JP2006302656A - Color conversion filter and organic el display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color conversion filter which can prevent gas penetration and an organic EL multi-color display which is made by using the above filter and which can maintain a stable luminescent property for a long period. <P>SOLUTION: A color conversion filter is composed of a transparent board, color conversion film layers of one or a plurality of kinds fixed on the transparent board, a flattened layer formed covering a color conversion layer and a gas-barrier layer formed on the flattened layer. The gas-barrier has a lamination of at least two pairs of an inorganic film and a polymer film, and an inorganic insulator film fixed on the above lamination. The organic EL display is made by using the above filter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a color conversion filter that enables high-definition, multicolor display excellent in environmental resistance and productivity, and a multicolor display organic EL display including the color conversion filter. In detail, color conversion filter for display of image sensor, personal computer, word processor, television, facsimile, audio, video, car navigation, electric desk calculator, telephone, portable terminal and industrial measuring instrument, and the color conversion The present invention relates to a multicolor organic EL display including a filter.

It has a thin film laminated structure of organic molecules having the following characteristics, which is excellent in viewing angle dependency and high-speed response with respect to a liquid crystal display element, etc., and has a high luminance of 1000 cd / m ² or more at an applied voltage of 10 V. Since an organic EL device that emits light is reported by Tang et al., Organic EL devices have been actively researched for practical use (Non-patent Document 1). reference). Similar devices using organic polymer materials are also being actively developed.

  Since an organic EL element can realize a high current density at a low voltage, it can be expected to have higher light emission luminance and light emission efficiency than an inorganic EL element or LED. As the display element, (1) high brightness and high contrast, (2) low voltage driving and high luminous efficiency, (3) high resolution, (4) wide viewing angle, (5) high response speed, (6) It has excellent features such as miniaturization and colorization, and (7) lightness and thinness. In view of the above, it is expected to be applied to “beautiful, light, thin, excellent” flat panel displays.

  Pioneer has already commercialized a green monochrome organic EL display for use in vehicles since November 1997, and has long-term stability and high-speed response to meet the diverse needs of society. Or, there is an urgent need for practical use of an organic EL display capable of high-definition full color display.

  One example of a method for multi-coloring or full-coloring an organic EL display is a method in which light emitters of three primary colors of red (R), green (G), and blue (B) are separately arranged in a matrix and light emitted respectively. (See Patent Documents 1 to 3). In the case of colorization using an organic EL element, it is technically difficult and cannot be manufactured at low cost because three types of RGB light emitting materials must be arranged on the matrix with high definition. In addition, since the lifetimes (luminance change characteristics) of the three kinds of light emitting materials are different from each other, there is a disadvantage that chromaticity is shifted due to long-term use.

  In addition, a method for transmitting three primary colors using a color filter for a backlight that emits white light (for example, see Patent Documents 4 to 6) is known. However, a long lifetime necessary for obtaining high-luminance RGB light is known. In addition, a high-luminance white light-emitting organic EL element has not yet been obtained.

  Alternatively, there is also known a method in which light emitted from a light emitter is absorbed by phosphors separated and arranged in a plane, and multicolor fluorescence is emitted from each phosphor (see Patent Document 7). Here, the method of emitting multicolor fluorescence from a certain light emitter using a phosphor has a track record in applications such as CRT and plasma display.

  In recent years, color conversion methods have been studied in which a fluorescent material that absorbs light in the light emitting region of an organic EL element and emits fluorescence in the visible light region is used as a filter (see, for example, Patent Documents 7 and 8). Since the light emission color of the organic EL element is not limited to white, an organic EL element with higher luminance can be applied as a light source. In a color conversion method using a blue light emitting organic EL element, blue light is converted into green light and The wavelength is converted into red light (see, for example, Patent Document 7 and Patent Documents 9 and 10). If such a color conversion layer containing a fluorescent dye is patterned with high definition, a full-color light-emitting display can be constructed even using weak energy rays such as near-ultraviolet light or visible light of a light emitter.

  As a patterning method for the color conversion layer, (1) as in the case of the inorganic phosphor, a fluorescent dye is dispersed in a liquid resist (photoreactive polymer), and the dispersion is used by spin coating or the like. A method of forming a film and patterning it to other values by a photolithography method (see Patent Documents 8 and 11), or (2) Dispersing the fluorescent dye in a basic matrix, and using an acidic aqueous solution, There is a method of etching (see Patent Document 10).

  An important practical issue as a color display is that it has a fine color display function and has long-term stability including color reproducibility (see Non-Patent Document 2). However, the organic EL element has a problem that current-luminance characteristics are 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. When oxidation proceeds during driving and during storage, the growth of dark spots proceeds and spreads over the entire light emitting surface. This dark spot is considered to be caused by 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. In particular, the growth is accelerated by (1) oxygen or moisture present around the element, and (2) oxygen or moisture present as an adsorbate in the organic laminated film. And (3) it is considered that it is also affected by moisture adsorbed on components at the time of device fabrication or moisture intrusion at the time of production.

  FIG. 1 shows a general cross-sectional structure of a conventional color conversion type organic EL display. In the color conversion filter 40, three types (red, green, and blue) of color conversion filter layers 42 (R, G, and B) are dispersedly arranged on the transparent substrate 41 to cover the color conversion filter layer 42. A flattening layer 43 for flattening the upper surface is provided. On the color conversion filter 40, an organic EL element 50 including a transparent electrode 51, an organic EL layer 52, and a reflective electrode 53 is formed. As described above, the color conversion filter layer 42 is obtained by dispersing a color conversion pigment in a resin. Here, since the drying at a temperature exceeding 200 ° C. cannot be performed due to the problem of thermal stability of the dye to be mixed, the color conversion filter layer 42 is mixed with moisture contained in the coating liquid or in the pattern forming process. There is a high possibility that moisture will be contained. Moisture contained in the color conversion filter layer 42 passes through the planarization layer 43 during storage or driving and reaches the organic EL element 50 (specifically, the organic EL layer 52) to promote the growth of dark spots. This is considered to be a factor.

