JP5297400B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device.

  Conventionally, light emitting devices using organic electroluminescence elements (hereinafter abbreviated as organic EL elements) have been researched and developed in various places.

  As an organic EL element, for example, a transparent electrode serving as an anode, a hole transport layer, a light emitting layer (organic light emitting layer), an electron injecting layer, and an electrode serving as a cathode are laminated on one surface side of a translucent substrate (transparent substrate). Those with a structure are known. In this type of organic EL element, light emitted from the light emitting layer by applying a voltage between the anode and the cathode is taken out through the transparent electrode and the translucent substrate.

  The organic EL element is a self-luminous light emitting element, has a relatively high light emission characteristic, and can emit light in various colors, and has a feature such as a display device (for example, Applications such as light emitters such as flat panel displays) and light sources (for example, backlights of liquid crystal display devices and illumination light sources) are expected, and some have already been put into practical use.

  However, in order to apply and deploy organic EL elements for these uses, development of organic EL elements with higher efficiency, longer life, and higher brightness is desired.

  As an example of a light-emitting device for the purpose of extending the life and facilitating external connection from the light extraction surface side, a light-transmitting first substrate and one surface side of the first substrate are formed. The organic EL element (element part) and the external connection that is disposed opposite to the first substrate so as to sandwich the organic EL element, and is electrically connected to each of the first electrode and the second electrode of the organic EL element A frame-shaped sealing portion formed between the first substrate and the second substrate so as to surround the organic EL element, the second substrate having the first electrode terminal and the second electrode terminal And a first connection part that connects the first electrode and the first electrode terminal, and a second connection part that connects the second electrode and the second electrode terminal. There has been proposed a light emitting device in which a part and a second connection part are arranged outside a sealing part (Patent Document 1). Here, the sealing portion is formed of a sealing resin such as an epoxy resin, and the first connection portion and the second connection portion are formed of a plating layer or cream solder.

JP 2008-186618 A

  However, in the light emitting device disclosed in Patent Document 1, the sealing portion that surrounds the organic EL element by joining the first substrate and the second substrate is formed of a sealing resin such as an epoxy resin. Therefore, the airtightness is insufficient, and the life is shortened due to the influence of moisture and gas entering from the outside (for example, oxygen, gas generated from cream solder, etc.). In Patent Document 1, the space surrounded by the first substrate, the second substrate, and the sealing portion is made an inert gas atmosphere, or the organic EL element is covered with a protective film such as polyimide, and the protective film Although a structure in which a sealing portion is formed so as to cover the surface of the organic EL element has been proposed, it is desired to develop a light emitting device that can more reliably prevent external moisture and gas from reaching the organic EL element. ing.

  The present invention has been made in view of the above reasons, and its purpose is to facilitate external connection from the light extraction surface side and to further reduce the lifetime while suppressing a decrease in light extraction efficiency. An object of the present invention is to provide a light emitting device that can be realized.

  The invention according to claim 1 is an organic EL element having a light emitting layer between a pair of electrodes spaced in the thickness direction, and a wiring layer electrically connected to each of the electrodes of the organic EL element. An organic EL element unit formed on the front surface side and a first glass substrate, and is disposed so as to face the organic EL element side of the organic EL element unit. A base substrate having a plurality of conductor patterns for external connection electrically connected to the respective wiring layers, and surrounding the organic EL element between the organic EL element unit and the base substrate, and A frame that is arranged so as not to surround a part of the wiring layer and each of the conductor patterns, and is joined to the organic EL element unit and the base substrate over the entire circumference. And a plurality of connecting portions made of a conductive paste for electrically connecting the part of the wiring layers and the conductor patterns, respectively, and a second glass substrate, and the base substrate A package substrate that is disposed on one surface side away from the organic EL element unit and faces the base substrate, and a frame-like shape that is interposed between the base substrate and the package substrate and surrounds the organic EL element unit A spacer portion, and a part of each conductor pattern is outside the spacer portion, and the spacer portion is formed at least partially using frit glass, and the base substrate and the package substrate respectively The organic EL element unit is provided on the other surface side of the plastic film and is connected to the light emitting layer. Reflections at said other surface of the emitted light with suppressing uneven structure, characterized in that there is a space between the surface and the package substrate of the rugged structure portion.

  The invention of claim 2 is characterized in that, in the invention of claim 1, a sealing liquid is sealed in a space surrounded by the organic EL element unit, the base substrate, and the frame.

  According to a third aspect of the present invention, in the first aspect of the invention, the plurality of organic EL element units are provided, and the plurality of organic EL element units are arranged to overlap each other between the base substrate and the package substrate. The wiring layer of the organic EL element unit on the side far from the base substrate is electrically conductive with a through wiring penetrating in the thickness direction of the plastic film of the organic EL element unit on the side close to the base substrate. Each of the through wirings is connected by a paste, and is connected to each of the conductor patterns associated with the wiring layer of the organic EL element unit on the side far from the base substrate by a conductive paste. .

  According to the first aspect of the present invention, there is an effect that the external connection from the light extraction surface side is easy and the life can be further extended while suppressing the decrease of the light extraction efficiency.

1 is a schematic cross-sectional view of a light emitting device according to Embodiment 1. FIG. It is a general | schematic disassembled perspective view of a light-emitting device same as the above. 6 is a schematic cross-sectional view of a light emitting device according to Embodiment 2. FIG. It is a general | schematic disassembled perspective view of a light-emitting device same as the above. 6 is a schematic cross-sectional view of a light emitting device according to Embodiment 3. FIG. It is a general | schematic disassembled perspective view of a light-emitting device same as the above.

