WO2013161000A1 - Light emitting element and method for manufacturing same - Google Patents

Light emitting element and method for manufacturing same Download PDF

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Publication number
WO2013161000A1
WO2013161000A1 PCT/JP2012/060930 JP2012060930W WO2013161000A1 WO 2013161000 A1 WO2013161000 A1 WO 2013161000A1 JP 2012060930 W JP2012060930 W JP 2012060930W WO 2013161000 A1 WO2013161000 A1 WO 2013161000A1
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layer
refractive index
light emitting
light
transmissive electrode
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PCT/JP2012/060930
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French (fr)
Japanese (ja)
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研至 河合
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パイオニア株式会社
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details
    • H05B33/04—Sealing arrangements, e.g. against humidity
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/10—Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/80—Constructional details
    • H10K50/85—Arrangements for extracting light from the devices
    • H10K50/856—Arrangements for extracting light from the devices comprising reflective means

Definitions

  • the present invention relates to a light emitting device such as an organic electroluminescence device (hereinafter referred to as an organic EL device) and a method for producing the same.
  • a light emitting device such as an organic electroluminescence device (hereinafter referred to as an organic EL device) and a method for producing the same.
  • An organic EL element in which an organic layer including a light emitting layer is sandwiched between an anode layer and a cathode electrode layer on a glass substrate is known.
  • this organic EL element when a voltage is applied between the anode and the cathode, a current flows and the light emitting layer emits light.
  • the emitted light is extracted from the glass substrate by making the anode transparent, for example. Since a part of the light emitted from the light emitting layer is confined and extinguished by total reflection between the anode-glass interface and the glass-air interface, only about 20% of the light generated in the light emitting layer is emitted. There is a problem that the light extraction efficiency is low because the light cannot be extracted outside.
  • a structure is formed inside the glass substrate on the light extraction side (see Patent Document 1), or a structure is formed on the outermost surface of the glass substrate (see Patent Document 2,).
  • Patent Document 3 There are proposals for improving the light extraction efficiency, such as forming a structure on a glass substrate (see Patent Document 3) or forming a concave mirror for each element on the opposite side of the light extraction side (see Patent Document 3). Has been made.
  • a reflective layer subjected to a condensing type atypical process is provided on the side opposite to the light extraction side of the electrode, but between the organic layer and the reflective layer. Is a simple space and has a low refractive index, is inefficient when reflected back to the element, and requires a step of centering the element and the reflecting surface, resulting in a low manufacturing yield.
  • the present invention has been made in view of the above-described problems and has a simple structure, and an object thereof is to provide a light-emitting element with high light extraction efficiency and a method for manufacturing the same.
  • a light emitting device includes a light emitting portion comprising an organic layer including a light emitting layer and first and second light transmissive electrode layers sandwiching the organic layer, and the light emitting portion is interposed through the first light transmissive electrode layer. And a transparent substrate to be supported.
  • the light emitting element includes a high refractive index resin layer having a refractive index higher than that of the transparent substrate and in contact with the second light transmissive electrode layer, and the high refractive index resin together with the second light transmissive electrode layer.
  • a reflective layer having a concavo-convex interface between the layers.
  • a method for manufacturing the above light emitting device comprising: Forming a light emitting portion comprising a first light transmissive electrode layer, an organic layer, and a second light transmissive electrode layer sequentially laminated on a transparent substrate; Forming a fluid resin layer of a high refractive index resin layer material on the second light transmissive electrode layer; Forming an uneven surface to be an uneven interface on the resin layer, and forming a high refractive index resin layer; Forming a reflective layer made of a reflective material on the concavo-convex surface.
  • the light extraction efficiency can be improved.
  • FIG. 1 shows a configuration of an organic EL element 1 that is an embodiment of the present invention.
  • a light emitting unit 6 including a first light transmissive electrode layer 3, an organic layer 4, and a second light transmissive electrode layer 5 is formed on a light transmissive substrate 2.
  • a high refractive index resin layer 7 and a reflective layer 8 are sequentially formed on the light emitting portion 6.
  • the organic layer 4 is typically formed by laminating a hole injection layer 4a, a hole transport layer 4b, a light emitting layer 4c, an electron transport layer 4d, and an electron injection layer 4e.
  • the laminated structure of the organic layer 4 it is also possible to laminate
  • the organic layer 4 is a light-emitting laminated body, and is not limited to these laminated structures, and a laminated structure including at least a light-emitting layer or a charge transport layer that can also be used is also included in the present invention.
  • the organic layer 4 may be configured by omitting the hole transport layer 4b, the hole injection layer 4a, or the hole injection layer 4a and the electron transport layer 4d from the stacked structure. May be.
  • the light emitting layer 4c is made of an organic EL material.
  • the organic EL material for example, any known material such as a fluorescent material or a phosphorescent material can be applied.
  • Examples of fluorescent materials that emit blue light include naphthalene, perylene, and pyrene.
  • fluorescent materials that give green light emission include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Alq3 (tris (8-hydroxy-quinoline) aluminum).
  • Examples of fluorescent materials that give yellow light include rubrene and perimidone derivatives.
  • Examples of fluorescent materials that give red light emission include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, and the like.
  • Examples of the phosphorescent material include ruthenium, rhodium, and palladium. Specific examples of the phosphorescent material include tris (2-phenylpyridine) iridium (so-called Ir (ppy) 3), tris (2-phenylpyridine) ruthenium, and the like.
  • a first light transmissive electrode layer 3 is formed on one surface of the organic layer 4, and a second light transmissive electrode layer 5 is formed on the other surface.
  • the first light transmissive electrode layer 3 is an anode
  • the second light transmissive electrode layer 5 is a cathode.
  • Each of the first light-transmissive electrode layer 3 and the second light-transmissive electrode layer 5 includes a light-transmissive electrode layer.
  • ITO Indium-tin-oxide
  • FTO fluorine-tin-oxide
  • oxide materials such as ZnO, ZnO—Al 2 O 3 (so-called AZO), In 2 O 3 —ZnO (so-called IZO), SnO 2 —Sb 2 O 3 (so-called ATO), RuO 2, etc. It can also be used.
  • the first light-transmissive electrode layer 3 and the second light-transmissive electrode layer 5 are present at positions where the organic layer 4 is sandwiched.
  • a metal with a low work function is preferable, for example, tin, magnesium, indium, calcium, aluminum, silver
  • a suitable metal such as or an alloy thereof is used.
  • Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.
  • the second light transmissive electrode layer 5 is made of an electric conductor having an electric conductivity of 10 6 S / m or more, and is about 360 nm or less, which is the shortest wavelength of visible light, that is, a wavelength range from ultra soft X-rays to ultraviolet rays.
  • a thin film having a thickness of 5 mm can be stacked on the oxide material film.
  • the material of the thin film to be laminated with the second light transmissive electrode layer 5 includes carbon such as metal, graphite, and graphene.
  • a silver thin film with a thickness of 20 nm as a thin film of the second light transmissive electrode layer 5 has a transmittance of 50%.
  • the Al film having a thickness of 10 nm as the thin film has a transmittance of 50%.
  • the 20 nm-thick MgAg alloy film as the thin film has a transmittance of 50%.
  • a thin film made of an electric conductor and having a thickness of a thin film having a thickness in the range of ultra-soft X-ray to ultraviolet wavelength and having a transmittance of at least 50% may be adopted.
  • the conductivity can be ensured if the lower limit of the thin film thickness is 1 nm.