A technique for disposing an insulating inorganic oxide film having a thickness of 0.01 to 200 μm between the color conversion filter 40 and the organic EL element 50 is known as a technique for preventing the moisture from entering the organic EL element. (See Patent Document 12). In order to maintain the lifetime of the organic EL layer, the disposed inorganic oxide film is required to have high gas barrier performance. Specifically, it is 10 ⁻¹³ cc · cm / cm ² · s · against water vapor and oxygen. It is considered desirable to have a gas permeability coefficient of cmHg or less (according to the gas permeability test method of JIS K7126: 1987).

As a method for forming such an inorganic oxide film, a method of forming SiO _x and SiN _x on the planarizing layer 43 of the color conversion filter 40 by DC sputtering is known (see Patent Documents 13 and 14). . SiO _x and SiN _x formed by this method are also known to improve the adhesion of the transparent electrode 51 formed thereon. A method of sintering low-melting glass is also known (see Patent Document 15). In addition to the above, a sol-gel method and a plasma enhanced chemical vapor deposition (PECVD) method are known as methods for forming an inorganic oxide film.

JP-A-57-157487 Japanese Patent Laid-Open No. 58-147899 JP-A-3-214593 JP-A-1-315988 JP-A-2-27396 Japanese Patent Laid-Open No. 3-194485 Japanese Patent Laid-Open No. 3-152897 JP-A-5-258860 JP-A-8-286033 Japanese Patent Laid-Open No. 9-208944 Japanese Patent Laid-Open No. 5-198921 JP-A-8-279394 Japanese Patent Laid-Open No. 7-146480 Japanese Patent Laid-Open No. 10-10518 JP 2000-214318 A Japanese Patent Laid-Open No. 5-134112 JP-A-7-218717 JP-A-7-306311 JP-A-5-119306 JP-A-7-104114 JP-A-6-300910 JP 7-128519 A JP-A-9-330793 JP-A-5-36475 C. W. Tang, S. A. VanSlike, Appl. Phys. Lett. 51, 913 (1987) Functional Materials, Vol. 18, No. 2, 96 (1998) Monthly Display, Vol. 3, No. 7, 119 (1997)

  However, pinholes are likely to occur in the inorganic oxide film formed at a temperature that does not deteriorate the color conversion ability of the organic pigment contained in the color conversion filter layer 32 (up to about 200 ° C.). It is difficult to form an inorganic oxide film having gas barrier performance sufficient to maintain or improve the lifetime of the organic EL element 40. On the other hand, an inorganic oxide film formed by a sol-gel method that can be carried out at a lower temperature contains moisture and / or volatile organic components, and the organic EL element 40 formed thereon is immediately deteriorated. It is expected that

  Accordingly, it is possible to effectively prevent moisture (water vapor) and / or gas such as oxygen held in the color conversion filter layer 32 from reaching the organic EL element 40 during storage or driving and promoting the growth of dark spots. There is a strong demand for structures that can be done.

  The present invention has been made in view of the above problems, and maintains a stable light emission characteristic over a long period of time, which is formed using a color conversion filter capable of preventing gas permeation and the color conversion filter. An object is to provide a multicolor organic EL display.

The color conversion filter according to the first embodiment of the present invention is a flat substrate formed by covering a transparent substrate, one or more color conversion filter layers provided on the transparent substrate, and the color conversion layer. And a gas barrier layer formed on the planarization layer, the gas barrier layer comprising a laminate of at least two pairs of an inorganic film and a polymer film, and an inorganic insulation provided on the laminate It is characterized by being comprised from the film | membrane. Here, each of the inorganic films may be independently formed of a conductive transparent metal oxide, an insulating oxide, an insulating nitride, an insulating carbide, or an insulating oxynitride. Each of the polymer films may be independently formed from an acrylic resin, a methacrylic resin, a polyester resin, or a polyolefin resin. Further, the inorganic insulating film is an insulating oxide, insulating nitride, insulating carbide, or insulating oxynitride, preferably SiO _x , AlO _x , SiN _x , AlN _x , SiO _x N _y , AlO _x. It may be formed from N _y , TiO ₂ , BN, or SiC.

  The organic EL display according to the second embodiment of the present invention is formed using the color conversion filter according to the first embodiment. Here, an organic EL element in which at least a transparent electrode, an organic EL layer, and a reflective electrode are sequentially stacked may be formed on the color conversion filter. Alternatively, the color conversion filter and an organic EL element in which at least a reflective electrode, an organic EL layer, and a transparent electrode are sequentially laminated on the support substrate may be bonded together.

  By adopting a structure having a gas barrier layer composed of the above laminate, the movement of moisture and oxygen from the color conversion filter layer to the organic EL element, which causes a decrease in the light emission characteristics of the organic EL element, is suppressed and stable over a long period of time. It is possible to provide a color organic EL display that can maintain the light emission characteristics.