(Embodiment 1)
Hereinafter, the light-emitting device of this embodiment will be described with reference to FIGS. 1 and 2.

  The light emitting device A includes an organic EL element in which wiring layers 15 and 17 electrically connected to the organic EL element 11 and the anode 12 and the cathode 14 of the organic EL element 11 are formed on one surface side of the transparent plastic film 10, respectively. A unit 1 is provided. In the present embodiment, the anode 12 and the cathode 14 constitute a pair of electrodes separated in the thickness direction.

  In addition, the light emitting device A includes a base substrate 20 that is formed using a first glass substrate and is disposed opposite to the organic EL element 11 side of the organic EL element unit 1. In the base substrate 20, conductor patterns 22 and 24 for external connection that are electrically connected to the wiring layers 15 and 17, respectively, are formed on a peripheral portion on one side facing the organic EL element unit 1.

  In addition, the light emitting device A includes a frame 30 that is interposed between the organic EL element unit 1 and the base substrate 20 and is joined to the organic EL element unit 1 and the base substrate 20 over the entire circumference. The frame body 30 is disposed so as to surround the organic EL element 11 and not to partially surround the wiring layers 15 and 17 and the conductor patterns 22 and 24.

  In addition, the light emitting device A includes connection portions 42 and 44 made of conductive paste for electrically connecting the part of the wiring layers 15 and 17 and the conductor patterns 22 and 24, respectively.

  The light emitting device A is formed by using a second glass substrate, and is disposed on the one surface side of the base substrate 20 so as to be separated from the organic EL element unit 1 and opposed to the base substrate 20. A frame-shaped spacer portion 60 is provided between the substrate 20 and the package substrate 50 so as to surround the organic EL element unit 1. In the present embodiment, the base substrate 20, the package substrate 50, and the spacer portion 60 constitute an airtight package in which the organic EL element unit 1 is accommodated.

  In the light emitting device A of this embodiment, a part of each of the conductor patterns 22 and 24 is outside the spacer portion 60, and the spacer portion 60 is formed using frit glass, and the base substrate 20 and the package substrate 50 are formed. Each is joined over the entire circumference.

  The organic EL element unit 1 includes a concavo-convex structure portion 19 that is provided on the other surface side of the plastic film 10 and suppresses reflection of light emitted from the organic EL element 11 on the other surface. Here, a space 70 exists between the surface of the uneven structure portion 19 and the package substrate 50.

  Hereinafter, each component will be described in detail.

  In the organic EL element 11, an organic EL layer 13 interposed between an anode 12 and a cathode 14 includes a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer in this order from the anode 12 side. Here, in the organic EL element 11, the anode 12 is laminated on the one surface side of the plastic film 10, and the cathode 14 faces the anode 12 on the opposite side of the anode 12 from the plastic film 10 side. The positional relationship between the anode 12 and the cathode 14 may be reversed.

  In the organic EL element unit 1 in the present embodiment, the anode 12 of the organic EL element 11 is constituted by a transparent electrode, and the cathode 14 is constituted by an electrode that reflects light from the light emitting layer. Light is extracted from the side.

  The laminated structure of the organic EL layer 13 is not limited to the above-described example. For example, a single-layer structure of a light emitting layer, a laminated structure of a hole transport layer, a light emitting layer, and an electron transport layer, or a hole transport layer and a light emitting layer. Or a stacked structure of a light emitting layer and an electron transport layer. A hole injection layer may be interposed between the anode and the hole transport layer. Further, the light emitting layer may have a single layer structure or a multilayer structure. For example, when the desired light emission color is white, the light emission layer may be doped with three types of dopant dyes of red, green, and blue. Alternatively, a laminated structure of a blue hole transporting light emitting layer, a green electron transporting light emitting layer and a red electron transporting light emitting layer may be adopted, or a blue electron transporting light emitting layer and a green electron transporting light emitting layer may be employed. A laminated structure with a red electron transporting light emitting layer may be adopted.

  The anode 12 is an electrode for injecting holes into the light emitting layer, and it is preferable to use an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function, and HOMO (Highest Occupied Molecular). Orbital) It is preferable to use a work function of 4 eV or more and 6 eV or less so that the difference from the level does not become too large. Examples of the electrode material of the anode 12 include ITO, tin oxide, zinc oxide, IZO, copper iodide, conductive polymers such as PEDOT and polyaniline, and conductive polymers doped with any acceptor, carbon nanotubes, and the like. The conductive light transmissive material can be exemplified. Here, the anode 12 may be formed as a thin film on the one surface side of the plastic film 10 by a sputtering method, a vacuum deposition method, a coating method, or the like.

  The sheet resistance of the anode 12 is preferably several hundred Ω / □ or less, particularly preferably 100 Ω / □ or less. Here, the film thickness of the anode 12 varies depending on the light transmittance of the anode 12, the sheet resistance, and the like, but is set to 500 nm or less, preferably in the range of 10 nm to 200 nm.

