JP4010286B2 - Manufacturing method of organic EL display - Google Patents

Description

  In recent years, the speed of information communication and the application range have been rapidly increasing. Among these, regarding display devices, high-definition display devices having low power consumption and high-speed response that can meet the demands of portability and moving image display have been widely devised.

  In particular, a driving type color display device using a thin film transistor (TFT) has been devised for the colorization type. In this case, in the method of extracting light to the substrate side on which the TFT is formed, since the aperture ratio does not increase due to the light shielding effect of the wiring part, recently, a method of extracting light to the opposite side of the substrate on which the TFT is formed, A so-called top emission method has been devised.

  By combining the top emission method and the color conversion method in which excitation light is absorbed by the separately arranged phosphors and multicolor fluorescence is emitted from each phosphor, a high-definition and high-brightness organic EL display can be provided. Possibility has been shown (see Patent Documents 1 and 2).

  A schematic cross-sectional view showing the structure of a conventional organic EL display is shown in FIG. On the substrate 602, the TFT 604, the lower electrode 606, the organic EL layer 608, and the upper electrode 610 are formed. On the other hand, a color conversion filter layer 612 and a black mask 614 are formed on the transparent substrate 616. Next, a peripheral sealing layer 618 is formed around the substrate 602 using, for example, a room temperature curable two-component epoxy adhesive, and is bonded to the transparent substrate 616. At this time, an internal space 620 is formed between the two substrates.

  In this structure, a part of the light emission from the organic EL layer 608 is reflected at the interface between the internal space 620 and the upper electrode 610 and / or the interface between the internal space 620 and the color conversion filter layer 612, so that the luminous efficiency of the display is improved. May fall.

  On the other hand, when the cover substrate is bonded to the top of the top emission type EL element by using an adhesive disposed on the entire surface of the element, an attempt is made to bond the cover substrate in a convexly curved state. (See Patent Document 3). By using such a process, bubbles (corresponding to a fine internal space) are prevented from entering between the EL element and the cover substrate.

JP-A-11-251059 JP 2000-77191 A Japanese Patent Laid-Open No. 11-283737 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-8-279394 JP-A-9-330793 JP-A-5-36475

  Therefore, in a display formed by bonding an organic EL light emitting element and a color conversion filter, it is desired to suppress reflection inside the display and improve luminous efficiency.

  In order to suppress reflection inside the display, it is conceivable to bond the organic EL light emitting element and the color conversion filter so as to contact each other. However, in this case, the pressure applied during bonding is not preferable because the organic EL light emitting element and the color conversion filter are deformed and accompanied by failure, or air bubbles are mixed in the contact surface. Therefore, it is effective to fill the internal space with a filling material.

  When the filling material is filled in the internal space, air bubbles are not generated on the contact surface with the organic EL light emitting element and / or the color conversion filter, and the filling material is deformed at the time of adhesion so that the substrate and color of the organic EL light emitting element It is important that the substrate of the conversion filter can be held in parallel. This is because such bubbles cause reflection and refraction of light from the organic EL light emitting element, resulting in a decrease in luminous efficiency and display quality.

  As one method, there is a method in which an organic EL light emitting element and a color conversion filter are pressure-bonded in a vacuum environment after a filling material is disposed on any substrate. Although this method can eliminate air that causes bubbles, a vacuum apparatus is required and the process becomes complicated.

  As another method, an injection port (opening) of a filling material is provided and bonded to an adhesive layer provided on the peripheral edge of one of the substrates, and then the filling material is injected from the injection port. After the filling, the injection port is sealed. It is conceivable to stop (end seal). In this method, a process such as installing an inlet for the adhesive layer and end sealing is added, resulting in an increase in cost.

  From the above, in the manufacture of a display formed by bonding an organic EL light emitting element and a color conversion filter, a filling material can be easily used without generating bubbles between the organic EL light emitting element and the color conversion filter. There is a demand for a method capable of improving the luminous efficiency and display quality of the display obtained by filling with the method.

  A method for producing an organic EL display according to the present invention includes: a step of forming a first electrode, an organic EL layer, and a second electrode on a substrate to prepare an organic EL light emitting element; and color conversion on a transparent substrate. Forming a filter layer; forming a taper-shaped filler layer on the color conversion filter layer to prepare a color conversion filter; and forming an outer peripheral sealing layer on a peripheral portion of the color conversion filter A step of bonding the organic EL light emitting element and the color conversion filter in a state where the substrate and the transparent substrate are substantially parallel; and a step of curing the outer peripheral sealing layer. And According to the above means, the following operation can be obtained.

  As described above, by forming the filler layer before bonding into a tapered shape as described in the present invention, it is possible to prevent enclosing air bubbles during bonding. The method of the present invention can be carried out under atmospheric pressure, and enables a display having excellent display quality to be formed by a simple process that does not use an end sealing process of a vacuum apparatus or a peripheral sealing layer.

