WO2009104563A1

WO2009104563A1 - Organic el display and manufacturing method thereof

Info

Publication number: WO2009104563A1
Application number: PCT/JP2009/052566
Authority: WO
Inventors: 誠内海
Original assignee: 富士電機ホールディングス株式会社
Priority date: 2008-02-20
Filing date: 2009-02-16
Publication date: 2009-08-27
Also published as: TW201002129A

Abstract

Disclosed is a low-cost organic EL display and the manufacturing method thereof with which the number of parts and the number of processing steps can be reduced, and with which the infiltration of moisture from adhesion sites can be prevented. The organic EL display (100) comprises a support substrate (10), an organic EL element (20) formed thereon and including a lower electrode (11), an organic layer (12) and an upper electrode (13), and a sealing substrate (30) arranged at a prescribed interval and opposite to the support substrate (10), wherein the support substrate (10) and the sealing substrate (30) are bonded together. There are a protruding sealing member (14), which is formed at the perimeter of the support substrate (10) surrounding the organic EL element (20), and a sealing film (15), which is formed on the upper electrode (13), the support substrate (10), and the sealing member (14) or on the upper electrode (13), the lower electrode (11), the support substrate (10), and the sealing member (14), and the sealing substrate (30), which is adhered to the support substrate (10) by means of an adhesive layer (16) that is formed on the side of the sealing member (14), is in contact with the support substrate (10) at the location where the sealing film (15) is formed on the sealing member (14).

Description

Organic EL display and manufacturing method thereof

The present invention relates to an organic EL display and a method for manufacturing the same, and more particularly to an organic EL display capable of preventing moisture from entering from the outside environment and realizing excellent luminous efficiency over a long period of time and a method for manufacturing the same.

In recent years, research on organic EL displays using self-luminous organic EL elements has been actively conducted. Organic EL displays are expected to achieve high luminous intensity and luminous efficiency because they can achieve high current density at low voltage. In particular, multi-color display capable of high-definition multi-color display and eventually full-color display is expected. The practical application of organic EL displays is expected.

An important practical issue for a color display is having a fine color display function and long-term stability including color reproducibility. However, the color organic EL display has a drawback that the light emission characteristic (current-luminance characteristic) is remarkably lowered by driving for a certain period.

A typical cause of the deterioration of the light emission characteristics is the growth of dark spots. This dark spot is a light emitting defect point. As the oxidation of the material proceeds during driving and storage, the growth of dark spots proceeds and spreads over the entire light emitting surface. The cause of dark spots is considered to be due to oxidation or aggregation of the laminated material constituting the element due to oxygen or moisture in the element. The growth proceeds not only during energization but also during storage, and in particular, (1) accelerated by oxygen or moisture present around the element, and (2) oxygen or moisture present as an adsorbate in the organic laminated film. (3) It is also considered that it is affected by moisture adsorbed on the component at the time of device fabrication or moisture penetration during production.

As a technique for preventing moisture from entering the organic EL element, a method of forming a frame-shaped desiccant at the position of the sealing material for bonding the substrate on which the organic EL element is formed and the sealing substrate (Patent Document 1) There is also known a method (Patent Document 2) in which a bent structure is formed at a site where a sealing material is formed, and a passage route for moisture or the like is lengthened. In addition, in order to efficiently prevent moisture from reaching the organic EL element, a technique of welding between substrates using a laser is also known (Patent Document 3).
JP 2005-340020 A JP 2005-38842 A JP 2006-338948 A

It can be said that the method of bonding a sealing substrate using a sealing material is a simple method. However, in this case, since moisture permeates through the portion of the sealing material, as a countermeasure, as disclosed in Patent Document 1 and Patent Document 2, moisture is adsorbed with a desiccant or A method has been adopted in which the lifetime of the panel is increased by lengthening the transmission path and extending the transmission time.

Also, there is a method of welding with a laser as described in Patent Document 3, but in this method, it is necessary to increase the number of steps for fixing the sealing portion. In order to put the organic EL display into practical use, it is important to reduce the cost by reducing the number of parts used and the number of steps. From such a point of view, it is required to obtain stable light emission characteristics over a long period of time using an adhesive such as an epoxy resin without using a desiccant, and this makes it possible to reduce the number of parts and man-hours.

Accordingly, an object of the present invention is to provide a low-cost organic EL display that can solve the above-described problems and prevent the ingress of moisture from an adhesion site while reducing the number of parts and man-hours, and a method for manufacturing the same. .

As a result of intensive studies, the inventor has found that the joint between the support substrate and the sealing substrate is formed on the sealing member formed on the supporting substrate, the sealing film formed on the sealing member, and the side of the sealing member. The present invention has been completed by finding that the above-mentioned problems can be solved by constituting the adhesive layer with the formed adhesive layer.