  The cathode 14 is an electrode for injecting electrons into the light emitting layer, and it is preferable to use an electrode material made of a metal, an alloy, an electrically conductive compound, and a mixture thereof having a low work function, and LUMO (Lowest Unoccupied It is preferable to use a material having a work function of 1.9 eV or more and 5 eV or less so that the difference from the molecular orbital level does not become too large. Examples of the electrode material of the cathode 14 include aluminum, silver, magnesium and the like, and alloys of these with other metals, such as a magnesium-silver mixture, a magnesium-indium mixture, and an aluminum-lithium alloy. Also, a metal conductive material, a metal oxide, etc., and a mixture of these and other metals, for example, an ultrathin film made of aluminum oxide (here, a thin film of 1 nm or less capable of flowing electrons by tunnel injection) A laminated film with a thin film made of aluminum can also be used. Moreover, when taking out light from the cathode 14 side, ITO, IZO, etc. should just be employ | adopted, for example.

  As a material for the light emitting layer, any material known as a material for an organic EL element can be used. For example, anthracene, naphthalene, pyrene, tetracene, coronene, perylene, phthaloperylene, naphthaloperylene, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, bisbenzoxazoline, bisstyryl, cyclopentadiene, quinoline metal complex, tris (8-hydroxyxyl) Norinato) aluminum complex, tris (4-methyl-8-quinolinato) aluminum complex, tris (5-phenyl-8-quinolinato) aluminum complex, aminoquinoline metal complex, benzoquinoline metal complex, tri- (p-terphenyl- 4-yl) amine, 1-aryl-2,5-di (2-thienyl) pyrrole derivative, pyran, quinacridone, rubrene, distyrylbenzene derivative, distyrylarylene derivative, distili And amine derivatives, and various fluorescent pigments, but include those including a material system and its derivatives described above, not limited to these. In addition, it is also preferable to use a mixture of light emitting materials selected from these compounds as appropriate. Further, not only a compound that emits fluorescence, typified by the above compound, but also a material system that emits light from a spin multiplet, for example, a phosphorescent material that emits phosphorescence, and a part thereof are included in a part of the molecule. A compound can also be used suitably. The light emitting layer made of these materials may be formed by a dry process such as vapor deposition or transfer, or by a wet process such as spin coating, spray coating, die coating, or gravure printing. You may do.

  The material used for the hole injection layer can be formed using a hole injection organic material, a metal oxide, a so-called acceptor organic material or inorganic material, a p-doped layer, or the like. Examples of the hole-injecting organic material include a material having hole transportability, a work function of about 5.0 to 6.0 eV, and exhibiting strong adhesion to the anode 12. Examples thereof include CuPc and starburst amine. The hole-injecting metal oxide is a metal oxide containing any of molybdenum, rhenium, tungsten, vanadium, zinc, indium, tin, gallium, titanium, and aluminum, for example. In addition, an oxide of a plurality of metals containing any one of the above metals, such as indium and tin, indium and zinc, aluminum and gallium, gallium and zinc, titanium and niobium, etc. It may be. The hole injection layer made of these materials may be formed by a dry process such as vapor deposition or transfer, or by a wet process such as spin coating, spray coating, die coating, or gravure printing. It may be a film.

  The material used for the hole transport layer can be selected from, for example, a group of compounds having hole transport properties. Examples of this type of compound include 4,4′-bis [N- (naphthyl) -N-phenyl-amino] biphenyl (α-NPD), N, N′-bis (3-methylphenyl)-(1 , 1′-biphenyl) -4,4′-diamine (TPD), 2-TNATA, 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (MTDATA) 4,4′-N, N′-dicarbazole biphenyl (CBP), spiro-NPD, spiro-TPD, spiro-TAD, TNB, and the like, arylamine compounds, amine compounds containing a carbazole group, An amine compound containing a fluorene derivative can be exemplified, and any generally known hole transporting material can be used.

The material used for the electron transport layer can be selected from the group of compounds having electron transport properties. Examples of this type of compound include metal complexes known as electron transporting materials such as Alq ₃ and compounds having a heterocyclic ring such as phenanthroline derivatives, pyridine derivatives, tetrazine derivatives, and oxadiazole derivatives. Instead, any generally known electron transport material can be used.

The material of the electron injection layer is, for example, a metal fluoride such as lithium fluoride or magnesium fluoride, a metal halide such as sodium chloride or magnesium chloride, aluminum, cobalt, zirconium, Titanium, vanadium, niobium, chromium, tantalum, tungsten, manganese, molybdenum, ruthenium, iron, nickel, copper, gallium, zinc, Si, and other metal oxides, nitrides, carbides, oxynitrides, etc., for example, oxidation Any insulating material such as aluminum, magnesium oxide, iron oxide, aluminum nitride, silicon nitride, silicon carbide, silicon oxynitride, boron nitride, silicon compounds including SiO ₂ and SiO, carbon compounds, etc. It can be selected and used. These materials can be formed into a thin film by being formed by a vacuum deposition method or a sputtering method.

  As a plastic material of the plastic film 10, polyethylene terephthalate (PET) is adopted, but not limited to PET, for example, polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), etc. It may be adopted and may be appropriately selected according to the desired application, refractive index, heat-resistant temperature, and the like. PET is a very inexpensive and highly safe plastic material. PEN has a higher refractive index and better heat resistance than PET, but is expensive.

  The plastic film 10 described above is less expensive than an inexpensive glass substrate such as an alkali-free glass substrate or a soda lime glass substrate, has a refractive index larger than that of the glass substrate, and the light emitting layer and anode of the organic EL element 11. The refractive index difference from 12 can be reduced. Therefore, the light extraction efficiency of the organic EL element unit 1 can be improved.