  In addition, by using a material having a transmittance of 50% or more for light with a wavelength of 400 to 800 nm and a refractive index of 1.2 to 2.5 as the filler layer, the light emission of the organic EL layer is efficiently color-converted. It becomes possible to permeate into the filter layer.

  The structure of the organic EL display of the present invention and the manufacturing method thereof will be described with reference to FIGS. In FIG. 1, (a) shows the organic EL light emitting element 160, (b) shows the color conversion filter 150 provided with the outer peripheral sealing layer 130, and (c) shows the color conversion filter 150 and the organic EL light emitting element 160. It is sectional drawing which shows the organic electroluminescent display 140 manufactured by bonding together. 2A and 2B are diagrams for explaining another manufacturing method of the present invention, in which FIG. 2A shows an organic EL light emitting device 160 (the same as that of FIG. 1A), and FIG. The color conversion filter 150 which provided the sealing layer 130 is shown, and (c) is sectional drawing which shows the organic EL display 140 manufactured by bonding the color conversion filter 150 and the organic EL light emitting element 160 together.

[Component]
(1) First substrate 102
As the first substrate 102, an insulating substrate made of glass, plastic, or the like, or a substrate in which an insulating thin film is formed over a semiconductive or conductive substrate can be used.

(2) TFT104
The TFT 104 is a switching element for performing active matrix driving. The TFTs 104 are arranged in a matrix on the first substrate 102, and a source electrode or a drain electrode is connected to the first electrode 108 corresponding to each pixel. Preferably, the TFT 104 is a bottom gate type in which a gate electrode is provided under a gate insulating film, and has a structure using a polycrystalline silicon film as an active layer.

  The wiring portion for the drain electrode and the gate electrode of the TFT 104 and the structure of the TFT itself can be formed by a method known in the art so as to achieve desired withstand voltage, off-current characteristics, and on-current characteristics. it can. In addition, in the organic EL display of the present invention using the top emission method, since light does not pass through the TFT portion, it is not necessary to reduce the TFT in order to increase the aperture ratio, and the degree of freedom in designing the TFT can be increased. Therefore, it is advantageous to achieve the above characteristics.

(3) Planarization insulating film 106
Although it is optional, it is preferable to form a planarization insulating film 106 on the TFT 104. The planarization insulating film 106 is provided in a portion other than a portion necessary for the connection between the source electrode or drain electrode of the TFT 104 and the first electrode 108 and the connection of other circuits. Facilitates formation. The planarization insulating film 106 can be formed of any material known in the art. Preferably, it is formed from inorganic oxide or nitride, polyimide or acrylic resin.

(4) First electrode 108
The first electrode 108 may be either an anode or a cathode. When the first electrode 108 is used as an anode, a material having a high work function is used 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 is used. Although it is not necessary for the top emission method of the present invention to be transparent, the first electrode 108 can be formed using a conductive metal oxide such as ITO or IZO. Further, when a conductive metal oxide such as ITO is used, a metal electrode having high reflectivity (a metal such as Al, Ag, Mo, and W, an amorphous metal or alloy such as NiP, NiB, CrP, and CrB, or It is preferable to use a microcrystalline alloy such as NiAl. Since this metal electrode has a lower resistivity than the conductive metal oxide, it functions as an auxiliary electrode, and at the same time, the light emitted from the organic EL layer 110 is reflected toward the color conversion filter 150 to effectively use the light. Is possible.

  When the first electrode 108 is used as a cathode, an electron injecting property made of an alkali metal such as lithium or sodium, an alkaline earth metal such as potassium, calcium, magnesium, or strontium, or a fluoride thereof, which is a material having a low work function. Metals, alloys and compounds with other metals are used. As described above, a metal electrode having a high reflectance (a material similar to the above can be used) may be used thereunder. In that case, the organic EL layer 110 can effectively emit light by reducing resistance and reflecting. Can be used.

  In the case of performing active matrix driving using TFTs as shown in FIG. 1A and FIG. 2A, the first electrode 108 is formed on the planarization insulating film 106 in a form separated from each other corresponding to each TFT 104. , Connected to the source electrode or drain electrode of the TFT 104. When connected to the source electrode, it functions as an anode, and when connected to the drain electrode, it functions as a cathode. The TFT 104 and the first electrode 108 are connected by a conductive plug filled in a contact hole provided in the planarization insulating film. The conductive plug may be formed integrally with the first electrode 108 or may be formed using a low-resistance metal such as gold, silver, copper, aluminum, molybdenum, or tungsten.

(5) Organic EL layer 110
In the color conversion type organic EL display of the present invention, the organic EL layer 110 emits light in the near ultraviolet to visible region, preferably in the blue to blue-green region. The light is then incident on the color conversion filter layer, and visible light having a desired color is emitted.

