JP4729754B2 - Display device using a plurality of organic EL light emitting elements - Google Patents

Description

  The present invention relates to a display device using an organic EL element, and more particularly to an apparatus that constitutes a display using a plurality of organic EL light emitting elements.

  As a method for realizing a full-color organic EL panel, there are a three-color coating method, a color conversion method (hereinafter referred to as CCM method), a color filter method, and the like. Among these methods, the CCM method and the color filter method do not require the use of a metal mask at the time of film formation, and the color conversion layer and the color filter may be formed on the panel by a photo process, so that a large area and high definition are achieved. It is considered advantageous. (See Non-Patent Document 1)

  In the case of realizing a display with a larger area, a method for realizing a single large panel by joining a plurality of panels is conventionally known. (See Patent Documents 1 and 2)

  FIG. 2 shows an example of a prior art method for realizing a large panel by joining a plurality of panels, and is composed of four small organic EL panels 5. FIG. 3 shows the structure of the organic EL panel 5 realized by the three-color painting method, which is a conventional full color realization method. In the organic EL panel 5 of FIG. 3, a plurality of switching elements 54 (TFTs and the like) are provided on a substrate 52, and a plurality of first electrodes 56 corresponding to the plurality of switching elements 54 are provided. . A red light emitting layer 58R, a green light emitting layer 58G, and a blue light emitting layer 58B made of an organic layer are provided on each of the plurality of first electrodes 56, and each of the light emitting layers 58 is separated by a separation wall 60. A transparent electrode 62 having an integral structure is provided on the light emitting layer 58 and the separation wall 60, and a protective layer 64 and a transparent seal 66 (glass or the like) constituting the display surface are formed thereon. Yes.

  Therefore, when a large panel is realized using a plurality of organic EL panels 5, the display surfaces of the large panels are combined with the display surfaces of the respective small organic EL panels 5. When observing from the front viewpoint of FIG. 2, the joint of the panel is not recognized, but when observing from the oblique viewpoint, the joint is caused by distortion of the display surface of the small organic EL panel 5 or reflection from the panel joint. Is recognized.

JP 2003-43954 A Japanese Patent Laid-Open No. 2002-372928 Japanese Patent Laid-Open No. 5-134112 JP-A-7-218717 JP-A-7-306311 JP-A-5-119306 JP-A-7-104114 JP 7-48424 A JP-A-8-279394 JP-A-6-300910 JP 7-128519 A JP-A-9-330793 JP-A-8-27934 JP-A-5-36475 Kenya Sakurai, “Technology Development Status and Prospects of Full-Color Organic EL by Color Conversion”, October Monthly Display, 59 pages (2002)

  The conventional method has a disadvantage that the joint portion of the small organic EL panel is visually recognized depending on the observation angle. More specifically, when observing from the front viewpoint of FIG. 2, the panel joint is not recognized, but when observing from the oblique viewpoint, the distortion of the display surface of the small organic EL panel 5 and the panel joint are observed. The junction is recognized by the reflection of the light or the change in light intensity or hue of the pixel adjacent to the junction. This is because when a large panel is realized using a plurality of small organic EL panels 5, the display surface of the large panel is formed integrally with the display surface of each small organic EL panel 5. .

  Accordingly, an object of the present invention is to provide a structure in which a joint portion is not visually recognized when a large panel is formed using a plurality of organic EL elements.

  The display device of the present invention is a display device that is formed using a plurality of organic EL elements and has a structure suitable for upsizing, and a) a pixel formed from a plurality of types of subpixels, and the plurality of types And b) a plurality of organic EL elements, wherein the plurality of types of sub-pixels are output from a plurality of types of color modulation units. And a plurality of organic EL elements are bonded together to form one display element. Here, the color conversion filter may have an integral structure. Further, it is desirable that the joint portion formed by bonding the organic EL elements has a structure in a position corresponding to the black matrix of the color conversion filter. Furthermore, you may provide an anti-reflective material in the junction part end surface of the horizontal direction of an organic EL element.

  As various aspects of the display device of the present invention, 1) a pixel is composed of three types of sub-pixels of red, blue and green, and sub-pixels adjacent to the lateral junction of the organic EL element are red and blue A configuration having a display color selected from the group consisting of: 2) a configuration in which a subpixel adjacent to a junction in the horizontal direction of the organic EL element has a smaller size than other subpixels; or 3) a pixel in red The blue sub-pixel is composed of three sub-pixels of blue and green, the green sub-pixel has a smaller size than the blue and red sub-pixels, and the black matrix adjacent to the green sub-pixel It is possible to adopt a configuration in which the lateral junction of the organic EL element is arranged.

  By adopting the configuration of the present invention described above, a color modulation part (including a color conversion layer and / or a color filter), which is a feature of the CCM method, is formed on a single large substrate by a photo process. Create a color conversion filter, separate from the color conversion filter, use a vacuum film formation process to configure multiple small organic EL elements required for a large panel and superimpose them to realize a large display panel It becomes possible to do. In other words, it is possible to efficiently manufacture a large display panel by separately manufacturing a photo process that can be adapted to an increase in the size of a substrate and a vacuum film formation process that is limited by the increase in size of the substrate. .

  In addition, regarding the disorder of alignment of elements that may occur when a plurality of organic EL elements are bonded together, the subpixel adjacent to the junction is appropriately selected, and the subpixel adjacent to the junction is reduced in size. Thus, it is possible to prevent the visual recognition of the joint by improving the tolerance for the disorder of alignment. Moreover, it becomes possible to prevent the visual recognition of a junction part also by providing an antireflection material in the junction part of an organic EL element.