  In addition, it is conceivable to form the organic EL element 11 on a glass substrate instead of the plastic film 10, but when the organic EL element 11 is formed on the glass substrate, the surface on which the organic EL element 11 is formed on the glass substrate. Therefore, it is necessary to prepare a glass substrate for forming an element that is polished with high accuracy so that the surface roughness of the substrate becomes small, and the cost increases. In addition, about the surface roughness of the said one surface of the plastic film 10, it is preferable to make arithmetic mean roughness Ra prescribed | regulated by JISB0601-2001 (ISO 4287-1997) below several nm. In this case, the plastic film 10 can be obtained at low cost with an arithmetic average roughness Ra of one nanometer or less on the one surface without performing particularly high-precision polishing.

  The plastic film 10 has a rectangular shape in plan view. The organic EL element unit 1 includes two wiring layers 15 (hereinafter referred to as the first wiring layer 15 and the first wiring layer 15) electrically connected to the anode 12 at one end in the longitudinal direction on the one surface side of the plastic film 10. And two wiring layers 17 (hereinafter referred to as second wiring layers 17) electrically connected to the cathode 14 are formed at the other end. In addition, although the planar view shape of the plastic film 10 is made into the rectangular shape, it is not restricted to this, For example, circular shape, triangular shape, pentagon shape, hexagonal shape, etc. may be sufficient. Further, the numbers of the first wiring layers 15 and the second wiring layers 17 are not particularly limited.

  In the organic EL element unit 1, the first wiring layer 15 is made of the same material as that of the anode 12, and the first wiring layer 15 is formed simultaneously with the anode 12. Therefore, compared with the case of forming different materials separately, the manufacturing process can be simplified and the cost can be reduced by reducing the material cost. The material of the second wiring layer 17 is the same as that of the cathode 14, and the second wiring layer 17 is formed simultaneously with the cathode 14. Therefore, compared with the case of forming different materials separately, the manufacturing process can be simplified and the cost can be reduced by reducing the material cost. The wiring layers 15 and 17 are not limited to a single layer structure, and may have a multilayer structure.

  The base substrate 20 uses, for example, a non-alkali glass substrate as the first glass substrate, but is not limited thereto, and for example, a blue soda glass substrate may be used.

  The base substrate 20 includes a conductor pattern 22 associated with the anode 12 (hereinafter referred to as a first conductor pattern 22) and a conductor pattern 24 associated with the cathode 14 (hereinafter referred to as a second conductor pattern 24). Are made of the same material and with the same thickness.

  The base substrate 20 has a rectangular shape in plan view. However, the shape is not limited to the rectangular shape. For example, the base substrate 20 may be appropriately changed according to the planar shape of the organic EL element unit 1. It may be a shape, pentagon, hexagon, or the like.

  The planar size of the base substrate 20 is set to be larger than the planar size of the organic EL element unit 1 so that most of the conductor patterns 22 and 24 are located outside the projection area of the organic EL element unit 1. It is. Here, each conductor pattern 22, 24 is formed in a rectangular shape in plan view, one end in the longitudinal direction is located in the projection region of the organic EL element unit 1, and the other end in the longitudinal direction is a spacer. It is located outside the part 60. The conductor patterns 22 and 24 are preferably formed by a dry process such as sputtering or vapor deposition. In addition, the planar view shape of each conductor pattern 22 and 24 is not specifically limited.

The frame 30 is formed of a high-viscosity ultraviolet curable resin (for example, an ultraviolet curable epoxy resin) or a high-viscosity thermosetting resin (for example, an ultraviolet curable epoxy resin). . Here, at the time of manufacturing the light emitting device A, before the base substrate 20 and the organic EL element unit 1 are overlapped, the above-described resin is dispensed to the arrangement region of the frame body 30 on the base substrate 20 (for example, a dispenser robot). When the frame 30 is bonded to the base substrate 20 and the organic EL unit 1, ultraviolet irradiation or partial heating is effective.

  The connecting portions 42 and 44 are formed of a conductive paste as described above. Here, at the time of manufacturing the light emitting device A, a conductive paste is supplied onto the one end of each of the conductor patterns 22 and 24 of the base substrate 20 by a dispenser (for example, a dispenser robot), and then the base substrate 20 and the organic EL. By superimposing the element unit 1 and joining the connection portions 42 and 44 to the conductor patterns 22 and 24 and the wiring layers 15 and 17, respectively, the conductor patterns 22 and 24 and the wiring layers 15 and 17 are connected to the connection portions 42 and 44. Electrical connection through At the time of this bonding, in addition to ultraviolet irradiation, local heating with laser light is effective. In addition, after this bonding, before the package substrate 50 and the spacer portion 60 are disposed, the package substrate 50 and the spacer unit 60 may be left at room temperature or left in a heated state to release the outgas from the conductive paste to the outside. . The conductive paste is composed of a conductive filler and a binder. As the conductive filler, gold powder, silver powder, copper powder, nickel powder, aluminum powder, plating powder, carbon powder, graphite powder, solder particles, and the like can be used. As the binder, organic binders such as epoxy resin, urethane, silicone, acrylic, polyimide, thermosetting resin, and thermoplastic resin can be used. Here, in order to prevent the deterioration of the organic EL element 11 due to the gas emitted from the binder, it is desirable to use a solventless binder.

