JP2010123313A - Method of manufacturing organic electroluminescence surface light emitter, organic electroluminescence surface light emitter,and display device and lighting system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an organic electroluminescence surface light emitter, and the organic electroluminescence surface light emitter improving light extraction efficiency, preventing peeling and unevenness resulting from even adhesion by adhering an emission surface of the surface light emitting element, that is a sealing film and light extraction film, without using a conventional adhesion layer. <P>SOLUTION: In the method of manufacturing the organic electroluminescence surface light emitter, the light extraction film 10A having a plurality of uneven structures is adhered on the sealing film 21 laminated on an electrode on a light emission side of the light emitting element having an organic light emitting layer 23 sandwiched between a pair of electrodes 22, 24. The uneven structure 12 of the light extraction film is formed of curable resin, and the uneven structure is cured and adhered by a curing means while being tightly adhered on the sealing film in a half cured state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence surface light emitter that can be effectively used for displays, illumination, backlights, and the like.

  In an in-solid light-emitting device that extracts light from the light-emitting layer itself, such as an organic electroluminescence light-emitting device, light emitted above the critical angle determined by the refractive index of the light-emitting layer and the refractive index of the output medium is totally reflected and confined inside. , Lost as guided light.

In the calculation based on the classic Snell's law, when the refractive index of the light emitting layer is n, the light extraction efficiency η = 1 / 2n ² at which the generated light is extracted to the outside is approximated. Therefore, about 80% of light is lost as guided light and lost light in the side surface direction of the device.

  In order to extract guided light to the outside, a region that disturbs the reflection / transmission angle is formed between the light emitting layer and the emission surface, the Snell's law is broken, and the transmission angle of light totally reflected as originally guided light is increased. It is necessary to change. Many methods have been proposed for improving the extraction efficiency by forming such a structure in an organic electroluminescent light emitting device.

  For example, Japanese Patent Laid-Open No. 9-63767 discloses an organic electroluminescence light emitting device having a concavo-convex structure on the substrate surface, and Japanese Patent Laid-Open No. 11-214163 discloses organic electroluminescence light emission having a three-dimensional structure or an inclined surface. There have been many attempts to extract guided light confined inside the device by physically changing the shape of the device and the substrate.

  As described above, in the classical calculation, the extraction efficiency of the organic electroluminescence light emitting element is about 17%, and it is described that 80% or more of the guided light is confined in the inside of the element. In an organic electroluminescence light emitting device, the phenomenon is further complicated due to a light interference effect and a microcavity effect.

  According to a report by Sone et al. (IDW'03, p1297), the luminance improvement degree in which irregularities are formed on the glass substrate of the organic electroluminescence light emitting element is reported to be 1.4 times.

  As described above, in an actual organic electroluminescence light emitting device, the brightness enhancement effect due to the extraction of the guided light is not so great as estimated from the classical theory. However, the guided light confined in the organic electroluminescence light emitting device is still to some extent. It can be taken out. In particular, when the organic electroluminescence light-emitting element is applied to a planar illumination application having a large light emitting area, the above proposal can be suitably applied.

  Recently, a light extraction film having a prism or lens-shaped uneven surface is attached to the exit surface of the surface light emitting element so that the uneven surface faces the exit surface of the surface light emitting element, and an optical path conversion function is provided to improve luminance. Means for making them disclosed is disclosed (for example, see Patent Documents 1 and 2).

In this case, as a method for adhering the prism array sheet and the emission surface of the surface light emitting element, a method of providing an adhesive layer with a UV curable resin adhesive and adhering has been proposed. However, it is difficult to uniformly apply a UV curable resin to the exit surface of the surface light emitting element to form an adhesive layer. If an adhesive layer is provided, the transmittance decreases depending on the thickness and material, and adhesive layers having different refractive indexes It has been found that light extraction efficiency is reduced by using, and the occurrence of unevenness becomes a new problem due to peeling and non-uniform adhesion.
JP 2000-148032 A JP 2006-59543 A

  Accordingly, the object of the present invention is to provide a light emitting efficiency and no peeling by bonding the exit surface of the surface light emitting element, that is, the sealing film and the light extracting film in the present invention without using a conventional adhesive layer. Another object of the present invention is to provide a method for producing an organic electroluminescent surface light emitter that is less likely to cause unevenness due to uniform adhesion, and an organic electroluminescent surface light emitter.

