JP2009230889A - Manufacturing method of color conversion filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a color conversion filter, preventing color mixture resulting from ink flowing out by highly accurately forming the pattern of the color conversion filter even when the color conversion filter is easily formed. <P>SOLUTION: This manufacturing method of the color conversion filter includes processes of: (a) forming a plurality of color filter layers each of which is formed by a plurality of stripe-shaped portions extending in a first direction; (b) forming a bank made of a photo-curing resin or a resin using both photo-curing and heat-curing in a plurality of the stripe-shaped portions extending in the first direction, and simultaneously forming an ink leakage preventing wall for connecting the banks adjoining each other at the ends of the banks on a transparent substrate; and (c) forming a color conversion layer which absorbs light of a specific wavelength to output light containing wavelengths different from the wavelength of absorbed light, by using an inkjet method. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a color conversion filter. In particular, the present invention relates to a method for manufacturing a color conversion filter including a color conversion layer having a highly accurate pattern.

  One method for realizing multicolor light emission using an organic EL element is a color conversion method. The color conversion method is a method of realizing multicolor by arranging a color conversion film that absorbs light emitted from an organic EL element and performs wavelength distribution conversion to emit light having different wavelength distributions on the front surface of the organic EL element. It is. As such a color conversion layer, a configuration in which a fluorescent dye is dispersed in a polymer resin has been proposed (see Patent Document 1). The color conversion method is easy to manufacture because it uses only one type of organic EL element (single color), and development to a large screen display is being actively studied.

  Furthermore, the color conversion method has an advantageous feature such that good color reproducibility can be obtained by further combining a color filter that transmits light in a specific wavelength range. However, in order to obtain sufficient efficiency with the proposed color conversion layer, the film thickness of the color conversion layer needs to be about 10 μm. In addition, in order to form an organic EL element on the upper surface of the color conversion layer, special techniques such as a technique for flattening the irregularities on the upper surface of the color conversion layer and a technique for blocking moisture generated from the color conversion layer are required. To do. These points increase the cost of the display.

  As a measure for solving the problems of the resin dispersion type color conversion layer, a method of forming a color conversion layer using a dry process such as a vapor deposition method or a sputtering method has been proposed (see Patent Document 2). In this method, if an optimum color conversion layer material is selected, a color conversion layer having a high efficiency and a film thickness of 1 μm or less can be formed without causing a problem of moisture generation.

  As a further measure for solving the above problem, a method of preparing an ink containing a constituent material and forming a patterned color conversion layer using an ink jet method is conceivable. When a high-definition pattern is formed by the ink jet method, it is necessary to precisely discharge a small amount of droplets, and the solid content that causes thickening of the ink cannot be increased too much. Therefore, the volume of the droplet for obtaining the required film thickness is inevitably increased. As a solution for increasing the volume of droplets, a method of forming a bank on a substrate has been proposed (see Patent Documents 3 to 6). However, when ink is dropped between the banks, the ink spreads along the banks, and there is a problem that color mixing is caused at the end portions.

JP-A-8-286033 JP-A-2-216790 JP 2000-353594 A Japanese Patent Laid-Open No. 2001-291583 JP 2005-78911 A JP 2005-78911 A JP 2004-288403 A JP 2005-166266 A JP 2007-234232 A International Publication No. 2006/054421 Pamphlet

  The advantage of forming the color conversion layer using the ink jet method is that the use efficiency of the ink is very high, and thereby the cost of forming the color conversion layer can be suppressed. However, the formation of a color conversion layer using an ink jet method has the problem of ink color mixing as described above. When this color mixture occurs, color irregularity may occur in the peripheral pixels, and various bank structures have been proposed to prevent ink color mixture.

  In Patent Documents 7 and 8, in order to prevent color mixing, an opening for pouring ink is formed at the end of a bank (the partition wall in Patent Documents 7 and 8), and a part of the bank is formed as a protrusion protruding to the pixel side. Alternatively, a mode is disclosed in which protrusions (structures) are distributed and arranged between banks at the ends of the banks.

  However, in both Patent Documents 7 and 8, since the bank has an inversely tapered shape, ink tends to flow on the surface of the bank due to a capillary phenomenon, and as a result, there is a possibility that color mixing may occur more due to wraparound.

  Further, in Patent Documents 7 and 8, a considerable number of steps are required for the formation of openings and the formation of banks, protrusions, and the like. Further, in these techniques, since the predetermined protrusion or the like is provided in the bank having the slit structure, there is a possibility that the ink which is the color conversion layer forming material is difficult to partially flow.

  In addition, in Patent Document 7, since the protrusions are formed at the same height as the bank, the flow of the filler is easily prevented, and the filler easily entrains gas and easily generates bubbles.

  In Patent Document 9, for the purpose of suppressing color mixing, a light emitting layer is provided with stripe-shaped same color pixels arranged side by side by light emission of the light emitting layer, and the height of the partition wall between the same color pixels is higher than the partition wall between different color pixels. A lower image display device is disclosed. That is, in Patent Document 9, the vertical and horizontal heights of the lattice-like banks are different. However, the vertical and horizontal bank forming means performs a two-photolithographic process in which a bank having a certain height is subjected to a one-photolithographic process or the like by half exposure and then added to another bank. In this method, the number of steps is large and a bank cannot be formed easily.