  The package substrate 50 uses, for example, a non-alkali glass substrate as the second glass substrate, but is not limited thereto, and for example, a blue soda glass substrate may be used. However, the package substrate 50 is preferably formed of a material having the same thermal expansion coefficient as that of the base substrate 20.

  The package substrate 50 has a rectangular shape in plan view. However, the shape is not limited to the rectangular shape, and the package substrate 50 may be appropriately changed according to the planar shape of the organic EL element unit 1 or the base substrate 1, for example. , Circular, triangular, pentagonal, hexagonal, etc.

  The planar size of the package substrate 50 is set to be larger than the planar size of the organic EL element unit 1 and smaller than the planar size of the base substrate 20, and the base substrate as viewed from the light extraction surface side of the light emitting device A. A part of each of the 20 conductor patterns 22 and 24 can be visually recognized. In short, a part of each of the conductor patterns 22 and 24 is located outside the projection area of the package substrate 50. Therefore, it is easy to connect (externally connect) an electric wire or the like to the conductor patterns 22 and 24 from the light extraction surface side of the light emitting device A.

  The spacer portion 60 is preferably formed in a frame shape along the outer peripheral edge of the package substrate 50. In the present embodiment, the spacer portion 60 is formed in a rectangular frame shape. In addition, when the planar view shape of the package substrate 50 and the organic EL element unit 1 is different, the shape may be along one of the outer peripheral lines.

  The spacer part 60 is formed using frit glass. Here, at the time of manufacturing the light emitting device A, the spacer portion 60 is disposed on the package substrate 50, the spacer portion 60 is sandwiched between the base substrate 20 and the package substrate 50, and then the spacer portion 60 is moved by laser light or the like. The base substrate 20 and the package substrate 50 may be bonded to each other by heating. In this case, an appropriate impurity may be added to the frit glass so that the frit glass is easily heated by the laser beam. In addition, you may perform a heating not only with a laser beam but with infrared rays, for example.

  The spacer portion 60 is not limited to being formed using only frit glass. For example, the frit glass formed on the opposing surfaces of the frame member made of an alloy and each of the base substrate 20 and the package substrate 50 in the frame member. You may form using. Here, as the alloy that is the material of the frame member, Kovar having a thermal expansion coefficient close to that of the base substrate 20 and the package substrate 50 is preferably used, but is not limited to Kovar. An alloy or the like may be used. Kovar is an alloy in which nickel and cobalt are blended with iron and has a low coefficient of thermal expansion near normal temperatures. Among these metals, the coefficient of thermal expansion of alkali-free glass, blue soda glass, borosilicate glass, etc. It has a value close to. An example of the component ratio of Kovar is wt%, nickel: 29 wt%, cobalt: 17 wt%, silicon: 0.2 wt%, manganese: 0.3 wt%, iron: 53.5 wt%. The component ratio of Kovar is not particularly limited, and an appropriate component ratio may be adopted so that the thermal expansion coefficients of Kovar are aligned with the thermal expansion coefficients of the base substrate 20 and the package substrate 50. In addition, as the frit glass in this case, it is preferable to employ a material capable of aligning the thermal expansion coefficient with the thermal expansion coefficient of the alloy. Here, when the alloy is Kovar, it is preferable to use Kovar glass as the material of the frit glass. Further, in forming the spacer portion 60, for example, frit glass is applied in a predetermined pattern (in this embodiment, a rectangular frame-shaped pattern) on both surfaces in the thickness direction of a plate material made of an alloy such as Kovar, The spacer part 60 can be formed by performing a punching process after drying and baking.

  As can be seen from the above description, in this embodiment, the linear expansion coefficients of the base substrate 20, the package substrate 50, and the spacer portion 60 are aligned. Here, to make the thermal expansion coefficients uniform is not limited to completely matching, but means that they are substantially the same, and the purpose is to select materials so that the difference in thermal expansion coefficients is as small as possible.

  In manufacturing the light emitting device A of the present embodiment, the frame body 30 is formed on the one surface side of the base substrate 20 before the base substrate 20 and the organic EL element unit 1 are disposed to face each other via the frame body 30. The connecting portions 42 and 44 are formed on the conductor patterns 22 and 24 using a dispenser or the like. Thereafter, the organic EL element unit 1 and the base substrate 20 are overlapped, and then the frame 30 is bonded to the base substrate 20 and the organic EL element unit 1 respectively. Subsequently, the connection portions 42 and 44 are electrically connected to each other by joining the conductor patterns 22 and 24 and the wiring layers 15 and 17, and then the gas emitted from the connection portions 42 and 44 is discharged to the outside. Thereafter, the spacer portion 60 is disposed on the side opposite to the light extraction surface side of the package substrate 50, and then the base substrate in a predetermined atmosphere (for example, an inert gas atmosphere such as a dry nitrogen atmosphere, a vacuum atmosphere, or the like). The spacer portion 60 is sandwiched between the substrate 20 and the package substrate 50, and the spacer portion 60 is heated by irradiating laser light from the base substrate 20 side or the package substrate 50 side to melt the frit glass, thereby making the spacer portion 60 the base substrate. 20 and the package substrate 50 are bonded to each other. In the light emitting device A of the present embodiment, airtightness can be ensured while the sealing margin is about 1 mm. Further, as a laser light source, for example, a YAG laser or the like may be used.