  An example of the display device of the present invention is shown in FIG. In the configuration of FIG. 1, a display device is configured by combining the color conversion filter 1 and a plurality of organic EL elements 2 (four examples are shown in FIG. 1).

  The color conversion filter 1 is integrally formed in an area corresponding to the display surface of the display device, and pixels formed from a plurality of types of subpixels are aligned over the entire display surface. A black matrix is provided in the area between and between the pixels. As shown in FIG. 4, the color conversion filter 1 includes a transparent substrate 110, a plurality of types of color modulation units and black matrices 130 provided on the transparent substrate 110, and a protection formed so as to cover the color modulation units and the black matrix. Layer 140. Each of the color modulation units is composed of a color filter layer 122, a color conversion layer 124, or a laminate of the color filter layer 122 / color conversion layer 124. Each of the color modulation units corresponds to the subpixel 120. Although FIG. 4 shows the case of three colors of the red subpixel 120R, the green subpixel 120G, and the blue subpixel 120B, it goes without saying that two types or four or more types of color modulation units may be used. . Further, as will be described later, the patterning of the color filter layer 122, the color conversion layer 124, and the black matrix for constituting the color conversion filter 1 can be performed using a general imagewise exposure-wet development method. Therefore, it is possible to form the large color conversion filter 1 by a relatively simple process using a substrate having a size necessary for forming a large display panel.

  In the color conversion filter 1, a plurality of types of sub-pixels 120 are arranged to form one pixel. The pixels are preferably formed to have a substantially square shape. Therefore, it is preferable to align the sub-pixels 120 having a substantially rectangular shape in each pixel. In the present invention, “lateral direction” means the direction of the short side of the rectangular shape of the subpixel 120, and “vertical direction” means the direction of the long side of the rectangular shape of the subpixel 120.

  FIG. 4 shows an example of a top emission type active matrix driving type organic EL element. In the plurality of organic EL elements 2, a plurality of switching elements 220 are provided on the substrate 210, and a plurality of first electrodes 230 corresponding to the plurality of switching elements 220 on a one-to-one basis are provided. An organic EL layer 240 is provided on the plurality of first electrodes 230, and a second electrode 250 formed integrally therewith is formed. As will be described later, it is also possible to use a passive matrix driving element as the organic EL element in the present invention. Further, the organic EL element 2 used in the present invention may adopt a top emission method in which light is extracted from the second electrode 250 side as shown in FIG. 4, or a bottom emission in which light is extracted from the substrate 210 side. A method may be adopted. When a bottom emission type organic EL element is used, in order to protect layers such as the organic EL layer 240 from the surrounding environment, after bonding to the color conversion filter 1, bonding is performed using an adhesive layer at the periphery of the color conversion filter 1. It is desirable to isolate the organic EL element from the surrounding environment using a sealing can or a sealing resin.

  A plurality of organic EL elements 2 are prepared to form an area corresponding to the display surface of the color conversion filter 1. The downsizing of the organic EL element 2 by adopting such a configuration has the following advantages. Since manufacture of an organic EL element involves operations such as vapor deposition and / or sputtering in a vacuum, the size of the substrate 210 is limited due to the size of the vacuum apparatus. By reducing the size of the organic EL element 2, such a restriction can be avoided, and it is easy to form a light emitting portion having uniform characteristics over the entire surface of the substrate 210. Furthermore, since the use of a large vacuum apparatus can be avoided, the manufacturing cost of the organic EL element 2 can be reduced. On the other hand, since the color conversion filter 1 does not require an operation in a vacuum, a large-sized filter can be easily manufactured without the above-described limitation.

  The display device of the present invention can be formed by combining a plurality of organic EL elements 2 to form one display element and further combining with one color conversion filter 1. At the time of bonding, the plurality of organic EL elements 2 may be electrically connected and controlled as a unit. Two adjacent organic EL elements can be electrically connected using any method known in the art, such as wire bonding, or connection on the back surface via vias. Alternatively, each organic EL element 2 may be controlled independently without being electrically connected.

  In the display device of the present invention formed by combining one color conversion filter 1 and a plurality of organic EL elements 2, the display surface is the surface of the substrate 110 of the color conversion filter 1 formed integrally. Therefore, in the display surface of the display device of the present invention, the joint portion is not visually recognized due to the distortion of the display surface at the front viewpoint or the oblique viewpoint.

  FIG. 5 shows a top view of the display device (joint region shown as 500 in FIG. 1) obtained from the present invention as seen from the color conversion filter side. In FIG. 5, four organic EL elements 2 a to 2 d are bonded to each other at the horizontal junction 270 and the vertical junction 280, and the red subpixel 120 </ b> R corresponding to the color modulation unit of the color conversion filter 1 is attached. The green sub-pixel 120G and the blue sub-pixel 120B are fixed, and form one pixel in which three types of sub-pixels are combined. A black matrix 130 is provided in a portion where no subpixel is provided. As can be seen from FIG. 5, the bonding portions (the horizontal bonding portion 270 and the vertical bonding portion 280) of the organic EL elements are arranged at positions corresponding to the black matrix 130 of the color conversion filter 1. In addition, each of the plurality of light emitting units provided in each of the four organic EL elements 2 a to 2 d has the same dimensions as the corresponding subpixel 120.