  An example of the configuration of the color conversion filter 10 of the present invention is shown in FIG. In FIG. 2, three (red, green, and blue) color conversion filter layers 12 (R, G, and B) having a predetermined pattern are formed on a transparent substrate 11, and these three color conversion filter layers 12 are formed. Are arranged in a matrix. A flattening layer 13 that covers the color conversion filter layer 12 and flattens the upper surface thereof is formed, and a gas barrier layer 14 is formed on the flattening layer 13. The gas barrier layer 14 has a structure having an inorganic insulating film 63 on a laminate of at least two pairs of inorganic films (61a, b) and polymer films (62a, b). Hereinafter, each layer will be described in detail.

  The transparent substrate 11 should be transparent to visible light (wavelength 400 to 700 nm), withstand the conditions (solvent, temperature, etc.) used to form the layer to be laminated, and to have dimensional stability. It is preferable that it is excellent. The transparent substrate 11 is preferably a glass substrate and a rigid resin substrate formed of a resin such as polyolefin resin, acrylic resin (including polymethyl methacrylate), polyester resin (including polyethylene terephthalate), polycarbonate resin, or polyimide resin. including. Alternatively, a flexible film formed from a polyolefin resin, an acrylic resin (including polymethyl methacrylate), a polyester resin (including polyethylene terephthalate), a polycarbonate resin, or a polyimide resin may be used as the transparent substrate 11. .

  The color conversion filter layer 12 is composed of a color filter layer, a color conversion layer, or a laminate of a color filter layer and a color conversion layer. The color filter layer is a layer that does not have a color conversion function and transmits light of a wavelength in a selected range to improve the color purity of output light. When using the laminated body of a color filter layer and a color conversion layer, a color filter layer is normally arrange | positioned between a transparent substrate and a color conversion layer. The color filter layer can be formed using any material known in the art such as a material used in a liquid crystal display or the like.

  The color conversion layer is a layer made of a color conversion dye and a matrix resin. The color conversion dye is a dye that converts the wavelength distribution of incident light and emits light in different wavelength ranges, and preferably converts the wavelength distribution of near-ultraviolet light or blue to blue-green light from the organic light emitting layer. Thus, it is a pigment that emits light in a desired wavelength band (for example, blue, green, or red).

  The color conversion dye in the present invention absorbs light in the near ultraviolet region or visible region, particularly light in the blue or blue-green region, emitted from a light emitter, and emits visible light having a different wavelength as fluorescence. Preferably, at least one fluorescent dye that emits fluorescence in the red region may be used, and may be combined with one or more fluorescent pigments that emit fluorescence in the green region.

  That is, when an organic EL element that emits light in the blue or blue-green region is used as the light source, if light from the element is passed through a simple red filter to obtain light in the red region, light having a wavelength in the red region is originally used. Because there is little, it becomes very dark output light. On the other hand, light in the red region having sufficient intensity can be output by converting the light in the blue or blue-green region from the element into light in the red region by the color conversion dye in the red conversion layer. It becomes. Therefore, in the present invention, the red color conversion filter layer 12R is preferably composed of a color conversion layer, and more preferably composed of a laminate of a color filter layer and a color conversion layer.

  On the other hand, the light in the green region may be output after the light from the element is converted into the light in the green region by another color conversion dye, similarly to the light in the red region. Alternatively, if the light emission of the element sufficiently includes light in the green region, the light from the element may simply be output through the green filter. Furthermore, regarding the light in the blue region, the light from the organic EL element can be output through a simple blue filter.

  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 blue to blue-green light emitted from a light emitter and emit green light include 3- (2′-benzothiazolyl) -7-diethylamino-coumarin (coumarin 6), 3- (2′-Benzimidazolyl) -7-diethylamino-coumarin (coumarin 7), 3- (2′-N-methylbenzimidazolyl) -7-diethylamino-coumarin (coumarin 30), 2,3,5,6-1H, 4H -Coumarin-based dyes such as tetrahydro-8-trifluoromethylquinolidine (9,9a, 1-gh) coumarin (coumarin 153), or basic yellow 51 which is a coumarin dye-based dye, solvent yellow 11, solvent yellow 116 And naphthalimide dyes. Furthermore, various dyes (direct dyes, acid dyes, basic dyes, disperse dyes, etc.) can be used if they are fluorescent.

  The color conversion dye used in the present invention includes polymethacrylate, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer resin, alkyd resin, aromatic sulfonamide resin, urea resin, melamine resin, benzoguanamine resin, and these resins. An organic color conversion pigment may be obtained by kneading into a mixture or the like in advance to obtain a pigment. In addition, these color conversion dyes and organic color conversion pigments (in the present specification, the above two are collectively referred to as color conversion dyes) may be used singly, and two kinds may be used to adjust the hue of fluorescence. A combination of the above may also be used.

  The color conversion pigment used in the present invention is contained in the color conversion layer in an amount of 0.01 to 5% by mass, more preferably 0.1 to 2% by mass, based on the weight of the color conversion layer. If the content of the color conversion dye is less than 0.01% by mass, sufficient wavelength conversion cannot be performed, or if the content exceeds 5%, the color conversion efficiency decreases due to effects such as density quenching. Bring.

  The matrix resin used in the color conversion layer of the present invention is insoluble by photocuring or photothermal combination type curable resin (resist) by light and / or heat treatment to generate radical species or ionic species to polymerize or crosslink. Infusible. In order to perform patterning of the color conversion layer, 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 generating thermal radicals, (2) a composition comprising a polyvinylcinnamic acid 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 the composition can be patterned with high definition 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 filter layer of the present invention, a photopolymerization initiator and a thermal polymerization initiator are added when the resin itself in the photocurable or photothermal combination type curable resin can be polymerized by light or heat. It is also possible not to.