  Patent Document 10 discloses a technique for obtaining a bank having substantially the same shape as Patent Document 9 by a slightly different formation method. That is, in Patent Document 10, when patterning a bank forming material containing a photosensitive resin by a photolithography process, a difference is provided in the exposure amount for each region, and a bank is formed with a different film thickness in each region. For this reason, although an application | coating process, a development process, and a baking process can be completed by one time, since a glass mask is changed for formation of the bank from which height differs, an exposure process cannot be performed easily.

  Therefore, even if the color conversion filter is simply formed, the problem to be solved by the present invention is to form a color conversion layer pattern with high accuracy to prevent color mixing caused by ink flow out. Another object of the present invention is to provide a method for manufacturing a color conversion filter. Further, another problem to be solved by the present invention is that even when the color conversion filter is simply formed, the filler entrains gas when the color conversion filter and the organic EL element are bonded together afterwards. It is an object of the present invention to provide a method for manufacturing a color conversion filter that does not generate bubbles.

  The present invention (first embodiment) is (a) a step of forming a plurality of types of color filter layers on a transparent substrate, each of the plurality of types of color filter layers being a plurality of stripes extending in a first direction. (B) forming a bank made of a photocurable or photothermal combination type curable resin on the color filter layer in a plurality of stripe-shaped portions extending in the first direction, and simultaneously forming the bank A step of forming on the transparent substrate an ink leakage prevention wall connecting adjacent banks at the end of the substrate, and (c) absorbing light of a specific wavelength on the color filter layer using an inkjet method, The present invention relates to a method of manufacturing a color conversion filter including a step of forming a color conversion layer that outputs light including a wavelength different from the absorbed wavelength.

  The present invention (second embodiment) is a process of (a) forming a black matrix on a transparent substrate and further forming a color filter layer, wherein each of the plurality of types of color filter layers is in a first direction. A step composed of a plurality of stripe-shaped portions extending; and (b) forming a bank of photocurable or photothermal combination curable resin on the color filter layer in the plurality of stripe-shaped portions extending in the first direction. At the same time, a step of forming on the black matrix an ink leakage prevention wall that connects adjacent banks at the end of the bank, and (c) a light having a specific wavelength is formed on the color filter layer using an inkjet method. And a step of forming a color conversion layer that outputs light including a wavelength different from the absorbed wavelength.

  These color conversion filter manufacturing methods can be applied to the manufacture of various large-screen displays. In such a color conversion filter manufacturing method, in the step (b), the height of the bank with respect to the upper surface of the color filter layer is set to 1. of the height of the ink leakage prevention wall with respect to the surface of the color filter layer. It is desirable to make it 25 to 2.5 times.

  By adopting the configuration as described above, even when the color conversion filter is simply manufactured, the color conversion layer pattern can be formed with high accuracy to prevent color mixing due to ink flow-out. A color conversion filter that can be obtained can be obtained. Therefore, a flat panel display or the like having high definition can be easily manufactured by using the color conversion filter manufactured by the method of the present invention. In particular, when the height of the bank and the ink leakage prevention wall is set to a predetermined relationship, in addition to the above effect, the filler does not cause a gas when the color conversion filter and the organic EL element are bonded together afterwards. It is also possible to advantageously prevent entrainment and generation of bubbles.

<Embodiment 1>
FIG. 1 shows a color conversion filter formed by the first manufacturing method of the present invention, FIG. 1 (a) is a plan view thereof, FIG. 1 (b) is a cross-sectional view taken along line bb ′ of FIG. 1C is a cross-sectional view taken along the line cc ′ of FIG. 1A, and FIG. 1D is a cross-sectional view taken along the line dd ′ of FIG. In these figures, reference numeral 10 is a transparent substrate, 12 is a black matrix, 14 is a red (R) color filter layer, 16 is a green (G) color filter layer, 18 is a blue (B) color filter layer, 20 is a bank, Reference numeral 22 denotes an ink leakage prevention wall, 24 denotes a red color filter layer, and 26 denotes a green color filter layer.

  The color conversion filter of FIG. 1 includes a black matrix 12, a red (R), a green (G), and a blue (B) color filter layer 14, 16, 18 on a transparent substrate 10, and different color filters. A bank 20 provided at the boundary of the layers 14, 16, 18, an ink leakage prevention wall 22 extending perpendicularly to the first direction in which the bank 20 extends to connect the ends of the bank 20, and red And two color conversion layers 24 and 26 of red and green provided on the green color filter layers 14 and 16.