  In the bonding of the organic EL elements 2, some organic EL elements 2 may be bonded to each other with a deviation from a predetermined position. Even when the organic EL element shifts as described above, in the display device of the present invention, the emission of light from the color conversion dye that performs wavelength distribution conversion of light from the light source in the color conversion layer 124 is non-directional and Even if a region where the light emitting portion does not exist is formed under the color conversion layer 124 because it is diffusive, light is also emitted from the region by light diffused from other portions, and normal subpixels and Similarly, light is emitted from the entire surface, and there is no change in light intensity and hue (emission of the entire pixel) that can be visually recognized. Further, as will be described later, it is possible to use no color conversion layer 124 in the blue subpixel 120B of the display device of the present invention. Even in this case, the blue light has low relative visibility to the naked eye, so Even if a region where no light emitting portion is present is formed, the light intensity and hue are not affected so as to be visually recognized. Furthermore, in the display device of the present invention, the light diffusible color conversion layer 124 is provided close to the surface of the substrate 110 which is the display surface, so that the light source is arranged away from the display surface and the color conversion layer is disposed. There is a further advantage that the viewing angle dependency is low as compared with a liquid crystal display and a color filter type EL display which are not provided.

  In one aspect of the present invention, as shown in FIG. 5, the subpixels adjacent to the lateral joint 270 are preferably a red subpixel 120R and a blue subpixel 120B. This is because, since red light and blue light emitted from these sub-pixels have low relative visibility to the naked eye, even if a deviation between the sub-pixel 120 (R or B) and the light emitting portion occurs, the above-described color conversion layer Combined with the diffusion effect 124, the joint can be prevented from being visually recognized.

  In another aspect of the present invention, as shown in FIG. 7, the subpixel adjacent to the lateral joint 270 can be a small subpixel 170 having a smaller size than the subpixel 120 of the other portion. FIG. 7 shows the case where red and blue small sub-pixels 170 are provided, and only the light-emitting portion 290 of the organic EL element 2a adjacent to the lateral junction 270 is shown. The small sub-pixel 170 preferably has an area of 40 to 75% of the area of the sub-pixel 120 in the other part. More preferably, the small sub-pixel 170 has a rectangular shape, and its short side has a size that is 50 to 80% of the short side of the sub-pixel 120 of the other part, and its long side is the sub-pixel of the other part. It is desirable to have a dimension of 80-100% of the 120 long sides. Here, each of the small sub-pixels 170 of two colors (red and blue in FIG. 7) has a product of the intensity of light emitted from the small sub-pixel 120 and the area thereof when driving, in the sub-pixel 120 of the same color in other parts. It is operated so that the electric current which becomes equivalent to the thing flows. By providing such a small subpixel 170 adjacent to the junction (especially the lateral junction 270) of the organic EL element 2, the width of the black matrix at the position corresponding to the junction is increased, and the organic EL element The tolerance of the sub-pixel adjacent to the joint portion with respect to the deviation of the bonding can be increased. That is, even if a slight shift occurs, the small subpixel 170 is in the region of the light emitting unit 290 below it, and the light intensity emitted from the small subpixel 170 is not affected. Therefore, the entire pixel adjacent to the joint is not affected by the light intensity and hue of the emitted light, and visual recognition of the joint can be prevented.

  In another aspect of the present invention, as shown in FIG. 6, the green subpixel is a small subpixel 170G over the entire color conversion filter, and the lateral junction 270 of the organic EL element 2 is adjacent to the green small subpixel 170G. Arranged at the position of the black matrix. In FIG. 6, only the light emitting portion 290 of the organic EL element 2 a that is adjacent to the lateral direction joint portion 270 is illustrated. The size of the small subpixel in this aspect may be the same as described above. By adopting this configuration, with respect to the green small subpixel 170G having high relative visibility to the naked eye, the tolerance of the green subpixel with respect to the shift at the time of organic EL element bonding is set in the black matrix at the position corresponding to the joint portion. In addition to the improvement in the joint portion due to the expansion of the width, the entire display device can be improved so that the effective area of the subpixel does not change. Even if a deviation occurs, the light intensity of the light emitted from the green small sub-pixel 170G does not change, and the blue sub-pixel 120B or the red sub-pixel 120R is adjacent to the connection portion. Since the sensitivity is low, the hue of the entire pixel is hardly affected. Therefore, the joint is not visually recognized due to a change in light intensity and / or hue at the joint.

  In another aspect of the present invention, as shown in FIG. 8, all types of subpixels are small subpixels 170 throughout the color conversion filter. In FIG. 8, only the light emitting portion 290 of the organic EL element 2 a that is adjacent to the lateral direction joint portion 270 is illustrated. With such a configuration, with respect to all types of sub-pixels, it is possible to improve the tolerance of the sub-pixels with respect to the shift at the time of organic EL element bonding, and to prevent the effective area of the sub-pixels from changing. Even if a deviation occurs, the light intensity of the light emitted from each small subpixel 170 does not change, and therefore the hue of the entire pixel is hardly affected. This effect can prevent visual recognition of the joint due to changes in light intensity and / or hue at the joint.

  In any of the above embodiments, since the external light incident on the color conversion filter 1 with a specific angle is reflected on the end face of the organic EL element 2, the joint may be visually recognized. . In order to prevent reflection at the end face of the joint portion formed at the time of bonding, an antireflection material can be provided on the end face of the joint portion of the organic EL element 2 as shown in FIG. For example, as the antireflection material, an ultraviolet curable adhesive or a polymer adhesive having a refractive index close to that of glass in the visible light wavelength region can be used. The refractive index of the glass used is about 1.5 to 1.6. As an adhesive, AVR200 (manufactured by Three Bond Co., Ltd., refractive index 1.56) or XNR5623 (manufactured by Nagase ChemteX Corporation) is an ultraviolet curable adhesive. , Refractive index 1.57). Alternatively, a film-like resin may be used as an antireflection material. The film resin that can be used preferably has a difference between the refractive index of the glass and the refractive index of the glass of 5% or less of the refractive index of the glass. The film-like resin can be made from polyester, polyethylene, cellophane, polyethylene laminate cellophane, polyvinylidene chloride, nylon, or polycarbonate.