That is, the organic EL display of the present invention is opposed to a support substrate, an organic EL element formed on the support substrate, including a lower electrode, an organic layer, and an upper electrode, and the support substrate with a predetermined distance therebetween. In an organic EL display comprising a sealing substrate disposed, and the support substrate and the sealing substrate being bonded together,
A convex sealing member formed on an outer peripheral portion surrounding the organic EL element on the support substrate;
A sealing film formed on the upper electrode, the supporting substrate and the sealing member, or on the upper electrode, the lower electrode, the supporting substrate and the sealing member;
A sealing substrate that is bonded to the support substrate by an adhesive layer formed on a side of the sealing member and that is in contact with the support substrate at a position of the sealing film formed on the sealing member When,
It is characterized by having.

In the organic EL display of the present invention, the sealing members may be formed in two rows, and the adhesive layer may be formed between the two rows of sealing members. Further, instead of the convex sealing member, a concave sealing member protruding on the substrate is formed, and the adhesive layer is formed in the concave portion of the concave sealing member. You can also

Furthermore, the sealing member is preferably made of an acrylic resin, a novolac resin, or a polyimide resin, and the sealing film is preferably an inorganic oxide film, an inorganic oxynitride film, or an inorganic nitride film. Furthermore, it is preferable that the sealing member is continuously formed on an outer peripheral portion surrounding the organic EL element on the support substrate.

Moreover, the manufacturing method of the organic EL display of this invention is the planarization film | membrane formed prior to the said organic EL element on the said support substrate in manufacturing the organic EL display of the said invention. It is characterized by forming at the same time.

According to the present invention, the above configuration can reduce the number of parts and man-hours while reducing the moisture intrusion route at the bonded portion between the substrates, and can achieve a long display life without using a desiccant. It has become possible to realize an organic EL display that has been improved.

It is typical sectional drawing which shows an example of the organic electroluminescent display of this invention. It is typical sectional drawing which shows the other example of the organic electroluminescent display of this invention. It is a plane transmission figure which shows the example of arrangement | positioning shape of a sealing member. It is sectional drawing which shows the example of the arrangement | positioning state of a sealing member and an adhesion layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Support substrate 10a Substrate 10b Flattening film 11 Lower electrode 11a Insulating film 11A Lower electrode wiring part 12 Organic layer 13 Upper electrode 13A Upper electrode wiring part 14 Sealing member 15 Sealing film 16 Adhesive layer 17 Lamination of color filters, etc. Body 20 Organic EL element 30

Sealing substrate

100, 200 Organic EL display

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The example shown below is merely an example, and the design can be changed as appropriate within the scope of ordinary creation ability of those skilled in the art.

<Organic EL display>
FIG. 1 shows a schematic cross-sectional view of a preferred example of the organic EL display of the present invention. As shown in the figure, an organic EL display 100 of the present invention includes a support substrate 10, an organic EL element 20 formed thereon and including a lower electrode 11, an organic layer 12, and an upper electrode 13, and above the organic EL element 20. And a sealing substrate 30 disposed opposite to the support substrate 10 at a predetermined interval, and the support substrate 10 and the sealing substrate 30 are bonded to each other. In the figure, reference numeral 11A denotes a wiring portion of the lower electrode 11, and reference numeral 13A denotes a wiring portion of the upper electrode 13.

In the organic EL display 100 of the present invention, the convex sealing member 14 is disposed at the outer peripheral portion surrounding the organic EL element 20 on the support substrate 10, that is, at the position where the support substrate 10 and the sealing substrate 30 are bonded. Is formed. Further, on the sealing member 14, the sealing film is continuously formed from the upper electrode 13 and the supporting substrate 10 (in the drawing, the supporting substrate 10, or the planarizing film 10b and the insulating film 11a formed thereon). 15 is formed. Here, the sealing member 14 can be continuously formed on the outer peripheral portion surrounding the organic EL element 20 on the support substrate 10 as shown in FIG. Further, as shown in FIG. 3B, the sealing member 14 may be formed so as to have a discontinuous portion in order to ensure the allowance for the flow of the adhesive.

In the organic EL display 100 of the present invention, the support substrate 10 and the sealing substrate 30 are bonded by the adhesive layer 16 formed on the side of the sealing member 14 and formed on the sealing member 14. Contact is made at the position of the sealing film 15. By adopting such a configuration, it is possible to contact between the substrates that have been conventionally bonded via an adhesive (sealant) in a state where the sealing film 15 and the sealing substrate 30 are in close contact with each other, The gap between the substrates can be reduced. Therefore, it is possible to suppress the intrusion of moisture into the interior more effectively and to obtain an organic EL display having a long life without using a desiccant.