(Formation process of the color filter layers 14, 16, 18)
First, as an optional step, the black matrix 12 is formed on the transparent substrate 10. The black matrix 12 may be formed on the entire surface of the transparent substrate 10 using a coating method (such as spin coating) and then patterned using a photolithographic method or the like, or formed in a pattern using a screen printing method or the like. May be. The black matrix 12 may be composed of a plurality of stripe-shaped portions extending in the first direction. Alternatively, the black matrix 12 is an integral unit having a lattice-like shape having a plurality of openings, which is formed of stripe-shaped portions extending in the first direction and the second direction (direction orthogonal to the first direction). It may be a layer. The black matrix 12 shown in FIG. 1 is a lattice shape type. The opening of the black matrix 12 is a position where a subpixel is formed.

  The transparent substrate 10 is rich in light transmittance, and is used for forming a black matrix 12, color filter layers 14, 16, 18 and color conversion layers 24 and 26 (not shown) and an organic EL element (not shown) (not shown). Solvent, temperature, etc.). Furthermore, it is preferable to use a material excellent in dimensional stability. Moreover, the material which does not cause the performance fall of a multicolor light emission display is preferable. Examples of the material of the transparent substrate 10 include glass, various plastics, various films, and the like.

  The black matrix 12 is a layer for blocking visible light and improving contrast. The black matrix 12 can be formed using a material for a normal flat panel display. The film thickness of the black matrix 12 can be arbitrarily set as long as the above functions are satisfied.

  Next, three color filter layers 14, 16, and 18 for RGB that transmit light in different wavelength ranges are formed independently. The color filter layers 14, 16, and 18 are layers for transmitting a specific wavelength region of visible light, setting the transmitted light to a desired hue, and improving the color purity of the transmitted light. The color filter layers 14, 16, and 18 can be formed using a commercially available material for a flat panel display. In recent years, pigment-dispersed materials in which pigments are dispersed in a photoresist are often used. As shown in FIG. 1, when three types of color filter layers are used, the blue color filter layer 18 that transmits light in the wavelength range of 400 nm to 550 nm, and the green color filter layer 16 that transmits light in the wavelength range of 500 nm to 600 nm. It is preferable to use a red color filter layer 14 that transmits light in a wavelength region of 600 nm or more. Each of the three types of color filter layers 14, 16, 18 is composed of a plurality of stripe-shaped portions extending in the first direction.

  Each of the color filter layers 14, 16, and 18 described above may be formed by forming a pattern on the entire surface of the transparent substrate 10 using a coating method (spin coating or the like) and then performing patterning using a photolithography method or the like. Alternatively, it may be formed in a pattern using a screen printing method or the like.

(Process for forming bank 20 and ink leakage prevention wall 22)
Next, a bank 20 made of a photocurable or photothermal combination curable resin is formed on the color filter layers 14, 16, 18 in a plurality of stripe-shaped portions extending in the first direction, and at the same time, at the end of the bank 20. An ink leakage prevention wall 22 that connects adjacent banks 20 is formed on the transparent substrate 10.

  In the present invention, the bank 20 is composed of a plurality of stripe-shaped portions extending in the first direction. When forming a high-definition pattern by the inkjet method, it is necessary to eject a small amount of droplets while precisely controlling the ejection volume, so the solid content of the ink that causes the ink to thicken is reduced. Cannot be too big. This inevitably increases the volume of ink required to obtain the required film thickness. The formation of the bank 20 is effective in preventing the ink from diffusing outside the desired region.

  The bank 20 preferably has liquid repellency with respect to ink for forming the color conversion layers 24 and 26 described later. The bank 20 can be formed by applying a photo-curing type or photo-thermosetting resin (for example, an acrylic resin containing a curable part) and patterning by a photolithographic method. Alternatively, the bank 20 can be formed by attaching a thermoplastic resin (for example, an acrylic resin) or a thermosetting resin to a desired portion using a screen printing method or the like.

As a material for forming the bank 20,
(1) A composition film composed of an acrylic polyfunctional monomer and oligomer having a plurality of acroyl groups or methacryloyl groups and light or a thermal polymerization initiator was subjected to light or heat treatment to generate photo radicals or heat radicals to be polymerized. thing,
(2) A composition comprising a polyvinyl cinnamate ester and a sensitizer dimerized by light or heat treatment and crosslinked.
(3) A composition film composed of a chain or cyclic olefin and bisazide is generated by nitrene generation by light or heat treatment and crosslinked with olefin, or (4) an epoxy group-containing monomer and a photoacid generator. Examples of the composition film include those obtained by polymerizing an acid (cation) by light or heat treatment. In particular, the photocurable or photothermal combination type curable resin (1) is highly fine and can be patterned, and is preferable in terms of reliability such as solvent resistance and heat resistance.

  Other materials for forming the bank 20 include polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone, polyvinyl butyral, polyphenylene ether, polyamide, polyetherimide, norbornene resin, methacrylic resin, and isobutylene maleic anhydride. Thermosetting resins such as copolymer resins and thermoplastic resins such as cyclic olefins, epoxy resins, phenol resins, urethane resins, acrylic resins, vinyl ester resins, imide resins, urethane resins, urea resins, and melamine resins Alternatively, a polymer hybrid containing polystyrene, polyacrylonitrile, polycarbonate, or the like and a trifunctional or tetrafunctional alkoxysilane can be used.

