JP2007115608A - Organic el display, its manufacturing method, and manufacturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display in which poor coverage of a passivation layer is eliminated by reducing fine unevenness, such as foreign substance, projection or the like on the surface of an overcoat layer, thereby preventing an occurrence of display defect etc. due to residual gas and moisture diffused to an organic EL layer, its manufacturing method and its manufacturing apparatus. <P>SOLUTION: In the method of manufacturing the organic EL display, after forming a color conversion filter layers 11 and 12 on a transparent substrate 13 and forming an overcoat layer 14 on the substrate to cover the color conversion filter layer, the surface of the overcoat layer is exposed in steam atmosphere of solvent 20 having property which dissolves the overcoat layer to flatten the surface, and an inorganic passivation layer and an organic EL light emitting element are successively formed on the overcoat layer having the flattened surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multicolor organic EL display including a color conversion filter layer, a manufacturing method thereof, and a manufacturing apparatus.

  FIG. 1 is a cross-sectional view schematically showing an example of an organic EL display having a color conversion filter layer. The color conversion filter layers 11R, 11G, 12R, 12G, and 12B of the organic EL display must have a thickness of 10 to 15 μm because concentration quenching occurs when the concentration of the fluorescent dye used in the color conversion filter layer is increased. Therefore, an overcoat layer 14 for filling and flattening between the color conversion filter layers of each color is necessary.

  Examples of the material for the overcoat layer 14 include a polyimide resin (Japanese Patent Laid-Open No. 1-229203), a photocurable or thermosetting organic polymer resin or photoresist having an acrylate- or methacrylate-based reactive vinyl group. (JP-A-6-300910, JP-A-7-128519, JP-A-8-279394), imide-modified silicone resins (JP-A-5-134112, JP-A-7-218717, JP-A-7 -306311), an epoxy-modified acrylate resin (Japanese Patent Laid-Open No. 7-48424) and a fluorine-based resin (Japanese Patent Laid-Open No. 5-36475, Japanese Patent Laid-Open No. 9-330793) are proposed as ultraviolet curable resins. Has been. Further, improvements have been proposed to improve mechanical reliability and heat resistance by using a straight silicone resin or a modified silicone resin as a hard coat layer (see JP 2000-182780 A and JP 2000). -91070).

On the other hand, Japanese Patent Application Laid-Open No. 2004-281251 describes that the surface of the organic EL layer 18 is exposed to an organic solvent in order to extend the life of the organic EL device.
JP-A-8-279394 JP 2000-182780 A JP 2004-281251 A

  Since the color conversion filter layers 11 and 12 have low heat resistance of the dye molecules and the matrix material, and the color conversion characteristics are deteriorated by heat, the baking temperature of the overcoat layer 14 needs to be 200 ° C. or lower. Therefore, there is a problem in using a high-temperature curable resin such as polyimide that is cured at a high temperature exceeding 200 ° C. On the other hand, thermosetting resins such as (meth) acrylates and silicones can be cured even at a baking temperature of 200 ° C. or lower. However, when cured at such a low temperature, an organic solvent is contained in the overcoat layer 14. Gas and moisture remain. When this residual gas or moisture diffuses into the organic EL layer 18, there is a problem that crystallization occurs in the amorphous constituent film, resulting in a non-light emitting portion, which causes deterioration and display defects. This problem is the same even when a photocurable resin is used.

  Therefore, the passivation layer 16 is formed on the overcoat layer 14 to block the diffusion of residual gas and moisture to the organic EL layer 18. Since the passivation layer 16 is formed by thinning silicon oxide or oxynitride by sputtering or low-temperature CVD, it has a high barrier property against residual gas and moisture (Japanese Patent Laid-Open No. 2003-229271 discloses that the passivation layer is in a vacuum). Is disclosed to do in). However, if there are foreign matters such as particles or development residues, fine irregularities, and particularly protrusions, on the surface of the overcoat layer 14, the passivation layer 16 cannot cover these fine irregularities and the like, resulting in poor coverage. As a result, the gas barrier property is lowered, and the diffusion of residual gas and moisture progresses in the organic EL layer 18 to cause problems such as deterioration and display defects.