(Support substrate)
The support substrate 10 is mainly composed of a substrate 10a, and further includes a color filter layer, a thin film transistor (TFT), and a planarization film 10b according to the structure of the organic EL display. The material of the substrate 10a is particularly limited as long as it can withstand various conditions (for example, a solvent used, a temperature, and the like) used in forming the

layers

11, 12, and 13 sequentially stacked on the support substrate 10. Is not to be done. Preferably, those having excellent dimensional stability are used. Examples of suitable materials include a glass substrate or a rigid resin substrate formed of an acrylic resin such as polyolefin or polymethyl methacrylate, a polyester resin such as polyethylene terephthalate, a polycarbonate resin, or a polyimide resin. Examples of other suitable materials include flexible films formed of acrylic resins such as polyolefin and polymethyl methacrylate, polyester resins such as polyethylene terephthalate, polycarbonate resins, and polyimide resins. Further, as the material of the planarizing film 10b, a material that can maintain the adhesion with the material of the

layers

11, 12, and 13 formed thereon and can withstand the process is selected. For example, a novolac resin, an acrylic resin, a polyimide resin, etc. Can be used. These materials can be produced by a normal photolithography process.

(Organic EL device)
The organic EL element 20 according to the present invention includes the lower electrode 11, the organic layer 12, and the upper electrode 13 as described above.

(Lower electrode)
The lower electrode 11 has a function of charge injection into the organic layer 12 and connection with an external drive circuit. Desirable materials when the lower electrode 11 functions as a reflective electrode are made of a highly reflective metal (aluminum, silver, molybdenum, tungsten, nickel, chromium, or the like) or an amorphous alloy (NiP, NiB, CrP, or CrB). The thing which becomes. Particularly preferable reflective electrode materials include those made of a silver alloy from the viewpoint that a reflectance of 80% or more in visible light can be obtained. For example, an alloy of silver and at least one of group 8 nickel, rubidium, lead, and platinum, or an alloy of silver and at least one of group 2A magnesium and calcium Can be used.

Desirable materials when the lower electrode 11 functions as a transparent electrode include conductive metal oxides such as SnO ₂ , In ₂ O ₃ , In—Sn oxide, In—Zn oxide, ZnO, or Zn—Al oxide. Can be used.

(Organic layer)
The organic layer 12 is disposed between the lower electrode 11 and the upper electrode 13 and is a layer that forms the core of the light emitting unit. The organic layer 12 includes at least an organic light emitting layer, and includes a hole transport layer, a hole injection layer, an electron transport layer, and / or an electron injection layer as necessary. For example, the following layer configuration can be adopted for the organic layer 12.
(1) Organic light emitting layer (2) Hole injection layer / organic light emitting layer (3) Organic light emitting layer / electron injection layer (4) Hole injection layer / organic light emitting layer / electron injection layer (5) Hole transport layer / Organic light emitting layer / electron injection layer (6) Hole injection layer / hole transport layer / organic light emitting layer / electron injection layer (7) Hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection Layer In each of the configurations (1) to (7), the electrode functioning as the anode is connected to the left side, and the electrode functioning as the cathode is connected to the right side.

A known material can be used for the organic light emitting layer. Examples of a material for obtaining blue to blue-green light emission include fluorescent brighteners such as benzothiazole, benzimidazole, or benzoxazole, metal chelated oxonium compounds (Alq ₃ (tris (8-quinolinol) aluminum) ), Styrylbenzene compounds (4,4′-bis (diphenylvinyl) biphenyl (DPVBi), etc.), aromatic dimethylidin compounds, condensed aromatic ring compounds, ring assembly compounds, or porphyrin compounds Compounds and the like are preferred.

Moreover, the organic light emitting layer which emits the light of a various wavelength range can also be formed by adding a dopant to a host compound. In this case, a distyrylarylene compound, N, N′-ditolyl-N, N′-diphenylbiphenylamine (TPD), Alq ₃ or the like can be used as the host compound. On the other hand, as dopants, perylene (blue purple), coumarin 6 (blue), quinacridone compounds (blue green to green), rubrene (yellow), 4-dicyanomethylene-2- (p-dimethylaminostyryl) -6- Methyl-4H-pyran (DCM, red), platinum octaethylporphyrin complex (PtOEP, red) or the like can be used.

For the hole transport layer, a material having a triarylamine partial structure, a carbazole partial structure, or an oxadiazole partial structure can be used. For example, it is preferable to use TPD, α-NPD, MTDAPB (o-, m-, p-), m-MTDATA, or the like.

For the hole injection layer, materials such as phthalocyanines (including copper phthalocyanine) or indanthrene compounds can be used.

The electron transport layer, aluminum complexes such as _{Alq 3, PBD (2- (4} -biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole) or TPOB (1, 3, 5 Oxadiazole derivatives such as tris (4-tert-butylphenyl-1,3,4-oxadiazolyl) benzene), TAZ (3- (biphenyl-4-yl) -4-phenyl-5- (4-tert- butylphenyl) -1,2,4-triazole), triazine derivatives, phenylquinoxalines, or thiophene such as BMB-2T (5,5'-bis (dimethoxyboryl) -2,2'-bithiophene) Derivative It is possible to use of the material.

For the electron injection layer, a material such as an aluminum complex such as Alq ₃ or an aluminum quinolinol complex doped with an alkali metal or an alkaline earth metal can be used.