  • the transparent substrate 2 carries the light emitting part 6 via the first light transmissive electrode layer 3.
  • the transparent substrate 2 is made of a light transmissive material such as a resin film such as glass, polyester, polymethacrylate, polycarbonate, or polysulfone.
  • Light 20 emitted from the light emitting unit 6 is output via the transparent substrate 2.
  • a high refractive index resin layer 7 is formed on the second light transmissive electrode layer 5.
  • the high refractive index resin layer 7 is in contact with the second light transmissive electrode layer 5 at a flat interface.
  • a material of the high refractive index resin layer 7 for example, an acrylic, epoxy, or styrene compound is used, and is selected from those having a refractive index higher than that of the transparent substrate 2.
  • the high refractive index resin layer 7 has a refractive index within the range of ⁇ 30% of the refractive index of the second light transmissive electrode layer 5 in order to keep the refraction angle of light rays at the interface with the second light transmissive electrode layer 5 low. It is desirable to select from those having a refractive index.
  • the refractive index of the transparent substrate 2 is 1.5, for example.
  • the refractive index of the organic layer 4 is, for example, 1.0 to 1.8.
  • the refractive index of each of the first light transmissive electrode layer 3 and the second light transmissive electrode layer 5 is, for example, 1.8 to 2.0.
  • the refractive index of the high refractive index resin layer 7 is, for example, 1.26 to 2.6.
  • the uneven interface 7b is formed on the reflective layer 8 that contacts the high refractive index resin layer 7.
  • the uneven interface 7b composed of a plurality of concave portions and convex portions is, for example, a microlens array shape interface.
  • the uneven interface 7b may be a predetermined rough surface, and may be an uneven surface that becomes a non-flat interface such as a pyramid array shape or a wavy surface in addition to the microlens array shape.
  • the concave / convex interface 7b is a concave mirror in which the lens or pyramid is concave in addition to the shape in which the lens or pyramid is convex on the high refractive index resin layer 7 side.
  • the reflective layer 8 sandwiches the high refractive index resin layer 7 together with the second light transmissive electrode layer 5.
  • a material of the reflective layer 8 for example, a metal such as aluminum or silver is used.
  • the thickness of the reflective layer 8 is not limited as long as the reflective action of the reflective layer 8 is maintained.
  • the thickness of the high refractive index resin layer 7 is, for example, 1 ⁇ m to 50 ⁇ m.
  • the film thickness of the high refractive index resin layer 7 is not limited to this, and can be determined as appropriate as long as it exceeds the maximum depth or height of each concave or convex surface of the concave-convex interface 7b. Further, it is desirable that the uneven interface 7b is uniformly distributed throughout the high refractive index resin layer 7.
  • the plurality of microlenses on the uneven interface 7b may have the same shape and size. Further, the shape, size, and height of each microlens of the uneven interface 7b may be configured randomly. In the case of such a random arrangement of microlenses, random reflection is obtained and the light scattering effect is increased. Note that the microlenses may be arranged with a gap between adjacent ones.
  • FIG. 3 shows the light-emitting portion 6, the high-refractive index resin layer 7, the reflective layer 8, and how the light beams 21 and 22 are reflected by these configurations.
  • the light beam 21 from the organic layer 4 is reflected by the reflective layer 8 at the same angle as the incident angle, as indicated by a broken line in FIG.
  • light incident on the light beam 21 at an angle greater than the critical angle repeats total reflection between the second light-transmissive electrode layer 5 and the reflective layer 8 and is not extracted to the organic layer 4 side. End up.
  • the light beam 22 from the organic layer 4 is reflected by the reflective layer 8 and the organic layer 4 as shown by the solid line in FIG. The reflection is repeated by the uneven interface 7b.
  • the reflection By repeating the reflection, most of the light beam 22 can be incident on the second light transmissive electrode layer 5 at an angle that can be taken out.
  • the light emitting element 1 of this example not only the first light transmissive electrode layer 3 but also the second light transmissive electrode layer 5 is used as the light transmissive electrode layer.
  • a high refractive index resin layer 7 is formed on the second light transmissive electrode layer 5, and a reflective layer 8 is further formed thereon.
  • the high refractive index resin layer 7 includes a plurality of high refractive index uneven interfaces 7b. Many of the light rays 22 from the organic layer 4 are repeatedly reflected at random by the reflective layer 8 and the uneven interface 7b, and can be incident on the second light-transmissive electrode layer 5 at an angle that can be taken out. Thereby, the extraction efficiency of the light beam 22 to the transparent substrate 2 side can be improved.
  • each concave or convex interface of the concavo-convex interface 7b into a shape having a curvature inside the high refractive index resin layer 7 using a resin having a refractive index higher than that of the transparent substrate, the organic layer 4
  • the light beam 22 is easily reflected. Moreover, it becomes easy to reflect the light beam 22 at various angles by making the concave or convex curvatures of the concave-convex interface 7b nonuniform.
  • the light emitting device 1 of the present embodiment further includes a reflecting plate 7c whose both surfaces act as reflecting surfaces.
  • the reflecting plate 7c is provided in the high refractive index resin layer 7 so as to extend in the second light transmitting electrode layer 5 perpendicularly to the flat interface, and two or more reflecting plates 7c are provided.
  • the reflection plates 7c may be provided at equal intervals, or may be provided at any position, for example, the interval becomes wider as the end of the light emitting element 1 is approached.
  • the reflecting surface of the reflecting plate 7 c is provided so as to cross a direction perpendicular to the thickness direction of the high refractive index resin layer 7.
  • the reflecting plate 7c may be a lattice-like body such as a disk-shaped honeycomb structure made of a thin metal plate such as aluminum or silver.
  • FIG. 5 shows the second light transmissive electrode layer 5, the high refractive index resin layer 7, the reflective layer 8, and how light is reflected by these configurations.
  • the light beam 22 from the organic layer 4 is reflected not only by the reflection layer 8 and the uneven interface 7b but also by the reflection plate 7c. Thereby, the light rays 22a and 22b which are incident on the second light-transmissive electrode layer 5 at an angle that can be taken out can be increased. Thereby, the extraction efficiency of the light beam 22 to the transparent substrate 2 side can be further improved.
  • a light emitting unit 6 including a first light transmissive electrode layer 3, an organic layer 4, and a second light transmissive electrode layer 5 is formed on a transparent substrate 2.
  • a first light transmissive electrode layer 3 made of a light transmissive electrode material such as ITO is formed on the transparent substrate 2 made of a light transmissive material such as glass or a resin film by, for example, sputtering.
  • a plasma treatment for modifying the surface of the first light transmissive electrode layer 3 may be performed.
  • the efficiency of hole injection into the organic layer 4 formed on the first light transmissive electrode layer 3 is improved by performing such plasma treatment. To do.
  • an organic layer 4 including a light emitting layer (not shown) containing an organic compound exhibiting electroluminescence characteristics is formed on the first light transmissive electrode layer 3.
  • a dry coating method such as a sputtering method or a vacuum deposition method, or a wet coating method such as a screen printing, a spray method, an ink jet method, a spin coating method, a gravure printing, or a roll coater method. It has been known.
  • the organic layer material is a low molecular organic compound
  • a dry film forming method such as vapor deposition
  • a wet method such as spin coating
  • a film forming method is used.
  • the hole injection layer 4a, the hole transport layer 4b, and the light emitting layer 4c (FIG. 2) are formed by a wet coating method
  • the electron transport layer 4d and the electron injection layer 4e are respectively dry-type.