  On the other hand, in the present invention, the ink leakage prevention wall 22 extends in a second direction perpendicular to the first direction in which the bank 20 extends, and is configured by a connecting portion at the end of the bank 20. The In the present embodiment, the ink leakage prevention wall 22 is formed on the substrate 10.

  Since the ink leakage prevention wall 22 is formed simultaneously with the bank 20, the material thereof is the same as the material used for the bank 20. However, the ink leakage prevention wall 22 must be capable of preventing ink leakage, but prevents the flow of the filler used when the color conversion filter and the organic EL element are bonded together afterwards. Must not be.

  The viscosity of the ink used as the material of the color conversion layers 24 and 26 described later is about 4 mPa · s, whereas the viscosity of the filler (for example, epoxy resin or acrylic resin having thermosetting property) is 300 mPa · s. Degree. Thus, the viscosity of the filler is extremely high compared to the viscosity of the ink that is the material for the color conversion layer. For this reason, it is preferable to control the height of the ink leakage prevention wall 22.

  Specifically, it is necessary to make the height of the bank 20 different from the height of the ink leakage prevention wall 22 in order to give the prevention wall an effect that does not block the flow of the filler while stopping the ink flow.

  Thus, in order to make the height of the bank 20 and the ink leakage prevention wall 22 different, the following method can be adopted.

  First, the black matrix 12 and the color filter layers 14, 16, and 18 are formed on the portion of the substrate 10 that forms the bank 20.

  On the other hand, in the portion of the substrate 10 where the ink leakage prevention wall 22 is formed, the opening is positioned when the black matrix 12 is formed. Next, in the step of patterning the striped color filter layers 14, 16, and 18, a portion where the color filter layers 14, 16, and 18 are not present is obtained. As a result, at the position where the ink leakage prevention wall 22 is formed, neither the black matrix 12 nor the color filter layers 14, 16, 18 are present on the substrate 10, and an opening is formed.

  Next, the bank 20 and the ink leakage prevention wall 22 are simultaneously formed on the laminate in which the black matrix 12 and the color filter layers 14, 16, and 18 are formed at the position where the bank 20 is formed on the transparent substrate 10. For example, the bank 20 is coated by applying an acrylic resin with a spin coater so that a desired film thickness is obtained. At the same time, the ink leakage prevention wall 22 forms an acrylic resin so as to connect the adjacent banks 20 so as to cross the striped color filter layers 14, 16 and 18. Due to such a form of formation, the positions of the uppermost portions of the underlying layers (the transparent substrate 10 or the color filter layers 14, 16, 18) are different, so that the heights of the banks 20 and the ink leakage prevention walls 22 are increased. Can be different. 1C, the end of the bank 20 is located not on the color filter layer 16 but on the black matrix 12, and such a positional relationship is based on the end of the bank 20. In other positions (most part of the bank 20), the bank 20 is located on the color filter layer 16. Needless to say, the bank 20 may be formed on the color filter layer 16 up to its end.

  As described above, when the heights of the bank 20 and the ink leakage prevention wall 22 are made different, the height of the bank 20 with respect to the upper surface of the color filter layers 14, 16, 18 is set to the color filter layers 14, 16, 18. It is preferable that the height of the ink leakage prevention wall 22 with respect to the surface of the ink is 1.25 to 2.5 times the height. The effect of preventing ink leakage is obtained by setting it to 1.25 times or more, while the effect of preventing mixing of bubbles is obtained by setting it to 2.5 times or less.

  As described above, when the black matrix 12 and the color filter layers 14, 16 and 18 are not formed immediately below the position where the ink leakage prevention wall 22 is formed, the bank 20 and the ink leakage prevention wall 22 are formed. The height of these 20 and 22 can be made different by a single process. This mode is a much simpler mode as compared to the case where a bank or the like is formed using a plurality of steps as in the techniques disclosed in Patent Documents 9 and 10.

(Step of forming color conversion layers 24 and 26)
Next, the conversion layers 24 and 26 are formed on the color filter layers 14 and 16 by using an inkjet method. The color conversion layers 24 and 26 are films having a function of absorbing light from a light source and emitting fluorescence having different wavelength distributions. FIG. 1 shows an example in which the red color conversion layer 24 and the green color conversion layer 26 are formed. If necessary, only the red color conversion layer 24 may be provided. Alternatively, a blue conversion layer (not shown) may be provided in addition to the red conversion layer 24 and the green conversion layer 26.

The ink for forming the color conversion layers 24 and 26 includes at least one color conversion pigment and a solvent. The color conversion dye that can be used in the present invention is an aluminum chelate dye such as Alq ₃ (tris (8-quinolinolato) aluminum complex); 3- (2-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6), 3- (2-benzimidazolyl) -7-diethylaminocoumarin (coumarin 7), coumarin dyes such as coumarin 135; low molecular organic fluorescent dyes such as naphthalimide dyes such as Solvent Yellow 43 and Solvent Yellow 44. Alternatively, polymeric fluorescent materials typified by polyphenylene, polyarylene and polyfluorene may be used as the color conversion dye.