  The above object of the present invention is achieved by the following configurations.

  1. Organic electroluminescence surface emission in which a light extraction film having a plurality of concavo-convex structures is bonded onto a sealing film laminated on a light emitting side electrode of a light emitting element having an organic light emitting layer sandwiched between a pair of electrodes A method for producing a body, wherein after the concave-convex structure of the light extraction film is formed of a curable resin, the concave-convex structure is adhered to the sealing film in a half-cured state and cured by a curing means. A method for producing an organic electroluminescent surface light emitter, which is bonded.

  2. 2. The method for producing an organic electroluminescent surface-emitting body according to 1 above, wherein the curing means is at least one of heating and active ray irradiation.

  3. 3. The method for producing an organic electroluminescent surface light emitter according to 1 or 2, wherein the light extraction film or the sealing film is subjected to a surface modification treatment.

  4). An organic electroluminescent surface light emitter manufactured by the method for manufacturing an organic electroluminescent surface light emitter according to any one of 1 to 3 above.

  5. 5. A display device using the organic electroluminescent surface light emitter described in 4 above.

  6). 5. An illuminating device using the organic electroluminescent surface light emitter described in 4 above.

  According to the present invention, the emission surface of the organic electroluminescence light-emitting element, that is, in the present invention, the sealing film and the light extraction film are bonded without using a conventional adhesive layer, so that the light extraction efficiency is high and there is no peeling. In addition, it is possible to provide a method for producing an organic electroluminescent surface light emitter and an organic electroluminescent surface light emitter that are less likely to cause unevenness due to uniform adhesion.

  Further, by using the organic electroluminescence surface light emitter, a display device with high contrast and no occurrence of color unevenness and a lighting device with high luminance can be obtained.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  The method for producing an organic electroluminescent surface light emitter according to the present invention includes a sealing layer formed on a light emitting side electrode of a light emitting element having an organic light emitting layer sandwiched between a pair of electrodes. A method for producing an organic electroluminescent surface light emitter, wherein a light extraction film having a plurality of uneven structures is adhered on a stop film, wherein the uneven structure of the light extraction film is formed of a curable resin, and then a half-cure In this state, the concavo-convex structure is adhered to the sealing film while being cured by a curing means.

  Here, “close contact” in the present invention refers to a state in which objects are in contact with each other without forming an air layer therebetween.

  As described above, the exit surface of the surface light emitting element and the light extraction film have conventionally been provided with a means for bonding the concavo-convex structure of the light extraction film via an adhesive layer. As a result of the use of adhesive layers with different refractive indexes, the light extraction efficiency is also reduced. Further, through the adhesive layer, unevenness due to peeling or non-uniform adhesion occurs. It was. As in the present invention, the concavo-convex structure is formed in a half-cured state after forming the concavo-convex structure of the light-extraction film with a curable resin without interposing the conventional adhesive layer between the exit surface of the surface light-emitting element and the light-extraction film. The organic electroluminescence surface light emitter has a high light extraction efficiency, does not peel off, and does not cause unevenness because it adheres uniformly to the sealing film while being adhered to the sealing film. It has been found that a method can be provided.

  Hereinafter, the present invention will be described in detail.

<Adhesive means>
First, the bonding means which is a feature of the present invention will be described.

  The organic electroluminescent surface light emitter (hereinafter also referred to as organic EL surface light emitter) of the present invention has a structure in which an organic electroluminescent light emitting element (hereinafter also referred to as organic EL light emitting element) and a light extraction film are joined. It is a feature of the present invention that the emission surface of the light emitting element and the light extraction film are bonded by curing of the curable resin without interposing the adhesive layer described in the preceding example.

  Specifically, the concavo-convex structure of the light extraction film is formed using a curable resin, and is adhered to the sealing film while being in a half-cured state, and then the curable resin is cured. This is a method of curing by means and firmly bonding to the sealing film.