  Matrix resin (color conversion layer) is a photocurable or photothermal combination type curable resin, a solution or dispersion containing a color conversion dye and an additive, spin coating method, roll coating method, casting method, dip coating method, etc. Is applied onto the transparent substrate 11 to form a resin layer, and a desired portion of the photocurable or photothermal combination type curable resin is polymerized by exposure. Patterning is performed after exposing the desired portion to insolubilize the photocurable or photothermal combination type curable resin. The patterning can be performed by a conventional method such as removing the resin in the unexposed portion using an organic solvent or an alkali solution in which the resin in the unexposed portion is dissolved or dispersed. The color conversion layer has a thickness of usually 5 μm or more, preferably 8 to 15 μm.

  The planarization layer 13 can be formed without impairing the function of the color conversion filter layer 12 and can be formed from a material having appropriate elasticity. A preferable material has high transparency in the visible range (transmittance of 50% or more in the range of 400 to 800 nm), a surface hardness of 2H or more, a Tg of 100 ° C. or more, and the color conversion filter layer 12. It is a polymer material that can form a smooth coating film and does not deteriorate the function of the color conversion layer. More preferably,

Examples of such polymeric materials, dispersed imide-modified silicone resin (see Patent Document 16 to 18), an inorganic metal compound _{(TiO 2, Al 2 O 3} , SiO 2 , etc.) acrylic, polyimide, in such as a silicone resin Materials (see Patent Documents 19 and 20), resins having reactive vinyl groups of acrylate monomers / oligomers / polymers, resist resins (see Patent Documents 12 and 21 to 23), fluorine-based resins (Patent Documents 23) , 24) and the like. Alternatively, the planarization layer 13 may be formed using an inorganic compound formed by a sol-gel method (see Non-Patent Document 3 and Patent Document 12). In addition, it is possible to dissipate heat from the organic EL element toward the transparent substrate 11 by using a photocurable resin such as an epoxy resin having a mesogenic structure having a high thermal conductivity.

  There is no particular limitation on the method of forming the planarization layer 13. For example, it can be formed by a conventional method such as a dry method (sputtering method, vapor deposition method, CVD method, etc.) or a wet method (spin coating method, roll coating method, casting method, etc.).

  The gas barrier layer 14 formed on the planarization layer 13 has excellent moisture / oxygen barrier properties, and is therefore a layer for preventing the transmission of moisture and oxygen from the color conversion filter layer 12. In order to transmit light from the organic EL element to the color conversion filter layer 12, the gas barrier layer 14 preferably has high transparency in the visible range (transmittance of 50% or more in the range of 400 to 800 nm). Further, since it is necessary to form a transparent electrode composed of a plurality of electrically independent portions on the gas barrier layer, the gas barrier layer 14 is required to have electrical insulation at least on its upper surface. Preferably, the gas barrier layer 14 has a film hardness of 2H or higher. As shown in FIG. 3, the gas barrier layer 14 of the present invention has a structure having an inorganic insulating film 63 on a laminate of at least two pairs of inorganic films (61a, b) and polymer films (62a, b). Have. A laminate of three or more pairs of inorganic film 61 / polymer film 62 may be used.

The inorganic film 61 (a, b) of the present invention includes ITO (In—Sn oxide), NESA film, Sn oxide, In oxide, IZO (In—Zn oxide), Zn oxide, and Zn—Al oxide. And a conductive transparent metal oxide in which a dopant such as F or Sb is added to these oxides, Zn—Ga oxide, or these oxides. When these conductive transparent metal oxides are used, it is effective to efficiently dissipate the heat generated in the organic EL element to the transparent substrate 11 side and the display peripheral direction due to its high heat conductivity. Alternatively, the inorganic film 61 (a, b) of the present invention includes an insulating oxide such as SiO _x , AlO _x , and TiO ₂ , an insulating nitride such as SiN _x , AlN _x , and BN, and SiO _x N. It can be formed using an insulating oxynitride such as _y , AlO _x N _y , or an insulating carbide such as SiC. In the present invention, the inorganic film 61a and the inorganic film 61b may be formed of the same material, or may be formed of different materials. The same applies to the case where three or more inorganic films are used.

  The inorganic film 61 (a, b) can be formed by vapor deposition, sputtering (including reactive sputtering), or chemical vapor deposition (CVD). In particular, when an oxide film is formed, it is preferable to use a sputtering method (including a reactive sputtering method) from the viewpoints of adhesion, film thickness uniformity, and productivity.

  The film thickness of the inorganic film 61 (a, b) can be increased as long as it has transparency in the visible range described above, but is usually in the range of 50 to 300 nm. By forming a film having a film thickness in such a range, the above-mentioned required characteristics including transparency in the visible range are satisfied, and at the same time, the occurrence of defects such as pinholes is suppressed, and a good gas (water content) And oxygen) barrier properties can be provided.

  The polymer film 62 (a, b) of the present invention is formed from an acrylic resin, a methacrylic resin, a polyester resin such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), or a polyolefin resin such as polyethylene and polypropylene. can do. The polymer film 62 (a, b) can be formed by a spin coat method, a roll coat method, a dip coat method, a knife coat method, a cast method or the like using a solution in which these resins are dissolved in a solvent. However, it is preferable to use a method in a gas phase such as a vacuum heating vapor deposition method, a plasma polymerization method, an ionization vapor deposition method, a sputtering method, or a chemical vapor deposition (CVD) method, which can be performed in an environment with a low moisture concentration. Thus, the polymer film 62 (a, b) is formed. Alternatively, the monomer is deposited on the inorganic film 61 (a, b) using the vapor phase method described above, and then polymerized in situ by heating, UV irradiation, etc., and polymer film 62 (a, b). ) May be formed.