  • a film may be sequentially formed by a coating method. Further, all these layers may be sequentially formed by a wet coating method.
  • a thin film having a film thickness of the order of nm of magnesium, calcium, potassium, sodium, lithium or an alloy thereof is formed by, for example, vapor deposition, and further, for example, ITO or the like is formed by sputtering.
  • a second light transmissive electrode layer 5 made of a light transmissive electrode material is formed.
  • a resin in a fluid state of a high refractive index resin layer material having a predetermined thickness is formed on the second light transmissive electrode layer 5 by, for example, a spin coating method or an ink jet method.
  • Layer 7d is deposited.
  • a reflector 7c may be further formed in the high refractive index resin layer 7 shown in FIG.
  • the high refractive index resin layer 7 including the reflecting plate 7c is, for example, an opaque disk-shaped member made of, for example, aluminum having a height (thickness) less than the thickness of the resin layer 7d on the second light transmissive electrode layer 5.
  • the honeycomb structure can be bonded in advance, and a fluid state resin can be applied thereon.
  • an uneven surface to be an uneven interface is formed on the resin layer 7d.
  • a mold M in which a plurality of hemispherical protrusions M7 on the uneven surface is formed in advance using a known surface processing technique. If pressure is applied with the hemispherical convex portion M7 of the mold M superimposed on the resin layer 7d, the uneven surface M7b is transferred to the high refractive index resin layer 7, and after removing the mold M as shown in FIG.
  • a plurality of hemispherical microlens array-shaped concave surfaces 7M7b can be formed on the high refractive index resin layer 7.
  • a mask (not shown) is used to cover all the microlens array-shaped concave surface M7b of the high refractive index resin layer 7, for example, by vapor deposition or the like.
  • a reflective layer 8 made of a reflective material such as a metal such as aluminum or silver is formed on the high refractive index resin layer 7 to form the uneven surface 7b.
  • the light emitting device 1 can be manufactured by the above-described steps.
  • Light emitting element 1 Transparent substrate 2 First light transmissive electrode layer 3 Organic layer 4 Second light transmissive electrode layer 5 Light emitting part 6 High refractive index resin layer 7 Uneven interface 7b Reflector 7c Reflective layer 8

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Abstract

[Problem] To provide a light emitting element having high light extraction efficiency. [Solution] This light emitting element includes: a light emitting section, which is configured of an organic layer including a light emitting layer, and transparent first and second light transmitting electrode layers that sandwich the organic layer; and a transparent substrate, which supports the light emitting section with the first light transmitting electrode layer therebetween. The light emitting element also has: a high refractive index resin layer in contact with the second light transmitting electrode layer; and a reflecting layer that sandwiches the high refractive index resin layer with the second light transmitting electrode layer, said reflecting layer being on the high refractive index resin layer. The light emitting element has a recessed and projected interface between the reflecting layer and the high refractive index resin layer.

Description

発光素子及びその製造方法Light emitting device and manufacturing method thereof
　本発明は、有機エレクトロルミネッセンス素子（以下、有機ＥＬ素子と称する）などの発光素子及びその製造方法に関する。 The present invention relates to a light emitting device such as an organic electroluminescence device (hereinafter referred to as an organic EL device) and a method for producing the same.
　ガラス基板上の陽極と陰極の電極層の間に発光層を含む有機層が挟持された有機ＥＬ素子が知られている。この有機ＥＬ素子は、陽極と陰極の間に電圧を印加すると電流が流れて発光層が発光する。発光光は例えば陽極を透明とすることによりガラス基板から取り出される。発光層から発せられた光の一部は陽極－ガラス界面間及びガラス－空気界面間での全反射により閉じ込められ消衰する故に、発光層で生成された光のうち約２０％程度の光しか外部に取り出すことができず、光取り出し効率が低いという問題がある。 An organic EL element in which an organic layer including a light emitting layer is sandwiched between an anode layer and a cathode electrode layer on a glass substrate is known. In this organic EL element, when a voltage is applied between the anode and the cathode, a current flows and the light emitting layer emits light. The emitted light is extracted from the glass substrate by making the anode transparent, for example. Since a part of the light emitted from the light emitting layer is confined and extinguished by total reflection between the anode-glass interface and the glass-air interface, only about 20% of the light generated in the light emitting layer is emitted. There is a problem that the light extraction efficiency is low because the light cannot be extracted outside.
　この問題に対して、例えば、光取り出し側のガラス基板内部に構造体を形成したり（特許文献１、参照）、ガラス基板の最表面に構造体を形成したり（特許文献２、参照）、ガラス基板に構造体を形成したり（特許文献３、参照）、光取り出し側の反対側に素子ごとに凹面鏡を形成したり（特許文献３、参照）、するなど光取り出し効率を向上させる提案がなされてきた。 For this problem, for example, a structure is formed inside the glass substrate on the light extraction side (see Patent Document 1), or a structure is formed on the outermost surface of the glass substrate (see Patent Document 2,). There are proposals for improving the light extraction efficiency, such as forming a structure on a glass substrate (see Patent Document 3) or forming a concave mirror for each element on the opposite side of the light extraction side (see Patent Document 3). Has been made.
特開２００６－２６９３２８号公報JP 2006-269328 A 特開２００３－５９６４１号公報JP 2003-59641 A 特開２００２－２６０８４５号公報JP 2002-260845 A 特開２０１０－１９８９０７号公報JP 2010-198907 A
　しかしながら、特許文献１に開示される構造の場合には、有機層内に低屈折率層が存在した場合には、当該低屈折率層と、裏面反射層として作用する陰極層との間が導波路構造になり、光取出し効率を向上させる目的でガラス基板上面に設けられた屈折材料層にまで光が十分に届かないという問題がある。 However, in the case of the structure disclosed in Patent Document 1, when a low refractive index layer is present in the organic layer, the low refractive index layer and the cathode layer that acts as the back reflective layer are guided. There is a problem that the light does not reach the refractive material layer provided on the upper surface of the glass substrate for the purpose of improving the light extraction efficiency because of the waveguide structure.
　また、特許文献２に開示される構造の場合には、ガラス基板の光取り出し表面（最表面）に構造体を形成しても、当該基板は有機層よりも遥かに厚いので、光路長が長くなり、発光領域外への光の逃げが大きくなるという問題がある。 In the case of the structure disclosed in Patent Document 2, even if a structure is formed on the light extraction surface (outermost surface) of the glass substrate, the optical path length is long because the substrate is much thicker than the organic layer. Thus, there is a problem that light escapes out of the light emitting area.
　さらに、特許文献３に開示される構造の場合には、ガラス基板と有機層間に構造体を形成している故に、その凹凸が有機層の凹凸になってしまい、電圧ムラなどが発生して欠陥になってしまう。それを防ぐために有機ＥＬ素子形成面に平坦化処理を行う必要があ
り、プロセスが複雑化するという問題がある。 Furthermore, in the case of the structure disclosed in Patent Document 3, since the structure is formed between the glass substrate and the organic layer, the unevenness becomes the unevenness of the organic layer, causing voltage unevenness and the like. Become. In order to prevent this, it is necessary to perform a planarization process on the surface on which the organic EL element is formed, and there is a problem that the process becomes complicated.