The organic EL layer 110 includes at least an organic EL light emitting layer, and has a structure in which a hole injection layer, a hole transport layer, an electron transport layer and / or an electron injection layer are interposed as required. Specifically, the following layer structure is adopted.
(1) Organic EL light emitting layer (2) Hole injection layer / organic EL light emitting layer (3) Organic EL light emitting layer / electron injection layer (4) Hole injection layer / organic EL light emitting layer / electron injection layer (5) Positive Hole injection layer / hole transport layer / organic EL light emitting layer / electron injection layer (6) Hole injection layer / hole transport layer / organic EL light emitting layer / electron transport layer / electron injection layer (in the above, the anode is organic EL The cathode is connected to the organic EL light-emitting layer or the electron injection layer)

  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, fluorescent whitening agents such as benzothiazole, benzimidazole, and benzoxazole, metal chelated oxonium compounds, styrylbenzene compounds Aromatic dimethylidin compounds are preferably used.

(6) Second electrode 112
The second electrode 112 is required to efficiently inject electrons or holes into the organic EL layer 110 and to be transparent in the emission wavelength region of the organic EL layer 110. The second electrode 112 preferably has a transmittance of 50% or more with respect to light having a wavelength of 400 to 800 nm.

  When the second electrode 112 is used as a cathode, the material is required to have a small work function in order to inject electrons efficiently. Furthermore, it is required to be transparent in the wavelength range of light emitted from the organic EL layer. In order to achieve both of these two characteristics, it is preferable that the second electrode 112 has a laminated structure including a plurality of layers. This is because a material having a low work function generally has low transparency. That is, in an area in contact with the organic EL layer 110, 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, An ultrathin film (10 nm or less) of an alloy or compound with a metal is used. By using these materials having a low work function, efficient electron injection can be performed, and by using an ultrathin film, it is possible to minimize the decrease in transparency due to these materials. A transparent conductive film such as ITO or IZO is formed on the ultrathin film. These conductive films function as auxiliary electrodes, and can reduce the resistance value of the entire second electrode 112 and supply a sufficient current to the organic EL layer 110.

  When the second electrode 112 is used as an anode, it is necessary to use a material having a high work function in order to increase the hole injection efficiency. In addition, it is necessary to use a highly transparent material for light emission from the organic EL layer 110 to pass through the second electrode. Therefore, in this case, it is preferable to use a transparent conductive material such as ITO or IZO.

  In the case of an active matrix driving organic EL light emitting device as shown in FIG. 1A and FIG. 2A, the second electrode 112 can be formed as a uniform electrode that is not patterned.

(7) Passivation layer 114
A passivation layer 114 covering the layers below the second electrode 112 formed as described above is provided. The passivation layer 114 is effective in preventing permeation of oxygen, low molecular components, and moisture from the external environment, and preventing functional degradation of the organic EL layer 110 due to them. The passivation layer 114 is an optional layer, but is preferably a layer provided for the above purpose. The passivation layer 114 is preferably transparent in the emission wavelength region in order to transmit the light emission of the organic EL layer 110 to the color conversion filter layer.

In order to satisfy these requirements, the passivation layer 114 has high transparency in the visible region (transmittance of 50% or more in the range of 400 to 800 nm), electrical insulation, and a barrier against moisture, oxygen, and low molecular components. Preferably, it is formed of a material having a film hardness of pencil hardness 2H or more. For example, materials such as inorganic oxides and inorganic nitrides such as SiO _x , SiN _x , SiN _x O _y , AlO _x , TiO _x , TaO _x , and ZnO _x can be used. There is no restriction | limiting in particular as a formation method of this passivation layer, It can form by conventional methods, such as a sputtering method, CVD method, a vacuum evaporation method, a dip method, a sol-gel method.

In addition, various polymer materials can be used for the passivation layer. Imide-modified silicone resin (see Patent Documents 4 to 6), a material in which an inorganic metal compound (TiO, Al ₂ O ₃ , SiO ₂ or the like) is dispersed in acrylic, polyimide, silicone resin or the like (see Patent Documents 7 and 8) A resin having a reactive vinyl group of acrylate monomer / oligomer / polymer, a resist resin (see Patent Documents 9 to 12), a fluororesin (see Patent Documents 12 and 13), or a mesogenic structure having high thermal conductivity. Examples thereof include a photocurable resin such as an epoxy resin and / or a thermosetting resin. Even when these polymer materials are used, the formation method is not particularly limited. 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 passivation layer 114 described above may be a single layer or a stack of a plurality of layers. The thickness of the passivation layer 114 (total thickness in the case of a laminate of a plurality of layers) is preferably 0.1 to 10 μm.

