JP4986904B2 - Light emitting device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a light emitting device and a method for manufacturing the same.

In recent years, light-emitting devices in which an organic or inorganic electroluminescence (EL) layer is provided between a pair of electrodes have been proposed. In a device using liquid crystal as a display element, a backlight is necessary. However, since a light emitting device using an organic EL layer or an inorganic EL layer is a self-luminous type, for example, the emission color is R (red), G (green) , B (blue) can be patterned to form a thin display device.
However, in a light-emitting device using an EL layer, the refractive index of the EL layer is generally high, and light is reflected by a substrate provided on the side where light emitted from the EL layer is extracted to the outside. There is a problem that it is difficult to take out light to the outside.

In order to improve light extraction efficiency, for example, a light-emitting device in which a large number of through holes are provided in a substrate on which light is extracted and a columnar optical waveguide is provided in the substrate by filling the through holes with a medium having a high refractive index is disclosed. (See Patent Document 1).
In addition, as a so-called top emission type light emitting device that extracts light from the sealing substrate side, a display device in which a large number of hemispherical beads for scattering light from the EL layer is provided on the upper electrode is disclosed. (See Patent Document 2).

JP 2006-278115 A JP 2007-128879 A

In the apparatus disclosed in Patent Document 1, a large number of through holes are provided in a substrate, and these holes are filled with a high refractive index medium to form an optical waveguide. Therefore, the manufacturing is complicated and the manufacturing cost may increase significantly. There is. In addition, even when a sealing substrate provided with an optical waveguide is used, the distance between the optical waveguide and the light emitting element is increased, and light is guided or reflected between the light emitting element and the optical waveguide. There is a risk of loss of extraction and interference (crosstalk) between adjacent pixels.
On the other hand, in the device disclosed in Patent Document 2, the distance between the light scattering surface (bead) and the light extraction surface (sealing substrate) tends to be large, and there is a risk of interference between adjacent pixels.

  An object of the present invention is to provide a light emitting device that efficiently extracts light emitted from an EL layer to the outside and suppresses interference between adjacent pixels, and a manufacturing method thereof.

In order to achieve the above object, the present invention provides the following light emitting device and manufacturing method thereof.
<1> On a support substrate, a lower electrode, an electroluminescence layer including at least a light emitting layer, an upper electrode, and a sealing substrate are sequentially provided, and light emitted from the electroluminescence layer is extracted from the upper electrode side. A light emitting device,
With an inert fluid is filled in a space between the supporting substrate and the sealing substrate, and extending in a columnar shape toward the sealing substrate on the upper electrode, the aspect ratio of the columnar portion (height A light emitting device characterized in that an optical waveguide member of alkali metal halide formed by vacuum film formation is disposed.
< 2 > The light emitting device according to <1> , wherein a distance between a bottom surface of the optical waveguide member and the light emitting layer is 10 μm or less.
< 3 > The light emitting device according to <1> or < 2 > , wherein a distance between a tip of the columnar portion of the optical waveguide member and the sealing substrate is 100 μm or less.
< 4 > The light emitting device according to any one of <1> to < 3 >, wherein a width of the columnar portion of the optical waveguide member is 1 μm to 100 μm.

< 5 > The light emitting device according to any one of <1> to < 4 >, wherein a refractive index of the columnar portion of the optical waveguide member is in a range of 1.5 to 2.5.
< 6 > The columnar portions of the optical waveguide member are arranged on the upper electrode so as to be separated from each other, and the inert fluid is interposed between adjacent columnar portions. The light emitting device according to any one of < 5 >.
< 7 > The columnar portion of the optical waveguide member is provided in a region occupying 30% or more of a light emitting region formed by overlapping the lower electrode, the electroluminescence layer, and the upper electrode. <1> to the light emitting device according to any one of < 6 >.
< 8 > The light emitting device according to any one of <1> to < 7 >, wherein a tip of the columnar portion of the optical waveguide member is convex.
< 9 > The light emitting device according to any one of <1> to < 8 >, wherein a buffer layer is provided between the upper electrode and the optical waveguide member.
< 10 > The light-emitting device according to any one of <1> to < 9 >, wherein an adhesive layer is provided between a tip of a columnar portion of the optical waveguide member and the sealing substrate.

< 11 > forming a lower electrode on the support substrate;
Forming an electroluminescence layer on the lower electrode;
Forming an upper electrode on the electroluminescent layer;
And extending columnar on the upper electrode, the aspect ratio of the columnar portion (height / width) is greater than 2, and forming an optical waveguide member formed of an alkali metal halide by vacuum deposition,
Providing a sealing substrate on the optical waveguide member for sealing, and filling a space between the sealing substrate and the support substrate with an inert fluid;
A method for manufacturing a light-emitting device, comprising:
< 12 > The method for manufacturing a light-emitting device according to < 11 >, wherein the lower electrode, the electroluminescence layer, and the upper electrode are formed by vapor deposition.

  Provided are a light emitting device and a manufacturing method thereof in which light emission from an EL layer is efficiently extracted to the outside and interference between adjacent pixels is suppressed.