If necessary, a mixture of two or more dyes may be used as the color conversion dye. The use of a dye mixture is an effective means when the wavelength shift width is wide, such as when converting from blue light to red light. The dye mixture may be a mixture of the aforementioned dyes. Or the mixture of the above-mentioned pigment | dye and the following pigment | dye may be sufficient.
(1) Quinacridone derivatives such as diethylquinacridone (DEQ);
(2) cyanine dyes such as 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM-1), DCM-2, and DCJTB;
(3) 4,4-difluoro-1,3,5,7-tetraphenyl-4-bora-3a, 4a-diaza-s-indacene;
(4) Lummogen F Red;
(5) Nile Red;
(6) xanthene dyes such as rhodamine B and rhodamine 6G; and (7) pyridine dyes such as pyridine 1.

  As the solvent for ink for forming the color conversion layer in the present invention, any solvent capable of dissolving the above color conversion pigment can be used. For example, a nonpolar organic solvent such as toluene, or a polar organic solvent such as chloroform, alcohol, or ketone can be used as the ink solvent. The ink solvent may be composed of a single component. Alternatively, an ink solvent may be prepared by mixing a plurality of solvents for the purpose of adjusting the viscosity, vapor pressure, solubility, fluidity and / or wettability.

  In this embodiment, an ink can be produced by mixing at least one color conversion dye in a solvent. In order to eliminate the influence of moisture and oxygen, it is preferable to prepare the ink in an inert gas (for example, a rare gas such as nitrogen or argon) atmosphere. Prior to making the ink, any means known in the art, such as degassing, treatment with a water absorbent, treatment with an oxygen absorbent, distillation, etc., is used to remove moisture and oxygen in the solvent. The solvent may be pretreated.

  The prepared ink was partitioned by the bank 20 and the ink leakage prevention wall 22 using any inkjet device and method known in the art, provided that it can be applied at the desired resolution. , Deposited on the color filter layers 14,16. The inkjet apparatus and method may be a thermal inkjet system or a piezo inkjet system. The ink deposited using the ink jet method spreads on the surface of the color filter layers 14 and 16, and does not spread except the necessary portion by the bank 20 and the ink leakage prevention wall 22.

  After the deposition, the solvent is removed by evaporation to form color conversion layers 24 and 26 made of at least one color conversion dye. The color conversion layers 24 and 26 are regions sandwiched between two banks 20 and two ink leakage prevention walls 22 (in FIG. 1, only one side of the ink leakage prevention wall 22 is illustrated), and is arranged in the first direction. It has a striped shape that extends. The removal of the solvent can be carried out by heating to a temperature at which the solvent evaporates in the aforementioned inert gas atmosphere or in vacuum. At this time, it is preferable to set the heating temperature so that the color conversion pigment in the ink does not deteriorate or thermally decompose.

(Other processes)
Finally, although not shown in FIG. 1, a barrier layer may be optionally formed so as to cover the bank 20, the ink leakage prevention wall 22, and the red color conversion layer 24 and the green color conversion layer 26. The barrier layer is effective in maintaining the characteristics of the color conversion layers 24 and 26 when the color conversion layers 24 and 26 are formed using a material that deteriorates due to the presence of water and / or oxygen.

The barrier layer is formed using a material having electrical insulation properties, barrier properties against gases and organic solvents, and having high transparency in the visible range (transmittance of 50% or more in the range of 400 to 700 nm). be able to. Materials that may be used include, for _{example, SiO x, AlO x, TiO} x, TaO x, inorganic oxides such as ZnO _x, inorganic nitrides such as SiN _x, and an inorganic oxide nitride such as SiN _x O _y . The barrier layer may be a single layer of the above-described material, or a laminate of a plurality of layers.

  The barrier layer can be formed by any method known in the art such as sputtering, CVD, and vacuum deposition. In terms of avoiding damage to the color conversion layers 24 and 26 during the formation of the barrier layer, a CVD method that can be carried out at a low temperature of 100 ° C. or less and that has low energy of particles used for film formation is used. Thus, it is preferable to form a barrier layer.

<Embodiment 2>
2 shows a color conversion filter formed by the second manufacturing method of the present invention, FIG. 2 (a) is a plan view thereof, FIG. 2 (b) is a cross-sectional view taken along line bb ′ of FIG. 2 (a), 2C is a cross-sectional view taken along the line cc ′ in FIG. 2A, and FIG. 2D is a cross-sectional view taken along the line dd ′ in FIG. In these drawings, the reference numerals given to the respective constituent elements are the same as those in the first embodiment shown in FIG.

  The second embodiment is the same manufacturing method as the second embodiment except that the ink leakage prevention wall 22 is formed not on the transparent substrate 10 but on the black matrix 12.

  In the second embodiment, the formation of the bank 20 on the color filter layers 14, 16 and 18 and the formation of the ink leakage prevention wall 22 at the end of the bank 20 can be simultaneously performed as follows.

  First, the black matrix 12 and the color filter layers 14, 16, and 18 are formed on the portion of the substrate 10 that forms the bank 20.