(8) Transparent substrate 116
The transparent substrate 116 needs to be transparent to the light converted by the color conversion filter layer. The transparent substrate 116 should be able to withstand the conditions (solvent, temperature, etc.) used for forming the color conversion filter layer and the black mask, and is preferably excellent in dimensional stability. The transparent substrate 116 preferably has a transmittance of 50% or more with respect to light having a wavelength of 400 to 800 nm.

  Preferred materials for the transparent substrate 116 include resins such as glass, polyethylene terephthalate, and polymethyl methacrylate. Borosilicate glass or blue plate glass is particularly preferable.

(9) Color Conversion Filter Layer In this specification, the color conversion filter layer is a general term for the color filter layer 118, the color conversion layer 120, and the laminate of the color filter layer 118 and the color conversion layer 120. The color conversion layer 120 absorbs light in the near ultraviolet region or visible region emitted from the organic EL layer 110, particularly light in the blue or blue-green region, 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 color conversion layers includes at least an organic fluorescent dye and a matrix resin.

1) Organic fluorescent dye In the present invention, preferably, at least one fluorescent dye emitting fluorescence in the red region is used, and further combined with one or more fluorescent dyes emitting green region fluorescence. This is because when the organic EL layer 110 that emits light in the blue to blue-green region is used as the light source, if light from the organic EL layer 110 is simply passed through a red filter to obtain light in the red region, 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 110 into light in the red region by the fluorescent dye, it is possible to output light in the red region having sufficient intensity. 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.

  Furthermore, regarding the blue region light, a blue conversion layer that performs wavelength distribution conversion of near-ultraviolet light or blue-green light emitted from the organic EL layer 110 and outputs blue light may be included. However, when the organic EL layer 110 emits blue to blue-green light, it is preferable to use only the blue color filter layer.

  When the organic EL layer 110 emits white light, a desired color can be obtained only by the color filter layer, but by using each color conversion layer, light emission of the three primary colors can be performed with higher efficiency than the case of only the color filter layer. Can be obtained.

  The organic fluorescent dye used in the present invention is a 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 fluorescent pigment may be obtained by kneading into a mixture or the like in advance to obtain a pigment. In addition, these organic fluorescent dyes and organic fluorescent pigments (in the present specification, the above two are collectively referred to as organic fluorescent dyes) may be used alone, or two or more of them may be used to adjust the hue of fluorescence. May be used in combination.

  The color conversion layer 120 of the present invention 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 color conversion layer. By using the organic fluorescent dye in the content range, it is possible to perform sufficient wavelength conversion without being accompanied by a decrease in color conversion efficiency due to effects such as concentration quenching.

2) Matrix resin Next, the matrix resin used in the color conversion layer of the present invention generates radical species or ion species by light and / or heat treatment of a photocurable or photothermal combination type curable resin (resist). Polymerized or cross-linked and insoluble and 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 color conversion layer of the present invention, when the resin itself in the photocurable or photothermal combination curable resin can be polymerized by light or heat, a photopolymerization initiator and a thermal polymerization initiator are not added. It is also possible.

  A matrix resin (color conversion layer) is formed by applying a solution or dispersion containing a photocurable or photothermal combination curable resin, an organic fluorescent dye and an additive on a support substrate, and forming a resin layer, and It is formed by polymerizing a desired portion of a photocurable or photothermal combination type curable resin 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.

3) Configuration and Shape Regarding red, it may be formed only from the red conversion layer 120R. However, when sufficient color purity cannot be obtained only by conversion with a fluorescent dye, a laminate of a red conversion layer 120R and a color filter layer 118R may be used as shown in FIG. When the color filter layer 118R is used in combination, the thickness of the color filter layer 118R is preferably 1 to 1.5 μm.

  Moreover, regarding green, it may be formed only from the green conversion layer 120G. However, when sufficient color purity cannot be obtained only by conversion with a fluorescent dye, a laminate of a green conversion layer 120G and a color filter layer 118G may be used as shown in FIG. When the color filter layer 118G is used in combination, the thickness of the color filter layer 118G is preferably 1 to 1.5 μm. Alternatively, when the light emission of the organic EL layer 110 sufficiently includes light in the green region, only the color filter layer 118G may be used. When only the color filter layer 118G is used, the thickness is preferably 0.5 to 10 μm.

  On the other hand, for blue, only the color filter layer 118B can be used as shown in FIG. When only the color filter layer 118B is used, the thickness is preferably 0.5 to 10 μm.

  The shape of the color conversion filter layer may be a stripe pattern separated for each color as well known, or may have a structure separated for each sub-pixel of each pixel.

(10) Black mask 122
A black mask 122 is preferably formed in a region between the color conversion filter layers corresponding to each color. By providing the black mask, it is possible to prevent leakage of light to the color conversion filter layer of the adjacent subpixel and obtain only a desired fluorescence conversion color without blur. You may provide a black mask around the area | region in which the color conversion filter layer on the transparent substrate 116 is provided on the condition that sealing of the organic EL display mentioned later is not prevented. The black mask 122 preferably has a thickness of 0.5 to 2.0 μm.