The organic layer 12 can be formed from each of the layers as described above. In addition to these layers, a buffer layer for further increasing the electron injection efficiency is optionally selected between the organic layer 12 and the upper electrode 13. It can also be formed (not shown). As the buffer layer, an electron injecting material such as an alkali metal, an alkaline earth metal or an alloy thereof, or a rare earth metal or a fluoride thereof can be used. Moreover, it is also preferable to form a damage mitigating layer (not shown) made of MgAg or the like on the organic layer 12 in order to mitigate damage when the upper electrode 13 is formed.

(Upper electrode)
The upper electrode 13 can be formed using the same material as that of the lower electrode 11 regardless of whether the upper electrode 13 functions as a reflective electrode or a transparent electrode.

Further, the transmittance of the upper electrode 12 is preferably 50% or more with respect to light having a wavelength of 400 to 800 nm in order to make the function of taking out the light emitted from the organic layer 12 upward. More preferably, it is 85% or more.

(Sealing member)
The sealing member 14 is formed on the support substrate 10 as described above, and the sealing film 15 is continuously formed on the sealing member 14 from above the upper electrode 13. As the material used for the sealing member 14, a material having an appropriate elasticity, small deformation with respect to the pressure generated at the time of bonding, and a property that does not break is preferable. For example, when the weight is 3.0 gf, the material has a film thickness retention rate of 50% or more. Since the sealing member 14 has appropriate elasticity, a close contact (contact) area between the support substrate 10 and the sealing substrate 30 can be increased. Specific materials for the sealing member 14 include acrylic resin, novolac resin, polyimide resin, and the like.

As the shape of the sealing member 14, in addition to the convex shape as shown in FIG. 1 and FIG. 4 (A), the sealing member 14 may be formed into two rows of convex shapes as shown in FIG. As shown to C), you may form in the concave shape which protrudes on a board | substrate. In either case, it is necessary to form the outer peripheral portion surrounding the organic EL element 20 on the support substrate 10. The sealing member 14 is formed with the same height as the gap between the sealing substrate 30 and the support substrate 10, and is formed with a thickness of 1 to 50 μm, for example. The adhesive layer 16 is formed on the side of the sealing member 14, but as shown in the figure, the adhesive layer 16 is formed in the case of the two rows of convex sealing members 14 shown in FIG. Can be formed between the two rows of sealing members 14, and in the case of the concave sealing member 14 shown in FIG. 4C, it is formed in the concave portion of the concave sealing member 14. can do.

The sealing film 15 is preferably formed of an inorganic oxide film, an inorganic oxynitride film, or an inorganic nitride film. Specifically, for example, silicon oxide, silicon oxynitride, silicon nitride, or the like can be used. As described above, the sealing film 15 covers the upper electrode 13, the support substrate 10, and the sealing member 14 (or the upper electrode, the lower electrode, the support substrate, and the sealing member). The sealing film 15 can be formed by a sputtering method or a CVD method. In particular, the sealing film 15 is preferably formed by a CVD method that enables high-speed film formation at a low temperature. Further, the thickness of the sealing film 15 can be set to 100 nm to 10 μm. In particular, from the viewpoint of reducing moisture permeability and maintaining productivity, it is desirable to form the sealing film 15 with a thickness of 1 to 5 μm.

(Adhesive layer)
The adhesive layer 16 is used to bond the support substrate 10 and the sealing substrate 30 (in the example shown in FIG. 1, the laminate 17 such as a color filter formed on the sealing substrate 30). Examples of the preferable adhesive layer 16 include those made of a UV (ultraviolet) curable adhesive. As another preferable adhesive 16, an element for supplementing the distance between the support substrate 10 and the sealing substrate 30, for example, spacer particles such as glass beads, is contained in the UV curable adhesive. Is mentioned. That is, in the present invention, the adhesive layer 16 may or may not contain spacer particles.

The formation position of the adhesive layer 16 may be either a position in contact with the sealing member 14 or a position away from the sealing member 14 as long as it is on the side of the sealing member 14. In particular, as described above, when the sealing member 14 has a concave structure at the center, it can be formed at the center of the sealing member 14.

(Sealing substrate)
The sealing substrate 30 is used to isolate the organic EL element 20 from the outside and make the light emitting function of the organic EL element 20 effective. The preferred sealing substrate 30 is formed of, for example, a glass substrate, a metal sealing substrate such as SUS or Al, or an acrylic resin such as polyolefin or polymethyl methacrylate, a polyester resin such as polyethylene terephthalate, a polycarbonate resin, or a polyimide resin. A rigid resin substrate may be mentioned. Examples of other preferable sealing substrate 30 include a flexible film formed of an acrylic resin such as polyolefin or polymethyl methacrylate, a polyester resin such as polyethylene terephthalate, a polycarbonate resin, or a polyimide resin.
Moreover, you may form the laminated body 17 and color conversion layers (not shown), such as a color filter, using a transparent base material as the sealing substrate 30, as shown in the figure.

(Laminates such as color filters)
The laminate 17 such as a color filter includes a color filter and a color conversion layer. The color filter is a layer that transmits only light in a desired wavelength range. The color filter is effective in that the color purity of the light whose wavelength distribution is converted by the color conversion layer can be improved when the laminate 17 has a laminated structure with the color conversion layer. Examples of the color filter include those using a commercially available liquid crystal color filter material such as a color mosaic manufactured by FUJIFILM Electronics Materials Corporation.