　さらにまた、特許文献４に開示される構造の場合には、電極の光取り出し側とは逆側に集光タイプの異型処理を行った反射層を設けているが、有機層と反射層の間は単なる空間であり屈折率が低く、反射されて素子に戻る際の効率が悪くまた、素子と反射面の中心合わせ工程が必要で、製造歩留まりが悪いという問題がある。 Furthermore, in the case of the structure disclosed in Patent Document 4, a reflective layer subjected to a condensing type atypical process is provided on the side opposite to the light extraction side of the electrode, but between the organic layer and the reflective layer. Is a simple space and has a low refractive index, is inefficient when reflected back to the element, and requires a step of centering the element and the reflecting surface, resulting in a low manufacturing yield.
　そこで、簡素な構造を有し且つ本発明は上記した如き問題点に鑑みてなされたものであって、光取り出し効率の高い発光素子及びその製造方法を提供することを目的とする。 Therefore, the present invention has been made in view of the above-described problems and has a simple structure, and an object thereof is to provide a light-emitting element with high light extraction efficiency and a method for manufacturing the same.
　本発明による発光素子は、発光層を含む有機層と前記有機層を挟む第１及び第２光透過性電極層とからなる発光部と、前記発光部を前記第１光透過性電極層を介して担持する透明基板と、を含む。該発光素子は、前記透明基板の屈折率より高い屈折率を有しかつ前記第２光透過性電極層に接する高屈折率樹脂層と、前記第２光透過性電極層と共に前記高屈折率樹脂層を挟みかつ凹凸界面を有する反射層とを更に有することを特徴とする。 A light emitting device according to the present invention includes a light emitting portion comprising an organic layer including a light emitting layer and first and second light transmissive electrode layers sandwiching the organic layer, and the light emitting portion is interposed through the first light transmissive electrode layer. And a transparent substrate to be supported. The light emitting element includes a high refractive index resin layer having a refractive index higher than that of the transparent substrate and in contact with the second light transmissive electrode layer, and the high refractive index resin together with the second light transmissive electrode layer. And a reflective layer having a concavo-convex interface between the layers.
　本発明による上記の発光素子の製造方法であって、
　透明基板上に順に積層された第１光透過性電極層、有機層及び第２光透過性電極層からなる発光部を形成するステップと、
　前記第２光透過性電極層上に高屈折率樹脂層材料の流動体状態の樹脂層を成膜するステップと、
　前記樹脂層上に凹凸界面となるべき凹凸表面を形成し、高屈折率樹脂層を形成するステップと、
　前記凹凸表面上に反射性材料からなる反射層を形成するステップと、を含むことを特徴とする発光素子の製造方法。 A method for manufacturing the above light emitting device according to the present invention, comprising:
Forming a light emitting portion comprising a first light transmissive electrode layer, an organic layer, and a second light transmissive electrode layer sequentially laminated on a transparent substrate;
Forming a fluid resin layer of a high refractive index resin layer material on the second light transmissive electrode layer;
Forming an uneven surface to be an uneven interface on the resin layer, and forming a high refractive index resin layer;
Forming a reflective layer made of a reflective material on the concavo-convex surface.
　本発明による発光素子によれば、光取り出し効率を向上させることができる。 According to the light emitting device of the present invention, the light extraction efficiency can be improved.
第１の実施例である発光素子の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element which is a 1st Example. 第１の実施例である発光素子における有機層の構成の一例を示す断面図である。It is sectional drawing which shows an example of a structure of the organic layer in the light emitting element which is a 1st Example. 図１の発光部、高屈折率樹脂層、反射層、及びこれらの構成による光線の反射の様子を示す断面図である。It is sectional drawing which shows the mode of the reflection of the light ray by the light emission part of FIG. 1, a high refractive index resin layer, a reflection layer, and these structures. 第２の実施例である発光素子の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element which is a 2nd Example. 図４の第２光透過性電極層、高屈折率樹脂層、反射層、及びこれらの構成による光線の反射の様子を示す断面図である。It is sectional drawing which shows the mode of the reflection of the light ray by the 2nd transparent electrode layer of FIG. 4, a high refractive index resin layer, a reflection layer, and these structures. 発光素子の製造プロセスを順に示す断面図である。It is sectional drawing which shows the manufacturing process of a light emitting element in order.
　以下、本発明に係る実施例について添付の図面を参照しつつ詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
　＜第１の実施例＞
　図１には、本発明の実施例である有機ＥＬ素子１の構成が示されている。 <First embodiment>
FIG. 1 shows a configuration of an organic EL element 1 that is an embodiment of the present invention.
　発光素子１において、透光性基板２上に、第１光透過性電極層３、有機層４及び第２光透過性電極層５とからなる発光部６が形成されている。次いで、発光部６上に高屈折率樹脂層７及び反射層８が順に形成されている。有機層４は、典型的には図２に示されるように、正孔注入層４ａ、正孔輸送層４ｂ、発光層４ｃ、電子輸送層４ｄ、及び電子注入層４ｅが積層されて構成される。なお、有機層４の積層構成において、基板以外の構成要素を逆の順に積層することも可能である。いずれにしても、有機層４は発光積層体であり、これら積層構成に限定されることなく、少なくとも発光層を含み、或いは兼用できる電荷輸送層を含む積層構成も本発明に含まれる。有機層４は、上記積層構造から正孔輸送層４ｂを省いて構成しても、正孔注入層４ａを省いて構成しても、正孔注入層４ａと電子輸送層４ｄを省いて構成してもよい。 In the light emitting element 1, a light emitting unit 6 including a first light transmissive electrode layer 3, an organic layer 4, and a second light transmissive electrode layer 5 is formed on a light transmissive substrate 2. Next, a high refractive index resin layer 7 and a reflective layer 8 are sequentially formed on the light emitting portion 6. As shown in FIG. 2, the organic layer 4 is typically formed by laminating a hole injection layer 4a, a hole transport layer 4b, a light emitting layer 4c, an electron transport layer 4d, and an electron injection layer 4e. . In addition, in the laminated structure of the organic layer 4, it is also possible to laminate | stack components other than a board | substrate in reverse order. In any case, the organic layer 4 is a light-emitting laminated body, and is not limited to these laminated structures, and a laminated structure including at least a light-emitting layer or a charge transport layer that can also be used is also included in the present invention. The organic layer 4 may be configured by omitting the hole transport layer 4b, the hole injection layer 4a, or the hole injection layer 4a and the electron transport layer 4d from the stacked structure. May be.
　発光層４ｃは、有機ＥＬ材料からなる。有機ＥＬ材料としては、例えば、蛍光材料や燐光材料などの任意の公知の材料を適用可能である。 The light emitting layer 4c is made of an organic EL material. As the organic EL material, for example, any known material such as a fluorescent material or a phosphorescent material can be applied.
　青色発光を与える蛍光材料としては、例えば、ナフタレン、ペリレン、ピレンなどが挙げられる。緑色発光を与える蛍光材料としては、例えば、キナクリドン誘導体、クマリン誘導体、Ａｌｑ３(tris (8-hydroxy-quinoline) aluminum) などのアルミニウム錯体などが挙げられる。黄色発光を与える蛍光材料としては、例えば、ルブレン、ペリミドン誘導体などが挙げられる。赤色発光を与える蛍光材料としては、例えば、ＤＣＭ（4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran）系化合物、ベンゾピラン誘導体、ローダミン誘導体などが挙げられる。燐光材料としては、例えば、ルテニウム、ロジウム、パラジウムなどが挙げられる。燐光材料として、具体的には、トリス（２－フェニルピリジン）イリジウム（所謂、Ｉｒ（ｐｐｙ）３）、トリス（２－フェニルピリジン）ルテニウム、などが挙げられる。 Examples of fluorescent materials that emit blue light include naphthalene, perylene, and pyrene. Examples of fluorescent materials that give green light emission include quinacridone derivatives, coumarin derivatives, and aluminum complexes such as Alq3 (tris (8-hydroxy-quinoline) aluminum). Examples of fluorescent materials that give yellow light include rubrene and perimidone derivatives. Examples of fluorescent materials that give red light emission include DCM (4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, and the like. Examples of the phosphorescent material include ruthenium, rhodium, and palladium. Specific examples of the phosphorescent material include tris (2-phenylpyridine) iridium (so-called Ir (ppy) 3), tris (2-phenylpyridine) ruthenium, and the like.
