this case depends on the respective carrier mobility and carrier concentration. In general, the mass ratio of the hole injection / transport compound / electron injection / transport compound is 1
/ 99-99 / 1, more preferably 10 / 90-90
/ 10, particularly preferably about 20/80 to 80/20.

The thickness of the mixed layer is preferably not less than the thickness corresponding to one molecular layer and less than the thickness of the organic compound layer. Specifically, the thickness is preferably 1 to 100 nm, more preferably 5 to 60 nm, particularly preferably 5 to 50 nm.

As a method of forming a mixed layer, co-evaporation in which evaporation is performed from different evaporation sources is preferable. However, when the vapor pressures (evaporation temperatures) are approximately the same or very close, they are mixed in advance in the same evaporation board. Alternatively, it can be deposited. In the mixed layer, it is preferable that the compounds are uniformly mixed, but in some cases, the compounds may exist in an island shape. The light-emitting layer is generally formed to a predetermined thickness by vapor-depositing an organic fluorescent substance or by dispersing and coating the resin in a resin binder.

Examples of the hole injecting / transporting compound include, for example, JP-A-63-295695 and JP-A-2-19.
1694, JP-A-3-792, JP-A5-
JP-A-234681, JP-A-5-239455,
JP-A-5-299174, JP-A-7-12622
No. 5, JP-A-7-126226, JP-A-8-
Various organic compounds described in, for example, Japanese Patent No. 100172 and EP0650955A1 can be used. For example, a tetraarylbendicine compound (triaryldiamine or triphenyldiamine: TPD), an aromatic tertiary amine, a hydrazone derivative, a carbazole derivative,
Triazole derivatives, imidazole derivatives, oxadiazole derivatives having an amino group, polythiophene and the like. These compounds may be used alone or in combination of two or more. When two or more kinds are used in combination, they may be stacked as separate layers or mixed.

The electron injecting and transporting compounds include quinoline derivatives such as organometallic complexes having 8-quinolinol such as tris (8-quinolinolato) aluminum (Alq3) or derivatives thereof as ligands, oxadiazole derivatives, perylene derivatives, and the like. A pyridine derivative, a pyrimidine derivative, a quinoxaline derivative, a diphenylquinone derivative, a nitro-substituted fluorene derivative, or the like can be used.

For forming the light emitting layer, the hole injection transport layer and the electron injection transport layer, a uniform thin film can be formed.
It is preferable to use a vacuum deposition method. When vacuum deposition is used, the amorphous state or the crystal grain size is 0.2 μm
The following homogeneous thin film is obtained. If the crystal grain size exceeds 0.2 μm, the light emission becomes non-uniform, the driving voltage of the device must be increased, and the charge injection efficiency is significantly reduced.

The conditions for vacuum deposition are not particularly limited.
The degree of vacuum is 0 ^-4 Pa or less, and the deposition rate is 0.01 to 1 nm /
It is preferable to set it to about sec. Further, it is preferable to form each layer continuously in a vacuum. If they are formed continuously in a vacuum, impurities can be prevented from adsorbing at the interface between the layers, so that high characteristics can be obtained. Further, the driving voltage of the element can be reduced, and the occurrence and growth of dark spots can be suppressed.

When a plurality of compounds are contained in one layer in the case where a vacuum evaporation method is used for forming each of these layers, it is preferable to co-deposit each boat containing the compounds by individually controlling the temperature.

The material of the anode (hole injection electrode) is preferably a material capable of efficiently injecting holes into a hole injection layer or the like, and is preferably a substance having a work function of 4.5 eV to 5.5 eV. Specifically, tin-doped indium oxide (ITO),
It is preferable that any one of zinc-doped indium oxide (IZO), indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), and zinc oxide (ZnO) be the main composition.
These oxides may deviate somewhat from their stoichiometric composition. The mixing ratio of SnO ₂ to In ₂ O ₃ is 1
-20% (mass percentage), more preferably 5-12% (mass percentage). The mixing ratio of ZnO to In ₂ O ₃ in IZO is usually about 12 to 32% (mass percentage).

The anode may contain silicon oxide (SiO ₂ ) to adjust the work function. The content of silicon oxide (SiO ₂ ) depends on the content of SiO ₂ with respect to ITO.
The molar ratio is preferably about 0.5 to 10%. By containing SiO ₂ , the work function of ITO increases.

The anode on the light extraction side has an emission wavelength band,
The light transmittance is usually 400 to 700 nm, particularly preferably 50% or more, more preferably 80% or more, and particularly preferably 90% or more for each emitted light. If the transmittance is too low, the light emission itself from the light emitting layer is attenuated, and it becomes difficult to obtain the luminance required for the light emitting element.