(Light conversion layer)
The light conversion layer is a layer containing a fluorescent dye for color conversion, and may contain a matrix resin. This layer is a layer for performing wavelength distribution conversion on the light emitted from the organic EL element 20 and emitting light in different wavelength ranges. Here, the fluorescent dye constituting the light conversion layer is a dye that emits light in a desired wavelength range (for example, red, green, or blue).

Examples of the fluorescent dye that absorbs light in the blue to blue-green region and emits fluorescence in the red region include rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine 101, rhodamine 110, sulforhodamine, basic violet 11, and basic red 2. Such as rhodamine dyes, cyanine dyes, pyridine dyes such as 1-ethyl-2- [4- (p-dimethylaminophenyl) -1,3-butadienyl] -pyridinium-perchlorate (pyridine 1), or oxazine System dyes and the like. Furthermore, various dyes (direct dyes, acid dyes, basic dyes, disperse dyes, etc.) can be used as long as they have fluorescence.

On the other hand, examples of fluorescent dyes that absorb light in the blue or blue-green region and emit fluorescence in the green region include, for example, 3- (2′-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6), 3- (2 '-Benzimidazolyl) -7-diethylaminocoumarin (coumarin 7), 3- (2'-N-methylbenzimidazolyl) -7-diethylaminocoumarin (coumarin 30), 2,3,5,6-1H, 4H-tetrahydro-8 A coumarin dye such as trifluoromethylquinolidine (9,9a, 1-gh) coumarin (coumarin 153), or basic yellow 51 which is a coumarin dye dye, and further naphthalimide such as solvent yellow 11 and solvent yellow 116 System dyes and the like. Furthermore, various dyes (direct dyes, acid dyes, basic dyes, disperse dyes, etc.) can be used if they are fluorescent.

As the matrix resin constituting the light conversion layer, acrylic resin, various silicone polymers, or any material that can be substituted for them can be used. For example, straight silicone polymers and modified resin silicone polymers can be used.

The example of FIG. 1 shown above is an integrated transparent electrode that functions as a common electrode, a switching element composed of a plurality of thin film transistors formed on a supporting substrate, a lower electrode composed of a plurality of parts connected in a one-to-one relationship. A so-called active matrix-driven organic EL display in which an organic layer is interposed between the two layers. This organic EL display includes a plurality of light emitting units.

Further, the organic EL display of the present invention is not limited to active matrix driving, and can be a so-called passive matrix driving organic EL display. FIG. 2 is a cross-sectional view showing the main part of the organic EL display 200 including a single organic EL element 20. Such passive matrix driving is not limited to the illustrated example, and may include a plurality of light emitting units controlled independently. For example, both the lower electrode and the upper electrode are electrode groups composed of a plurality of stripe electrodes, and the extending direction of the stripe electrodes constituting the lower electrode intersects with the extending direction of the stripe electrodes constituting the upper electrode. An example in which an organic layer is interposed between these electrodes is given. In such a case, it is preferable to make the above-described crossing directions orthogonal to each other because a display for displaying an arbitrary image and / or character can be configured.

In both cases of passive matrix driving and active matrix driving, when a lower electrode composed of a plurality of electrodes is formed, an insulating oxide (SiOx, TiO ₂ , ZrO ₂ , AlOx, etc.) or an insulating property is used. The insulating film 11a can also be formed in the gaps between the plurality of electrodes on the support substrate 10 using nitride (AlNx, SiNx, etc.), a polymer material, or the like.

The example shown in FIG. 1 is a display for realizing monochrome display, but the present invention is not limited to such an example, and includes a multi-color display. When realizing display of multi-color display, there are three types of units including the layered body 17 such as the organic EL element 20, the light conversion layer, and the color filter shown in FIG. The color conversion layers included in the body 17 are red, green, and blue color conversion layers, and the color filters included in the stacked body 17 are associated with the color conversion layers of each unit, so that the three types of units Are combined into a pixel.

<Method for manufacturing organic EL display>
When the organic EL display shown in FIG. 1 is manufactured, the following forming steps can be employed.

(Organic EL element formation process)
[Lower electrode formation process]
In this step, the lower electrode 11 is formed on the support substrate 10. In the case of using a metal having a high reflectivity, vapor deposition or sputtering using resistance heating or electron beam heating can be used. In the case of vapor deposition, the film formation rate can be 0.1 to 10 nm / second at a film formation pressure of 1.0 × 10 ⁻⁴ Pa or less. On the other hand, when a sputtering method such as a DC magnetron sputtering method is used, an inert gas such as Ar can be used as the sputtering gas, and the film forming pressure can be set to about 0.1 to 2.0 Pa. In any of vapor deposition and sputtering, it is preferable that the forming atmosphere is a vacuum because excellent adhesion with an adjacent layer can be realized.