  The curable resin used may be either an actinic ray curable resin or a thermosetting resin, or a combination of both. The actinic radiation curable resin is superior in terms of strength, ease of handling, and wet heat durability after curing, so the total amount is actinic radiation curable resin, or the proportion of actinic radiation curable resin used is It is preferable to make it 60 mass% or more.

  The actinic radiation curable resin is mainly composed of a resin that is cured through a crosslinking reaction upon irradiation with actinic rays (also referred to as actinic energy rays) such as ultraviolet rays and electron beams. As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and cured by irradiation with actinic radiation such as ultraviolet rays or electron beams to form a curable resin. .

  Typical examples of the actinic radiation curable resin include an ultraviolet curable resin, an electron beam curable resin, and the like, but a resin curable by ultraviolet irradiation is preferable from the viewpoint of excellent adhesion and mechanical strength.

  As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, ultraviolet curable acrylate resins are preferred.

  As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, ultraviolet curable acrylate resins are preferred.

  As the ultraviolet curable acrylate resin, a polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups and / or methacryloyloxy groups in the molecule.

  Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, glycerin triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol Ritolol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, Tetramethylol methane trimethacrylate, tetramethylol methane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate Acrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate, isobornyl acrylate and the like preferably. These compounds are used alone or in admixture of two or more. Moreover, oligomers, such as a dimer and a trimer of the said monomer, may be sufficient.

  Moreover, it is preferable to contain a photoinitiator for concavo-convex structure formation for acceleration | stimulation of hardening of actinic radiation curable resin. The amount of the photopolymerization initiator is preferably contained in a mass ratio of photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100.

  Specific examples of the photopolymerization initiator include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.

  On the other hand, as a thermosetting resin, for example, a silicone resin, an acrylic resin, an epoxy resin, a polyimide resin, a urethane resin, an allyl ester resin, a resin containing an adamantane structure, a resin containing a silsesquioxane structure Alternatively, a resin having an organic-inorganic hybrid structure can be used. As the actinic radiation curable resin, for example, an ultraviolet curable resin is used. Examples of the ultraviolet curable resin include an unsaturated polyester resin, an epoxy resin, a vinyl ester resin, a phenol resin, a thermosetting polyimide resin, and a thermosetting polyamideimide.

As unsaturated polyester resin, for example, orthophthalic acid resin, isophthalic acid resin, terephthalic acid resin, bisphenol resin, propylene glycol-maleic acid resin, dicyclopentadiene or derivatives thereof are introduced into the unsaturated polyester composition. Low-shrinkage resin with low styrene volatile resin and thermoplastic resin (polyvinyl acetate resin, styrene / butadiene copolymer, polystyrene, saturated polyester, etc.) with low molecular weight or film-forming wax compound added Reactive types such as bromating unsaturated polyester directly with Br ₂ or copolymerizing heptic acid or dibromoneopentyl glycol, halides such as chlorinated paraffin, tetrabromobisphenol, antimony trioxide, phosphorus compounds Combination Additive-type flame retardant resin that uses sesame or aluminum hydroxide as an additive, toughness resin that is hybridized with polyurethane or silicone, or toughened with IPN (high strength, high elastic modulus, high elongation), etc. is there.

  Examples of the epoxy resin include glycidyl ether type epoxy resins including bisphenol A type, novolak phenol type, bisphenol F type, brominated bisphenol A type, glycidyl amine type, glycidyl ester type, cyclic aliphatic type, and heterocyclic epoxy type. The special epoxy resin containing can be mentioned.

  Examples of vinyl ester resins include those obtained by dissolving an oligomer obtained by a ring-opening addition reaction between an ordinary epoxy resin and an unsaturated monobasic acid such as methacrylic acid in a monomer such as styrene. There are also special types such as vinyl monomers having vinyl groups at the molecular ends and side chains.

  Examples of vinyl ester resins of glycidyl ether type epoxy resins include bisphenol type, novolak type, brominated bisphenol type, etc., and special vinyl ester resins include vinyl ester urethane type, isocyanuric acid vinyl type, side chain vinyl ester type, etc. There is. The phenol resin is obtained by polycondensation using phenols and formaldehydes as raw materials, and there are a resol type and a novolac type.