  On the other hand, the non-opening portion (black matrix itself) is positioned in the portion of the substrate 10 where the ink leakage prevention wall 22 is formed when the black matrix 12 is formed. Next, after forming the striped color filter layers 14, 16, and 18, various portions are subjected to patterning, for example, patterning by a photolithography method, thereby obtaining portions where the color filter layers 14, 16, and 18 are not present. . As a result, the color filter layers 14, 16 and 18 do not exist on the substrate 10 at the position where the ink leakage prevention wall 22 is formed, and an opening is formed.

  As a result, the bank 20 and the ink leakage prevention wall 22 can be simultaneously formed on the laminate in which the color filter layers 14, 16, and 18 are formed only on the formation position of the bank 20 on the transparent substrate 10. Also in such a form of formation, the bank 20 and the ink leakage prevention wall 22 can have different heights. 2C, the end of the bank 20 is located not on the color filter layer 16 but on the black matrix 12, and such a positional relationship is based on the end of the bank 20. In other positions (most part of the bank 20), the bank 20 is located on the color filter layer 16. Needless to say, the bank 20 may be formed on the color filter layer 16 up to its end.

  In the above description of the first and second embodiments, an example using three color filter layers has been shown with reference to FIGS. However, on the condition that the bank is formed on the color filter layer in a plurality of stripe-shaped portions extending in the first direction, and at the same time, an ink leakage prevention wall that connects adjacent banks is formed at the end of the bank. It is apparent that the manufacturing method of (1) can be applied to the manufacture of a color conversion filter using two or more color filter layers.

<Formation of color conversion filter>
Example 1
The color conversion filter of Example 1 was formed as follows according to FIG. That is, a color matrix CK-7001 (available from Fuji Film Co., Ltd.) is coated on a transparent substrate 10 (Corning 1737 glass), and a black matrix having a plurality of rectangular openings using a photolithographic method. 12 was formed. The black matrix 12 had a film thickness of 1 μm. Two types of rectangular openings are formed, and the first rectangular opening is formed at the position of the sub-pixel. Each of the first rectangular openings had a vertical direction of 300 μm × a horizontal direction of 100 μm, and the interval between adjacent rectangular openings was 30 μm in the vertical direction and 10 μm in the horizontal direction. In addition, the second rectangular opening is formed in a portion where a leakage prevention wall described later is formed. The second rectangular opening is located at a position of 200 μm from the end of the effective pixel (pixel that performs light emitting display) in the vertical direction of the substrate from the end of the effective pixel (pixel that performs light-emitting display) to the peripheral direction of the substrate. It formed in the position facing a 1st rectangular opening part on the basis of an edge part. Each of the second rectangular openings had a vertical width of 100 μm and a horizontal width of 100 μm, and the interval between adjacent rectangular openings was 10 μm in the horizontal direction.

  Next, color mosaic CR-7001 (available from Fuji Film Co., Ltd.) was applied, and a red color filter layer 14 composed of a plurality of stripe-shaped portions extending in the vertical direction was formed using a photolithographic method. As shown in FIG. 1, each of the plurality of stripe-shaped portions has a portion of the stripe-shaped portion superimposed on the black matrix 12, has a thickness of 1.5 μm and a width of 110 μm, and is arranged at intervals of 220 μm. . Further, at the outer peripheral portion in the vertical direction of the substrate, an opening having a vertical width of 100 μm and a horizontal width of 100 μm was formed at a position corresponding to the second rectangular opening of the black matrix 12 at the same time.

  Further, the green color filter layer 16 and the blue color are used in the same manner as the red color filter layer 14 except that the color mosaics CG-7001 and CB-7001 (both available from Fuji Film Co., Ltd.) are used. A color filter layer 18 was formed. In both the green color filter layer 16 and the blue color filter layer 18, each of the plurality of stripe-shaped portions has a part of the stripe-shaped portion superimposed on the black matrix 12 and has a film thickness of 1.5 μm and a width of 110 μm. And arranged at intervals of 220 μm. Further, at the outer peripheral portion in the vertical direction of the substrate, an opening having a vertical width of 100 μm and a horizontal width of 100 μm was formed at a position corresponding to the second rectangular opening of the black matrix 12 at the same time.

  As described above, the black matrix 12 and the color filter layers 14, 16, 18 are formed on the transparent substrate 10, and at the same time, the black matrix 12 and the color filter layers 14, 16, A region where no 18 was formed was obtained.

  Next, a bank 20 was formed on the black matrix 12 and the color filter layers 14, 16 and 18. A photo-curable acrylic resin (V259PA / P5, manufactured by Nippon Steel Chemical Co., Ltd.) is applied, patterned by a photolithographic method, and extended in a vertical direction on a portion serving as a boundary between different color filter layers 14, 16, and 18. A bank 20 composed of a plurality of stripe-shaped portions was formed. Each of the stripe-shaped portions constituting the bank 20 had a width of 10 μm, and the height including the black matrix 12, the color filter layers 14, 16, 16 and the bank 20 was 5 μm.