[Organic layer formation process]
In this step, the organic layer 12 is formed on the lower electrode 11. As the organic layer 12, an organic light emitting layer and an optional hole transport layer, hole injection layer, electron transport layer, and electron injection layer are deposited in a predetermined order using resistance heating or electron beam heating. Can be formed. It is important to form each layer constituting the organic layer 15 with a film thickness sufficient to achieve desired characteristics. The thickness of each layer constituting the organic layer 12 is 2 to 50 nm for the organic light emitting layer, 2 to 50 nm for the hole transport layer, 2 to 200 nm for the hole injection layer, 2 to 50 nm for the electron transport layer, The electron injection layer is preferably 2 to 50 nm.

Further, the buffer layer optionally formed between the organic layer 12 and the upper electrode 13 can be formed by vapor deposition using resistance heating or electron beam heating, and the film thickness depends on the driving voltage and transparency. Is preferably 10 nm or less.

[Upper electrode formation process]
In this step, the upper electrode 13 is formed on the organic layer 12. The upper electrode 13 can be formed using a sputtering method or a vapor deposition method. For example, an inert gas such as Ar can be used as the sputtering gas, and a DC magnetron sputtering method or the like can be used at a film forming pressure of about 0.1 to 2.0 Pa. At this time, in order to prevent the organic layer 12 from deteriorating, it is preferable not to directly irradiate the organic layer 12 with plasma formed on the target.

(Sealing member forming step)
In this step, the sealing member 14 is formed on the support substrate 10. The sealing member 14 may be formed on the support substrate 10 at the same time as the planarization film 10b prior to the organic EL element, or at the same time as the formation process of the insulating film 11a covering between adjacent lower electrode patterns. May be. Therefore, the sealing member 14 can be formed before the lower electrode 11 is formed. Moreover, in order to ensure sufficient thickness, it is also possible to divide and form in multiple times. As the forming method, for example, a method of forming by applying a material of each layer by a spin coating method, a roll coating method, a casting method, a dip coating method or the like and then patterning by a photolithography method or the like can be used.

(Sealing film forming process)
In this process, the sealing film 15 is formed on at least the upper electrode 13, the support substrate 10, and the sealing member 14. Moreover, it forms also on the lower electrode 11 and the insulating film 11a as needed. The sealing film is a continuous integral film. The sealing film 15 can be formed using a sputtering method, a CVD method, or a vapor deposition method. For example, it can be formed by a plasma CVD method using monosilane, ammonia or the like as a reaction gas at a pressure of about 10 to 200 Pa.

(Sealing structure forming process)
[Sealed body forming step]
A laminated body 17 (color filter and color conversion layer) such as a color filter is formed on the sealing substrate 30 as necessary. The laminated body 17 such as a color filter is formed by applying a material of each layer by a known lamination method, that is, a spin coating method, a roll coating method, a casting method, a dip coating method, and the like, and then patterning by a photolithography method or the like. Can be formed. Among these known formation methods, the formation method of the color filter layer is particularly established as the formation method of the color filter layer. Therefore, the formation method by the photolithographic method is preferable after the application by the spin coating method. When forming a plurality of types of color modulators such as color filters on one transparent substrate 30, a full color display can be realized by forming a plurality of types of color modulators in a matrix.

[Light conversion layer forming step]
In this process, a light conversion layer is formed on the sealing substrate 30 as necessary. When a light conversion layer is formed using a plurality of types of color conversion dyes, a plurality of types of color conversion dyes are premixed at a predetermined ratio to obtain a premixture obtained by mixing the matrix with a matrix resin. It can also be used for vapor deposition. Alternatively, multiple types of color conversion dye-containing matrix resins can be arranged in separate heating sites, and the resins containing the respective color conversion dyes can be separately heated to perform co-evaporation. In particular, co-evaporation is advantageous when there are large differences in characteristics such as vapor deposition rate and / or vapor pressure among a plurality of types of color conversion dyes.

In the case where a passivation film that covers the entire surface is optionally formed on the light conversion layer, a method such as plasma CVD can be used. In particular, from the viewpoint of preventing the deterioration of the light conversion layer, it is preferable to form the film at a substrate temperature of 100 ° C. or less.

[Bonding process of supporting substrate and sealing substrate]
As shown in FIG. 1, this is a step of bonding the support substrate 10 and the sealing substrate 30 using an adhesive 16. As a bonding condition, any known bonding method can be used. In order to reduce the influence of heat on the organic layer 12, it is preferable to select an epoxy resin system that uses both ultraviolet curing and thermal curing. The gap between the support substrate 10 and the sealing substrate 30 is supported by the sealing member 14. Thus, the organic EL display 100 of the present invention shown in FIG. 1 is obtained.

Hereinafter, the present invention will be described in detail by examples, and the effects of the present invention will be demonstrated. FIG. 2 is a sectional view of an essential part of an organic EL display driven by a passive matrix according to an embodiment of the present invention.
Example 1
In this example, an organic EL display (number of pixels 2 × 2 (red only), pixel width 0.3 mm) was produced.