  Hereinafter, the structure of the color conversion filter 1 of the present invention will be described in detail. The transparent substrate 110 needs to be transparent to visible light (wavelength 400 to 700 nm), preferably to light converted by the color modulation unit 120. Further, the transparent substrate 110 should withstand the conditions (solvent, temperature, etc.) used for forming the color modulation section 120 and other layers (described later) provided as necessary, and further to improve dimensional stability. It is preferable that it is excellent. Preferred materials for the transparent substrate 110 include glass and resins such as polyethylene terephthalate and polymethyl methacrylate. Borosilicate glass or blue plate glass is particularly preferable.

  Each of the color modulation units 120 includes a color filter layer 122, a color conversion layer 124, or a color filter layer 122 / color conversion layer 124 stack. Two or more types of color modulation units can be provided, but preferably three types of color modulation units, more preferably three color modulation units capable of rendering white color by mixing, most preferably a red modulation unit It is desirable to provide 120R, a green modulation unit 120G, and a blue modulation unit 120B.

  The color filter layer 122 used in the color modulation unit 120 is a component in a specific wavelength region of light emitted from the organic EL layer 240 of the organic EL element 2 used as a light source and / or light subjected to wavelength distribution conversion by the color conversion layer 124. This is a layer for transmitting only light and obtaining output light with high color purity. The color filter layer 122 can be formed using a color filter material used for a flat panel display such as a liquid crystal display. In recent years, a pigment-dispersed color filter material in which a pigment is dispersed in a photoresist has been widely used. ing. In the present invention, preferably, a blue color filter layer 122B that transmits a wavelength of 400 nm to 550 nm, a green color filter layer 122G that transmits a wavelength of 500 nm to 600 nm, and a red color filter layer 122R that transmits a wavelength of 600 nm or more are used. be able to.

  In the present invention, the color conversion layer 124 is a layer for performing wavelength distribution conversion of light emitted from the organic EL layer 240 of the organic EL element 2 and converting the light into light including a component in a desired wavelength range. . The red conversion layer 124R includes a red conversion dye for absorbing light in the near ultraviolet region or visible region, particularly blue or blue region, and converting it into light in the red region. The green conversion layer 124G includes a green conversion dye for absorbing light in the near ultraviolet region or visible region, in particular, blue or blue region and converting it into light in the green region. Further, the blue conversion layer 124B includes a blue conversion dye for absorbing light in the near ultraviolet region and converting it into light in the blue region. These color conversion layers 124 may contain a plurality of types of conversion dyes. For example, the red conversion layer 124R includes a conversion dye that converts light in the blue region into light in the green region and a dye that converts light in the green region into light in the red region, thereby improving overall color conversion efficiency. May be.

  Examples of red conversion dyes that absorb light in the blue to blue-green region and emit light in the red region include rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine 101, rhodamine 110, sulforhodamine, basic violet 11, and basic red 2. Pyridine dyes such as rhodamine dyes, cyanine dyes, 1-ethyl-2- [4- (p-dimethylaminophenyl) -13-butadienyl] -pyridium-perchlorate (pyridine 1), or oxazine dyes Etc.

  Examples of green conversion dyes that absorb light in the blue or blue-green region and emit light in the green region include 3- (2′-benzothiazolyl) -7-diethylaminocoumarin (coumarin 6) and 3- (2′-benzimidazolyl). ) -7-N, N-diethylaminocoumarin (coumarin 7), 3- (2′-N-methylbenzimidazolyl) -7-N, N-diethylaminocoumarin (coumarin 30), 2,3,5,6-1H, Coumarin dyes such as 4H-tetrahydro-8-trifluoromethylquinolidine (9,9a, 1-gh) coumarin (coumarin 153), or basic yellow 51 which is a coumarin dye dye, and solvent yellow 11 and solvent yellow. And naphthalimide dyes such as 116.

  The color modulation unit 120 (each of the color filter 122 and the color conversion layer 124) applies the material of each layer using a spin coat method, a roll coat method, a cast method, a dip coat method, etc., and then a photolithography method. It can form by patterning using etc.

  In the present invention, when the organic EL layer 240 emits blue to blue-green light and contains a sufficient amount of components in the blue region, the blue conversion layer 124B may not be used. In that case, blue light with improved color purity can be emitted through the blue filter layer 122B.

  A black matrix 130 is provided in a portion of the display area of the transparent substrate 110 where the color modulation unit 120 is not formed. That is, the black matrix 130 is provided in the area between the sub-pixels and around each pixel. The black matrix 130 is formed of a black material, and is an effective layer for limiting external light incidence into the display device, improving the contrast ratio, and preventing visual recognition of the joint portion of the organic EL element 2. is there. The black matrix 130 can be formed using a material commonly used for flat panel displays such as a liquid crystal display. The black matrix 130 can be formed by applying the material of each layer using a spin coat method, a roll coat method, a cast method, a dip coat method, etc., and then patterning using a photolithographic method or the like. Alternatively, the black matrix 130 may be formed using a screen printing method.