The thickness of the anode is 50 to 500 nm, in particular, 50 to 500 nm.
The range of -300 nm is preferred. The upper limit is not particularly limited. However, if the thickness is too large, there is a fear that the transmittance may decrease or the film may peel off. If the thickness is too small, a sufficient effect cannot be obtained, and there is a problem in film strength at the time of production and the like.

As the cathode, the following can be used as necessary as an electrode having an electron injecting property. For example,
K, Li, Na, Mg, La, Ce, Ca, Sr, B
a, Sn, Zn, Zr, or other metal element alone, or a binary or ternary alloy system containing them to improve stability, for example, Ag.Mg (Ag: 0.1 to 50 in atomic ratio)
%), Al.Li (Li: atomic ratio, 0.01 to 14)
%), In.Mg (Mg: 50-80% by atomic ratio),
Al.Ca (Ca: 0.01 to 20% in atomic ratio) and the like.

The thickness of the cathode thin film may be a certain thickness or more for sufficiently injecting electrons, and may be 0.1 nm or more, preferably 0.5 nm or more, particularly 1 nm or more. The upper limit is not particularly limited, but the thickness is usually 1 to 500.
It may be set to about nm.

At the end of electrode formation, Al is used as an auxiliary electrode.
Alternatively, a fluorine-based compound may be deposited and sputtered. The electrodes are formed by vapor deposition, sputtering, or the like.

Further, it is preferable to seal the element with a sealing plate or the like in order to prevent deterioration of the organic layer and the electrodes of the element. The sealing plate is bonded and sealed using an adhesive resin layer (adhesive) in order to prevent moisture from entering. The sealing gas is preferably an inert gas such as Ar, He, and N ₂ .
The sealing gas has a water content of 100 ppm or less,
It is more preferably at most 10 ppm, particularly preferably at most 1 ppm. Although there is no particular lower limit for the water content, it is usually about 0.1 ppm.

The material of the sealing plate is preferably a flat plate, and may be a transparent or translucent material such as glass, quartz, and resin. Particularly, glass and resin are preferable. As such a glass material, an alkali glass is preferable from the viewpoint of cost. In particular, a soda glass material having no surface treatment can be used at a low cost, and is preferable.

The height of the sealing plate may be adjusted to a desired height by using a spacer.

The adhesive is not particularly limited as long as it can maintain stable adhesive strength and has good airtightness, but it is preferable to use a cationic curing type ultraviolet curing epoxy resin adhesive. .

Although there is no particular limitation on the material of the substrate, a transparent or translucent material such as glass or resin is used to extract emitted light from the substrate side. Alternatively, the color of the emitted light may be controlled by using a color filter film, a fluorescence conversion filter film containing a fluorescent substance, or a dielectric reflection film on the substrate, or coloring the substrate itself.

Note that having translucency means transmitting 70% or more, preferably 80% or more, of light in the visible light region.

The organic EL display panel of the present invention
The display device may have a segment type display portion or a dot matrix type display portion, but may have both of these display portions.

The dot matrix type display section has an XY matrix type electrode in which a pair of electrodes are arranged so as to face each other and cross each other, and an organic material layer is sandwiched between the electrodes at the crossing portion. Thus, a pixel is formed. When a color filter is provided, it is preferable to provide the color filter on the transparent electrode side of the pixel. Here, a pixel refers to a region of an image display array that can be excited and emitted independently of other regions.

The above-mentioned plurality of electrodes are usually stripe-shaped electrodes, and a pair of electrodes are arranged so as to be substantially orthogonal. In manufacturing, a stripe-shaped electrode is often formed by forming one electrode and then forming the other electrode, and a dot matrix type display portion is often formed using an interlayer insulating film. There may be cases where the other stripe-shaped electrode to be formed later is not formed on substantially the same plane, or where one stripe in the same direction does not become a continuous film. I don't mind.

For example, the following method is available for forming a dot matrix type display section. A predetermined color filter layer is formed on a transparent substrate (glass or the like) as necessary, and an acrylic resin or polyimide is formed on the transparent electrode forming surface of the color filter layer, preferably to improve the flatness of this surface. 1-5m formed of transparent resin such as
An overcoat layer having a thickness of mm is provided. This overcoat layer also functions as a protective layer for the color filter. The overcoat layer is patterned, and a transparent electrode is formed on the patterned overcoat layer. Note that a transparent and electrically insulating inorganic oxide layer may be provided as a passivation layer between the transparent electrode layer and the overcoat layer.