Fusion glass (Corning 1737 glass, 50 × 50 × 1.1 mm) was used as the support substrate 10. An Ag film having a thickness of 100 nm was deposited on the support substrate 10 by a sputtering method, and patterning was performed by a photolithographic method to form a stripe-shaped lower electrode 11 having a width of 0.3 mm.

Next, a continuous pattern having a width of 200 μm and a thickness of 5 μm is formed at a position corresponding to the outer peripheral portion of the support substrate 10 by photolithography using an acrylic material (PC-405G, manufactured by JSR) as the sealing member 14. did.

The support substrate 10 on which the sealing member 14 was formed was placed in a resistance heating vapor deposition apparatus, and Li having a film thickness of 1.5 nm was deposited on the lower electrode 11 using a mask to form a cathode buffer layer. Subsequently, an organic layer 12 was obtained by sequentially depositing four layers of an electron transport layer / an organic EL layer / a hole transport layer / a hole injection layer using a resistance heating vapor deposition apparatus. The internal pressure of the vacuum chamber during film formation was 1 × 10 ⁻⁴ Pa. Each layer constituting the organic layer 15 was deposited at a deposition rate of 0.1 nm / s. A 20 nm thick Alq ₃ (tris (8-quinolinol) aluminum was formed as an electron transport layer, a 30 nm thick DPVBi was formed as an organic EL layer, and a 10 nm thick α-NPD was formed as a hole transport layer. As the hole injection layer, copper phthalocyanine having a film thickness of 100 nm was formed.

Subsequently, MgAg with a film thickness of 5 nm was deposited to form a damage mitigation layer when forming the transparent electrode. The laminate on which the organic layer 12 was formed was moved to the counter sputtering apparatus without breaking the vacuum. A metal mask was placed to deposit IZO having a film thickness of 100 nm, and a stripe-shaped transparent upper electrode 13 having a width of 0.3 mm extending in a direction perpendicular to the stripe of the lower electrode 11 was formed.

Next, the support substrate 10 on which the upper electrode 13 is formed is transferred to a plasma CVD chamber, and a silicon nitride film is formed on the upper electrode 13, the support substrate 11 and the sealing member 14 using monosilane gas and ammonia gas. A sealing film 15 was obtained. The film forming pressure was 100 Pa, and the RF power was 2 kW. As described above, an organic EL element 20 composed of the lower electrode 11 / the organic layer 12 / the upper electrode 13 and having the sealing film 15 formed thereon was obtained.

On the other hand, a red filter material (CR7001, manufactured by FUJIFILM Electronics Materials) is applied to the transparent substrate (sealing substrate) 30, and 0.5 mm × 0.5 mm at a position corresponding to the light emitting portion of the organic EL element 20. A red color filter layer having a thickness of 1.5 μm was formed.

Next, the laminate on which the color filter layer was formed was conveyed to a resistance heating vapor deposition apparatus, and a light conversion layer containing coumarin 6 and DCM-2 was produced. A 300 nm-thick photoconversion layer was formed by co-evaporation in which coumarin 6 and DCM-2 were heated in separate crucibles in the vapor deposition apparatus. At this time, the heating temperature of each crucible was controlled so that the deposition rate of coumarin 6 was 0.3 nm / s and the deposition rate of DCM-2 was 0.005 nm / s. In the light conversion layer of this example, the molar ratio of coumarin 6 and DCM-2 is 49: 1 based on the total number of constituent molecules.

Next, the support substrate 10 on which the organic EL element 20 is formed and the transparent substrate 30 on which the color filter layer is formed are carried into a bonding apparatus having an oxygen concentration of 5 ppm or less and a water concentration of 5 ppm or less to form the organic EL element 20. An adhesive layer 16 was formed dropwise on the inside of the sealing member 14 on the support substrate 10 using an epoxy-based ultraviolet curable adhesive. After depressurizing the inside of the apparatus to about 10 Pa, the positions of the light emitting portion of the organic EL element 20 and the red color filter layer were aligned, the both laminates were bonded together, and the inside of the apparatus was returned to atmospheric pressure.

Next, using a mask, only the adhesive layer 16 was irradiated with ultraviolet rays to be temporarily cured, placed in a heating furnace and heated to 80 ° C. for 1 hour, and then naturally cooled in the furnace for 30 minutes. Thereafter, the bonded body was taken out from the apparatus to obtain an organic EL display.

(Example 2)
The sealing member 14 is formed on the outer periphery of the support substrate 10 as a two-row pattern having a width of 100 μm and an interval of 500 μm, and the adhesive layer 16 is formed between the two rows of the sealing member 14 as in Example 1. Similarly, an organic EL display was produced.

(Example 3)
A first sealing member pattern having a thickness of 3 μm and a width of 700 μm was formed on the outer peripheral portion of the support substrate 10 by photolithography using an acrylic resin (PC-405G, manufactured by JSR). Again, using the same acrylic resin, two rows of sealing member patterns having a thickness of 2 μm, a width of 100 μm, and an interval of 500 μm were formed on the first sealing member pattern by photolithography. Through the above operation, the concave sealing member 14 was formed on the support substrate 10. Other steps were performed in the same manner as in Example 1. In this case, the adhesive layer 16 is formed in the concave portion of the concave sealing member 14.