  Hereinafter, a light emitting device and a method for manufacturing the same according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 schematically shows an example of the configuration of a light emitting device according to the present invention. The light-emitting device 10 includes a lower electrode 14, an electroluminescence (EL) layer 16 including at least a light-emitting layer, and an upper electrode 18 in this order on a support substrate 12, and emits light emitted from the EL layer 16 to the upper electrode. This is a top emission type light emitting device 10 taken out from the 18th side. Further, in this apparatus 10, the space between the sealing substrate 26 and the support substrate 12 is filled with an inert fluid 28, and the light that extends in a column shape on the upper electrode 18 toward the sealing substrate 26. A waveguide member 22 is arranged.

In the light emitting device 10 having such a configuration, since the optical waveguide member 22 is provided on the upper electrode 18, the distance between the optical waveguide member 22 and the EL layer 16 is short, and light emission from the EL layer 16 is emitted from the optical waveguide member. It is easy to be taken into 22. The light from the EL layer 16 taken into the optical waveguide member 22 propagates through the columnar bodies 22a each functioning as an optical waveguide to the vicinity of the sealing substrate 26 serving as a light extraction surface. Therefore, the light emitted from the EL layer 16 is efficiently extracted outside, and interference between adjacent pixels is suppressed.
Hereinafter, each constituent member and manufacturing method of the light-emitting device 10 will be described using an organic EL element as an example.

<Support substrate>
The support substrate 12 is not particularly limited as long as it has a strength capable of supporting the organic electroluminescence element 20 and the optical waveguide member 22 formed thereon, and a known substrate can be used. For example, zirconia-stabilized yttrium oxide (YSZ), inorganic materials such as glass, polyesters such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin And organic materials such as poly (chlorotrifluoroethylene).

  When glass is used as the support substrate 12, it is preferable to use alkali-free glass in order to reduce ions eluted from the glass. When soda lime glass is used, it is preferable to use a glass with a barrier coat such as silica.

When the support substrate 12 made of an organic material is used, it is preferable that the substrate is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability. In particular, when a plastic support substrate 12 is used, it is preferable to provide a moisture permeation preventive layer or a gas barrier layer on one or both surfaces of the support substrate 12 in order to suppress moisture and oxygen permeation. As a material for the moisture permeation preventive layer or the gas barrier layer, inorganic materials such as silicon nitride, silicon oxide, silicon oxynitride, and aluminum oxide, and laminates of these inorganic materials and organic materials such as acrylic resins can be preferably used. The moisture permeation preventing layer or the gas barrier layer can be formed by, for example, a high frequency sputtering method.
Moreover, when using a thermoplastic support substrate, you may provide a hard-coat layer, an undercoat layer, etc. further as needed.

  There is no restriction | limiting in particular about the shape of the support substrate 12, a structure, a magnitude | size, etc., It can select suitably according to the use of the organic EL element 20, a purpose, etc. In general, the shape of the support substrate 12 is preferably a plate shape from the viewpoints of handleability, ease of formation of the organic EL element 20, and the like. The structure of the support substrate 12 may be a single layer structure or a laminated structure. Moreover, the support substrate 12 may be comprised with the single member, and may be comprised with two or more members.

  Since the light emitting device 10 according to the present invention is a top emission type and does not need to take out light emission from the support substrate 12 side, for example, a metal substrate such as stainless steel, Fe, Al, Ni, Co, Cu, and alloys thereof. Alternatively, a silicon substrate may be used. If it is a metal support substrate, even if it is thin, it has high strength and high gas barrier properties against moisture and oxygen in the atmosphere. When a metal support substrate is used, an insulating film for ensuring electrical insulation may be provided between the support substrate 12 and the lower electrode 14.

<Organic EL device>
The organic EL element 20 has a configuration in which an organic EL layer 16 including at least a light emitting layer is disposed between upper and lower electrodes 18 and 14. One of the upper and lower electrodes 18 and 14 is an anode and the other is a cathode. Since the light emitting device 10 according to the present invention extracts light emitted from the EL layer 16 from the upper electrode 18 side, at least the upper electrode 18 It is formed so as to have optical transparency. For example, although the following layer configurations can be adopted, the present invention is not limited to the following layer configurations, and may be appropriately determined according to the purpose and the like.