  The polymer film 62 (a, b) of the present invention has a function of filling a defect such as a pinhole in the inorganic film 61 when the defect occurs. Since it is unlikely that a defect such as a pinhole will occur at the same position of two or more inorganic films 61 (or inorganic insulating films 63), by adopting a laminated structure of the inorganic film 61 and the polymer film 62 It is possible to provide better gas barrier properties.

  The polymer film 62 (a, b) of the present invention can have an arbitrary film thickness such that the entire film thickness of the gas barrier layer 14 is 30 μm or less so that the viewing angle characteristics of the display are not deteriorated. Each polymer film 62 (a, b) has a film thickness of 0.5 to 2 μm.

The inorganic insulating film 63 of the present invention includes an insulating oxide such as SiO _x and AlO _x , an insulating nitride such as SiN _x and AlN _x , and an insulating oxide such as SiO _x N _y and AlO _x N _y. It can be formed using nitride. By using such a material, it is possible to ensure the electrical independence of the transparent electrode composed of a plurality of portions formed thereon, and at the same time improve the adhesion of the transparent electrode. Alternatively, the inorganic insulating film 63 can be formed using an insulating oxide such as TiO ₂ , an insulating nitride such as BN, or an insulating carbide such as SiC.

  Furthermore, as shown in FIG. 4, it is preferable to form the inorganic insulating film 63 so as to completely cover the color conversion filter layer 12, the planarization layer 13, the inorganic film 61, and the polymer film 62. By adopting such a configuration, it is possible to prevent the planarization layer 13 and / or the polymer film 62 from coming into contact with the atmosphere after the gas barrier layer 14 is formed and adsorbing oxygen and moisture contained in the atmosphere. The oxygen and moisture can be prevented from deteriorating the organic EL element after the display is formed.

  The inorganic insulating film 63 can be formed by vapor deposition, sputtering (including reactive sputtering), or chemical vapor deposition (CVD). In particular, when an oxide film is formed, it is preferable to use a sputtering method (including a reactive sputtering method) from the viewpoints of adhesion, film thickness uniformity, and productivity.

  The film thickness of the inorganic insulating film 63 can be increased as long as it has transparency in the visible region as described above, as in the case of the inorganic film 61 (a, b), but is usually in the range of 50 to 300 nm. By forming the inorganic insulating film 63 having a film thickness in such a range, the above-mentioned required characteristics including transparency in the visible region are satisfied, and at the same time, the occurrence of defects such as pinholes is suppressed, It becomes possible to provide gas (water, oxygen and low molecular components) barrier properties.

  When producing a multicolor display using the color conversion filter 10 of the present invention, as shown in FIG. 2, three types of red conversion filter layer 12R, green conversion filter layer 12G, and blue conversion filter layer 12B are used. It is desirable to form a color conversion filter layer. The pattern of the color conversion filter layer 12 (R, G, B) for each color depends on the application used. A rectangular or circular red color conversion filter layer 12R, green color conversion filter layer 12G, and blue color conversion filter layer 12B may be taken as a set and arranged in a matrix on the entire surface of the transparent substrate 11. Alternatively, one set of a red color conversion filter layer 12R, a green color conversion filter layer 12G, and a blue color conversion filter layer 12B having a stripe shape (having a desired width and a length corresponding to a dimension in one direction of the transparent substrate 11). And they may be arranged in parallel on the entire surface of the transparent substrate 11. Alternatively, if desired, the color conversion filter layers 12 of a specific color can be arranged more (numerically or in area) than the color conversion filter layers 12 of other colors.

  FIG. 5 shows an organic EL display of the present invention obtained by forming the organic EL element 20 on the color conversion filter 10 of the present invention. The organic EL element 20 includes an organic EL layer 22 sandwiched between a transparent electrode 21 and a reflective electrode 23.

  The transparent electrode 21 preferably has a transmittance of 50% or more, more preferably 85% or more with respect to light having a wavelength of 400 to 800 nm. The transparent electrode 21 is made of ITO (In—Sn oxide), NESA film, Sn oxide, In oxide, IZO (In—Zn oxide), Zn oxide, Zn—Al oxide, Zn—Ga oxide, Alternatively, a conductive transparent metal oxide in which a dopant such as F or Sb is added to these oxides can be used. The transparent electrode 21 is formed using a vapor deposition method, a sputtering method (including a reactive sputtering method) or a chemical vapor deposition (CVD) method, and preferably formed using a sputtering method (including a reactive sputtering method). The The transparent electrode 21 desirably has a thickness of usually 50 nm or more, preferably 50 nm to 1 μm, more preferably 100 to 300 nm. As will be described later, when a transparent electrode 21 composed of a plurality of partial electrodes is required, the transparent electrode 21 composed of a plurality of partial electrodes may be formed using a mask giving a desired shape, or vice versa. You may form the transparent electrode 21 which consists of a some partial electrode using the separation partition which has a taper-shaped cross-sectional shape.

  The transparent electrode 21 can be used as either an anode or a cathode. When the transparent electrode 21 is used as a cathode, it is desirable to provide a buffer layer at the interface with the organic EL layer 22 to improve the electron injection efficiency. As the material of the buffer layer, alkali metals such as Li, Na, K, or Cs, alkaline earth metals such as Ba and Sr, alloys containing them, rare earth metals, or fluorides of these metals can be used. However, it is not limited to them. The film thickness of the buffer layer can be appropriately selected in consideration of the driving voltage, transparency, and the like, but in a normal case, it is preferably 10 nm or less.

  The organic EL layer 22 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. Each of these layers is formed to have a film thickness sufficient to realize desired characteristics in each layer. For example, what consists of the following layer structures is employ | adopted.