  In view of the above problems, the present invention reduces the fine irregularities such as foreign matters and protrusions on the surface of the overcoat layer, thereby improving the poor coverage of the passivation layer and reducing the residual gas and moisture in the organic EL layer. It is an object of the present invention to provide an organic EL display capable of preventing the occurrence of display defects due to diffusion, a manufacturing method thereof, and a manufacturing apparatus.

  In order to achieve the above object, an organic EL display manufacturing method according to the present invention includes a step of forming a color conversion filter layer on a transparent substrate, and an overcoating on the substrate so as to cover the color conversion filter layer. A step of forming a coat layer, a step of exposing the surface of the overcoat layer to a vapor atmosphere of a solvent having a characteristic of dissolving the overcoat layer, and flattening the surface. A step of sequentially forming an inorganic passivation layer and an organic EL light emitting element on the overcoat layer.

  The overcoat layer forming step preferably includes coating on the substrate using a coating solution containing a curable resin that is a main component of the overcoat layer and the solvent.

  In another aspect, the present invention is an organic EL display, which is formed on the substrate so as to cover the transparent substrate, the color conversion filter layer formed on the substrate, and the color conversion filter layer. An overcoat layer, the surface of which is flattened by exposing the surface to a vapor atmosphere of a solvent having a characteristic of dissolving the overcoat layer, and on the overcoat layer. It includes an inorganic passivation layer formed and an organic light emitting element formed on the inorganic passivation layer.

  Further, according to another aspect of the present invention, there is provided an organic EL display manufacturing apparatus, comprising: a means for forming a color conversion filter layer on a transparent substrate; and an overcoat on the substrate so as to cover the color conversion filter layer. Means for forming a coat layer, a sealed chamber for exposing the surface of the overcoat layer in a vapor atmosphere of a solvent having a property of dissolving the overcoat layer, and flattening the surface And means for sequentially forming an inorganic passivation layer and an organic EL light emitting element on the converted overcoat layer.

  By exposing the surface of the overcoat layer to the solvent in this way, the surface portion of the overcoat layer is once dissolved, and foreign matter such as particles and development residues on the surface, and minute irregularities such as abnormal protrusions are present in the overcoat layer. It becomes buried or melts and becomes smooth. That is, since there are no irregularities that cannot be covered by the passivation layer, the gas barrier property of the passivation layer is dramatically improved. Accordingly, residual gas and moisture from the lower layer are blocked by the passivation layer and do not diffuse into the organic EL layer, so that problems such as deterioration and display defects due to this can be solved.

  In addition, by exposing the overcoat layer to a solvent, the taper portion of the end surface of the overcoat layer having a large amount of minute foreign matters is smoothed similarly to the surface of the overcoat layer. Thereby, peeling of the passivation layer formed on the overcoat layer and disconnection of the anode electrode formed on the passivation layer can be prevented. Therefore, according to the present invention, it is possible to provide a highly reliable organic EL display that can be driven stably for a long period of time, a manufacturing method, and a manufacturing apparatus.

  Hereinafter, an embodiment of an organic EL display, a manufacturing method thereof, and a manufacturing apparatus according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically showing an example of the structure of an organic EL display according to the present invention.

(1. Substrate)
The substrate 13 needs to be transparent to the light converted by the color conversion filter layers 11 and 12. The substrate 13 should be able to withstand the conditions (solvent, temperature, etc.) used for forming the color conversion filter layers 11 and 12, the black mask (not shown), the overcoat layer 14 and the partition layer (not shown). Further, it is preferable that the dimensional stability is excellent. The substrate 13 preferably has a transmittance of 50% or more with respect to light having a wavelength of 400 to 800 nm.