Anode / light-emitting layer / cathode Anode / hole transport layer / light-emitting layer / electron transport layer / cathode Anode / hole transport layer / light-emitting layer / block layer / electron transport layer / cathode Anode / hole transport layer / Light emitting layer / block layer / electron transport layer / electron injection layer / cathode ・ Anode / hole injection layer / hole transport layer / light emission layer / block layer / electron transport layer / cathode ・ Anode / hole injection layer / hole transport Layer / light-emitting layer / block layer / electron transport layer / electron injection layer / cathode • anode / hole transport layer / block layer / light-emitting layer / electron transport layer / cathode • anode / hole transport layer / block layer / light-emitting layer / Electron transport layer / electron injection layer / cathode ・ Anode / hole injection layer / hole transport layer / block layer / light emitting layer / electron transport layer / cathode ・ Anode / hole injection layer / hole transport layer / block layer / light emission Layer / electron transport layer / electron injection layer / cathode

-Anode-
As long as the anode has a function as an electrode for supplying holes to the organic EL layer 16, the shape, structure, size and the like are not particularly limited, and the anode depends on the use and purpose of the organic EL element 20. Thus, it can be appropriately selected from known electrode materials.
As a material which comprises an anode, a metal, an alloy, a metal oxide, an electroconductive compound, or a mixture thereof is mentioned suitably, for example. As specific examples, conductive metal oxides such as tin oxide (ATO, FTO) doped with antimony or fluorine, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), gold Metals such as silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, and organic conductivity such as polyaniline, polythiophene and polypyrrole Examples thereof include materials and laminates of these and ITO.
In the light emitting device 10 of the present invention, in order to extract light emitted from the EL layer 16 from the upper electrode 18 side, when the upper electrode 18 is used as an anode, it is preferable that the light emitting device 10 is made of a material having high light transmittance. Among the above materials, a conductive metal oxide is preferable, and ITO is particularly preferable in terms of productivity, high conductivity, transparency, and the like.

Examples of the method for forming the anode include a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as CVD and plasma CVD method. In view of suitability with the material constituting the anode, the material may be selected as appropriate. For example, when ITO is used as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.
The position where the anode is formed can be appropriately selected according to the use and purpose of the organic EL element 20. When the lower electrode 14 is used, the position is formed on the support substrate 12. When the upper electrode 18 is used, the organic EL layer is used. 16 may be formed entirely or partially.

  The patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like. Further, the mask may be overlapped, and vacuum deposition, sputtering, or the like may be performed, or may be performed by a lift-off method or a printing method.

The thickness of the anode may be appropriately selected according to the material constituting the anode, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.
Further, the resistance value of the anode is preferably 10 ³ Ω / □ or less and more preferably 10 ² Ω / □ or less in order to reliably supply holes to the organic EL layer 16.

  The light transmittance of the upper electrode 18 is preferably 60% or more, and more preferably 70% or more. The transparent anode is described in detail in Yutaka Sawada's “New Development of Transparent Electrode Film” published by CMC (1999), and the matters described here can be applied to the present invention. For example, when using a plastic support substrate with low heat resistance, a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

-Cathode-
The cathode usually has a function as an electrode for injecting electrons into the organic EL layer 16, and there is no particular limitation on the shape, structure, size, etc., and it is known depending on the use, purpose, etc. of the organic EL element 20. The electrode material can be selected as appropriate. Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloy, lithium-aluminum alloy, magnesium- Examples thereof include silver alloys, rare earth metals such as indium and ytterbium. These may be used singly or in combination of two or more from the viewpoint of achieving both stability and electron injection.

  Among these, the material constituting the cathode is preferably an alkali metal or an alkaline earth metal from the viewpoint of electron injection, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability. The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01 to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc.) Say. The cathode material is described in detail in, for example, Japanese Patent Laid-Open Nos. 2-15595 and 5-121172, and the materials described in these publications can also be applied to the present invention.

  There is no restriction | limiting in particular about the formation method of a cathode, It can form according to a well-known method. For example, materials constituting the cathode from wet methods such as printing methods and coating methods, physical methods such as vacuum deposition methods, sputtering methods and ion plating methods, chemical methods such as CVD methods and plasma CVD methods, etc. The film can be formed according to a method appropriately selected in consideration of suitability for the above. For example, when a metal or the like is selected as the cathode material, the cathode can be formed according to a sputtering method or the like, one or more of them simultaneously or sequentially.

  What is necessary is just to select the thickness of a cathode suitably according to the material which comprises a cathode, and the taking-out direction of light, and it is about 1 nm-about 5 micrometers normally.

The patterning for forming the cathode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like. Further, it may be performed by vacuum deposition, sputtering or the like with overlapping masks, or by a lift-off method or a printing method.
The formation position of the cathode is not particularly limited, and may be formed entirely on the support substrate 12 when the lower electrode 14 is used, or on the organic EL layer 16 when the upper electrode 18 is used. It may be formed.

  A dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be formed between the cathode and the organic EL layer 16 in a thickness of 0.1 to 5 nm. This dielectric layer can also be understood as a kind of electron injection layer. The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

-Organic EL layer-
The organic EL layer 16 is sandwiched between upper and lower electrodes (anode and cathode) 18 and 14 and includes at least a light emitting layer. A region where the lower electrode 14, the organic EL layer 16 and the upper electrode 18 overlap with each other emits light. Therefore, for example, full color display can be performed by patterning the light emitting layer corresponding to each color so that the R, G, B pixels are arranged vertically and horizontally on the support substrate 12.
Examples of the layers other than the light emitting layer constituting the organic EL layer 16 include layers such as a hole transport layer, an electron transport layer, a charge block layer, a hole injection layer, and an electron injection layer as described above. A preferable layer configuration includes, for example, an aspect in which a positive hole transport layer, a light emitting layer, and an electron transport layer are laminated in this order from the anode side, and further, for example, between the hole transport layer and the light emitting layer, or light emission. A charge blocking layer or the like may be provided between the layer and the electron transport layer. A hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer. Each layer may be divided into a plurality of secondary layers. Each layer constituting the organic EL layer 16 can be formed by any of a dry film forming method such as a vapor deposition method and a sputtering method, a transfer method, and a printing method.