　有機層４の一方の面上には第１光透過性電極層３が形成され、他方の面上には第２光透過性電極層５が形成されている。第１光透過性電極層３は陽極であり、第２光透過性電極層５は陰極である。第１光透過性電極層３及び第２光透過性電極層５の各々は、光透過性電極層からなる。例えばＩＴＯ(Indium-tin-oxide)やＦＴＯ(fluorine-tin-oxide)が光透過性電極材料として用いられる。また、ＺｎＯ、ＺｎＯ－Ａｌ2Ｏ3（所謂、ＡＺＯ）、Ｉｎ2Ｏ3－ＺｎＯ（所謂、ＩＺＯ）、ＳｎＯ2－Ｓｂ2Ｏ3（所謂、ＡＴＯ）、ＲｕＯ2などの酸化物系材料を用いることもできる。第１光透過性電極層３及び第２光透過性電極層５は、有機層４を挟む位置に存在する。 A first light transmissive electrode layer 3 is formed on one surface of the organic layer 4, and a second light transmissive electrode layer 5 is formed on the other surface. The first light transmissive electrode layer 3 is an anode, and the second light transmissive electrode layer 5 is a cathode. Each of the first light-transmissive electrode layer 3 and the second light-transmissive electrode layer 5 includes a light-transmissive electrode layer. For example, ITO (Indium-tin-oxide) or FTO (fluorine-tin-oxide) is used as the light transmissive electrode material. Also, oxide materials such as ZnO, ZnO—Al 2 O 3 (so-called AZO), In 2 O 3 —ZnO (so-called IZO), SnO 2 —Sb 2 O 3 (so-called ATO), RuO 2, etc. It can also be used. The first light-transmissive electrode layer 3 and the second light-transmissive electrode layer 5 are present at positions where the organic layer 4 is sandwiched.
　なお、電子を供給する陰極の第２光透過性電極層５の材料としては、効率良く電子注入を行う為に仕事関数の低い金属が好ましく、例えば、スズ、マグネシウム、インジウム、カルシウム、アルミニウム、銀などの適当な金属又はそれらの合金が用いられる。具体例としては、マグネシウム－銀合金、マグネシウム－インジウム合金、アルミニウム－リチウム合金などの低仕事関数合金電極が挙げられる。 In addition, as a material of the 2nd transparent electrode layer 5 of the cathode which supplies an electron, in order to inject an electron efficiently, a metal with a low work function is preferable, for example, tin, magnesium, indium, calcium, aluminum, silver A suitable metal such as or an alloy thereof is used. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.
　第２光透過性電極層５には、１０6Ｓ／ｍ以上の電気伝導率を有する電気伝導体からなり、可視光の最短波長の略３６０ｎｍ以下すなわち、超軟Ｘ線から紫外線の波長の範囲の膜厚を有する薄膜を、上記酸化物系材料の膜に積層して用いることができる。第２光透過性電極層５と積層する当該薄膜の材料には、金属やグラファイト、グラフェン(graphene)などの炭素が含まれる。第２光透過性電極層５の薄膜としての膜厚２０ｎｍの銀薄膜は透過率５０％を有する。同薄膜としての膜厚１０ｎｍのＡｌ膜は透過率５０％を有する。同薄膜としての膜厚２０ｎｍのＭｇＡｇ合金膜は透過率５０％を有する。透光性導電薄膜は、電気伝導体からなり且つ超軟Ｘ線から紫外線の波長の範囲の膜厚を有する薄膜の膜厚を有し且つ少なくとも５０％の透過率を有する薄膜を採用することが好ましい。なお、薄膜で第２光透過性電極層５を構成する場合、その薄膜膜厚の下限値は１ｎｍあれば導電性を確保することができる。 The second light transmissive electrode layer 5 is made of an electric conductor having an electric conductivity of 10 6 S / m or more, and is about 360 nm or less, which is the shortest wavelength of visible light, that is, a wavelength range from ultra soft X-rays to ultraviolet rays. A thin film having a thickness of 5 mm can be stacked on the oxide material film. The material of the thin film to be laminated with the second light transmissive electrode layer 5 includes carbon such as metal, graphite, and graphene. A silver thin film with a thickness of 20 nm as a thin film of the second light transmissive electrode layer 5 has a transmittance of 50%. The Al film having a thickness of 10 nm as the thin film has a transmittance of 50%. The 20 nm-thick MgAg alloy film as the thin film has a transmittance of 50%. As the light-transmitting conductive thin film, a thin film made of an electric conductor and having a thickness of a thin film having a thickness in the range of ultra-soft X-ray to ultraviolet wavelength and having a transmittance of at least 50% may be adopted. preferable. When the second light transmissive electrode layer 5 is formed of a thin film, the conductivity can be ensured if the lower limit of the thin film thickness is 1 nm.
　透明基板２は、第１光透過性電極層３を介して発光部６を担持している。透明基板２は、例えばガラスやポリエステル、ポリメタクリレート、ポリカーボネート、ポリスルホンなどの樹脂フィルムなどの光透過性材料からなる。発光部６から発せられた光２０が透明基板２を介して出力される。 The transparent substrate 2 carries the light emitting part 6 via the first light transmissive electrode layer 3. The transparent substrate 2 is made of a light transmissive material such as a resin film such as glass, polyester, polymethacrylate, polycarbonate, or polysulfone. Light 20 emitted from the light emitting unit 6 is output via the transparent substrate 2.
　第２光透過性電極層５上には高屈折率樹脂層７が形成されている。高屈折率樹脂層７は、第２光透過性電極層５に平坦界面にて接している。高屈折率樹脂層７の材料としては、例えばアクリル系、エポキシ系、スチレン系の化合物が用いられ、透明基板２の屈折率より高い屈折率を有するものから選択される。さらに、高屈折率樹脂層７は光線が第２光透過性電極層５との界面での屈折角を低く抑えるために第２光透過性電極層５の屈折率の±３０％以内の範囲の屈折率を有するものから選択されることが望ましい。 A high refractive index resin layer 7 is formed on the second light transmissive electrode layer 5. The high refractive index resin layer 7 is in contact with the second light transmissive electrode layer 5 at a flat interface. As a material of the high refractive index resin layer 7, for example, an acrylic, epoxy, or styrene compound is used, and is selected from those having a refractive index higher than that of the transparent substrate 2. Further, the high refractive index resin layer 7 has a refractive index within the range of ± 30% of the refractive index of the second light transmissive electrode layer 5 in order to keep the refraction angle of light rays at the interface with the second light transmissive electrode layer 5 low. It is desirable to select from those having a refractive index.