  As a material for the substrate 13, in addition to glass, resins such as polyethylene terephthalate and polymethyl methacrylate are preferable. Among the glasses, borosilicate glass and blue plate glass are particularly preferable.

(2. Color conversion filter layer)
In this specification, the color conversion filter layer is a general term for a laminate of the fluorescence conversion layer 11 and / or the color filter layer 12. The fluorescence conversion layer 11 absorbs near-ultraviolet to visible light, particularly blue to blue-green light emitted from the organic EL layer 18 and emits visible light having different wavelengths as fluorescence. In order to enable full color display, an independent color conversion filter layer that emits light of at least the blue (B) region, the green (G) region, and the red (R) region is provided. Each of the RGB fluorescence conversion layers 11 includes at least an organic fluorescent dye and a matrix resin.

(2-A. Organic fluorescent dye)
It is preferable to use at least one fluorescent dye that emits fluorescence in at least the red region, and this may be combined with one or more fluorescent pigments that emit fluorescence in the green region. This is because when the organic EL layer 18 that emits light in the blue or blue-green region is used as a light source, if light from the organic EL layer 18 is passed through a simple red filter to obtain light in the red region, the red region is originally formed. This is because the output light becomes extremely dark due to the small amount of light of the wavelength.

  Therefore, by converting the light in the blue or blue-green region from the organic EL layer 18 into the light in the red region by the fluorescent dye, the light in the red region having sufficient intensity can be output. Examples of fluorescent dyes that absorb light in the blue to blue-green region emitted from the luminescent material and emit fluorescence in the red region include rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine 101, rhodamine 110, sulforhodamine, basic violet 11 Pyridine dyes such as rhodamine dyes such as basic red 2, cyanine dyes, 1-ethyl-2- [4- (p-dimethylaminophenyl) -1,3-butadienyl] -pyridinium perchlorate (pyridine 1) Or oxazine dyes. Furthermore, various dyes (direct dyes, acid dyes, basic dyes, disperse dyes, etc.) can be used if they are fluorescent.

  Examples of fluorescent dyes that absorb light in the blue to blue-green region emitted from the luminescent material and emit green region fluorescence include 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- Coumarin dyes such as 8-trifluoromethylquinolidine (9,9a, 1-gh) coumarin (coumarin 153), or basic yellow 51 which is a coumarin dye dye, or naphthalimides 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.

  With respect to light in the blue region, light emitted from the organic EL layer 18 can be output through a simple blue filter 12B.

  In addition, the organic fluorescent dye is previously added to polymethacrylic acid ester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer resin, alkyd resin, aromatic sulfonamide resin, urea resin, melamine resin, benzoguanamine resin, and a mixture of these resins. It may be kneaded into a pigment to form an organic fluorescent pigment (in this specification, pigmented in this way is also collectively referred to as an organic fluorescent dye). In addition, these organic fluorescent dyes may be used alone or in combination of two or more in order to adjust the hue of fluorescence.

  The fluorescence conversion layer 11 contains 0.01 to 5% by mass, more preferably 0.1 to 2% by mass of an organic fluorescent dye based on the weight of the fluorescence conversion layer 11. By using an organic fluorescent dye with a content in this range, sufficient wavelength conversion can be performed without accompanying color conversion efficiency due to curing such as concentration quenching.

(2-B. Matrix resin)
The matrix resin is a photocurable or photothermal combined type curable resin (resist) that is generated by radical and ionic species by light and / or heat treatment, and polymerized or cross-linked to be insoluble and infusible. Further, in order to perform patterning of the fluorescence conversion layer 11, it is desirable that the photocurable or photothermal combination type curable resin is soluble in an organic solvent or an alkaline solution in an unexposed state.