<Optical waveguide member>
The optical waveguide member 22 is disposed on the upper electrode 18 and has a plurality of columnar portions 22 a and support portions 22 b extending from the upper electrode 18 toward the sealing substrate 26.
The shape of the optical waveguide member 22 may be any shape as long as it captures light generated in the organic EL layer 16, confines it in the columnar portion 22a, propagates it to the tip, and emits the propagated light from the tip. From the viewpoint of strength, ease of formation, light propagation, ratio with pixel size, etc., the height (h) of each columnar portion 22a is preferably in the range of 5 μm to 500 μm, more preferably in the range of 10 μm to 200 μm. The width (w) of the columnar portion 22a is preferably in the range of 1 μm to 100 μm, more preferably 5 μm to 20 μm. In order to improve light extraction efficiency and prevent interference between adjacent pixels, the aspect ratio (height / width) of the columnar portion 22a is preferably greater than 2, and more preferably greater than 10.

  The tip of the columnar portion 22a of the optical waveguide member 22 is preferably convex. For example, as shown in FIG. 1, if the tip of the columnar portion 22a is hemispherical, the light guided to the tip of the optical waveguide member 22 is not reflected and directed toward the sealing substrate 26 (light extraction surface). Easily radiated. Therefore, the light extraction efficiency can be improved more reliably.

  Further, the columnar portions 22a of the optical waveguide member 22 are arranged on the upper electrode 18 so as to be separated from each other, and an inert fluid 28 having a refractive index lower than that of the optical waveguide member 22 is interposed between the adjacent columnar portions 22a. It is preferable. The refractive index difference between the optical waveguide member 22 and the inert fluid 28 is preferably 0.2 or more, and more preferably 0.3 or more. Columnar portions 22a of the optical waveguide member 22 are spaced apart, and an inert fluid 28, for example, an inert gas such as argon or nitrogen, or paraffins, liquid paraffins, perfluoroalkane or perfluoroamine, If an inert liquid such as a perfluorinated ether such as a perfluoroether, a chlorinated solvent, or silicone oil is present, the light taken into the optical waveguide member 22 interferes with the adjacent columnar portions 22a. This can be prevented more reliably.

  In addition, the arrangement | positioning method of the columnar part 22a of the optical waveguide member 22 in a pixel is not specifically limited, For example, as shown in FIG. 2, several columnar part 22a is arrange | positioned at random in the light emission area | region (pixel area | region) 30. Alternatively, by arranging regularly as shown in FIG. 3 and FIG. 4, the density of the columnar portions 22 a in the pixels 30 may be increased to further improve the light extraction efficiency. Further, as shown in FIGS. 5A to 5C, columnar portions whose cross sections are hexagons 32a, rectangles 32b, triangles 32c, or other polygons are regularly or irregularly arranged. May be.

The optical waveguide member 22 may be formed so that the columnar portion 22 a is disposed on the upper electrode 18, but normally, in the light emitting region 30 where the lower electrode 14, the organic EL layer 16, and the upper electrode 18 overlap. On the other hand, the larger the area occupied by the columnar portion 22a of the optical waveguide member 22, the more the light extraction efficiency can be improved. Specifically, if the columnar portion 22a of the optical waveguide member 22 is formed to occupy 30% or more of the light emitting region 30, most of the light emitted from the organic EL layer 16 is taken into the optical waveguide member 22. Thus, since the light is guided to the sealing substrate 26 side through the columnar portion 22a, the light extraction efficiency can be reliably improved.
However, as described above, since the adjacent columnar portions 22a are appropriately spaced apart and the inert fluid 28 is interposed, interference can be effectively prevented, so that the columnar portions 22a of the waveguide member in the light emitting region. The area occupied by is preferably 95% or less of the light emitting region.

  The distance between the bottom surface of the optical waveguide member 22 and the light emitting layer is preferably 10 μm or less, and more preferably 1 μm or less in order to make it easy to capture light generated in the organic EL layer 16 into the optical waveguide member 22. The distance between the bottom surface of the optical waveguide member 22 and the light emitting layer may be adjusted by the organic layer other than the light emitting layer interposed between the light emitting layer and the optical waveguide member 22 and the thickness of the upper electrode 18.