(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 the above configuration, 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)

Any known material can be used as the material of the organic light emitting layer. For example, in order to obtain light emission from blue to blue-green, for example, a condensed aromatic ring compound, a ring assembly compound, a metal complex (such as an aluminum complex such as Alq ₃ ), a styrylbenzene compound (4,4′-bis (diphenyl) (Vinyl) biphenyl (DPVBi), etc.), porphyrin-based compounds, benzothiazole-based, benzimidazole-based, benzoxazole-based fluorescent whitening agents, and aromatic dimethylidin-based compounds are preferably used (non-patent literature). 2 and Non-Patent Document 3). Or you may form the organic light emitting layer which emits the light of a various wavelength range by adding a dopant to a host compound. Examples of host compounds include distyrylarylene compounds (for example, IDE-120 manufactured by Idemitsu Kosan Co., Ltd.), N, N′-ditolyl-N, N′-diphenylbiphenylamine (TPD), aluminum tris (8-quinolinolate) (Alq ₃ ). ) Etc. can be used. 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.

  As a material for the hole injection layer, Pc (including CuPc) or indanthrene compounds can be used. The hole transport layer can be formed using a material having a triarylamine partial structure, a carbazole partial structure, or an oxadiazole partial structure. Materials that can be used preferably include TPD, [alpha] -NPD, MTDAPB (o-, m-, p-), m-MTDATA, and the like.

Materials for the electron transport layer include aluminum complexes such as Alq ₃ ; oxadiazole derivatives such as PBD and TPOB; triazole derivatives such as TAZ; triazine derivatives such as those having the structure shown below; phenylquinoxalines; A thiophene derivative such as BMB-2T can be used. As the material for the electron injection layer, 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.

  Each layer constituting the organic EL layer 22 can be formed using any means known in the art such as vapor deposition (resistance heating or electron beam heating).

  The reflective electrode 23 is preferably formed using a highly reflective metal, amorphous alloy, or microcrystalline alloy. High reflectivity metals include Al, Ag, Mo, W, Ni, Cr, and the like. High reflectivity amorphous alloys include NiP, NiB, CrP, CrB, and the like. High reflectivity microcrystalline alloys include NiAl and the like. The reflective electrode 23 may be used as a cathode or an anode. When the reflective electrode 23 is used as a cathode, the aforementioned buffer layer may be provided at the interface between the reflective electrode 23 and the organic EL layer 22 to improve the efficiency of electron injection into the organic EL layer 22. Alternatively, when the reflective electrode 23 is used as a cathode, an alkali metal such as lithium, sodium, or potassium, which is a material having a low work function, calcium, magnesium, or the like, which is a material having a low work function compared to the above-described high reflectance metal, amorphous alloy, or microcrystalline alloy Further, an alkaline earth metal such as strontium can be added and alloyed to improve electron injection efficiency. When the reflective electrode 23 is used as the anode, the conductive transparent metal oxide layer described above is provided at the interface between the reflective electrode 23 and the organic EL layer 22 to improve the efficiency of hole injection into the organic EL layer 22. May be.

  The reflective electrode 23 can be formed using any means known in the art such as vapor deposition (resistance heating or electron beam heating), sputtering, ion plating, laser ablation, etc., depending on the material used. . As will be described later, when a reflective electrode 23 composed of a plurality of partial electrodes is required, the reflective electrode 23 composed of a plurality of partial electrodes may be formed using a mask giving a desired shape, or vice versa. The reflective electrode 23 including a plurality of partial electrodes may be formed using a separation partition wall having a tapered cross-sectional shape.

  When producing a display, it is desirable to produce the transparent electrode 21 and the reflective electrode 23 in a matrix driveable configuration. For example, each of the transparent electrode 21 and the reflective electrode 23 is formed from a plurality of stripe-shaped partial electrodes, and extends in a direction (preferably a direction orthogonal) where the stripe of the transparent electrode 21 and the stripe of the reflective electrode 23 intersect. Constitute. If such a structure is taken, if one of the partial electrodes of the transparent electrode 21 and one of the partial electrodes of the reflective electrode 23 are selected and a voltage is applied, the organic EL layer located at the intersection of them emits light. Passive matrix driving is possible.

  Alternatively, either the transparent electrode 21 or the reflective electrode 23 is formed as a common electrode integrally formed, and the other electrode is manufactured from a plurality of partial electrodes, and a switching element (TFT or the like) is provided for each of the plurality of partial electrodes. ) Can be employed in a one-to-one connection. With such a configuration, it is possible to perform active matrix driving in which an organic EL layer at a corresponding position emits light by turning on a switching element corresponding to a desired position.

  In the above description, the example in which the organic EL element 20 is formed on the color conversion filter 10 has been described. However, as illustrated in FIG. 6, the reflective electrode 33, the organic EL layer 32, and the transparent electrode are provided on a separate support substrate 34. An organic EL display may be formed by pasting the organic EL element 30 having 31 formed thereon with the color conversion filter 10 in a state where the transparent electrode 31 and the gas barrier layer 14 are opposed to each other.

  Each of the transparent electrode 31, the organic EL layer 32, and the reflective electrode 33 can be formed using the materials described for the transparent electrode 21, the organic EL layer 22, and the reflective electrode 23. However, when the transparent electrode 31 composed of a plurality of partial electrodes is required, it is desirable to form the transparent electrode 31 composed of a plurality of partial electrodes using a mask that gives a desired shape. In addition, when the reflective electrode 33 composed of a plurality of partial electrodes is required, the reflective electrode 33 composed of a plurality of partial electrodes may be formed using a mask that gives a desired shape, or by a photolithographic method. The reflective electrode 33 composed of a plurality of partial electrodes may be formed by patterning.