(Comparative Example 1)
In Example 1, an organic EL display was produced in the same manner as in Example 1 except that the sealing member 14 was not formed.

The organic EL displays of Examples 1 to 3 and Comparative Example 1 formed as described above were continuously driven at a current density of 0.1 A / cm ² in an environment of 60 ° C. and 60 RH%, and voltage and luminance were measured. The value obtained by dividing the luminance by the current value is calculated as the luminous efficiency, and the retention ratio of the luminous efficiency at 1000 hours when the initial luminous efficiency is 1 is shown in Table 1 below.

From the results in Table 1 above, it can be seen that in each example satisfying the conditions of the present invention, excellent results were obtained in the maintenance efficiency of luminous efficiency. As described above, in each of the examples within the scope of the present invention, excellent results were obtained in the life characteristics, while in Comparative Example 1 that deviates from the scope of the present invention, it can be seen that the life is short. This is probably because, in Comparative Example 1, no sealing member was provided, so that moisture entered from the adhesive layer.

According to the present invention, it is possible to improve the life characteristics of an organic EL display that has been a problem in the past. For this reason, the organic EL display of the present invention can achieve excellent luminous efficiency over a long period of time. Therefore, it can be said that the present invention is a promising technology in a situation where development of an organic EL display having higher light emission efficiency has been demanded in recent years.

Claims

A support substrate, an organic EL element formed on the support substrate and including a lower electrode, an organic layer, and an upper electrode, and a sealing substrate disposed opposite to the support substrate at a predetermined interval; In the organic EL display in which the support substrate and the sealing substrate are bonded together,
A convex sealing member formed on an outer peripheral portion surrounding the organic EL element on the support substrate;
A sealing film formed on the upper electrode, the supporting substrate and the sealing member, or on the upper electrode, the lower electrode, the supporting substrate and the sealing member;
A sealing substrate that is bonded to the support substrate by an adhesive layer formed on a side of the sealing member and that is in contact with the support substrate at a position of the sealing film formed on the sealing member When,
An organic EL display comprising:
The organic EL display according to claim 1, wherein the sealing members are formed in two rows, and the adhesive layer is formed between the two rows of sealing members.
The recessed sealing member which protrudes on a board | substrate is formed instead of the said convex sealing member, and the said contact bonding layer is formed in the recessed part of this concave sealing member. Organic EL display.
2. The organic EL display according to claim 1, wherein the sealing member is made of acrylic resin, novolac resin or polyimide resin.
3. The organic EL display according to claim 2, wherein the sealing member is made of an acrylic resin, a novolac resin or a polyimide resin.
4. The organic EL display according to claim 3, wherein the sealing member is made of acrylic resin, novolac resin or polyimide resin.
2. The organic EL display according to claim 1, wherein the sealing film is an inorganic oxide film, an inorganic oxynitride film, or an inorganic nitride film.
3. The organic EL display according to claim 2, wherein the sealing film is an inorganic oxide film, an inorganic oxynitride film, or an inorganic nitride film.
4. The organic EL display according to claim 3, wherein the sealing film is an inorganic oxide film, an inorganic oxynitride film, or an inorganic nitride film.
The organic EL display according to claim 1, wherein the sealing member is continuously formed on an outer peripheral portion surrounding the organic EL element on the support substrate.
The organic EL display according to claim 2, wherein the sealing member is continuously formed on an outer peripheral portion surrounding the organic EL element on the support substrate.
The organic EL display according to claim 3, wherein the sealing member is continuously formed on an outer peripheral portion surrounding the organic EL element on the support substrate.
A support substrate, an organic EL element formed on the support substrate and including a lower electrode, an organic layer, and an upper electrode, and a sealing substrate disposed opposite to the support substrate at a predetermined interval; In manufacturing an organic EL display in which the support substrate and the sealing substrate are bonded together,
The organic EL display is a convex sealing member formed on the outer peripheral portion surrounding the organic EL element on the support substrate;
A sealing film formed on the upper electrode, the supporting substrate and the sealing member, or on the upper electrode, the lower electrode, the supporting substrate and the sealing member;
A sealing substrate that is bonded to the support substrate by an adhesive layer formed on a side of the sealing member and that is in contact with the support substrate at a position of the sealing film formed on the sealing member When,
Have
The method for manufacturing an organic EL display, wherein the sealing member is formed on the supporting substrate simultaneously with a planarizing film formed prior to the organic EL element.
14. The method of manufacturing an organic EL display according to claim 13, wherein the sealing members are formed in two rows, and the adhesive layer is formed between the two rows of sealing members.
14. A concave sealing member protruding on a substrate is formed instead of the convex sealing member, and the adhesive layer is formed in a concave portion of the concave sealing member. Manufacturing method of organic EL display.