  On the other hand, light emitted from the tip of the columnar portion 22a is extracted to the outside through the sealing substrate 26. However, if the distance between the tip of the columnar portion 22a and the sealing substrate 26 is too large, loss of light extraction and adjacent pixels are extracted. Interference (crosstalk) may increase. Therefore, the distance between the tip of the columnar portion 22a of the optical waveguide member 22 and the sealing substrate 26 is preferably 100 μm or less, and more preferably 50 μm or less. The distance between the tip of the columnar portion 22 a of the optical waveguide member 22 and the sealing substrate 26 is the height of the optical waveguide member 22 and the thickness of the sealing member 24 used when the sealing substrate 26 is fixed to the support substrate 12. It can be adjusted by spacer particles dispersed in the sealing member 24, the thickness of the adhesive layer disposed between the optical waveguide member 22 and the sealing substrate 26, and the like.

  The refractive index of the optical waveguide member 22 is not limited as long as the light from the organic EL layer 16 can be taken to the leading end toward the sealing substrate 26. However, the light from the organic EL layer 16 is not limited. The refractive index of the organic EL layer 16 is preferably equal to or higher than that of the organic EL layer 16 so as to be confined inside and propagate to the tip. Although depending on the material of the organic EL layer 16, the refractive index of the organic EL layer 16 is usually about 1.6. Therefore, the refractive index of the columnar portion 22a of the optical waveguide member 22 is preferably in the range of 1.5 to 2.5.

The material of the optical waveguide member 22 is not limited as long as the light from the organic EL layer 16 can be taken in and propagated to the tip, but is formed of a material having a refractive index in the above range (1.5 to 2.5). Is preferred. Preferred materials include inorganic substances such as alkali metal and alkaline earth metal halides, phosphates, borates, etc. In particular, from the viewpoint of light transmittance, refractive index, ease of formation, etc., CsI, CsBr Alkali metal halides such as RbBr are preferred.
For example, a plurality of columnar bodies made of alkali metal halides are grown on the upper electrode 18 substantially vertically in the light extraction direction so as to have a gap therebetween by electron beam evaporation. Thereby, a columnar crystal having a high light transmittance and a high refractive index can be formed on the upper electrode 18. At this time, the diameter and tip shape of the columnar body can be changed by appropriately selecting the deposition conditions such as the degree of vacuum, the deposition rate, and the substrate temperature. For example, as shown in FIGS. 8 and 9, by growing CsI crystals, columnar bodies whose tips are convex, such as conical, spheroidal, and pyramidal, can be formed densely.
If the optical waveguide member 22 is formed of an alkali metal halide, it has a hygroscopic property and thus has a function of suppressing deterioration of the organic EL layer 16.

A buffer layer may be provided between the upper electrode 18 and the optical waveguide member 22. For example, when the upper electrode 18 is formed of a metal film and the optical waveguide member 22 is formed of resin, a sufficient adhesive force may not be obtained. In addition, when the upper electrode 18 and the optical waveguide member 22 are in contact with each other, one of them may adversely affect the other and promote deterioration. Therefore, if a buffer layer made of, for example, silicon nitride or zinc sulfide is provided on the upper electrode 18 and the optical waveguide member 22 is formed through the buffer layer, adhesion can be improved and deterioration can be prevented. In addition, a buffer layer such as silicon nitride or zinc sulfide has a high refractive index and contributes to an improvement in light extraction efficiency.
The buffer layer may be formed with a thickness of about 10 nm to 500 nm, for example, by vapor deposition such as vacuum deposition, sputtering, or CVD.

  If the lower electrode 14, the organic EL layer 16, the upper electrode 18, and the optical waveguide member 22 are formed by vapor deposition, the organic EL layer 16 and the optical waveguide member 22 deteriorate due to moisture and oxygen in the atmosphere at the manufacturing stage. This can be effectively suppressed. FIG. 6 shows an example of the configuration of an organic EL element manufacturing system 50 including a plurality of chambers 51 to 63 each performing a dedicated process. If a plurality of vapor deposition chambers are provided and any one of the lower electrode 14, the organic EL layer 16, the upper electrode 18, and the optical waveguide member 22 is formed by vapor deposition, sealing from the support substrate 12 to the sealing substrate 26 is performed. The process up to can be completed in an airtight tank. If such a manufacturing system 50 is used, the light emitting device 10 can be continuously manufactured without affecting the element lifetime due to moisture, oxygen, etc., which is advantageous in terms of the manufacturing process. In addition to the vapor deposition chamber and the sealing chamber, an inspection chamber before sealing may be provided.

  The method for forming the optical waveguide member 22 is not particularly limited, and can be suitably formed by, for example, embossing (imprint). FIG. 7 shows an example of a method for forming the optical waveguide member 22 by embossing. First, a mold 36 having a concavo-convex pattern 38 corresponding to the shape of the optical waveguide member to be formed is prepared. The patterning mold 36 can be manufactured using glass, metal, silicon, resin, or the like. For example, a desired uneven pattern 38 may be formed by photolithography.

  After preparing the mold 36, a curable resin (UV curable resin, thermosetting resin, etc.) is applied on the upper electrode 18 to form an uncured resin layer 34 (FIG. 7A). Next, the pattern surface of the mold 36 is pressed against the uncured resin layer 34, and cured by applying UV irradiation or heating according to the resin layer 34 (FIG. 7B). After curing, the mold 36 is pulled away to form the optical waveguide member 34 having the columnar portion 34a reflecting the uneven pattern 38 of the mold 36 on the upper electrode 18 (FIG. 7C). In addition to the curable resin, a thermoplastic resin may be applied to form a resin layer, and then the heated pattern surface of the mold 36 may be pressed.