  Specifically, the matrix resin is obtained by subjecting a composition film comprising (1) an acrylic polyfunctional monomer and oligomer having a plurality of acryloyl groups and methacryloyl groups, and light or thermal polymerization initiator to light or heat treatment, Or a polymer obtained by polymerizing by generating thermal radicals, (2) a composition comprising a polyvinyl cinnamate ester and a sensitizer dimerized by light or heat treatment, and (3) a chain or cyclic olefin A composition film composed of bisazide is irradiated with light or heat to generate nitrene and crosslinked with olefin, and (4) a composition film composed of a monomer having an epoxy group and an acid generator is subjected to light or heat treatment, Including those polymerized by generating an acid (cation). In particular, a polymer obtained by polymerizing a composition comprising the acrylic polyfunctional monomer and oligomer (1) and light or a thermal polymerization initiator is preferred. This is because this composition allows high-definition patterning and has high reliability such as solvent resistance and heat resistance after polymerization.

  The photopolymerization initiator, sensitizer, and acid generator that can be used in the present invention are preferably those that initiate polymerization by light having a wavelength that is not absorbed by the fluorescent conversion dye contained therein. In the fluorescence conversion layer 11, when the resin itself in the photocurable or photothermal combination type curable resin can be polymerized by light or heat, the photopolymerization initiator and the thermal polymerization initiator may not be added. Is possible.

(2-C. Configuration and shape)
The fluorescence conversion layer 11 is polymerized by applying a solution or dispersion containing an organic fluorescent dye, a matrix resin and an additive on the substrate 13 to form a resin layer, and exposing a desired portion of the resin. To form. Patterning is performed after exposing a desired portion to insolubilize the resin. The patterning can be carried out by a conventional method such as removing the resin in the unexposed portion using an organic solvent or an alkali solution that dissolves or disperses the resin in the unexposed portion.

  The red region may be formed only by the fluorescence conversion layer 11R. However, when sufficient color purity cannot be obtained only by conversion with a fluorescent dye, a laminate of a fluorescence conversion layer 11R and a color filter layer 12R may be used as shown in FIG. When the color filter layer 12R is used in combination, the thickness of the color filter layer 12R is preferably 1 to 1.5 μm.

  The green region may be formed only by the fluorescence conversion layer 11G, and when sufficient color purity cannot be obtained only by the conversion with the fluorescent dye, the fluorescence conversion layer 11G and the color filter layer as shown in FIG. It is good also as a laminated body with 12G. When the color filter layer 12G is used in combination, the thickness of the color filter layer 12G is preferably 1 to 1.5 μm. Alternatively, when the light emission of the organic EL layer 18 sufficiently includes light in the green region, only the color filter layer 12G may be used. When only the color filter layer 12G is used, the thickness is preferably 0.5 to 10 μm.

  On the other hand, regarding the blue region, as shown in FIG. 1, only the color filter layer 12B can be used. When only the color filter layer 12B is used, the thickness is preferably 0.5 to 10 μm. For the color filter layer 12, each color and a known color filter can be used.

  The present invention is also applicable when only the color filter layer 12 that does not include the fluorescence conversion layer 11 is applied. Further, the shape of the color conversion filter layer may be a stripe pattern separated for each color as is well known, or may have a structure separated for each sub-pixel of each pixel.

(3. Overcoat layer)
The overcoat layer 14 has high transparency in the visible range (transmittance of 50% or more in the range of 400 to 700 nm), Tg of 100 ° C. or more, surface hardness of 2H or more in pencil hardness, and on the color conversion filter. It is required that a coating film can be formed on the order of μm and that the function of the color conversion filter is not deteriorated.

  In addition, the overcoat layer 14 is required to have the following functions. (1) Do not cause pattern erosion or functional deactivation of the phosphor layer. (2) The step of the phosphor layer can be filled, and the film can be formed as thin as possible (about several μm) while maintaining the viewing angle characteristics. (3) Good light transmission. (4) It has heat resistance. (5) The surface is smooth. (6) Adhesion with the substrate and the passivation layer is good. (7) Excellent chemical resistance. (8) Excellent moisture resistance. (9) There is no degassing of residual monomer or solvent. (10) It has mechanical strength. (11) The pattern end has a gentle taper (the extraction electrode is formed in the upper part in a later step, and thus the pattern end needs a gentle taper to prevent disconnection of the extraction). (12) Patterning is possible. (13) There are no fine irregularities (1 μm or less) on the surface, in particular no protrusions.