　透明基板２の屈折率は例えば１．５である。有機層４の屈折率は例えば１．０～１．８である。第１光透過性電極層３及び第２光透過性電極層５の各々の屈折率は例えば１．８～２．０である。高屈折率樹脂層７の屈折率は例えば、１．２６～２．６である。 The refractive index of the transparent substrate 2 is 1.5, for example. The refractive index of the organic layer 4 is, for example, 1.0 to 1.8. The refractive index of each of the first light transmissive electrode layer 3 and the second light transmissive electrode layer 5 is, for example, 1.8 to 2.0. The refractive index of the high refractive index resin layer 7 is, for example, 1.26 to 2.6.
　高屈折率樹脂層７に接触する反射層８には凹凸界面７ｂが形成されている。複数の凹部と凸部からなる凹凸界面７ｂは例えばマイクロレンズアレイ形状界面である。なお、凹凸界面７ｂは所定の粗面であればよく、マイクロレンズアレイ形状の他にピラミッドアレイ形状や波状面などの非平坦界面となる凹凸面でもよい。さらに、マイクロレンズアレイ形状やピラミッドアレイ形状などの場合、凹凸界面７ｂは、高屈折率樹脂層７側に各々レンズやピラミッドが凸である形状の他に、各々レンズやピラミッドが凹である凹面鏡として構成しても良い。反射層８は、第２光透過性電極層５と共に高屈折率樹脂層７を挟んでいる。反射層８の材料としては、例えばアルミニウムや銀などの金属が用いられる。なお、反射層８の反射作用を維持する厚さであれば膜厚は限定されない。一方、高屈折率樹脂層７の厚さは例えば１μｍ～５０μｍである。高屈折率樹脂層７の膜厚はこれに限られず、凹凸界面７ｂの各凹又は凸の各深さ又は高さの最大値を超えれば適宜定めることができる。また、凹凸界面７ｂは、高屈折率樹脂層７内に均一に且つ全体に亘って分布していることが望ましい。 An uneven interface 7 b is formed on the reflective layer 8 that contacts the high refractive index resin layer 7. The uneven interface 7b composed of a plurality of concave portions and convex portions is, for example, a microlens array shape interface. The uneven interface 7b may be a predetermined rough surface, and may be an uneven surface that becomes a non-flat interface such as a pyramid array shape or a wavy surface in addition to the microlens array shape. Further, in the case of a microlens array shape or a pyramid array shape, the concave / convex interface 7b is a concave mirror in which the lens or pyramid is concave in addition to the shape in which the lens or pyramid is convex on the high refractive index resin layer 7 side. It may be configured. The reflective layer 8 sandwiches the high refractive index resin layer 7 together with the second light transmissive electrode layer 5. As a material of the reflective layer 8, for example, a metal such as aluminum or silver is used. Note that the thickness of the reflective layer 8 is not limited as long as the reflective action of the reflective layer 8 is maintained. On the other hand, the thickness of the high refractive index resin layer 7 is, for example, 1 μm to 50 μm. The film thickness of the high refractive index resin layer 7 is not limited to this, and can be determined as appropriate as long as it exceeds the maximum depth or height of each concave or convex surface of the concave-convex interface 7b. Further, it is desirable that the uneven interface 7b is uniformly distributed throughout the high refractive index resin layer 7.
　凹凸界面７ｂの複数のマイクロレンズ形状や大きさが同一に形成されてもよい。また、凹凸界面７ｂのそれぞれのマイクロレンズ形状、大きさ、高さはランダムに構成してもよい。かかるマイクロレンズのランダム配置の場合はランダムな反射が得られ光の散乱効果を大きくする。なお、マイクロレンズは、隣接するもの同士の間に間隙を有して配置してもよい。 The plurality of microlenses on the uneven interface 7b may have the same shape and size. Further, the shape, size, and height of each microlens of the uneven interface 7b may be configured randomly. In the case of such a random arrangement of microlenses, random reflection is obtained and the light scattering effect is increased. Note that the microlenses may be arranged with a gap between adjacent ones.
　図３には、発光部６、高屈折率樹脂層７、反射層８、及びこれらの構成による光線２１及び２２の反射の様子が示されている。 FIG. 3 shows the light-emitting portion 6, the high-refractive index resin layer 7, the reflective layer 8, and how the light beams 21 and 22 are reflected by these configurations.
　仮に、凹凸界面７ｂが存在しない場合には、図３に破線で示されるように、有機層４からの光線２１は反射層８で入射角と同じ角度で反射する。その結果、光線２１のうち、臨界角以上の角度で入射する光は、第２光透過性電極層５と反射層８との間で全反射を繰り返して、有機層４側には取り出されなくなってしまう。 If the uneven interface 7b does not exist, the light beam 21 from the organic layer 4 is reflected by the reflective layer 8 at the same angle as the incident angle, as indicated by a broken line in FIG. As a result, light incident on the light beam 21 at an angle greater than the critical angle repeats total reflection between the second light-transmissive electrode layer 5 and the reflective layer 8 and is not extracted to the organic layer 4 side. End up.
　これに対して、凹凸界面７ｂを有する高屈折率樹脂層７を有する本実施例の発光素子１においては、図３に実線で示されるように、有機層４からの光線２２は反射層８及び凹凸界面７ｂにより反射を繰り返す。反射の繰り返しにより、光線２２の大部分が第２光透過性電極層５に対して取出し可能な角度で入射し得る。 On the other hand, in the light emitting element 1 of the present example having the high refractive index resin layer 7 having the uneven interface 7b, the light beam 22 from the organic layer 4 is reflected by the reflective layer 8 and the organic layer 4 as shown by the solid line in FIG. The reflection is repeated by the uneven interface 7b. By repeating the reflection, most of the light beam 22 can be incident on the second light transmissive electrode layer 5 at an angle that can be taken out.
　上記したように、本実施例の発光素子１においては、第１光透過性電極層３のみならず、第２光透過性電極層５をも光透過性電極層としている。そして、第２光透過性電極層５上には高屈折率樹脂層７と、更に、その上に反射層８が形成されている。高屈折率樹脂層７は、複数の高屈折率の凹凸界面７ｂを含んでいる。有機層４からの光線２２の多くは反射層８及び凹凸界面７ｂによりランダムに反射を繰り返し、第２光透過性電極層５に対して取出し可能な角度で入射し得る。これにより、透明基板２側への光線２２の取出し効率を向上させることができる。 As described above, in the light emitting element 1 of this example, not only the first light transmissive electrode layer 3 but also the second light transmissive electrode layer 5 is used as the light transmissive electrode layer. A high refractive index resin layer 7 is formed on the second light transmissive electrode layer 5, and a reflective layer 8 is further formed thereon. The high refractive index resin layer 7 includes a plurality of high refractive index uneven interfaces 7b. Many of the light rays 22 from the organic layer 4 are repeatedly reflected at random by the reflective layer 8 and the uneven interface 7b, and can be incident on the second light-transmissive electrode layer 5 at an angle that can be taken out. Thereby, the extraction efficiency of the light beam 22 to the transparent substrate 2 side can be improved.
　透明基板の屈折率よりも高い屈折率の樹脂を用いた高屈折率樹脂層７の内部にて、凹凸界面７ｂの各凹又は凸の界面を曲率を有する形状とすることにより、有機層４からの光線２２を反射させ易くなる。また、凹凸界面７ｂの各凹又は凸の曲率を不均一とすることによっても光線２２を様々な角度で反射させ易くなる。 By forming each concave or convex interface of the concavo-convex interface 7b into a shape having a curvature inside the high refractive index resin layer 7 using a resin having a refractive index higher than that of the transparent substrate, the organic layer 4 The light beam 22 is easily reflected. Moreover, it becomes easy to reflect the light beam 22 at various angles by making the concave or convex curvatures of the concave-convex interface 7b nonuniform.