  Simultaneously with the formation of the bank 20, an ink leakage prevention wall 22 was formed in a portion where the black matrix 12 and the color filter layers 14, 16, 18 were not formed. Since these bases 12 and 14 to 18 are not provided, an ink leakage prevention wall 22 having a height of 2 μm lower than the bank 20 is formed so as to connect the adjacent banks 20 to the pixel outer peripheral portion.

  A red color conversion layer 24 and a green color conversion layer 26 were formed in the region defined by the color filter layers 14 and 16 banks 20 and the ink leakage prevention wall 22 thus formed.

For the red color conversion layer 24, 1000 parts by weight of toluene and 4- (dicyanomethylene) -2-methyl-6- (4-dimethylaminostyryl) 4H-pyran (the first dye) and coumarin 6 as the second dye ( Ink was prepared by mixing 50 parts by weight of a mixture with DCM) (molar ratio of coumarin 6: DCM = 48: 2). The prepared ink was loaded into an ink jet apparatus (Litrex 120L manufactured by Lightlex). Next, in a nitrogen atmosphere, 42 pL of ink per subpixel was adhered to the region. Without breaking the nitrogen atmosphere, the laminate with the ink attached was moved into a vacuum drying furnace and heated to 100 ° C. under a pressure of 1.0 × 10 ⁻³ Pa to remove toluene. The obtained red color conversion layer 24 had a thickness of 500 nm.

For the green conversion layer 26, 1000 parts by weight of toluene, and 50 parts by weight of a mixture of coumarin 6 as the first dye and diethylquinacridone (DEQ) as the second dye (molar ratio is coumarin 6: DEQ = 48: 2). Were mixed to prepare an ink. The prepared ink was loaded into an ink jet apparatus (Litrex 120L manufactured by Lightlex). Next, in a nitrogen atmosphere, 42 pL of ink per subpixel was adhered to the region. Without breaking the nitrogen atmosphere, the laminate with the ink attached was moved into a vacuum drying furnace and heated to 100 ° C. under a pressure of 1.0 × 10 ⁻³ Pa to remove toluene. The obtained green color conversion layer 26 had a film thickness of 500 nm.

Next, the laminated body on which the red conversion layer 24 and the green conversion layer 26 were formed was moved into the plasma CVD apparatus without breaking the vacuum. Using a plasma CVD method, silicon nitride (SiN) with a thickness of 1 μm was deposited to form a barrier layer, and the color conversion filter of Example 1 was obtained. Here, monosilane (SiH ₄ ), ammonia (NH ₃ ), and nitrogen (N ₂ ) were used as source gases. Moreover, the temperature of the laminated body at the time of barrier layer formation was maintained at 100 degrees C or less.

(Example 2)
The color conversion filter of Example 2 was formed as follows according to FIG. That is, a color conversion filter was formed in the same manner as in Example 1 except that the second rectangular opening of the black matrix 12 was not formed. Thus, the color conversion filter of Example 2 was obtained by using the base layer for forming the ink leakage prevention wall 22 as the black matrix 12 instead of the transparent substrate 10.

(Comparative Example 1)
In FIG. 1, a color conversion filter of Comparative Example 1 was obtained in the same manner as in Example 1 except that the ink leakage prevention wall 22 was not formed between adjacent banks 20.

<Formation of organic EL display>
Next, the color conversion filters of Examples 1 and 2 and Comparative Example 1 obtained in this way were each bonded to an organic EL element prepared in advance as follows to form an organic EL display. .

  The color conversion filter and the organic EL element were moved into a bonding apparatus maintained in an environment of 5 ppm oxygen and 5 ppm water.

  Set the process surface of the color conversion filter (the surface on which the barrier layer is formed) facing upward, and use a dispenser to attach an epoxy UV curing adhesive (XNR-5516: Nagase ChemteX) to the outer periphery of each of the panel areas. Co., Ltd.) was applied seamlessly to form an adhesive layer.

  Near the center of each screen, 20 μl of a thermosetting epoxy adhesive was dropped as a filler using a mechanical valve.

  The organic EL element was set in a state where the process surface of the organic EL element (surface from which light from the light emitting layer was emitted) was opposed to the process surface of the color conversion filter.

  The pressure inside the bonding apparatus is reduced to about 10 Pa, the color conversion filter and the organic EL element are brought close to about 30 μm, their pixel positions are aligned, and then a slight load is applied while returning the pressure inside the bonding apparatus to atmospheric pressure. did. At this time, the thermosetting epoxy adhesive dripped at the center of each screen spreads the gap between the color conversion filter formed by the photo spacer and the organic EL element over the entire surface of each screen.

  Only the adhesive layer was irradiated with ultraviolet rays from the color conversion filter side to be temporarily cured, and taken out to a general environment. Then, it divided | segmented into each panel using the automatic glass scriber and the break device. The divided individual panels were heated to 80 ° C. in a heating furnace for 1 hour and naturally cooled in the furnace for 30 minutes. As described above, organic EL displays using the color conversion filters of Examples 1 and 2 and Comparative Example 1 were obtained.