  As the overcoat layer 14, a thermosetting or photocurable resin (photoresist) having an acrylate or methacrylate reactive vinyl group, an epoxy-modified acrylate ultraviolet-curable resin, a fluororesin, a straight silicone type or a modified type It is preferable to use a silicone-based thermosetting resin. As the modified silicone, imide-modified silicone and the like are preferable. Others such as polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone, polyvinyl butyral, polyphenylene ether, polyamide, polyetherimide, norbornene resin, methacrylic resin, isobutylene maleic anhydride copolymer resin, cyclic olefin Thermofunctional resin such as thermoplastic resin, epoxy resin, phenol resin, acrylic resin, vinyl ester resin, imide resin, urethane resin, urea resin, melamine resin, or trifunctional with polystyrene, polyacrylonitrile, polycarbonate, etc. Alternatively, a polymer hybrid containing a tetrafunctional alkoxysilane can be used. The thermosetting resin preferably has a property of curing at 200 ° C. or lower, and more preferably 150 ° C. or lower.

  Examples of the method for forming the overcoat layer 14 include conventional methods such as a dry method (sputtering method, vapor deposition method, CVD method, etc.) and a wet method (spin coating method, roll coating method, casting method, flexographic printing method, etc.). Can be formed. When the wet method is used, it is preferable to use a coating solution containing the curable resin and a solvent having a property of dissolving the resin used in the solvent exposure treatment described later. The overcoat layer 14 may be a single layer or a plurality of layers.

  It is necessary not to form the overcoat layer 14 on the sealing portion and / or the connecting portion (not shown) on the substrate 13. Therefore, the most convenient and accurate method is to form a film on the entire surface of the substrate 13 by a conventional method using a photosensitive material (photoresist), and then to form a necessary shape by a photolithographic method. It is. However, in this case, a monomer containing an organic solvent is thinned by a photo process, exposed to light, developed, and baked, so that organic solvent gas and moisture remain particularly in the film when baking at 200 ° C. or lower. In addition, the overcoat layer 14 can also be formed by applying a resin in a necessary shape by a flexographic printing method.

(3-A. Solvent exposure)
After forming the overcoat layer 14 by the above, the process which exposes the overcoat layer 14 to a solvent is performed. FIG. 2 is a cross-sectional view schematically showing an example of a sealed chamber for performing the solvent exposure treatment. As shown in FIG. 2, a plurality of substrate support pins 31 for supporting the substrate 13 are arranged on the bottom surface of the sealed chamber 32, and a substrate carry-in door for taking in and out the substrate 13 on the side surface. 33 is installed. The bottom of the chamber 32 is filled with the solvent 30, and the inside of the sealed chamber 32 is a solvent vapor atmosphere.

  The solvent 30 has a property of dissolving the overcoat layer 14 and can be selected according to the resin used for the overcoat layer 14. For example, in the case of a (meth) acrylate-based resin, it is preferable to use diethylene glycol dimethyl ether (DG), propylene glycol monomethyl ether acetate (PGMEA), or the like, and in the case of a silicone-based resin, methanol, acetone, or the like is used. preferable. In addition, the solvent 30 desirably has a boiling point as low as possible from the viewpoint of solvent removal in a subsequent step, and preferably has a temperature in the range of 50 to 150 ° C, for example.

  The substrate 13 with the overcoat layer 14 formed thereon is placed in the sealed chamber 32 and exposed to the solvent for a time sufficient to dissolve the outermost surface of the overcoat layer 14. Although the exposure time varies depending on the resin and the solvent, for example, a range of 10 to 60 seconds is sufficient.