  Examples of thermosetting polyimide resins include maleic acid-based polyimides such as polymaleimide amine, polyamino bismaleimide, bismaleimide, diallyl bisphenol-A resin, bismaleimide / triazine resin, nadic acid-modified polyimide, and acetylene-terminated polyimide. There is.

  Heating can be performed with hot air, infrared rays, a heating roll, microwave, or the like, but it is preferable to perform the heating with hot air in terms of simplicity.

  The heating temperature is preferably increased stepwise from 30 to 180 ° C, and preferably in the range of 50 to 140 ° C. The heating temperature for curing the thermosetting resin to a half-cure state and the temperature for curing performed on the sealing film may be the same or different, and the latter temperature is preferably set high.

  The concavo-convex structure of the present invention may contain additives and solvents in addition to the curable resin. Examples of the additives include a heat stabilizer, a light-resistant stabilizer, an ultraviolet absorber, an antistatic agent, a lubricant, and a plastic. Agents, particles, fillers and the like can be mentioned, and the content thereof can be selected within a range not impairing the object of the present invention.

  Here, the method of bonding the concavo-convex structure of the light extraction film and the sealing film via the curable resin will be specifically described with an example using an actinic radiation curable resin.

  Apply the actinic radiation curable resin together with a suitable solvent on a transparent substrate with a bar coater or extrusion coater, etc., and press the mold with irregularities of the desired size and depth before the resin is cured. After that, actinic radiation is irradiated from the transparent substrate side until the actinic radiation curable resin is half-cured (semi-cured), and immediately peels to form a concavo-convex structure on the transparent substrate. Next, while the concavo-convex structure formed is half-cured (semi-cured), it is in close contact with the sealing film, and in this state, irradiation with active rays is further performed to perform main curing, thereby realizing strong adhesion.

The actinic radiation curable resin is preferably an ultraviolet curable resin. In this case, the ultraviolet ray to be irradiated can be a light source such as a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, or a xenon arc. The irradiation conditions vary depending on individual lamps, but the amount of light irradiated may be any degree 20~10000mJ / cm ^2, preferably from 50~2000mJ / cm ^2. The irradiation time is preferably 0.5 seconds to 5 minutes, and more preferably 3 seconds to 2 minutes in view of the curing efficiency and work efficiency of the ultraviolet curable resin.

  The above “semi-curing” means irradiation with active rays or heating in the case of a thermosetting resin so that the gel fraction of the curable resin measured by the following measurement is 30 to 80% by mass. If the gel fraction of the semi-cured curable resin is less than 30% by mass, the degree of crosslinking is insufficient, resulting in low mechanical strength and poor handleability, while the gel fraction is 80% by mass. When it exceeds, adhesive strength with a sealing film will fall.

  In the case of ultraviolet rays, for example, UVC (250-260 nm), UVB (280-320 nm), UVA (320-390 nm), and UVV (395) are measured with an ultraviolet light amount measuring device (manufactured by EIT, UV Power Pack). -445 nm) is obtained, and the conditions under which the curable resin is “semi-cured” are appropriately determined.

<Gel fraction>
About 0.1 g of semi-cured curable resin was taken and weighed to measure the mass (W1). Next, this was wrapped in a microporous tetrafluoroethylene membrane (membrane mass W2), immersed in about 50 ml of ethyl acetate for 7 days, and then the soluble component was extracted. This was dried and the total mass (W3) was measured. From these measured values, the gel fraction (mass%) of the curable resin semi-cured by the following formula is obtained.

Gel fraction (mass%) = {(W3-W2) / W1} × 100
Further, in order to improve the adhesion with the sealing film, the light extraction film or the sealing film is preferably subjected to a surface modification treatment, and more preferably, the sealing film is subjected to a surface modification treatment. .

  Various methods including a conventionally known method can be used for the surface modification treatment. For example, more preferable methods include corona discharge treatment, atmospheric pressure plasma treatment, and UV irradiation treatment.