　＜第２の実施例＞
　以下、第２の実施例について第１の実施例と異なる部分について主に説明する。 <Second embodiment>
In the following, the differences between the second embodiment and the first embodiment will be mainly described.
　図４には、本実施例の発光素子１は、両面が反射面として作用する反射板７ｃを更に含む。反射板７ｃは、第２光透過性電極層５に平坦界面に対し垂直に拡がるように高屈折率樹脂層７内に設けられ、２つ以上の反射板７ｃが設けられることが望ましい。この場合、反射板７ｃは、等間隔に設けられても良いし、例えば発光素子１の端部に近付く程間隔が広くなるなど任意の位置に設けることができる。反射板７ｃの反射面は、高屈折率樹脂層７の厚さ方向に垂直な方向をよぎるように設けられている。反射板７ｃは例えばアルミニウムや銀などの金属の薄板からなる盤状のハニカム構造体などの格子状体でもよい。 4, the light emitting device 1 of the present embodiment further includes a reflecting plate 7c whose both surfaces act as reflecting surfaces. It is desirable that the reflecting plate 7c is provided in the high refractive index resin layer 7 so as to extend in the second light transmitting electrode layer 5 perpendicularly to the flat interface, and two or more reflecting plates 7c are provided. In this case, the reflection plates 7c may be provided at equal intervals, or may be provided at any position, for example, the interval becomes wider as the end of the light emitting element 1 is approached. The reflecting surface of the reflecting plate 7 c is provided so as to cross a direction perpendicular to the thickness direction of the high refractive index resin layer 7. The reflecting plate 7c may be a lattice-like body such as a disk-shaped honeycomb structure made of a thin metal plate such as aluminum or silver.
　図５には、第２光透過性電極層５、高屈折率樹脂層７、反射層８、及びこれらの構成による光線の反射の様子が示されている。有機層４からの光線２２は、反射層８及び凹凸界面７ｂのみならず、反射板７ｃによっても反射される。これにより、第２光透過性電極層５に対して取出し可能な角度で入射する光線２２ａ及び２２ｂを増加させることができる。これにより、透明基板２側への光線２２の取出し効率を更に向上させることができる。 FIG. 5 shows the second light transmissive electrode layer 5, the high refractive index resin layer 7, the reflective layer 8, and how light is reflected by these configurations. The light beam 22 from the organic layer 4 is reflected not only by the reflection layer 8 and the uneven interface 7b but also by the reflection plate 7c. Thereby, the light rays 22a and 22b which are incident on the second light-transmissive electrode layer 5 at an angle that can be taken out can be increased. Thereby, the extraction efficiency of the light beam 22 to the transparent substrate 2 side can be further improved.
　＜発光素子の製造方法＞
　以下、図６を参照しつつ、発光素子１の製造方法について説明する。 <Method for manufacturing light-emitting element>
Hereinafter, a method for manufacturing the light-emitting element 1 will be described with reference to FIG.
　先ず、図６（ａ）に示すように、透明基板２上に第１光透過性電極層３、有機層４、及び第２光透過性電極層５からなる発光部６を形成する。 First, as shown in FIG. 6 (a), a light emitting unit 6 including a first light transmissive electrode layer 3, an organic layer 4, and a second light transmissive electrode layer 5 is formed on a transparent substrate 2.
　例えばガラスや樹脂フィルムなどの光透過性材料からなる透明基板２上に、例えばスパッタリング法などにより、例えばＩＴＯなどの光透過性電極材料からなる第１光透過性電極層３を成膜する。なお、第１光透過性電極層３の形成後に、第１光透過性電極層３の表面を改質するためのプラズマ処理が行われても良い。例えば、第１光透過性電極層３がＩＴＯからなる場合、かかるプラズマ処理を施すことによって、この後に第１光透過性電極層３上に形成される有機層４への正孔注入効率が向上する。 For example, a first light transmissive electrode layer 3 made of a light transmissive electrode material such as ITO is formed on the transparent substrate 2 made of a light transmissive material such as glass or a resin film by, for example, sputtering. In addition, after the formation of the first light transmissive electrode layer 3, a plasma treatment for modifying the surface of the first light transmissive electrode layer 3 may be performed. For example, when the first light transmissive electrode layer 3 is made of ITO, the efficiency of hole injection into the organic layer 4 formed on the first light transmissive electrode layer 3 is improved by performing such plasma treatment. To do.
　そして、第１光透過性電極層３上に、エレクトロルミネセンス特性を呈する有機化合物を含有する発光層（図示せず）を含む有機層４を形成する。有機ＥＬパネルの機能層を成膜する手法として、スパッタリング法や真空蒸着法などの乾式塗布法や、スクリーン印刷、スプレイ法、インクジェット法、スピンコート法、グラビア印刷、ロールコータ法などの湿式塗布法が知られている。一般的に、有機層の材料が低分子有機化合物である場合には蒸着法などの乾式成膜法が用いられ、有機層の材料が高分子有機化合物である場合にはスピンコート法などの湿式成膜法が用いられる。また、例えば、正孔注入層４ａ、正孔輸送層４ｂ、発光層４ｃ（図２）を湿式塗布法により成膜して、電子輸送層４ｄ及び電子注入層４ｅ（図２）を、それぞれ乾式塗布法により順次成膜しても良い。また、これらの全ての層を湿式塗布法により順次成膜しても良い。 Then, an organic layer 4 including a light emitting layer (not shown) containing an organic compound exhibiting electroluminescence characteristics is formed on the first light transmissive electrode layer 3. As a method for forming a functional layer of an organic EL panel, a dry coating method such as a sputtering method or a vacuum deposition method, or a wet coating method such as a screen printing, a spray method, an ink jet method, a spin coating method, a gravure printing, or a roll coater method. It has been known. In general, when the organic layer material is a low molecular organic compound, a dry film forming method such as vapor deposition is used, and when the organic layer material is a high molecular organic compound, a wet method such as spin coating is used. A film forming method is used. Further, for example, the hole injection layer 4a, the hole transport layer 4b, and the light emitting layer 4c (FIG. 2) are formed by a wet coating method, and the electron transport layer 4d and the electron injection layer 4e (FIG. 2) are respectively dry-type. A film may be sequentially formed by a coating method. Further, all these layers may be sequentially formed by a wet coating method.
　そして、有機層４上に、例えば蒸着法などにより、マグネシウム、カルシウム、カリウム、ナトリウム、リチウム又はこれらの合金の膜厚ｎｍオーダーの薄膜を成膜し、さらに、スパッタリング法などにより、例えばＩＴＯなどの光透過性電極材料からなる第２光透過性電極層５を成膜する。 Then, on the organic layer 4, a thin film having a film thickness of the order of nm of magnesium, calcium, potassium, sodium, lithium or an alloy thereof is formed by, for example, vapor deposition, and further, for example, ITO or the like is formed by sputtering. A second light transmissive electrode layer 5 made of a light transmissive electrode material is formed.