  FIG. 3 is a cross-sectional view schematically showing the surface of the overcoat layer 14 before and after exposure to a solvent. On the surface of the overcoat layer 14 before exposure, as shown in FIG. 3A, foreign matter 34 having an overhang shape such as a development residue and particles when developing a photoresist, and irregularities or protrusions 35 are generated. is doing. In the above-described solvent exposure treatment, the foreign matter 34 is dissolved in the solvent or buried 34a in the outermost surface of the partially dissolved layer 14 as shown in FIG. 35a.

  The tapered portion 36 at the end of the overcoat layer 14 needs to have a gentle shape with a contact angle with the substrate 13 as small as possible to prevent peeling of the passivation layer and disconnection of the extraction electrode. As shown in FIG. 3A, the tapered portion 36 before exposure has a large contact angle with the substrate 13 and has an arc shape. However, as shown in FIG. 3B, the tapered portion 36a before exposure is formed. Has a small contact angle with the substrate 13 and has a substantially straight and gentle shape.

(3-B. Drying and post-baking)
In order to remove the solvent used for the exposure treatment from the overcoat layer 14, vacuum drying is performed. Although vacuum drying is based on the kind of resin and solvent, it is preferable to carry out at the temperature of 25-50 degreeC for 0.5 to 1 hour. The thermosetting resin needs to be post-baked and cured after applying the resin. However, depending on the type of resin and solvent, the resin surface may not be dissolved even after the solvent exposure treatment after curing. . In such a case, after the resin is applied, a solvent exposure treatment is performed, and then post-baking is performed for curing. When post-baking is performed after the exposure treatment, the solvent is removed by post-baking, so that vacuum drying can be omitted. The post bake is preferably 180 to 200 ° C, more preferably 120 to 150 ° C.

(4) Passivation Layer The passivation layer 16 is formed for the purpose of preventing moisture and gas permeation from the overcoat layer 14 and its lower layer, and preventing functional degradation of the organic EL layer 18 caused by them. Therefore, when foreign matters such as abnormal protrusions and residues are present on the surface of the overcoat layer 14, the solvent or moisture in the lower layer diffuses from the insufficiently covered portion of the passivation layer 16 to the organic EL layer 18, and dark spots are generated. This may cause deterioration of the panel performance.

  The passivation layer 16 is preferably transparent in the emission wavelength region in order to transmit the light emitted from the organic EL layer 18 to the color conversion filter layer. The passivation layer 16 has high transparency in the visible region (transmittance of 50% or more in the range of 400 to 800 nm), electrical insulation, barrier properties against moisture, oxygen and low molecular components, preferably 2H. It is formed of a material having the above film hardness. For example, materials such as inorganic oxides and inorganic nitrides such as SiOx, SiNx, SiNxOy, AlOx, TiOx, TaOx, and ZnOx can be used. There is no restriction | limiting in particular as the formation method of the passivation layer 16, It can form by common methods, such as a sputtering method, CVD method, a vacuum evaporation method, a dip method, a sol-gel method.

(5) Organic Light-Emitting Element The organic light-emitting element is a general term for a laminate of the anode 17, the organic EL layer 18, and the cathode 19. A material having a large work function is used for the anode 17 in order to efficiently inject holes. In particular, in an ordinary organic EL element, since light is emitted through the anode, the anode is required to be transparent, and a conductive metal oxide such as ITO or IZO is used.

  The cathode 19 is a material having a low work function, such as an alkali metal such as lithium or sodium, an alkaline earth metal such as potassium, calcium, magnesium, or strontium, or an electron injecting metal such as a fluoride thereof, or the like. Alloys and compounds with metals are used. A metal electrode (Al, Ag, Mo, W, etc.) with high reflectivity may be used underneath, and in that case, low resistance and effective use of light emission of the organic EL layer 18 by reflection can be achieved.