On the surface including the patterned transparent electrode layer,
An interlayer insulating film having a thickness of 10 nm to 100 μm is provided so that the insulating film remains at portions other than the portions where the transparent electrodes are formed. The insulating film can be formed of a resin such as polyimide, acrylic resin, or epoxy resin, in addition to inorganic compounds such as SiO ₂ and SiN _x .

Further, in this case, according to the present invention, as described above, in addition to the insulating film, a spacer member is formed on the insulating film, and an overhang member having a larger width than the spacer is formed on the spacer member. Then, a method of element isolation is adopted (JP-A-9-330792, etc.). The spacer member in this case may be a conductor, but is preferably made of resin (for example, polyimide) or SOG in consideration of simplification of processing for preventing current short-circuit between lines, current short-circuit, and current leak. An insulator such as (spin-on-glass) is used. Further, since the overhang member is formed by a photo pattern, a photosensitive resin (for example, polyimide) is used.

Thereafter, an organic layer including a light emitting layer in the above-mentioned organic EL device is formed, and a counter electrode is provided so as to intersect with the transparent electrode. Can be. It is preferable that the above-mentioned insulating film be left even after the formation of the element, and the presence of the above-mentioned insulating film can reduce a leak current.
When a black matrix is used, a black matrix layer may be provided between the color filter layers.

The organic EL display panel of the present invention
Usually, it is used as a DC drive type or pulse drive type EL element, but it can be AC drive. The applied voltage is
Usually, it is about 2 to 30V.

[0088]

The present invention will be specifically described below with reference to examples. Comparative examples are also described. <Example 1> Corning product name 7 as a glass substrate
The 059 substrate was scrub-cleaned using a neutral detergent.

Then, ITO as a transparent conductive film was formed on the substrate to a thickness of about 100 nm by sputtering, a resist pattern was formed by photolithography, and then etched with dilute hydrochloric acid to remove the resist to obtain an ITO pattern.

As shown in FIG. 1, an insulating film is patterned at a predetermined position of the ITO pattern using a photosensitive polyimide, and further, an insulating film (0.1 μm thick) is formed.
Above, a spacer structure for cathode separation as shown in FIG. 1 was installed as follows.

The polyimide was adjusted to a concentration of 15% by mass and spin-coated to a thickness of 2 μm.
Post-baking was performed at 5 ° C. for 1 hour to form an intermediate spacer film. Subsequently, a positive resist was applied, and exposed and developed to form a desired photo pattern, thereby forming a cap-shaped photosensitive resin body (overhang member). The intermediate spacer film of polyimide, which is exposed during the development of the positive resist, is subsequently removed from the positive resist by the developing solution to form a final spacer member.
As a result, an element isolation structure using the spacer structure was formed. In this case, the total thickness of the spacer structure is 5
μm (thickness of the overhang member was 3 μm).

Next, under a reduced pressure of 1 × 10 ⁻⁴ Pa or less,
N, N'-diphenyl-N, N'-m-tolyl-4,
4′-diamino-1,1′-biphenyl (TPD) was deposited at a deposition rate of 0.2 nm / sec to a thickness of 55 nm to form a hole injection transport layer.

Further, while maintaining the reduced pressure, Alq3:
Tris (8-quinolinolato) aluminum (Alq ₃₎
Was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 50 nm to form an electron injection transport / light-emitting layer.

Further, while maintaining the reduced pressure, MgAg (mass ratio 10: 1) was vapor-deposited at a vapor deposition rate of 0.2 nm / sec to a thickness of 200 nm to form a cathode.
Evaporated.

The above-described film formation by vapor deposition of the hole injection / transport layer by TPD, the electron injection / transport / emission layer by Alq ₃ , the cathode by MgAg, and the protective layer by Al is performed as shown in FIG. The rotation was performed while the substrate 1 was largely inclined with respect to the deposition direction. This allows
The film could be formed with good step coverage.

Further, while maintaining the reduced pressure, polymerization was carried out at room temperature (25 ° C.) by a CVD method to form a polymonochloroparaxylylene-based protective film as shown in FIG. The thickness of the protective film was 1.0 μm.

Thereafter, the element surface was sealed with a glass plate (1.1 mm thick) using an adhesive in an atmosphere of an inert gas (specifically, argon) having a dew point of minus 70 ° C. (see FIG. 1). .

Thus, the size of one pixel is 330
A sample of a simple matrix type display panel having a size of μm × 330 μm and a pixel number of 128 × 64 dots was prepared.