(11) Overcoat layer 124
The overcoat layer 124 covering the color conversion filter layer can be formed without impairing the function of the color conversion filter layer, and can be formed from a material having appropriate elasticity. A preferable material has a pencil hardness of 2H or more, a Young's modulus of 0.3 MPa or more, can form a smooth coating film on the color conversion filter layer, and the function of the color conversion layer 120 is deteriorated. It is a polymer material that does not. More preferably, the material is a polymer material having high transparency in the visible region (transmittance of 50% or more in the range of 400 to 800 nm), electrical insulation, and barrier properties against moisture, oxygen, and low molecular components. It is. The overcoat layer 124 is an optional layer, but is preferably a layer provided for the above purpose.

Examples of such a polymer material include an imide-modified silicone resin (see Patent Documents 4 to 6) and an inorganic metal compound (TiO, Al ₂ O ₃ , SiO _2, etc.) dispersed in acrylic, polyimide, silicone resin, etc. Materials (see Patent Documents 7 and 8), resins having reactive vinyl groups of acrylate monomers / oligomers / polymers, resist resins (see Patent Documents 9 to 12), fluororesins (see Patent Documents 12 and 13), or Examples thereof include a photocurable resin and / or a thermosetting resin such as an epoxy resin having a mesogenic structure having a high thermal conductivity. The method for forming the overcoat layer 124 using these polymer materials is not particularly limited. 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 overcoat layer 124 may have a thickness of about 1 to 10 μm. When formed by a cast method or a spin coat method, the overcoat layer 124 preferably has a thickness of about 3 to 5 μm.

(12) Filler layer 128
The filler layer 128 fills the internal space 620 formed in the display of the conventional method (FIG. 3), suppresses the reflection of the light emission of the organic EL layer 110 at the internal space interface, and converts the light emission to the color conversion filter. Provided for efficient transmission.

  The filler layer 128 ′ before bonding shown in FIG. 1B and FIG. 2B is formed in a tapered shape so as not to take in bubbles. The tapered shape in the present invention means a shape having a point or straight line having the maximum thickness, and the film thickness monotonously decreasing from the point or straight line toward the peripheral portion. For example, the filler layer 128 ′ before bonding has a ridgeline 200 (straight line having the maximum thickness) at the center portion as shown in FIG. It may be a decreasing shape. Alternatively, as shown in FIG. 2B, a shape in which one end portion is a ridgeline 200 and the film thickness monotonously decreases from the ridgeline 200 toward the other end thereof may be used. Alternatively, it may be a cone-shaped shape having a vertex (a point having the maximum thickness) in the central portion and from which the film thickness monotonously decreases toward the peripheral portion. In the present invention, the position of the ridge line 200 or the vertex can be selected as appropriate, but also in that case, the film thickness of the filler layer 128 ′ before bonding is monotonously decreased from the ridge line 200 or the vertex toward the peripheral portion. It is necessary to.

  The filler for forming the filler layer 128 is an inert substance that does not adversely affect the characteristics of the organic EL light emitting element and the color conversion filter. Further, the filler has a consistency that can maintain a tapered shape before bonding and can be smoothly deformed by a pressure applied at the time of bonding. Further, the filler may be a substance that is cured or thickened by stimulation (UV, visible light, heat, etc.) after bonding or outer periphery sealing. By hardening or increasing the viscosity after bonding, the structure of the obtained display can be stabilized. In the case of curing or thickening after bonding, the cured or thickened filler preferably has an elastic modulus of 1.0 MPa or less, preferably 0.1 MPa or less. By having such an elastic modulus, when an external stress is applied to the organic EL display manufactured according to the present invention, it is possible to reduce the concentration of the external stress on the organic EL layer 110. Furthermore, the filler used in the present invention does not have an adhesion function. This is because the bonding function is provided by the outer peripheral sealing layer 130 in the present invention.

  The inert substance used as the filler has a visible light transmittance of 20% to 95%, preferably 60% to 95%, and a refractive index of 1.2 to 2.5 with respect to light having a wavelength of 400 to 800 nm. Have In the case of a substance that cures or thickens after bonding or peripheral sealing, it should have the aforementioned visible light transmittance and refractive index after curing or thickening. By having the refractive index, reflection at the interface between the filler layer and the organic EL light emitting element and the interface between the filler layer and the color conversion filter can be suppressed. Furthermore, by having the above visible light transmittance, the light of the organic EL light-emitting element can be efficiently transmitted to the color conversion filter through the filler layer 128.

  Examples of such fillers include UV curable resins, thermosetting resins, fluorinated inert liquids, fluorinated oils, and the like. The thermosetting resin includes a silicone resin in which gelation proceeds by heating. A preferred filler in the present invention contains a silicone resin.