  Preferred materials for the optical waveguide member 22 formed by embossing include organic materials having a high refractive index such as polystyrene resins and polysilane resins, and composite materials in which high refractive index fine particles such as titanium oxide are dispersed in the resin. .

<Sealing substrate, etc.>
After the optical waveguide member 22 is formed, the organic EL element 20 and the optical waveguide member 22 are sealed in order to prevent deterioration by moisture and oxygen in the atmosphere.
As the sealing substrate 26, a substrate having optical transparency and a high barrier property against oxygen and moisture is used. Preferably, a resin film provided with a glass substrate or a barrier layer can be used. The thickness of the sealing substrate 26 is preferably 0.05 to 2 mm from the viewpoints of light transmittance, strength, weight reduction, and the like.

As the resin film-made sealing substrate 26, the same material as the support substrate 12 such as PET, PEN, PES, or the like can be used. The thickness of the barrier layer may be determined according to the material and required barrier properties, but is usually 100 nm to 5 μm, more preferably 1 μm to 5 μm.
As the sealing member 24 that fixes the sealing substrate 26 on the support substrate 12 and prevents ventilation, an adhesive is preferable, and a photo-curing adhesive such as an epoxy resin or a thermosetting adhesive can be used. For example, a thermosetting adhesive sheet can be used.

Further, an adhesive layer may be provided between the end of the columnar portion 22 a of the optical waveguide member 22 and the sealing substrate 26. For example, when the optical waveguide member 22 is formed by crystal growth of an alkali metal halide and the width (thickness) of the columnar portion 22a is on the order of μm, the optical waveguide member 22 is thin and brittle. Therefore, for example, if an adhesive is applied and bonded to the tip of the columnar portion 22a of the optical waveguide member 22 or the surface of the sealing substrate 26 facing the optical waveguide member 22, the optical waveguide member 22 is caused by an external impact or the like. Can be effectively prevented from being destroyed.
Such an adhesive layer is preferably light transmissive and has a refractive index equal to or lower than that of the sealing substrate 26, and examples thereof include silicone resins, fluorine resins, and acrylic resins.

  During sealing, the space between the sealing substrate 26 and the support substrate 12 is filled with a gas or liquid inert fluid 28. Examples of the inert gas include argon and nitrogen. Examples of the inert liquid include paraffins, liquid paraffins, fluorine-based solvents such as perfluoroalkane, perfluoroamine, and perfluoroether, chlorine-based solvents, and silicone oils.

  By connecting external wirings (not shown) to the upper and lower electrodes 18 and 14, respectively, and applying a direct current (which may include an alternating current component if necessary) voltage (usually 2 to 15 volts) or a direct current The organic EL layer 16 in the region sandwiched between the two electrodes can emit light. As for the driving method, JP-A-2-148687, JP-A-6-301355, JP-A-5-290080, JP-A-7-134558, JP-A-8-234665, and JP-A-8-2441047, and Japanese Patent No. 2784615. No. 5, U.S. Pat. Nos. 5,828,429 and 6023308, and the like.

  Through the steps as described above, the top emission type light emitting device 10 according to the present invention is manufactured. In this device 10, light emitted from the organic EL layer 16 enters the optical waveguide member 22, propagates through the optical waveguide member 22, and is emitted from the tip near the sealing substrate 26. Therefore, loss of light extraction is suppressed, light extraction efficiency is improved, and crosstalk is effectively suppressed.

Example 1
1. Production of Organic EL Element An Ag anode was formed in a stripe shape with a thickness of 15 nm and a width of 2 mm on a support substrate (material: glass, 20 mm square). The support substrate on which the anode is formed is placed on a substrate holder in a vacuum deposition apparatus through a mask (opening: 5 mm square) from which an area for forming an organic layer is exposed, and then the inside of the apparatus is evacuated to 5 × The degree of vacuum was 10 ⁻⁵ Pa. On the anode, as a hole injection layer, F4-TCNQ was co-deposited with respect to 2-TNATA and 2-TNATA so as to be 1.0% by mass to form a thickness of 100 nm. Next, NPD was formed to a thickness of 10 nm as a hole transport layer. After forming the hole transport layer, co-evaporation was performed so that Ir (ppy) ₃ was 5 mass% with respect to CBP and CBP, and a light emitting layer was formed to a thickness of 30 nm. Next, BAlq was formed to a thickness of 40 nm as an electron transport layer. On the electron transport layer, a LiF film is further laminated with a thickness of 1 nm, and then a cathode made of ITO formed on Al and Al is formed at a thickness of 15 nm and 100 nm, respectively, and a stripe having a width of 2 mm so as to cross the anode. Formed into a shape. Thereby, a pixel of a 2 mm square organic EL element was produced.