In the organic EL display of the color conversion system of the present invention, light in the near ultraviolet to visible region, preferably light in the blue to blue-green region emitted from the organic EL layer 18 is incident on the color conversion filter layer to obtain a desired color. Emits visible light having The organic EL layer 18 includes at least an organic EL light emitting layer, and has a structure in which a hole injection layer, a hole transport layer, and / or an electron injection layer are interposed as necessary. Specifically, those having the following layer structure are employed.
(A) Organic EL light emitting layer (b) Hole injection layer / organic EL light emitting layer (c) Organic EL light emitting layer / electron injection layer (d) Hole injection layer / organic EL light emitting layer / electron injection layer (e) positive Hole injection layer / hole transport layer / organic EL light emitting layer / electron injection layer In the above, the anode is connected to the organic EL light emitting layer or the hole injection layer, and the cathode is connected to the organic EL light emitting layer or the electron injection layer. The

  Known materials are used as the material for each of the above layers. In order to obtain light emission from blue to blue-green, in the organic EL light emitting layer, for example, optical brighteners such as benzothiazole, benzimidazole, and benzoxazole, metal chelated oxonium compounds, styrylbenzene compounds, aromatics Group dimethylidin compounds are preferably used.

Example 1
On the glass substrate, red, green and blue color filter layers each having a thickness of 1.5 μm, and red and green fluorescence conversion layers each having a thickness of 10 μm are laminated, and the color conversion filter layer is formed. Formed. Subsequently, an overcoat layer was formed to planarize the color conversion filter layer.

  An acrylic coating solution (trade name: NN810, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used as the overcoat layer. First, this was applied to a thickness of 5 μm by spin coating, developed and patterned by a normal photolithography method, and then hot. An overcoat layer was formed by post-baking at 200 ° C. with a plate. Next, the entire substrate on which this overcoat layer has been formed is placed in a sealed chamber, and propylene glycol monomethyl ether acetate (PGMEA, boiling point 146 ° C.) is used as a solvent, and exposed at a temperature of 23 ° C. for 10 seconds in a solvent vapor atmosphere. Only the outermost surface of the overcoat layer was dissolved. Furthermore, drying was performed for 30 minutes at 180 ° C. in a vacuum drying furnace.

  As a result of observing the surface of the overcoat layer with a substrate inspection machine and an SEM image, it was confirmed that this surface was free of sensitive abnormal protrusions and foreign matter that could not be covered, and was a smooth surface. It was also confirmed that the tapered portion at the end of the overcoat layer also has a gentle shape with a small contact angle. Regarding the residual solvent, the sample was cut out and subjected to thermal desorption analysis (TDS) up to 200 ° C., but it was not detected as before the solvent exposure treatment.

  The vacuum-dried substrate was stored in a load lock chamber of a sputtering apparatus for forming a passivation layer, and 300 nm of SiOx was formed by magnetron sputtering. An anode (IZO) having a thickness of 200 nm was formed thereon, and patterning was performed at a pitch of 100 μm by a photolithographic method.

Next, the substrate on which the anode was formed was mounted in a resistance heating vapor deposition apparatus, and a hole injection layer, a hole transport layer, an organic light emitting layer, and an electron injection layer were sequentially formed without breaking the vacuum. During film formation, the internal pressure of the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. As the hole injection layer, copper phthalocyanine (CuPc) was laminated to a thickness of 100 nm. As the hole transport layer, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) was laminated to 20 nm. The organic light emitting layer was formed by laminating 30 nm of 4,4-bis (2,2′-diphenylvinyl) biphenyl (DPVBi). The electron injection layer was formed by laminating 20 nm of aluminum chelate (Alq).

  On top of this, using a mask capable of obtaining a stripe pattern having a width of 0.30 mm and a gap of 0.03 mm perpendicular to the anode (ITO) line, a 200 nm thick Mg / Ag (weight ratio of 10: 1) A cathode consisting of layers was formed without breaking the vacuum.