  If the spacer member 60 is provided with the above-described frame member, the distance between the base substrate 20 and the package substrate 50 can be stably maintained even when the frit glass is melted, and hermetically sealed. Therefore, the hermeticity of the package composed of the base substrate 20, the package substrate 50, and the spacer portion 60 can be improved, and the organic EL element 11 can be formed while increasing the area of the light emitting portion of the organic EL element 11. Long life can be achieved. Further, if the spacer portion 60 is provided with the above-described frame member, the design freedom of the distance between the base substrate 20 and the package substrate 50 is increased. Note that the frame member is not limited to a rectangular cross section, and a ring member having a circular cross section may be used.

  In the light emitting device A of the present embodiment, as described above, the organic EL element unit 1 includes the concavo-convex structure portion 19, and the space 70 exists between the concavo-convex structure portion 19 and the package substrate 50. Therefore, it is possible to reduce the reflection loss of the light emitted from the light emitting layer of the organic EL element 11 and reach the package substrate 50, and the light extraction efficiency can be improved.

  Here, the refractive index of each of the light emitting layer of the organic EL element 11 and the plastic film 10 is larger than the refractive index of air or an inert gas which is an external atmosphere from which light is extracted. Therefore, in the case where the space between the plastic film 10 and the package substrate 50 is an air atmosphere or an inert gas atmosphere without the above-described concavo-convex structure portion 19 being provided, the first made of the plastic film 10 is used. Total reflection occurs at the interface between the medium and the second medium made of air or inert gas, and light incident on the interface is reflected at an angle greater than the total reflection angle. Then, the light reflected at the interface between the first medium and the second medium is reflected multiple times inside the organic EL layer 13 or the plastic film 10 and attenuates without being extracted outside, so that the light extraction efficiency is lowered. Also, light extraction efficiency is further reduced because Fresnel reflection occurs for light incident on the interface between the first medium and the second medium at an angle less than the total reflection angle.

  On the other hand, in this embodiment, since the uneven | corrugated structure part 19 is provided in the said other surface side of the plastic film 10, the light extraction efficiency to the exterior of the organic EL element unit 1 can be improved.

  The concavo-convex structure portion 19 has a two-dimensional periodic structure in which a large number of protrusions 19 a are periodically arranged in a two-dimensional plane parallel to the one surface of the plastic film 10. In the example shown in FIG. 1, the protrusion 19 a has a quadrangular pyramid shape, but the shape of the protrusion 19 a may be a cone other than the quadrangular pyramid (for example, a triangular pyramid, a hexagonal pyramid, a cone, etc.). However, it may be hemispherical or other shapes.

  Here, the period P of the two-dimensional periodic structure indicates that the wavelength in the medium is λ (the wavelength in vacuum is divided by the refractive index of the medium when the wavelength of light emitted from the light emitting layer is in the range of 300 to 800 nm. Value), it is desirable to set appropriately within a range of 1/4 to 10 times the wavelength λ.

  When the period P is set in the range of 5λ to 10λ, for example, the light extraction efficiency is improved by the geometrical optical effect, that is, the area of the surface where the incident angle is less than the total reflection angle. Further, when the period P is set in a range of λ to 5λ, for example, the light extraction efficiency is improved by the action of extracting light having a total reflection angle or more by diffracted light. Further, when the period P is set in the range of λ / 4 to λ, the effective refractive index in the vicinity of the concavo-convex structure portion gradually decreases as the distance from the one surface of the plastic film 10 increases. This is equivalent to interposing a thin film layer having a refractive index intermediate between the refractive index of the medium of the concavo-convex structure portion 19 and the refractive index of the medium of the space 70 between the film 10 and the space 70, and reduces Fresnel reflection. It becomes possible. In short, if the period P is set in the range of λ / 4 to 10λ, reflection (total reflection or Fresnel reflection) can be suppressed, and the light extraction efficiency of the organic EL element unit 1 is improved. However, the upper limit of the period P for improving the light extraction efficiency by the geometric optical effect is applicable up to 1000λ. In addition, the concavo-convex structure portion 19 does not necessarily have a periodic structure such as a two-dimensional periodic structure, and the light extraction efficiency can be improved even in a concavo-convex structure having a random concavo-convex size or a concavo-convex structure having no periodicity. When uneven structures of different sizes coexist (for example, when an uneven structure with a period P of 1λ and an uneven structure of 5λ or more coexist), the unevenness with the largest occupation ratio in the uneven structure portion 19 among them. The light extraction effect of the structure becomes dominant.

  The concavo-convex structure portion 19 is configured by a prism sheet (for example, a light diffusion film such as LIGHTUP (registered trademark) GM3 manufactured by Kimoto Co., Ltd.), but is not limited thereto. For example, the uneven structure portion 19 may be formed on the other surface of the plastic film 10 by an imprint method (nanoimprint method). The imprinting method is not limited to the thermal imprinting method (thermal nanoimprinting method), and an optical imprinting method (optical nanoimprinting method) may be employed.

  For the concavo-convex structure portion 19, a hard coat for preventing the surface from being scratched is applied, or a prism sheet having a sufficiently high hardness is used, or a transparent material having a sufficiently high hardness after curing is used. It is desirable to use it. As a hard coat agent for applying a hard coat, for example, TYZ series manufactured by Toyo Ink ([searched on December 22, 2009], Internet <URL: http://www.toyoink.co.jp/products/ lioduras / index.html>) and other high refractive index type (refractive index of about 1.63 to 1.74) hard coating agents can be employed. The TYZ series is an ultraviolet curable hard coat agent in which zirconia is mixed as a filler in an epoxy resin or the like.