  The required amount of filler can be readily determined by one skilled in the art. It is necessary to use an amount of the filler that can completely fill at least the area where the light from the organic EL light emitting element 160 passes, that is, the area where the color conversion filter layer of the color conversion filter 150 is provided. It is. Further, on the condition that the volume of the space sealed by the outer peripheral sealing layer 130 is not exceeded, a larger amount of filler may be used than completely filling the area through which light passes. For example, as shown in FIG. 1B or FIG. 2B, when using a tapered shape having one ridgeline 200 and having a thickness that decreases linearly from the ridgeline 200 toward the peripheral edge, The thickness of the portion needs to be at least twice the thickness of the filler layer 128 of the resulting display. Also, when using a conical taper shape having one apex from which the thickness decreases linearly toward the periphery, the apex thickness is the thickness of the filler layer 128 of the resulting display. It is necessary to be at least three times the size. Considering the reduction in viewing angle dependency and the diffusion of light in the filler layer, the thickness of the filler layer 128 of the display obtained is preferably 1 to 10 μm. Accordingly, the thickness of the tapered ridgeline 200 shown in FIG. 1B or 2B is preferably 10 to 20 μm. Moreover, when using the cone-shaped taper shape which has one vertex, it is preferable that the thickness of a vertex part is 15-30 micrometers.

(13) Outer peripheral sealing layer 130
The outer peripheral sealing layer 130 is provided on the outer peripheral portion of the color conversion filter 150, and adheres the organic EL light-emitting element 160 and the color conversion filter 150, and protects internal components from oxygen, moisture, and the like in the external environment. Have The outer peripheral sealing layer 130 is formed from an ultraviolet curable adhesive. Such an ultraviolet curable adhesive does not cause a change in viscosity or gelation before being cured, and the color conversion filter layer and the organic EL light emitting element are moved by relative movement between the organic EL light emitting element 160 and the color conversion filter 150. Enables precise alignment with the light emitting part.

Once alignment is complete, the UV curable adhesive is cured by irradiating with UV light. For example, it is preferable to cure within 10 to 60 seconds when irradiated with 100 mW / cm ² ultraviolet rays. By curing within this time range, it is possible to sufficiently cure the ultraviolet curable adhesive and develop appropriate adhesive strength without causing adverse effects on other components due to ultraviolet irradiation. . Moreover, it is preferable that it is in the above-mentioned time range also from a viewpoint of the efficiency of a production process.

  The ultraviolet curable adhesive may include glass beads, silica beads, and the like having a diameter of 5 to 50 μm, preferably 5 to 20 μm. These beads define the inter-substrate distance (distance between the substrate 102 and the transparent substrate 116) and the film thickness of the filler layer 128 when the organic EL light-emitting element 160 and the color conversion filter 150 are bonded together. Bear the pressure applied for bonding. Further, it also bears the stress generated when the display is driven (especially the stress at the outer periphery of the display), thereby preventing display deterioration due to the stress.

  1 and 2 illustrate the case where the outer peripheral sealing layer 130 is provided on the transparent substrate 116 of the color conversion filter 150, the outer peripheral sealing may be performed on the substrate 102 of the organic EL light emitting element 160 as necessary. A layer may be provided.

[Production method]
In one manufacturing method of the present invention, as shown in FIG. 1, an organic EL display 140 is formed by laminating an organic EL light emitting element 160 and a color conversion filter 150.

  The color conversion filter 150 is formed on the transparent substrate 116 by forming a color conversion filter layer corresponding to each color of RGB, a black mask 122 positioned between and around them, and a filler layer 128 having a tapered shape. can get. In the embodiment shown in FIG. 1, the red color conversion filter layer includes a red color filter layer 118R and a red color conversion layer 120R, the green color conversion filter layer includes a green color filter layer 118G and a green color conversion layer 120G, and blue color conversion. The filter layer is made of a blue color filter layer 118B. After each color conversion filter layer and the black mask 122 are formed, an overcoat layer 124 is formed so as to cover them as necessary. Next, the filler layer 128 having a tapered shape is formed. The filler layer 128 may be formed by printing a filler using, for example, a gravure roll having a corresponding tapered recess. Or you may form by using the board | substrate (polymer film etc.) which has a recessed part corresponding to a corresponding taper shape, filling the recessed part with a filler, and transferring it on a color conversion filter layer. As described above, the color conversion filter 150 can be obtained.

  On the other hand, the TFT 104, the planarization insulating layer 106, the first electrode 108, the organic EL layer 110, the second electrode 112, and the passivation layer 114 are sequentially formed on the first substrate 102 by using means known in the art. The organic EL light emitting device 160 is formed by stacking.