If necessary, the protective layer 140 may be formed so as to cover the color modulation unit 120 and the black matrix 130. The protective layer 140 is a layer for flattening the unevenness formed by the color modulation unit 120 and the black matrix 130 and isolating the color modulation unit 120 from the surrounding environment and the organic EL element 2. The organic material that can be used to form the protective layer 140 is, for example, an imide-modified silicone resin (see, for example, Patent Documents 3 to 5), an acrylic, polyimide, or an inorganic metal compound (TiO ₂ , dispersed in a silicone resin). Al ₂ O ₃ , SiO _2, etc., see Patent Documents 6 and 7), epoxy-modified acrylate resins, UV curable resins such as acrylate monomers / oligomers / polymers containing reactive vinyl groups (see Patent Document 8), resist resins (See Patent Documents 9 to 12), inorganic compounds (which may be formed by a sol-gel method, see Patent Document 13), photo-curing and / or thermosetting resins such as fluorine-based resins (Patent Documents 12 and 14) Reference). When forming the protective layer 140 from the above materials, for example, a dry method (sputtering method, vapor deposition method, CVD method, etc.) and a wet method (spin coating method, roll coating method, casting method, dip coating method). Any method known in the art may be used.

Further, a passivation layer may be formed on the protective layer 140 as necessary. The passivation layer is a material that exhibits high transparency in the visible range (transmittance of 50% or more in the range of 400 to 700 nm), Tg of 100 ° C. or more, and surface hardness of 2H or more of pencil hardness, and blocks gas and water vapor. The material can be selected. Preferred materials for forming the passivation layer _{comprises SiO x, SiN x, SiN x} O y, AlO x, TiO x, TaO x, an inorganic oxide or an inorganic nitride such as ZnO _x. The passivation layer may be a single layer of the above-described inorganic oxide or inorganic nitride, or may have a laminated structure in which a plurality of them are laminated. For the formation of the passivation layer, a dry method (sputtering method, vapor deposition method, CVD method, etc.) and a wet method (spin coating method, roll coating method, casting method, dip coating method, sol-gel method, etc.) Any known method can be used.

  Next, the structure of the organic EL element 2 of the present invention is shown in detail.

  The substrate 210 may be transparent or opaque, should be able to withstand the conditions (solvent, temperature, etc.) used to form the layer to be laminated, and has excellent dimensional stability. Is preferred. Preferred materials include metals, ceramics, glass, semiconductors such as silicon, and resins such as polyethylene terephthalate and polymethyl methacrylate. Alternatively, a flexible film formed from polyolefin, acrylic resin, polyester resin, polyimide resin, or the like may be used as the substrate. In the case of adopting a bottom emission method in which light emitted from the organic light emitting layer is extracted from the substrate 210 side, the substrate 10 preferably has a transmittance of 50% or more with respect to light having a wavelength of 400 to 800 nm. As the transparent substrate 10, it is preferable to use glass, silicon, and resins such as polyethylene terephthalate and polymethyl methacrylate, and it is more preferable to use borosilicate glass or blue plate glass.

  The plurality of switching elements 220 are connected to each of the plurality of first electrodes 230 on a one-to-one basis, and are elements for controlling lighting / extinguishing of the sub-pixels. The switching element can be formed using an element such as a thin film transistor (TFT) or MIM, for example.

  The first electrode 230 is composed of a plurality of portions, and is an electrode for injecting carriers (either holes or electrons) into the organic EL layer 240.

In the case of employing a top emission method in which light emitted from the organic EL layer 240 is extracted from the second electrode 250 side, the first electrode 250 preferably has reflectivity. The reflective first electrode 250 can be formed by stacking a highly reflective metal, amorphous alloy, or microcrystalline alloy and a conductive metal oxide. The conductive metal oxide includes SnO ₂ , In ₂ O ₃ , ITO, IZO, ZnO: Al, and the like, and is a layer that is desirably provided in order to improve hole injection efficiency. High reflectivity metals include Al, Ag, Mo, W, Ni, Cr, and the like. High reflectivity amorphous alloys include NiP, NiB, CrP, CrB, and the like. The highly reflective microcrystalline alloy includes NiAl and the like. The highly reflective metal, amorphous alloy or microcrystalline alloy can be formed by any method known in the art such as vapor deposition or sputtering. Even when the top emission method is employed, the first electrode 250 can be used as a cathode. In this case, the first electrode 250 is formed from the above-described highly reflective metal, amorphous alloy, or microcrystalline alloy. Alternatively, the first electrode 250 may be formed using an alloy (for example, Mg / Ag alloy) of a metal having a high reflectance and a metal having a low work function. When the first electrode 250 is used as a cathode, it is desirable to provide an electron injecting buffer layer at the interface with the organic EL layer 240 of the cathode to improve the electron injection efficiency.

  As the material of the buffer layer, alkali metals such as Li, Na, K, or Cs, alkaline earth metals such as Ba and Sr, alloys containing them, rare earth metals, or fluorides of these metals can be used. However, it is not limited to them. The film thickness of the buffer layer can be appropriately selected in consideration of the driving voltage, transparency, and the like, but in a normal case, it is preferably 10 nm or less.

When the bottom emission method is employed, the first electrode 230 is formed of a conductive metal oxide such as SnO ₂ , In ₂ O ₃ , ITO, IZO, ZnO: Al. The first electrode 230 can be formed by stacking a conductive metal oxide by a sputtering method. When the bottom emission method is employed, the first electrode 230 preferably has a transmittance of 50% or more, more preferably 85% or more with respect to light having a wavelength of 400 to 800 nm. The first electrode 230 is desirably 50 nm or more, preferably 50 nm to 1 μm, more preferably 100 to 300 nm. It is also possible to use the first electrode 230 as a cathode in the bottom emission method. In this case, it is desirable to improve the electron injection efficiency by providing the aforementioned buffer layer at the interface with the organic EL layer 240 of the cathode.