  The support substrate 34 may be transparent or opaque, should be able to withstand the conditions (solvent, temperature, etc.) used to form the layer to be laminated, and has excellent dimensional stability. It is preferable. Preferred materials include metals, ceramics, glass, semiconductors such as silicon, and resins such as polyethylene terephthalate and polymethyl methacrylate. Alternatively, a flexible film formed from polyolefin, acrylic resin, polyester resin, polyimide resin, or the like may be used as the substrate. When an active matrix driving type organic EL display is formed, a plurality of switching elements are provided on the support substrate 34 and connected to the respective partial electrodes of the reflective electrode 33 formed of a plurality of partial electrodes on a one-to-one basis. It is desirable to use the transparent electrode 31 as a common electrode composed of an integral part.

  The color conversion filter 10 and the organic EL element 30 can be bonded together using any means known in the art such as an ultraviolet curable adhesive.

  Hereinafter, the production of a color organic EL display to which the gas barrier layer comprising the laminate of the present invention is applied will be described with reference to FIGS. In the following Examples and Comparative Examples, a color organic EL display having 60 × 80 pixels (each pixel includes RGB subpixels) and a pixel pitch of 0.33 mm was produced.

Example 1
A blue color filter material (manufactured by FUJIFILM Electronics Materials Co., Ltd .: Color Mosaic CB-7001) was applied on Corning glass (50 × 50 × 1.0 mm) as the transparent substrate 11 by spin coating. Next, patterning by a photolithographic method was performed to form a blue conversion filter layer 12B composed of a plurality of stripes having a width of 0.1 mm, a pitch of 0.33 mm, and a film thickness of 10 μm.

  Next, coumarin 6 (0.7 parts by mass) was dissolved in propylene glycol monomethyl ether acetate (PEGMA, 120 parts by mass) as a fluorescent dye. Next, 100 parts by mass of photopolymerizable resin VPA100 / P5 (manufactured by Nippon Steel Chemical Co., Ltd.) was added and dissolved to obtain a coating solution. This coating solution is applied onto the transparent substrate 11 by spin coating, and patterning is performed by photolithography, so that green conversion comprising a plurality of stripes having a width of 0.1 mm, a pitch of 0.33 mm, and a thickness of 10 μm is performed. A filter layer 12G was formed.

  Next, coumarin 6 (0.6 parts by mass), rhodamine 6G (0.3 parts by mass), and basic violet 11 (0.3 parts by mass) were dissolved in 120 parts by mass of PEGMA as fluorescent dyes. Next, 100 parts by mass of a photopolymerizable resin VPA100 / P5 was added and dissolved to obtain a coating solution. This coating solution is applied onto the transparent substrate 11 by spin coating, and patterned by photolithography to convert red into a plurality of stripes having a width of 0.1 mm, a pitch of 0.33 mm, and a film thickness of 6 μm. A filter layer 12R was formed.

  On the substrate on which the RGB color conversion filter layer 12 was formed, a UV curable resin (epoxy-modified acrylate) was applied by a spin coating method and exposed to a high-pressure mercury lamp to form a planarization layer 13. At this time, the pattern of the color conversion filter layer 12 of each color was not deformed. Here, the flattening layer 13 covers a region (display region) where the color conversion filter layer is formed and forms a pattern in a wider region, but the film thickness from the substrate is measured at the end of the pattern. Then, the planarizing film 13 was formed so as to be 8 μm. Further, in the display area, the height of the planarization layer 13 from the substrate is 10 μm or more, and although the level difference between the color conversion filter layers and the level difference in the gap are traced to some extent, the leveling is sufficiently flat (the level difference is Peak-to-Valley). And about 0.5 μm).

Next, a gas barrier layer 14 composed of a laminate of two pairs of inorganic films 61 (a, b) and polymer films 62 (a, b) and an inorganic insulating film 63 was formed. The inorganic films 61a and 61b were 300 nm thick SiO _x films formed by RF magnetron sputtering at room temperature. At this time, Si _x was generated by reactive sputtering using Si as the sputtering target and a mixed gas of Ar and oxygen as the sputtering gas. The polymer films 62a and 62b are formed by depositing acrylic monomer on the inorganic film 61a or 61b by vacuum heating vapor deposition and then heating at 180 ° C. for 30 minutes to polymerize the acrylic monomer to form an acrylic resin. did. The film thicknesses of the polymer films 62a and 62b were each 1 μm. Finally, an SiO _x film having a film thickness of 300 nm was formed on the polymer film 62b by the same method as the inorganic films 61a and 61b, and the inorganic insulating film 63 was obtained.

  Next, IDIXO (made by Idemitsu Kosan Co., Ltd., a mixture of indium and zinc oxide and indium oxide) was formed on the entire surface of the gas barrier layer 14 by sputtering. Next, patterning is performed by a photolithographic method using OFRP-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a resist, and a plurality of striped partial electrodes having a width of 0.094 mm, a pitch of 0.11 mm, and a film thickness of 100 nm are formed. A transparent electrode 21 was formed.

Next, the substrate having the structure below the transparent electrode 21 is mounted in a resistance heating vapor deposition apparatus, and an organic EL layer 22 composed of four layers of a hole injection layer / a hole transport layer / an organic light emitting layer / an electron injection layer, Films were sequentially formed without breaking the vacuum. During film formation, the internal pressure of the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. Copper phthalocyanine (CuPc) with a film thickness of 100 nm is used as the hole injection layer, and 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α with a film thickness of 20 nm is used as the hole transport layer. -NPD) as the organic light-emitting layer, 30 nm-thick 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi), and as the electron injection layer, 20 nm-thick tris (8-hydroxy) A quinoline) aluminum complex (Alq ₃ ) was laminated.