2. Production of Optical Waveguide Member CsI was vacuum-deposited to a thickness of 200 μm on the organic EL element using the ITO obtained above as an upper electrode.
(1) Preparation of CsI vapor deposition source 75 g of CsI powder (purity: 4N) was placed in a zirconia powder molding die (inner diameter: 35 mm) and pressurized with a powder mold press molding machine at a pressure of 50 MPa, and the tablet (diameter: 35 mm) , Thickness: 20 mm). Next, this tablet was subjected to a vacuum drying treatment at a temperature of 200 ° C. for 2 hours with a vacuum dryer to obtain a CsI vapor deposition source having a water content of 0.3% by mass.
(2) Formation of optical waveguide member The organic EL element was placed on a substrate holder in a vapor deposition apparatus through a mask (opening: 5 mm square) from which a pixel region of the organic EL element was exposed. After the CsI vapor deposition source was placed at a predetermined position in the apparatus, the inside of the apparatus was evacuated to a vacuum degree of 1 × 10 ⁻³ Pa. The organic EL element was heated to 100 ° C. with a substrate heater located on the side opposite to the vapor deposition surface of the organic EL element. CsI was deposited by irradiating the deposition source with an electron beam with an acceleration voltage of 4.0 kV with an electron gun. At this time, the emission current was adjusted, and vapor deposition was performed at a rate of 10 μm / min until a thickness of 200 μm was reached. After completion of vapor deposition, the inside of the apparatus was returned to atmospheric pressure, and the organic EL element on which CsI was deposited was taken out from the inside of the apparatus. On the upper electrode of the organic EL element, a deposited film (thickness: 200 μm) having a structure in which CsI columnar crystals were densely grown in a substantially vertical direction was formed. When the deposited film was observed and measured with a scanning electron microscope, the average diameter of the columnar crystals was about 5 μm, the average aspect ratio was 30, and the occupation ratio with respect to the pixel area was 75%.

3. Adhesion of Sealing Substrate The organic EL element on which the optical waveguide member made of CsI was formed was moved into a glove box substituted with a nitrogen atmosphere, and the sealing substrate was attached. As the sealing substrate, a 10 mm square glass substrate having a thickness of 1 mm was used. After applying a photosensitive epoxy resin in which a glass spacer (diameter: 300 μm) is dispersed around the pixel on the support substrate of the organic EL element, the sealing substrate is pressed and the epoxy resin is cured using a UV lamp. An organic EL device was obtained.

4). Evaluation of the organic EL panel The anode and cathode are connected to the power source from the sealing substrate of the produced organic EL device, driven with a drive current of ^2.5 mA / cm ² , and the luminance meter CS-made by Konica Minolta from the front of the organic EL device. The peak intensity of the EL spectrum was measured with a 1000 model.

Example 2
In the production of the optical waveguide member, an organic EL device according to the present invention was produced in the same manner as in Example 1 except that the vapor deposition material was changed to CsBr.

Example 3
An organic EL device according to the present invention was produced in the same manner as in Example 1 except that the vapor deposition material was changed to RbBr in the production of the optical waveguide member.

Example 4
An organic EL device according to the present invention was produced in the same manner as in Example 1 except that the optical waveguide member was produced while controlling the degree of vacuum during vapor deposition of CsI to 0.5 Pa by introducing Ar gas.

Example 5
An organic EL device according to the present invention was produced in the same manner as in Example 1 except that the vapor deposition rate at the time of vapor deposition of CsI was changed to 2 μm / min in the production of the optical waveguide member.

Example 6
In bonding the sealing substrate, an acrylic adhesive (refractive index: 1.4) is applied and dried on the sealing substrate facing the pixel region of the organic EL element to form a 20 μm adhesive layer, and then a spacer. An organic EL device according to the present invention was produced in the same manner as in Example 1 except that the organic EL element and the sealing substrate were bonded with a photosensitive epoxy resin that did not contain. At this time, it was confirmed that most of the tip of the optical waveguide member was in contact with the adhesive layer.

Example 7
In the adhesion of the sealing substrate, an organic EL device according to the present invention was produced in the same manner as in Example 6 except that the sealing substrate was adhered without forming an adhesive layer. At this time, it was confirmed that a part of the tip of the optical waveguide member was in contact with the sealing substrate.

Example 8
An organic EL device according to the present invention was produced in the same manner as in Example 1 except that the diameter of the spacer dispersed in the photosensitive epoxy resin was changed to 400 μm in the adhesion of the sealing substrate.

Example 9
An organic EL device according to the present invention was produced in the same manner as in Example 1 except that in the production of the organic EL element, a ZnS layer (thickness: 50 nm) was further formed on the ITO cathode by sputtering.

Comparative Example An organic EL device was produced in which a sealing substrate was bonded to the organic EL element produced in Example 1 without producing an optical waveguide member.

  The shape of the optical waveguide member of the organic EL device obtained in each example is shown in Table 1, and the optical characteristics of the organic EL device are shown in Table 2. In addition, the peak intensity in Table 2 is the peak intensity of the organic EL device of each example when the peak intensity of the organic EL device of the comparative example is 1.