  Next, the color conversion filter 150 and the organic EL light emitting device 160 formed as described above are placed in a dry nitrogen atmosphere (desirably, both oxygen and moisture concentrations are 1 ppm or less). Then, an ultraviolet curable adhesive is applied to the outer periphery of the color conversion filter 150 using a dispenser robot. Thereafter, as shown in FIG. 1C, the organic EL light-emitting element 160 and the color conversion filter 150 are brought into close contact with each other. This adhesion process can be carried out at a pressure higher than atmospheric pressure, preferably at atmospheric pressure.

  At this time, the organic EL light emitting element 160 and the color conversion filter 150 are disposed substantially in parallel, and the substrate 102 and the transparent substrate 116 are disposed substantially in parallel, and are brought close to each other while maintaining the state. Preferably, the substrate 102 and the transparent substrate 116 are arranged in parallel, and both substrates are brought close to each other while maintaining the state. The first contact is the ridgeline 200 of the tapered filler layer 128. Thereafter, as the two substrates further approach, the boundary line of the contact portion advances toward the left and right ends in a state parallel to the ridgeline. At the same time, the gas existing between the passivation layer 114 and the color conversion filter 150 is also pushed out in either the left or right direction. Since the thickness of the tapered filler layer 128 ′ monotonously decreases, there is a closed space for trapping gas between the filler layer 128 ′ and the organic EL light emitting device 150 (passivation layer 114). It is never formed. Finally, the outer peripheral sealing layer 130 comes into contact with the opposing substrates, and both substrates are brought close to each other until the filler layer 128 has a desired thickness, and all the color conversion filter layers provided in the color conversion filter 150 are A uniform thickness filler layer 128 is formed thereon.

Subsequently, the light emitting portion of the organic EL light emitting element and the color conversion filter layer are aligned. In the case of active matrix driving, the first electrode 108 and the color conversion filter layer are aligned. After that, the outer peripheral sealing layer 130 is formed by irradiating the aforementioned ultraviolet curable adhesive with ultraviolet rays to cure the adhesive. The ultraviolet irradiation is preferably performed, for example, at an illuminance of 100 mW / cm ² for 30 seconds.

  The filler layer may be cured or thickened before, after, or simultaneously with the curing of the ultraviolet curable adhesive. When a thermosetting resin or a silicone resin is used as the filler, it may be cured, thickened or gelled by heating. When a UV curable resin is used as the filler, it may be cured or thickened by being exposed to ultraviolet rays together with the ultraviolet curable adhesive.

  As described above, by using the filler layer 128 and the outer peripheral sealing layer 130 and fixing the filler layer 128 to have a thickness of 1 to 10 μm, it prevents moisture from entering from the outside environment, The organic EL display 140 with long-term reliability can be configured.

  Alternatively, another method of the present invention shown in FIG. 2 is performed in the same manner as described above except that the shape of the filler layer 128 ′ before bonding is different. Also in this case, the ridge line 200 of the filler layer 128 ′ first contacts the organic EL light emitting element 160, and the boundary line of the contact portion is parallel to the ridge line as the organic EL light emitting element 160 and the color conversion filter 150 approach each other. Proceed toward the left edge in the state. Since the thickness of the taper-shaped filler layer 128 ′ monotonously decreases, a closed space for trapping gas is formed between the filler layer 128 ′ and the organic EL light emitting device 150 (passivation layer 114). There is nothing to do.

  As described above, by using the filler layer 128 ′ having a tapered shape, it is possible to more easily produce the organic EL display 140 having excellent characteristics free from bubbles.

  In the above, an active matrix drive display using TFTs as switching elements has been described as an example. However, an element known in the art such as MIM may be used as the switching element. Alternatively, the method of the present invention can be used for passive matrix drive displays.

  In the case of forming a passive matrix drive display, the first electrode 108 divided into a plurality of portions having a line pattern shape is formed on the substrate 102 without forming the TFT 104 and the planarization insulating film 106. Also in this case, the first electrode can be used as either an anode or a cathode. The second electrode 112 is divided into a plurality of portions and is formed in a line pattern shape extending in a direction orthogonal to the line pattern of the first electrode 108. Further, in the alignment step, the color conversion filter layer is aligned with the portion where the line patterns of the first electrode and the second electrode intersect.

  On the glass substrate, a TFT, an anode, an organic EL layer, a cathode, and a passivation layer were sequentially formed to obtain an organic EL light emitting device 160 shown in FIG. The anode was divided into a plurality of portions having dimensions of 300 μm in the long side direction and 90 μm in the short side direction, and arranged in a matrix. The interval between the divided parts of the anode was set to a pitch of 330 μm in the long side direction and a pitch of 110 μm in the short side direction.