  The organic light-emitting device thus obtained was sealed using a sealing glass and a UV curable adhesive in a dry nitrogen atmosphere in a glove box. As a result of evaluating the organic EL display thus obtained, there was no occurrence of dark spots (non-light emitting portions) caused by defects in the passivation layer due to the overcoat layer.

(Example 2)
After forming a color conversion filter layer on a glass substrate in the same manner as in Example 1, an overcoat layer was formed as follows. A siloxane-based coating solution (KP854, manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the overcoat layer, and this was first printed on the overcoat layer pattern with a thickness of 5 μm by flexographic printing. The solvent used for the exposure of KP854 is methanol (boiling point: 64.7 ° C.), has a fast drying property, and is stable against the solvent after post-baking. Therefore, before post-baking, it was exposed to a sealed chamber in a solvent vapor atmosphere at 23 ° C. for 15 seconds to dissolve only the outermost surface. Thereafter, it was cured by heating at 150 ° C. using a hot plate.

  The KP854 used in this example can be cured at 80 ° C. or higher, but was cured at 150 ° C. in order to perform sufficient degassing and dehydration. In the case of this example, since the solvent exposure was performed before post-baking, vacuum drying after post-baking was not performed. However, thermal desorption analysis (TDS) was performed in the same manner as in Example 1, but no residual solvent was detected.

  Further, when the surface of the overcoat layer was observed with a substrate inspection machine and an SEM image in the same manner as in Example 1, it was found that there were no protrusions or foreign matters that could not be covered during the formation of the passivation layer, and the tapered portion had a gentle shape. confirmed. And after forming a passivation layer and an organic light emitting element on this overcoat layer like Example 1, it sealed and manufactured the organic EL display. As a result of evaluating the organic EL display of this example, there was no occurrence of dark spots (non-light emitting portions) caused by defects in the passivation layer due to the overcoat layer.

It is sectional drawing which shows one structural example of an organic electroluminescent display typically. It is a schematic diagram which shows an example of the airtight chamber used for the solvent exposure process of an overcoat layer. It is a schematic diagram which shows the surface state of an overcoat layer, Comprising: (a) is the surface state before solvent exposure, (b) is the surface state after solvent exposure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Fluorescence conversion layer 12 Color filter 13 Substrate 14 Overcoat layer 16 Passivation layer 17 Anode 18 Organic EL layer 19 Cathode 20 Solvent 21 Substrate support pin 22 Sealed chamber 23 Substrate carry-in door 34 Foreign material 35 Protrusion 36 Taper part

Claims (4)

  A step of forming a color conversion filter layer on a transparent substrate, a step of forming an overcoat layer on the substrate so as to cover the color conversion filter layer, and a solvent having a characteristic of dissolving the overcoat layer A step of exposing the surface of the overcoat layer in a vapor atmosphere to planarize the surface, and a step of sequentially forming an inorganic passivation layer and an organic EL light emitting element on the overcoat layer having the planarized surface. The manufacturing method of the organic electroluminescent display containing.   2. The organic material according to claim 1, wherein the overcoat layer forming step includes applying the curable resin, which is a main component of the overcoat layer, onto the substrate using a coating solution containing the solvent. Manufacturing method of EL display.   A transparent substrate, a color conversion filter layer formed on the substrate, and an overcoat layer formed on the substrate so as to cover the color conversion filter layer, the characteristics of dissolving the overcoat layer An overcoat layer whose surface is exposed and planarized in a vapor atmosphere of a solvent, an inorganic passivation layer formed on the overcoat layer, and an organic light-emitting device formed on the inorganic passivation layer, Organic EL display including   Means for forming a color conversion filter layer on a transparent substrate, means for forming an overcoat layer on the substrate so as to cover the color conversion filter layer, and a solvent having a property of dissolving the overcoat layer A sealed chamber for flattening the surface of the overcoat layer by exposing the surface of the overcoat layer in a vapor atmosphere, and means for sequentially forming an inorganic passivation layer and an organic EL light emitting element on the overcoat layer having the flattened surface. A device for manufacturing an organic EL display.

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