The peak intensity of the organic EL device of each example was remarkably improved as compared with the organic EL device of the comparative example. The peak intensity is larger when the refractive index of the optical waveguide member is higher, and is larger when the tip shape is convex. When the distance between the light emitting layer and the optical waveguide member or the distance between the optical waveguide member and the sealing substrate is increased, the light emission is easily spread and visible.
Moreover, the impact resistance of the optical waveguide member was improved by interposing an adhesive layer between the sealing substrate and the optical waveguide member.

As mentioned above, although this invention was demonstrated, this invention is not limited to the said embodiment and Example.
For example, the light-emitting device according to the present invention may be used as a light source for an image forming apparatus or the like, or a pixel may be formed by patterning a light-emitting layer to RGB to be a display device. In the above embodiment, the case where an organic EL layer is formed as an EL layer has been described. However, the present invention relates to a light emitting layer such as ZnS: Mn, BaAl ₂ S ₄ : Eu, a light emitting layer, and at least one electrode. The present invention may also be applied to a light emitting device in which an inorganic EL layer including a dielectric layer such as TiO ₂ , Ta ₂ O ₅ , or BaTiO ₃ is formed.

It is a schematic plan view which shows an example of the organic electroluminescent light-emitting device concerning this invention. It is the schematic which shows an example of arrangement | positioning of the optical waveguide member in a light emission area | region. It is the schematic which shows the other example of arrangement | positioning of the optical waveguide member in a light emission area | region. It is the schematic which shows the other example of arrangement | positioning of the optical waveguide member in a light emission area | region. It is the schematic which shows the other example of the cross-sectional shape of an optical waveguide member. (A) Hexagon (B) Square (C) Triangle It is the schematic which shows an example of a structure of an organic EL element manufacturing system. It is a figure which shows an example of the method of forming an optical waveguide member by the imprint method. It is the SEM image which observed the columnar body formed by crystal-growing CsI from diagonally upward. It is the SEM image which observed the columnar body formed by crystal-growing CsI from the horizontal direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light-emitting device 12 Support substrate 14 Lower electrode 16 Electroluminescent layer 18 Upper electrode 20 Organic electroluminescent element 22 Optical waveguide member 22a Column-shaped part 24 Sealing member 26 Sealing substrate 28 Inert fluid 36 Type 38 Uneven pattern 50 Organic EL element manufacture system

Claims (12)

A light-emitting device that has a lower electrode, an electroluminescent layer including at least a light-emitting layer, an upper electrode, and a sealing substrate in order on a support substrate, and extracts light emitted from the electroluminescent layer from the upper electrode side. There,
With an inert fluid is filled in a space between the supporting substrate and the sealing substrate, and extending in a columnar shape toward the sealing substrate on the upper electrode, the aspect ratio of the columnar portion (height A light emitting device characterized in that an optical waveguide member of alkali metal halide formed by vacuum film formation is disposed. The light emitting device according to claim 1, wherein a distance between a bottom surface of the optical waveguide member and the light emitting layer is 10 μm or less. The light emitting device according to claim 1 or claim 2, wherein the distance between the tip and the encapsulation substrate of the columnar portion of the optical waveguide member is 100μm or less. The width of the columnar portion of the optical waveguide member, the light emitting device according to any one of claims 1 to 3, characterized in that the 1 m to 100 m. Refractive index of the columnar portion of the optical waveguide member, the light emitting device according to any one of claims 1 to 4, characterized in that in the range of 1.5 to 2.5. And spaced columnar portion of the optical waveguide member is mutually disposed on the upper electrode, claim, characterized in that the between the columnar portion adjacent inert fluid is interposed 1 to claim 5 The light emitting device according to any one of the above. The columnar portion of the optical waveguide member is provided in a region occupying 30% or more of a light emitting region configured by overlapping the lower electrode, the electroluminescence layer, and the upper electrode. The light emitting device according to any one of claims 1 to 6 . The light emitting device according to any one of claims 1 to 7 , wherein a tip of the columnar portion of the optical waveguide member is convex. The light emitting device according to any one of claims 1 to 8, characterized in that the buffer layer is provided between the optical waveguide member and the upper electrode. The light emitting device according to the adhesive layer is provided on any one of claims 1 to 9, wherein between the tip and the encapsulation substrate of the columnar portion of the optical waveguide member. Forming a lower electrode on the support substrate;
Forming an electroluminescence layer on the lower electrode;
Forming an upper electrode on the electroluminescent layer;
And extending columnar on the upper electrode, the aspect ratio of the columnar portion (height / width) is greater than 2, and forming by vacuum deposition of the optical waveguide member of an alkali metal halide,
Providing a sealing substrate on the optical waveguide member for sealing, and filling a space between the sealing substrate and the support substrate with an inert fluid;
A method for manufacturing a light-emitting device, comprising: The method of manufacturing a light emitting device according to claim 11 , wherein the lower electrode, the electroluminescence layer, and the upper electrode are formed by vapor deposition.