<Comparative Example 1> In Example 1, instead of forming the polyparaxylylene-based protective film 7, as shown in FIG.
A sample was obtained in the same manner except that a film was formed to a thickness of 0 μm.
Also when depositing the Teflon protective film, as shown in FIG. 3, the substrate 1 was rotated while being largely inclined with respect to the deposition direction of the deposition source 20.

<Comparative Example 2> In Comparative Example 1, a glass having only a glass seal without providing a Teflon protective film was obtained.

Each sample of Example 1 and Comparative Examples 1 and 2 was
Immediately after the production, each was driven line-sequentially under the conditions of a drive voltage of 20 V and a duty ratio of 1/64. In each case, light emission without a dark spot was confirmed.

Further, each of the above-mentioned samples was used for 85
After storage at 500C for 500 hours, the dark spot diameter (μm) and the emission area when the same driving was performed were examined. The luminescent area was evaluated by the ratio (%) of the value after storage to the initial value. Table 1 shows the results.

[0103]

[Table 1]

<Comparative Examples 3 to 5> Example 1, Comparative Examples 1 and 2
In each of the samples, a sample of an organic EL display panel without a spacer structure was obtained.

The characteristics of each of the above samples were evaluated in the same manner as in Example 1 and Comparative Examples 1 and 2. Table 2 shows the results.

[0106]

[Table 2]

From the above results, the following is considered. It is considered that the deterioration is caused by moisture and oxygen that penetrate through an adhesive portion for bonding the element forming glass and the glass sealing plate, and moisture and gas contained in a spacer structure for element isolation. As a comparative example, it can be seen that the deterioration is fast with glass sealing alone, but the deterioration is suppressed by forming a vapor-deposited Teflon film. However, a film is not formed on the entire surface of the light emitting element due to the spacer structure for element isolation, and a film is formed only on a part of the spacer structure, so that the effect is insufficient. In the case of forming polymonochloroparaxylylene by the CVD method of the present invention,
Since a film is formed on the entire surface of the light emitting element and a film is formed also on a fine structure portion of element isolation, a high effect is obtained. As is evident from the results in Tables 1 and 2, those having the spacer structure have a wider range of improvement in the life due to the polymonochloroparaxylylene CVD film than those having no spacer structure.

<Examples 2 and 3><Comparative Examples 6 and 7> In the samples of Example 1 and Comparative Example 3, polydichloroparaxylylene and polymonobromo were used instead of polymonochloroparaxylylene, respectively. Each protective film of para-xylylene was formed at room temperature by the CVD method, and a total of four types of samples were prepared. The characteristics were evaluated in the same manner.

As described above, it has been found that the present invention is effective for an element isolation structure using a spacer structure.

[0110] Further, Japanese Patent Application Laid-Open No. H11-111452
In the device structure disclosed in the above publication, the effect of using the polyparaxylylene-based protective film is considered to be substantially the same as the result in Table 2.

Therefore, it was found that the effect of using the polyparaxylylene-based protective film was particularly exhibited in the element structure having the spacer structure of the present invention.

[0112]

According to the present invention, by using a polyparaxylylene-based protective film, it is possible to prevent a structure on a substrate from being deteriorated by moisture, oxygen, or the like. Also,
At the same time, the release of moisture, gas, and the like from inside the structure is suppressed, and deterioration due to this is also prevented. The polyparaxylylene-based protective film can be formed by a CVD method, and a pinhole-free dense film can be formed up to a fine structure portion. Therefore, when used as a protective film of an organic EL display panel, for the above reasons,
The life can be significantly improved. Further, since the film can be formed at room temperature without heating during the film formation, the organic EL element body structure is not damaged.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an organic EL display panel of the present invention.

FIG. 2 is a cross-sectional view schematically showing an organic EL display panel of a comparative example.

FIG. 3 is an explanatory diagram of rotary evaporation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection / transport layer 4 Light emitting layer (also has an electron injection / transport function) 5 Cathode 6 Auxiliary electrode 7, 71 Protective film 8 Spacer member 9 Overhang member 10 Sealing plate 20 Evaporation source

Claims (3)

[Claims] 1. An organic EL device body structure comprising an anode, a light emitting layer, and a cathode laminated on a substrate in this order, and an organic EL device.
An organic EL display panel having a spacer structure for separating an L element main body structure, and further having a polyparaxylylene-based protective film that uniformly covers these structures. 2. The organic EL display panel according to claim 1, wherein the spacer structure has a spacer member provided on the substrate and an overhang member having a width larger than that of the spacer member provided thereon. 3. The organic EL device according to claim 1, wherein said polyparaxylylene-based protective film is formed at room temperature by a CVD (chemical vapor deposition) method.
A method for manufacturing an L display panel.