<Evaluation>
For the organic EL displays using the color conversion filters of Examples 1 and 2 and Comparative Example 1, the color mixing rate and the bubble rate were evaluated. In the present invention, “mixed color” refers to the case where the ink wraps around the adjacent color region at the end of the stripe-shaped portion constituting the bank (located at the outer periphery of the filter) and the different color inks are mixed together. Means state. The “mixed color occurrence rate” means the ratio of the number of subpixels in which “mixed color” occurs to the total number of red and green subpixels. On the other hand, the “bubble generation rate” means the ratio of the number of subpixels where “bubbles” are generated to all the subpixels.

  Note that both the color mixture generation rate and the bubble generation rate were evaluated by observation with a microscope (× 10). These results are shown in Table 1.

  According to Table 1, both the organic EL displays of Examples 1 and 2 using the color conversion filter in which the bank is formed on the color filter layer and at the same time the ink leakage prevention wall that connects adjacent banks is formed are used. It was found that no color mixing occurred. From these results, it can be seen that the layer serving as the base of the ink leakage prevention wall may be a transparent substrate or a black matrix.

  On the other hand, in the organic EL display of Comparative Example 1 using the color conversion filter in which the ink leakage prevention wall is not formed, the ink wraps around the other color area adjacent to the bank edge, and the different color inks are mixed. It turned out that color mixing occurred.

  In addition, with respect to the bubble generation rate, it was found that Examples 1 and 2 had the same preferable results as Comparative Example 1.

  From the above, it was confirmed that if the bank and the ink leakage prevention wall were formed at the same time, it was possible to prevent color mixing, and it was also confirmed that a suitable result equivalent to the conventional one could be obtained for the generation of bubbles.

  According to the method of manufacturing a color conversion filter of the present invention, a bank is formed on the color filter layer, and at the same time, an ink leakage prevention wall that connects adjacent banks is formed at the end of the bank, which is a problem in the past. Occurrence of mixed colors can be prevented. For this reason, according to this invention, the color conversion filter containing the color conversion layer which has a highly accurate pattern can be obtained.

  In particular, in the present invention, since the bank and the ink leakage prevention wall are formed at the same time, the color conversion filter can be formed much more easily than in the case where the bank is formed by using a plurality of processes as in the prior art. Can do. Therefore, the present invention is promising in that it can provide a method for manufacturing a color conversion filter used for a flat panel display, which will be required to be manufactured more easily and inexpensively in the future.

The color conversion filter formed with the 1st manufacturing method of this invention is shown, Fig.1 (a) is the top view, FIG.1 (b) is bb 'sectional drawing of Fig.1 (a), FIG. FIG. 1C is a cross-sectional view taken along the line cc ′ of FIG. 1A, and FIG. 1D is a cross-sectional view taken along the line dd ′ of FIG. It is sectional drawing which shows the color conversion filter obtained by the method of this invention. The color conversion filter formed with the 2nd manufacturing method of this invention is shown, Fig.2 (a) is the top view, FIG.2 (b) is bb 'sectional drawing of Fig.2 (a), FIG. 2C is a cross-sectional view taken along the line cc ′ of FIG. 2A, and FIG. 2D is a cross-sectional view taken along the line dd ′ of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transparent substrate 12 Black matrix 14 Red color filter layer 16 Green color filter layer 18 Blue color filter layer 20 Bank 22 Ink leakage prevention wall 24 Red conversion layer 26 Green conversion layer

Claims (3)

(A) a step of forming a plurality of types of color filter layers on a transparent substrate, each of the plurality of types of color filter layers comprising a plurality of stripe-shaped portions extending in a first direction;
(B) On the color filter layer, a bank made of a photocurable or photothermal combination type curable resin is formed in a plurality of stripe-shaped portions extending in the first direction, and at the same time, adjacent banks are connected at the end of the bank. Forming an ink leakage prevention wall on the transparent substrate;
And (c) forming a color conversion layer that absorbs light of a specific wavelength and outputs light having a wavelength different from the absorbed wavelength by using an inkjet method on the color filter layer. A method for manufacturing a color conversion filter. (A) A step of forming a black matrix on a transparent substrate and further forming a color filter layer, each of the plurality of types of color filter layers being composed of a plurality of stripe-shaped portions extending in the first direction. And the process
(B) On the color filter layer, a bank made of a photocurable or photothermal combination type curable resin is formed in a plurality of stripe-shaped portions extending in the first direction, and at the same time, adjacent banks are connected at the end of the bank. Forming an ink leakage prevention wall on the black matrix;
And (c) forming a color conversion layer that absorbs light of a specific wavelength and outputs light having a wavelength different from the absorbed wavelength by using an inkjet method on the color filter layer. A method for manufacturing a color conversion filter.   In the step (b), the height of the bank with respect to the upper surface of the color filter layer is set to 1.25 to 2.5 times the height of the ink leakage prevention wall with respect to the upper surface of the color filter layer. The manufacturing method of the color conversion filter of Claim 1 or 2.

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