  The second electrode 250 is a common electrode that is integrally formed, and is an electrode for injecting carriers (either holes or electrons) into the organic EL layer 240.

When the top emission method is employed, the second electrode 250 is required to be transparent with respect to light emitted from the organic EL layer 240. In this case, the second electrode 250 preferably has a transmittance of 50% or more, more preferably 85% or more with respect to light having a wavelength of 400 to 800 nm. The second electrode 250 is made of a conductive metal oxide such as SnO ₂ , In ₂ O ₃ , ITO, IZO, ZnO: Al. When the second electrode 250 is used as a cathode, it is desirable to improve the electron injection efficiency by providing the aforementioned buffer layer at the interface with the organic EL layer 240 of the cathode.

  When the bottom emission method is employed, the second electrode 250 is a reflective electrode. In this case, the second electrode 250 is formed of the above-described highly reflective metal, amorphous alloy, or microcrystalline alloy. Alternatively, when the second electrode 250 is a cathode, the second electrode 250 may be formed using an alloy (for example, Mg / Ag alloy) of a metal having a high reflectance and a metal having a low work function. When the second electrode 250 is used as a cathode, it is desirable to improve the electron injection efficiency by providing the aforementioned buffer layer at the interface with the organic EL layer of the cathode. Further, when the bottom emission method is adopted, the second electrode 250 can be used as an anode. In this case, a laminated structure of the above-described conductive metal oxide and a reflective metal is desirable. The conductive metal oxide is disposed on the organic EL layer side and used to improve the hole injection efficiency.

The organic EL layer 240 sandwiched between the first electrode 230 and the second electrode 250 includes at least an organic light emitting layer, and includes a hole transport layer, a hole injection layer, an electron transport layer and / or an electron injection layer as necessary. Including. Each of these layers is formed to have a film thickness sufficient to realize desired characteristics in each layer. For example, what consists of the following layer structures is employ | adopted.
(1) Organic light emitting layer (2) Hole injection layer / organic light emitting layer (3) Organic light emitting layer / electron injection layer (4) Hole injection layer / organic light emitting layer / electron injection layer (5) Hole transport layer / Organic light emitting layer / electron injection layer (6) Hole injection layer / hole transport layer / organic light emitting layer / electron injection layer (7) Hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection Layer (In the above configuration, the electrode functioning as the anode is connected to the left side, and the electrode functioning as the cathode is connected to the right side)

  The material of the organic light emitting layer can be selected according to the desired color tone. For example, in order to obtain light emission from blue to blue-green, fluorescent whitening such as benzothiazole, benzimidazole, and benzoxazole It is possible to use one or more materials such as agents, styrylbenzene compounds, or aromatic dimethylidene compounds. Alternatively, the organic light emitting layer may be formed by using the above-mentioned material as a host material and adding a dopant thereto. As a material that can be used as a dopant, for example, perylene (blue), which is known to be used as a laser dye, can be used.

Materials for the electron transport layer include oxadiazole derivatives such as PBD and TPOB; triazole derivatives such as TAZ; triazine derivatives; phenylquinoxalines; thiophene derivatives such as BMB-2T and BMB-3T; aluminum tris (8 An aluminum complex such as (quinolinolato) (Alq ₃ ) can be used.

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

  As a material for the hole injection layer, phthalocyanine (Pc) (including copper phthalocyanine (CuPc)) or indanthrene compounds can be used.

  As a material for the hole transport layer, a material having a triarylamine partial structure, a carbazole partial structure, or an oxadiazole partial structure (for example, TPD, α-NPD, PBD, m-MTDATA, etc.) can be used.

  Each layer constituting the organic EL layer 240 can be formed using any means known in the art such as vapor deposition (resistance heating or electron beam heating).

  In the above description, the active matrix driving type organic EL element using the switching element 220 has been described. However, in the present invention, a passive matrix driving type organic EL element can also be used. In the passive matrix driving type organic EL element, a first electrode 230 including a plurality of stripe-shaped portions extending in a first direction is formed on a substrate 210, an organic EL layer 240 is formed thereon, and a second electrode is formed. It can be obtained by forming the second electrode 250 composed of a plurality of stripe-shaped portions extending in the direction. Here, the first direction and the second direction are directions that intersect each other, and preferably are orthogonal directions. As the materials for forming the substrate 210, the first electrode 230, the organic EL layer 240, and the second electrode 250, the materials described above can be used.

If necessary, an EL element passivation layer may be provided so as to cover the structure below the second electrode 250. The EL element passivation layer is effective in preventing functional deterioration of the organic EL layer by blocking gas and water vapor, and is SiO _x , SiN _x , SiN _x O _y , AlO _x , TiO _x , TaO _x , ZnO. It can be formed using an inorganic oxide material such as _x or an inorganic nitride material. The EL element passivation layer may be a single layer of the above-described inorganic oxide or inorganic nitride, or may have a laminated structure in which a plurality of them are laminated. For the formation of the EL element passivation layer, the dry method (sputtering method, vapor deposition method, CVD method, etc.) and the wet method (spin coating method, roll coating method, casting method, dip coating method, sol-gel method, etc.) Any method known in the art can be used.