　次に、図６（ｂ）に示すように、第２光透過性電極層５上に、例えばスピンコート法、インクジェット法などにより、所定膜厚の高屈折率樹脂層材料の流動体状態の樹脂層７dを成膜する。なお、この工程において図４に示す高屈折率樹脂層７内に反射板７ｃを更に形成しても良い。反射板７ｃを含む高屈折率樹脂層７は、例えば、第２光透過性電極層５上に樹脂層７dの厚さ未満の高さ（厚さ）を有する例えばアルミニウムなどからなる不透明な盤状のハニカム構造体を予め接着しておいて、その上から流動体状態の樹脂を塗布することにより形成することができる。 Next, as shown in FIG. 6B, a resin in a fluid state of a high refractive index resin layer material having a predetermined thickness is formed on the second light transmissive electrode layer 5 by, for example, a spin coating method or an ink jet method. Layer 7d is deposited. In this step, a reflector 7c may be further formed in the high refractive index resin layer 7 shown in FIG. The high refractive index resin layer 7 including the reflecting plate 7c is, for example, an opaque disk-shaped member made of, for example, aluminum having a height (thickness) less than the thickness of the resin layer 7d on the second light transmissive electrode layer 5. The honeycomb structure can be bonded in advance, and a fluid state resin can be applied thereon.
　次に、図６（ｃ）に示すように、凹凸界面となるべき凹凸表面を樹脂層７ｄに形成する。例えば、公知の表面加工技術を用いて当該凹凸表面の複数の半球凸部Ｍ７を形成したモールドＭを予め形成しておく。該モールドＭの半球凸部Ｍ７を樹脂層７ｄに重ねて圧力をかければ、凹凸表面Ｍ７ｂが高屈折率樹脂層７に転写され、図６（ｄ）に示すように、モールドＭを除いた後に、複数の半球状のマイクロレンズアレイ形状凹面７Ｍ７ｂを高屈折率樹脂層７上に形成できる。 Next, as shown in FIG. 6C, an uneven surface to be an uneven interface is formed on the resin layer 7d. For example, a mold M in which a plurality of hemispherical protrusions M7 on the uneven surface is formed in advance using a known surface processing technique. If pressure is applied with the hemispherical convex portion M7 of the mold M superimposed on the resin layer 7d, the uneven surface M7b is transferred to the high refractive index resin layer 7, and after removing the mold M as shown in FIG. A plurality of hemispherical microlens array-shaped concave surfaces 7M7b can be formed on the high refractive index resin layer 7.
　次に、図６（ｅ）に示すように、高屈折率樹脂層７のマイクロレンズアレイ形状凹面Ｍ７ｂのすべてを覆うように、マスク（図示せず）を用いて、例えば蒸着法などにより、例えばアルミニウムや銀などの金属などの反射性材料からなる反射層８を高屈折率樹脂層７上に成膜して、凹凸界面７ｂを形成する。 Next, as shown in FIG. 6E, a mask (not shown) is used to cover all the microlens array-shaped concave surface M7b of the high refractive index resin layer 7, for example, by vapor deposition or the like. A reflective layer 8 made of a reflective material such as a metal such as aluminum or silver is formed on the high refractive index resin layer 7 to form the uneven surface 7b.
　上記した工程により、発光素子１を製造することができる。 The light emitting device 1 can be manufactured by the above-described steps.
　発光素子１
　透明基板２
　第１光透過性電極層３
　有機層４
　第２光透過性電極層５
　発光部６
　高屈折率樹脂層７
　凹凸界面７ｂ
　反射板７ｃ
　反射層８ Light emitting element 1
Transparent substrate 2
First light transmissive electrode layer 3
Organic layer 4
Second light transmissive electrode layer 5
Light emitting part 6
High refractive index resin layer 7
Uneven interface 7b
Reflector 7c
Reflective layer 8

Claims (5)

  1. 　発光層を含む有機層と前記有機層を挟む第１及び第２光透過性電極層とからなる発光部と、前記発光部を前記第１光透過性電極層を介して担持する透明基板と、を含む発光素子であって、
    　前記透明基板の屈折率より高い屈折率を有しかつ前記第２光透過性電極層に接する高屈折率樹脂層と、前記第２光透過性電極層と共に前記高屈折率樹脂層を挟みかつ凹凸界面を有する反射層と、を更に有することを特徴とする発光素子。     A light emitting part comprising an organic layer including a light emitting layer and first and second light transmissive electrode layers sandwiching the organic layer; a transparent substrate carrying the light emitting part via the first light transmissive electrode layer; A light emitting device comprising:
    A high refractive index resin layer having a refractive index higher than the refractive index of the transparent substrate and in contact with the second light transmissive electrode layer; and an unevenness sandwiching the high refractive index resin layer together with the second light transmissive electrode layer And a reflective layer having an interface.
  2. 　前記凹凸界面は非平坦界面であることを特徴とする請求項１に記載の発光素子。 2. The light emitting device according to claim 1, wherein the uneven interface is a non-flat interface.
  3. 　前記高屈折率樹脂層は、前記第２光透過性電極層の屈折率の±３０％以内の範囲の屈折率を有することを特徴とする請求項２に記載の発光素子。 The light emitting device according to claim 2, wherein the high refractive index resin layer has a refractive index within a range of ± 30% of a refractive index of the second light transmitting electrode layer.
  4. 　前記高屈折率樹脂層は、その厚さ方向に垂直な方向をよぎる両面が反射面として作用する少なくとも１つの反射部を更に含むことを特徴とする請求項２に記載の発光素子。 3. The light emitting device according to claim 2, wherein the high refractive index resin layer further includes at least one reflecting portion in which both surfaces crossing a direction perpendicular to the thickness direction act as a reflecting surface.
  5. 　発光層を含む有機層と前記有機層を挟む第１及び第２光透過性電極層とからなる発光部と、前記発光部を前記第１光透過性電極層を介して担持する透明基板と、前記透明基板の屈折率より高い屈折率を有しかつ前記第２光透過性電極層に接する高屈折率樹脂層と、前記第２光透過性電極層と共に前記高屈折率樹脂層を挟みかつ凹凸界面を有する反射層とを有する発光素子の製造方法であって、
    　透明基板上に順に積層された第１光透過性電極層、有機層及び第２光透過性電極層からなる発光部を形成するステップと、
    　前記第２光透過性電極層上に高屈折率樹脂層材料の流動体状態の樹脂層を成膜するステップと、
    　前記樹脂層上に凹凸界面となるべき凹凸表面を形成し、高屈折率樹脂層を形成するステップと、
    　前記凹凸表面上に反射性材料からなる反射層を形成するステップと、を含むことを特徴とする発光素子の製造方法。     A light emitting part comprising an organic layer including a light emitting layer and first and second light transmissive electrode layers sandwiching the organic layer; a transparent substrate carrying the light emitting part via the first light transmissive electrode layer; A high refractive index resin layer having a refractive index higher than the refractive index of the transparent substrate and in contact with the second light transmissive electrode layer; and an unevenness sandwiching the high refractive index resin layer together with the second light transmissive electrode layer A method of manufacturing a light emitting device having a reflective layer having an interface,
    Forming a light emitting portion comprising a first light transmissive electrode layer, an organic layer, and a second light transmissive electrode layer sequentially laminated on a transparent substrate;
    Forming a fluid resin layer of a high refractive index resin layer material on the second light transmissive electrode layer;
    Forming an uneven surface to be an uneven interface on the resin layer, and forming a high refractive index resin layer;
    Forming a reflective layer made of a reflective material on the concavo-convex surface.
PCT/JP2012/060930 2012-04-24 2012-04-24 Light emitting element and method for manufacturing same WO2013161000A1 (en)

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