  In the light emitting device A of the present embodiment, it is important that a space 70 exists between the surface of the uneven structure portion 19 and the package substrate 50. If the surface of the concavo-convex structure portion 19 is an interface between the concavo-convex structure portion 19 and the package substrate 50, the refractive index interface exists between the package substrate 50 and external air. Then, total reflection occurs again. On the other hand, in this embodiment, since the light of the organic EL element 11 can be once extracted into the space 70, the interface between the inert gas in the space 70 and the package substrate 50, the package substrate 50, and the outside Total reflection loss does not occur at the interface with air.

  The light-emitting device A of the present embodiment described above is for a package that is formed using a second glass substrate and is arranged on the one surface side of the base substrate 20 so as to be separated from the organic EL element unit 1 and facing the base substrate 20. A substrate 50 and a frame-like spacer portion 60 that is interposed between the base substrate 20 and the package substrate 50 and surrounds the organic EL element unit 1 are provided, and a part of each of the conductor patterns 22 and 24 is a spacer portion. Since the spacer portion 60 is located on the outer side and the spacer portion 60 is formed at least partially using frit glass and is joined to the base substrate 20 and the package substrate 50 over the entire circumference, the moisture resistance can be improved. It is possible to further extend the life.

  Further, in the light emitting device A of the present embodiment, the organic EL element unit 1 includes the concavo-convex structure portion 19, and the space 70 exists between the surface of the concavo-convex structure portion 19 and the package substrate 50. The reflection loss of the light emitted from the light emitting layer of the EL element 11 and reaching the package substrate 50 can be reduced, and the light extraction efficiency can be improved.

  Therefore, in the light emitting device A of the present embodiment, external connection from the light extraction surface side is easy, and the lifetime can be further extended while suppressing a decrease in light extraction efficiency.

By the way, in the light-emitting device A of this embodiment, when light passes through the package substrate 50, a loss due to Fresnel reflection (Fresnel loss) occurs. Therefore, in the light emitting device A of the present embodiment, it is desirable to reduce the Fresnel loss when passing through the package substrate 50. As a means for suppressing the Fresnel loss, for example, an anti-reflection coat (hereinafter, abbreviated as an AR film) made of a single-layer or multilayer dielectric film is provided on at least one surface in the thickness direction of the package substrate 50. It is conceivable to provide it. Here, when the AR film is formed of, for example, a magnesium fluoride film having a refractive index n of 1.38, if the design wavelength λ ₀ is 550 nm, the thickness of the AR film is λ ₀ / 4n = 550 / ( 4 × 1.38) = 99.6 nm. Similarly, when the AR film is composed of, for example, an aluminum oxide film having a refractive index n of 1.58, if the design wavelength λ ₀ is 550 nm, the thickness of the AR film is λ ₀ / 4n = 550 / (4 × 1.58) = 87.0 nm. The AR film may be a stacked film (two-layer AR film) of a magnesium fluoride film having a thickness of 99.6 nm and an aluminum oxide film having a thickness of 87.0 nm. Note that a material other than magnesium fluoride or aluminum oxide may be adopted as the material of the dielectric film.

  In the light emitting device A of this embodiment, by providing an AR film on at least one surface, preferably both surfaces, in the thickness direction of the package substrate 50, Fresnel loss can be reduced and light extraction efficiency can be improved.

  As another means for suppressing the Fresnel loss, it is conceivable to provide a moth-eye structure on at least one surface side in the thickness direction of the package substrate 50. The moth-eye structure has a two-dimensional periodic structure in which tapered fine protrusions are arranged in a two-dimensional array, and is reflected by a medium (for example, air) that enters between the fine protrusions adjacent to each other. A prevention unit is configured. Here, when the moth-eye structure is formed by processing the package substrate 50 by the nanoimprint method, the refractive index of the fine protrusions is the same as the refractive index of the package substrate 50. In this case, the effective refractive index of the antireflection portion is continuously between the refractive index (= 1.51) of the package substrate 50 and the refractive index of the medium (= 1) in the thickness direction of the antireflection portion. A state in which the refractive index interface that changes and causes Fresnel loss disappears can be obtained in a pseudo manner. Therefore, in the moth-eye structure, the dependency on the wavelength and the incident angle can be reduced and the reflectance can be reduced as compared with the AR film.

  The height of the fine protrusions and the period of the fine protrusions in the moth-eye structure may be set to, for example, 200 nm and 100 nm, respectively, but these numerical values are examples and are not particularly limited.

  The moth-eye structure described above can be formed by, for example, a nanoimprint method, but may be formed by a method other than the nanoprint method (for example, laser processing technology). Further, the moth-eye structure may be constituted by, for example, a moth-eye type non-reflective film manufactured by Mitsubishi Rayon Co., Ltd.

(Embodiment 2)
The basic configuration of the light emitting device A of the present embodiment is substantially the same as that of the first embodiment, and as shown in FIGS. 3 and 4, in a space surrounded by the organic EL element unit 1, the base substrate 20, and the frame body 30. The difference is that a sealing liquid (for example, silicone oil, paraffin oil, etc.) 90 is sealed. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  The manufacturing method of the light emitting device A of the present embodiment is substantially the same as that of the first embodiment, and after providing the frame body 30 on the one surface of the base substrate 20, the space surrounded by the base substrate 20 and the frame body 30 is provided. The liquid 90 may be injected.