Example 1
A 40-inch SVGA standard display (800 × 600 pixels, each pixel is composed of RGB sub-pixels) was produced. In this example, four organic EL light emitting elements (20 inches) having a 1200 × 300 light emitting portion corresponding to 400 × 300 pixels were used. The size of each RGB subpixel was 0.148 × 0.704 mm, and the interval between subpixels was 0.130 mm. Therefore, the pixel size was 0.704 mm × 0.704 mm, the pixel interval was 0.312 mm, and the pixel pitch was 1.016 mm.

  First, a 20-inch organic EL element (equivalent to 400 × 300 pixels) was formed.

First, Mo having a resistivity of 1.5 × 10 ⁻⁵ [Ω · cm] was deposited on a Corning glass substrate as an auxiliary electrode portion of the first electrode with a film thickness of 300 nm and a width of 100 μm. A DC magnetron sputtering method was used for depositing Mo, and after applying a resist agent “OFRP-800” (trade name, manufactured by Tokyo Ohka Kogyo Co.) on Mo, patterning was performed by a photolithography method.

  Next, ITO was formed on the entire surface by sputtering. Then, after applying a resist agent “OFRP-800” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) on ITO, patterning is performed by a photolithography method, and the width is 0.204 mm, the gap is 0.074 mm, located in the RGB sub-pixel, A first electrode having a stripe pattern extending in the vertical direction with a thickness of 100 nm was formed. In this example, the first electrode was used as the anode.

  Next, using a positive photoresist [WIX-2A] (trade name, manufactured by Nippon Zeon Co., Ltd.), an insulating film having a thickness of 1 μm was formed on the entire surface of the substrate except for the opening corresponding to the subpixel. The angle of the insulating film end with respect to the substrate surface is an acute angle.

  In this embodiment, a positive photoresist is used as the insulating film. However, a negative photoresist such as acrylate, or an inorganic oxide film such as a polyimide material, SiOx, SiOxNy, SiNx, or TiOx can be used.

  The film thickness of the insulating film needs to have a withstand voltage calculated from the voltage applied when driving the panel. The positive photoresist used in this example could have a sufficient withstand voltage when formed with a film thickness of about 800 nm or more.

  Next, using a negative photoresist [ZPN1100] (trade name, manufactured by ZEON CORPORATION), the stripe pattern is arranged in the center between adjacent pixels and extends in the horizontal direction (direction orthogonal to the stripe pattern of the first electrode). A partition wall having a thickness of 4 μm was formed. The width of the partition wall is equal to or less than the interval of the pixel gap, preferably (interval of the pixel gap) −50 μm or less, and may be 100 μm or more. In this embodiment, the partition has a reverse taper cross-sectional shape, the top width of the partition is 230 μm, the bottom width is 130 μm, and the pitch at the bottom is 1.016 mm.

Next, the substrate on which the partition walls were formed was mounted in a resistance heating vapor deposition apparatus, and a hole injection layer, a hole transport layer, an organic light emitting layer, and an electron injection layer were sequentially formed without breaking the vacuum. During film formation, the internal pressure of the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. As the hole injection layer, copper phthalocyanine (CuPc) having a thickness of 100 nm was stacked. As the hole transport layer, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) having a thickness of 20 nm was laminated. 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi) as the host material and 4,4′-bis [2- {4- (N, N-diphenylamino) phenyl} vinyl] as the guest material An organic light emitting layer having a film thickness of 30 nm was stacked using biphenyl (DPAVBi). As an electron injection layer, aluminum tris (8-quinolinolato) (Alq ₃ ) having a thickness of 20 nm was stacked.

  Subsequently, using a metal mask without breaking the vacuum, Mg / Ag having a thickness of 200 nm (10: 1 weight ratio) was deposited to form a second electrode used as a cathode. The second electrode was formed by a stripe pattern extending in the lateral direction having a width of 0.786 mm and a gap of 0.230 mm.

  Finally, including the display part, it cut out from the board | substrate to 20 inch size (406.4 mm x 304.8 mm), and obtained four organic EL elements.

  Next, a 40-inch integrated color conversion filter was produced.

  On a coning glass (845 mm × 645 mm × 1.1 mm) as a transparent substrate, a resist resin containing a black pigment is applied using a spin coating method, patterning is performed by a photolithographic method, and a color modulation unit (subpixel) A black matrix having a film thickness of 2 μm was formed, leaving an opening for forming ().

  Next, after applying a blue filter material (Fuji Hunt Electronics Technology: Color Mosaic CB-7001) by spin coating, patterning is performed by photolithography, width 0.148 mm, pitch 1.016 mm, film thickness 6 μm. A blue filter layer having a stripe pattern extending in the vertical direction was formed to obtain a blue modulator.

  Next, coumarin 6 (0.7 parts by weight) as a fluorescent dye was dissolved in 120 parts by weight of a solvent, propylene glycol monoethyl acetate (PGMEA). To this solution, 100 parts by weight of photopolymerizable resin [V259PA / P5] (Nippon Steel Chemical Co., Ltd.) was added and dissolved to obtain a coating solution. This coating solution is applied onto a transparent substrate on which a blue filter layer is formed by using a spin coating method, and patterned by a photolithographic method. The longitudinal direction has a width of 0.148 mm, a pitch of 1.016 mm, and a film thickness of 10 μm. A green color conversion layer having a stripe pattern extending in a green color was formed to obtain a green color modulation part.