  Subsequently, using a mask capable of obtaining a stripe pattern having a width of 0.3 m and a pitch of 0.330 mm extending in a direction orthogonal to the stripe pattern of the transparent electrode 21 without breaking the vacuum, a 200 nm thick Mg / Ag ( A reflective electrode 23 composed of a plurality of striped partial electrodes was formed by depositing a mass ratio of 10/1) to obtain a laminate of the color conversion filter 10 / organic EL element 20 having the structure shown in FIG.

  The laminated body thus obtained was sealed with a sealing glass (not shown) and a UV curable adhesive in a glove box in a dry nitrogen atmosphere (both oxygen and moisture concentrations were 10 ppm or less), and an organic EL display was obtained. Got.

(Comparative Example 1)
Example 1 was repeated except that a single layer SiO _x film (film thickness 300 nm) was used as the gas barrier layer 14 to produce a color organic EL display. The single-layer SiO _x film in this comparative example was produced under the same conditions as the inorganic film 61a in Example 1.

(Comparative Example 2)
A color organic EL display was produced by repeating Example 1 except that the gas barrier layer 14 was not formed. Therefore, the color organic EL display of this comparative example has the structure of the prior art as shown in FIG.

(Evaluation)
In accordance with Example 1 and Comparative Examples 1 and 2, three color organic EL displays were produced, and a continuous driving test under accelerated conditions was performed. As driving conditions, the current amount per pixel was set to 100 μA at a driving frequency of 60 Hz and a duty ratio of 1/60. The non-light-emitting area at the start (initial) of the continuous driving test was specified, and the light emission luminance was measured. Thereafter, a continuous driving test was performed for 500 hours under an acceleration condition at a temperature of 85 ° C., a non-light-emitting area at the end of the continuous driving test (after the acceleration test) was specified, and emission luminance was measured. The results are shown in Table 1. In addition, the increase rate of the non-light-emitting area and the luminance retention after the acceleration test are shown as a ratio in which the initial value in each example and comparative example is 1. The increase rate ratio of the non-light emitting area after the acceleration test is the ratio of the increase rate of the non-light emitting area in Example 1 and Comparative Example 2 where the increase rate in Comparative Example 1 is 1. The results shown in Table 1 are average values of three color organic EL displays for each of the examples and comparative examples.

  As can be seen from Table 1, in the display of Comparative Example 1 using a single SiOx layer as the gas barrier layer and not using the gas barrier layer 14, the area of the non-light-emitting portion is more than doubled after the acceleration test. As a result, the luminance retention was less than 50%. On the other hand, in the display of the gas barrier layer 14 made of the laminate of the present invention, an increase in the non-light emitting area was significantly suppressed, and at the same time, a high luminance retention was shown.

  From the above, the gas barrier layer 14 made of the laminate of the present invention is effective in suppressing deterioration of the characteristics of the organic EL element, and by using this, an organic EL display that maintains stable light emission characteristics over a long period of time is provided. It became possible.

It is sectional drawing which shows an example of the organic EL display of a prior art. It is sectional drawing which shows one Embodiment of the color conversion filter of this invention. It is sectional drawing which shows one Embodiment of the gas barrier layer of the color conversion filter of this invention. It is sectional drawing which shows another embodiment of the gas barrier layer of the color conversion filter of this invention. It is sectional drawing which shows one Embodiment of the organic electroluminescent display of this invention. It is sectional drawing which shows another embodiment of the organic electroluminescent display of this invention.

Explanation of symbols

10, 40 Color conversion filter 11, 41 Transparent substrate 12, 42 (R, G, B) Color conversion filter layer 13, 43 Flattening layer 14 Gas barrier layer 20, 30, 50 Organic EL element 21, 31, 51 Transparent electrode 22 , 32, 52 Organic EL layer 23, 33, 53 Reflective electrode 34 Support substrate 61 (a, b) Inorganic film 62 (a, b) Polymer film 63 Inorganic insulating film

Claims (7)

A transparent substrate; one or more color conversion filter layers provided on the transparent substrate; a planarization layer formed to cover the color conversion layer; and a gas barrier layer formed on the planarization layer A color conversion filter comprising:
2. The color conversion filter according to claim 1, wherein the gas barrier layer comprises a laminate of at least two pairs of inorganic films and polymer films, and an inorganic insulating film provided on the laminate.   Each of the inorganic films is independently formed of a conductive transparent metal oxide, an insulating oxide, an insulating nitride, an insulating carbide, or an insulating oxynitride. Item 2. The color conversion filter according to Item 1.   The color conversion filter according to claim 1, wherein each of the polymer films is independently formed of an acrylic resin, a methacrylic resin, a polyester resin, or a polyolefin resin.   The color conversion filter according to claim 1, wherein the inorganic insulating film is formed of an insulating oxide, an insulating nitride, an insulating carbide, or an insulating oxynitride. 5. The inorganic insulating film is formed of SiO _x , AlO _x , SiN _x , AlN _x , SiO _x N _y , AlO _x N _y , TiO ₂ , BN, or SiC. Color conversion filter.   An organic EL display in which an organic EL element in which at least a transparent electrode, an organic EL layer, and a reflective electrode are sequentially stacked is formed on the color conversion filter according to claim 1. An organic EL formed by bonding the color conversion filter according to claim 1 and an organic EL element in which at least a reflective electrode, an organic EL layer, and a transparent electrode are sequentially laminated on a support substrate. display.

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