  In the light emitting device A of the present embodiment, the heat generated in the organic EL element 11 can be efficiently dissipated through the liquid 90, so that the temperature rise of the organic EL element 11 can be suppressed and long. The lifetime can be increased, and the current flowing to the organic EL element 11 can be increased to increase the luminance.

(Embodiment 3)
The basic configuration of the light-emitting device A of the present embodiment is substantially the same as that of the first embodiment, and is different in that, for example, two organic EL element units 1 are provided as shown in FIGS. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted. However, in FIG. 5 and FIG. 6, in order to distinguish between the two organic EL element units 1, reference numerals with A and B are shown in parentheses.

  In the present embodiment, a plurality (two in the illustrated example) of organic EL element units 1 are arranged so as to overlap each other between the base substrate 20 and the package substrate 50. The number of organic EL element units 1 is not limited to two, and may be three or more.

  Between the organic EL element units 1 adjacent in the thickness direction of the base substrate 20, a frame body 30 having the same shape as the frame body 30 interposed between the base substrate 20 and the organic EL element unit 1 (1A) is interposed. The frame 30 is bonded to the organic EL element units 1 on both sides.

  The wiring layers 15 and 17 of the organic EL element unit 1 (1B) on the side far from the base substrate 20 are provided in the thickness direction of the plastic film 10 of the organic EL element unit 1 (1A) on the side close to the base substrate 20. The through wires 16 and 18 made of through-hole wires are electrically connected to the connecting portions 42 and 44 made of conductive paste. The through wirings 16 and 18 are electrically connected to the conductor patterns 22 (22B) and 24 (24B) associated with the wiring layers 15 and 17 of the organic EL element unit 1 (1B) on the side far from the base substrate 20, respectively. Are connected by connection portions 42 and 44 made of a conductive paste. By using the connection portions 42 and 44 made of the through wirings 16 and 18 and the conductive paste in this manner, the connection by the bonding wire is not necessary, so that the low number in the case where the plurality of organic EL element units 1 are arranged in a stacked manner is low. Can be turned upside down.

  For the organic EL element unit 1 (1B) other than the organic EL element unit 1 (1A) closest to the base substrate 20, the material is selected so that not only the anode 12 but also the cathode 14 has translucency. is there.

  In the light emitting device A of the present embodiment, if the light emission colors of all of the plurality of organic EL units 1 are set to be the same, it is possible to extend the life in the case of lighting with high brightness.

  Further, in the light emitting device A of the present embodiment, if the light emitting color is designed to be different by changing the material of the light emitting layer for each organic EL element unit 1, color matching is possible. In the case of performing color matching control of the light emitting device A of the present embodiment, for example, control for controlling the light output ratio of each organic EL element unit 1 according to the color of mixed color light set by operation of an operation unit (not shown). A circuit may be provided separately.

DESCRIPTION OF SYMBOLS A Light-emitting device 1 Organic EL element unit 10 Plastic film 11 Organic EL element 12 Anode 13 Organic EL layer 14 Cathode 15 Wiring layer 16 Through wiring 17 Wiring layer 18 Through wiring 19 Uneven structure part 20 Base substrate 22 Conductive pattern 24 Conductive pattern 30 Frame Body 42 Connection portion 44 Connection portion 50 Package substrate 60 Spacer portion 70 Space 90 Liquid

Claims (3)

  An organic EL element having a light emitting layer between a pair of electrodes spaced in the thickness direction and an organic layer in which a wiring layer electrically connected to each electrode of the organic EL element is formed on one surface side of a transparent plastic film Each of the wiring layers is formed on a peripheral portion on one surface side that is formed using an EL element unit and a first glass substrate and is opposed to the organic EL element side of the organic EL element unit and faces the organic EL element unit. A base substrate having a plurality of conductor patterns for external connection electrically connected to the organic EL element, the organic EL element is surrounded between the organic EL element unit and the base substrate, and a part of each of the wiring layers; A frame body that is arranged so as not to surround each conductor pattern and is joined to each of the organic EL element unit and the base substrate over the entire circumference, and each wiring layer A plurality of connecting portions made of a conductive paste for electrically connecting the part and the conductor patterns, respectively, and a second glass substrate, and the organic EL element on the one surface side of the base substrate A package substrate disposed away from the unit and facing the base substrate, and a frame-shaped spacer portion interposed between the base substrate and the package substrate and surrounding the organic EL element unit, A part of each conductor pattern is outside the spacer part, and at least a part of the spacer part is formed using frit glass, and is joined to the base substrate and the package substrate over the entire circumference. The organic EL element unit is provided on the other surface side of the plastic film and is disposed in front of the light emitted from the light emitting layer. With suppressing uneven structure reflection on the other surface, the light emitting device which is characterized in that a space exists between the surface and the package substrate of the rugged structure portion.   The light-emitting device according to claim 1, wherein a sealing liquid is sealed in a space surrounded by the organic EL element unit, the base substrate, and the frame.   A plurality of the organic EL element units are provided, and the plurality of organic EL element units are arranged so as to overlap each other between the base substrate and the package substrate, and the organic EL element unit on the side far from the base substrate The wiring layer of the organic EL element unit on the side close to the base substrate is connected with a through wiring penetrating in the thickness direction of the plastic film, and each through wiring is connected to the base substrate. The light-emitting device according to claim 1, wherein the light-emitting device is connected to each conductor pattern associated with the wiring layer of the organic EL element unit on a side farther from a conductive paste.

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