  Then, coumarin 6 (0.6 parts by weight), rhodamine 6G (0.3 parts by weight), and basic violet 11 (0.3 parts by weight) as fluorescent dyes were mixed with 120 parts by weight of propylene glycol monoethyl acetate (PGMEA) as a solvent. Was dissolved. To this solution, 100 parts by weight of a photopolymerizable resin “V259PA / P5” (trade name, Nippon Steel Chemical Co., Ltd.) was added and dissolved to obtain a coating solution. This coating solution is applied onto the transparent substrate on which each of the above layers is formed by using a spin coating method, and patterned by a photolithographic method, so that a vertical width of 0.148 mm, a pitch of 1.016 mm, and a thickness of 10 μm is achieved. A red conversion layer having a stripe pattern extending in the direction was formed to obtain a red modulation portion.

  As described above, a UV curable resin (epoxy-modified acrylate) is applied by spin coating on the transparent substrate on which the color modulation portions for each color of RGB are formed, and a protective layer having a thickness of 5 μm is applied by irradiation with a high-pressure mercury lamp. As a result, a 40-inch color conversion filter was obtained. At this time, the pattern of each color modulation part was not deformed, and the upper surface of the protective layer was flat.

  Next, four 20-inch organic EL elements are bonded to the 40-inch color conversion filter obtained above. First, the glass substrate bonding surface (surface corresponding to the bonding portions 270 and 280) of the 20-inch size organic EL element was smoothly polished with a high-precision abrasive so as to enable high-precision bonding. As the high-precision abrasive, cerium oxide to which cerium oxide or zirconium oxide is added can be used. Next, a support having a flat surface is prepared, a glass substrate of an organic EL element is placed thereon, alignment is performed, and AVR200 (manufactured by ThreeBond Co., Ltd., refractive index 1.56) is used as an ultraviolet curable resin. The bonded surfaces of four 20-inch organic EL elements were bonded. Next, after uniformly applying a low viscosity acrylic adhesive to a 40 inch size color conversion filter, while confirming the alignment position, a bonded body composed of four 20 inch size EL elements obtained above was placed, The resin was cured by irradiation with ultraviolet rays.

  Finally, the organic EL light emitting element side of the color conversion filter / organic EL light emitting element laminate obtained by the above combination (that is, the laminate side of both electrodes and the organic EL layer) is placed in a dry nitrogen atmosphere (oxygen) in the glove box. And a water concentration of 10 ppm or less) were sealed with a sealing can (glass or metal can be used).

The obtained 40-inch display emitted light with a luminance of 100 to 300 cd / m ² by applying a driving voltage of 16 to 30V.

(Example 2)
Example 1 except for forming a joined body composed of four 20-inch size organic EL elements by sandwiching a polyester film-like resin between the glass substrate bonding surfaces of the organic EL elements and bonding them with an adhesive. A 40-inch display using four 20-inch organic EL elements and a 40-inch color conversion filter was formed using the same procedure as described above. By making the thickness of the polyester film-like resin used 25 μm or less, irregular reflection on the organic EL element joint end face due to poor filling of the adhesive is prevented, and the joint end face of the organic EL element is visually recognized. Has the effect of preventing.

It is a perspective view which shows the display apparatus of this invention. It is a perspective view which shows the display apparatus using the small organic EL panel of a prior art. It is sectional drawing which shows the structure of the small organic EL panel of a prior art. It is sectional drawing which shows the structure of the display apparatus of this invention. It is a top view which shows the junction part of the organic EL element in the display apparatus of this invention. It is a top view which shows the junction part of the organic EL element in another aspect of this invention. It is a top view which shows the junction part of the organic EL element in another aspect of this invention. It is a top view which shows the junction part of the organic EL element in another aspect of this invention. It is sectional drawing which shows the junction part of the organic EL element in another aspect of this invention.

Explanation of symbols

1 Color conversion filter 2 (ad) Organic EL light emitting element 5 Small organic EL panel 6 TFT
52, 210 Substrate 54, 220 Switching element 56, 230 First electrode 58 (R, G, B) Organic EL layer 60 Separation wall 62, 250 Second electrode 64 Protective layer 66 Transparent seal 110 Transparent substrate 120 (R, G, B) B) Color modulation part (sub-pixel)
122 (R, G, B) Color filter layer 124 (R, G, B) Color conversion layer 130 Black matrix 140 Protective layer 170 (R, G, B) Small subpixel 240 Organic EL layer 270 Horizontal junction 280 Vertical Directional joint 290 Light emitting part 300 Antireflection material 500 Bonding region

Claims (4)

A pixel formed from a plurality of types of subpixels, a color conversion filter in which a black matrix provided between and around the plurality of types of subpixels is aligned, and a plurality of organic EL elements, The plurality of types of sub-pixels are formed from a plurality of types of color modulation units, each of the plurality of organic EL elements has a plurality of light-emitting units corresponding to the plurality of types of sub-pixels, and the plurality of organic EL elements are pasted. Are combined to form one display element, and the bonding portion by the bonding of the organic EL element is in a position corresponding to the black matrix of the color conversion filter, and the pixel has three types of red, blue and green The green sub-pixel has a smaller size than the blue and red sub-pixels, and the black matrix is adjacent to the green sub-pixel. Machine and joint lateral EL elements are arranged, all the sub-pixels adjacent to one side of the junction of the lateral is green subpixel, all sub-pixels adjacent to the other side Is a blue or red sub-pixel .   The display device according to claim 1, wherein the color conversion filter has an integral structure.   The display device according to claim 1, wherein each of the plurality of types of sub-pixels has a size smaller than each of the plurality of light emitting units.   The display device according to claim 1, wherein an antireflection material is provided on a lateral end surface of the organic EL element.

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