  On a transparent glass substrate, a black mask with a thickness of 1.5 μm, red, green and blue color filter layers each having a thickness of 1.5 μm, and red and green color conversion each having a thickness of 10 μm Layers were laminated. Next, a photosensitive photoresist (Zeon 1100, manufactured by Nippon Zeon Co., Ltd.) based on a novolac resin is spin-coated, and is molded so as to cover the color conversion filter layer and the black mask using a photolithographic method, and has a thickness of 5 μm. The overcoat layer 124 was obtained. And the transparent silicone resin (Toshiba Silicone company make, TSE3051) is apply | coated on it using a gravure roll, it has a ridgeline in the center part, and the filler layer before bonding which the height of a ridgeline part is 20 micrometers 128 'was formed, and the color conversion filter 150 (excluding the outer periphery sealing layer 130) shown by Fig.1 (a) was obtained. Each color filter layer and color conversion layer had a dimension of 85 × 295 μm.

  Next, the color conversion filter 150 and the organic EL light emitting device 160 formed as described above were placed under a dry nitrogen atmosphere (preferably, oxygen and moisture concentrations of 1 ppm or less) in the glove box. An ultraviolet curable adhesive (trade name 30Y-437, manufactured by ThreeBond Co., Ltd.) in which beads having a diameter of 20 μm were dispersed was applied to the outer peripheral portion of the transparent substrate 116 of the color conversion filter 150 using a dispenser robot.

Thereafter, as shown in FIG. 1C, the organic EL light-emitting element 162 and the color conversion filter 152 were brought into close contact with each other while maintaining the substrate 102 and the transparent substrate 116 substantially in parallel. Subsequently, after aligning the first electrode 108 (that is, the light emitting part of the organic EL light emitting element) and the color conversion filter layer, the adhesive is cured by irradiating with ultraviolet rays at an illuminance of 100 mW / cm ² for 30 seconds. Thus, the outer peripheral sealing layer 130 was formed. Further, a heat treatment at 80 ° C. for 60 minutes was performed to gel the transparent silicone resin, whereby an organic EL display 140 was obtained.

  Example 1 was repeated to obtain an organic EL display except that the position of the ridgeline 200 of the filler layer 128 ′ before bonding was changed to the end portion shown in FIG.

  Example 1 was repeated to obtain an organic EL display except that TUV6001 (manufactured by GE Toshiba Silicon), which is a UV curable resin, was used as a filler, and heat treatment at 80 ° C. for 60 minutes was not performed.

It is a schematic sectional drawing which shows the organic EL display of this invention, (a) shows the organic EL light emitting element 160, (b) shows the color conversion filter 150, and (c) shows the color conversion filter 150 and organic EL light emission. It is sectional drawing which shows the organic electroluminescent display 140 manufactured by bonding the element 160 together. It is a schematic sectional drawing which shows the organic electroluminescent display of this invention produced by another method, (a) shows the organic electroluminescent light emitting element 160, (b) shows the color conversion filter 150, and (c) is color. It is sectional drawing which shows the organic electroluminescent display 140 manufactured by bonding the conversion filter 150 and the organic electroluminescent light emitting element 160 together. It is a schematic sectional drawing which shows the organic EL display of a prior art.

Explanation of symbols

102, 602 First substrate 104, 604 TFT
106 planarization insulating layer 108 first electrode 110, 608 organic EL layer 112 second electrode 114 passivation layer 116, 616 transparent substrate 118 color filter layer 120 color conversion layer 122, 614 black mask 124 overcoat layer 128 filler layer 128 ′ Filler layer before bonding 130 Outer peripheral sealing layer 140 Organic EL display of the present invention 150 Color conversion filter 160 Organic EL light emitting element 600 Conventional organic EL display 606 Anode 610 Cathode 612 Color conversion filter layer 618 Peripheral sealing layer 620 Interior space

Claims (7)

Forming a first electrode, an organic EL layer, and a second electrode on a substrate to prepare an organic EL light-emitting element;
Forming a color conversion filter layer on a transparent substrate;
Forming a tapered filler layer on the color conversion filter layer to prepare a color conversion filter;
Forming an outer peripheral sealing layer on a peripheral edge of the color conversion filter;
Bonding the organic EL light emitting element and the color conversion filter in a substantially parallel state ;
And a step of curing the outer peripheral sealing layer. A method of manufacturing an organic EL display, comprising:   The method for manufacturing an organic EL display according to claim 1, wherein the filler layer has a tapered shape having a ridge line at a central portion.   The method for manufacturing an organic EL display according to claim 1, wherein the filler layer has a tapered shape having a ridge line at an end.   The method for manufacturing an organic EL display according to claim 1, wherein the filler layer has a tapered shape having a vertex. The method for manufacturing an organic EL display according to claim 2 , wherein the filler layer has a thickness of 10 to 20 μm along the ridgeline. The method for manufacturing an organic EL display according to claim 4 , wherein the filler layer has a film thickness of 15 to 30 μm at the apex.   The said filler layer is formed using the material selected from the group which consists of UV curable resin, a thermosetting resin, a fluorine-type inert liquid, and fluorine-type oil. Manufacturing method of organic EL display.

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