  For the corona discharge treatment, various types of corona surface reformers (for example, Corona Master manufactured by Shinko Electric Measurement Co., Ltd.) may be used. For example, power supply: AC100V, output voltage: 0-20kV, oscillation frequency: 0-40kHz At 0.1 to 60 seconds and at a temperature of 0 to 60 ° C.

  In the atmospheric pressure plasma treatment, various types of atmospheric pressure plasma generators (for example, Aiplasma manufactured by Matsushita Electric Works Co., Ltd.) may be used. For example, the plasma treatment speed is 10 to 100 mm / s, and the power source is 200 or 220V AC (30A). ), Compressed air: 0.5 MPa (1 NL / min), 10 kHz / 300 W to 5 GHz, power: 100 W to 400 W, irradiation time: 0.1 second to 60 seconds.

The same applies to UV irradiation, and various types of UV-LED irradiation devices (for example, UV-LED irradiation device ZUV-C30H manufactured by OMRON Corporation) may be used. For example, wavelength: 200 to 400 nm, power source: 100 V AC, light source The peak illuminance is 400 to 3000 mW / cm ² and the irradiation time is 1 to 60 seconds.

<< Organic electroluminescence surface emitter >>
Next, the organic EL surface light emitter according to the present invention will be described in detail.

  Organic EL light emitting elements include so-called bottom emission types and top emission types. A bottom emission type organic EL light-emitting device includes an insulating substrate such as a glass substrate, a transparent electrode (ITO or the like) as a first electrode or one electrode, and a multilayer organic film (an organic light-emitting layer) that emits light by applying an electric field. In other words, the organic EL light-emitting element is configured by a light-emitting mechanism in which reflective metal electrodes as the second electrode or the other electrode are sequentially stacked. A large number of organic EL light emitting elements are arranged in a matrix, and another substrate or sealing film called a sealing can is provided to cover the laminated structure, thereby blocking the light emitting structure from the outside atmosphere. Then, for example, by applying an electric field between the transparent electrode as the anode and the metal electrode as the cathode, carriers (electrons and holes) are injected into the organic multilayer film, and the organic multilayer film emits light. This light emission is emitted from the glass substrate side to the outside.

  On the other hand, in the top emission type organic EL light emitting device, one of the electrodes described above is a reflective metal electrode, the other electrode is a transparent electrode such as ITO, and the light emitting layer is formed by applying an electric field therebetween. It is characterized by emitting light and emitting the emitted light from the other electrode side. The top emission type has a feature that it can also be used as a light emitting area on the drive circuit. In the top emission type, a transparent material such as a glass plate or a transparent sealing film (sealing film) is used as a sealing can in the bottom emission type.

In general, an organic EL light-emitting element has a problem in that moisture, oxygen, or the like invades into a cathode or an organic layer, thereby causing deterioration such as a decrease in luminance and dark spots and edge growth. In order to prevent the intrusion of moisture and oxygen, sealing for protecting the cathode and the organic layer is indispensable. As this sealing means, the following configuration has been proposed. That is,
(1) Means for sandwiching and sealing a substrate on which a circuit and a light emitting portion are formed with a sealing substrate.

(2) Means for sealing by forming a thin film of an organic substance (resin), an inorganic compound, a metal or the like having a low gas permeability on the entire circuit and the light emitting part by forming a single layer or a combination of multiple layers.
Etc. In the present invention, the sealing film mentioned in (2) is used.

  First, an organic EL surface light emitter according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. The organic EL surface light emitter of the present invention is not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  As a light extraction film, as shown in FIGS. 1 (a), 1 (b), 2 (a), and 2 (b), a truncated pyramid shape (FIG. 1) in which the tip side contracts on one side of the translucent substrate 11; It is preferable to use a prism array sheet 10 </ b> A in which a truncated cone-like (FIG. 2) concavo-convex structure 12 is formed continuously in the vertical and horizontal directions. In the figure, a quadrangular pyramid-shaped convex portion and a frustum-shaped convex portion are shown, but the shape is not limited to these. Triangular frustum, hexagonal frustum, honeycomb shape, elliptical pyramid shape, polygonal pyramid shape, and a continuous pyramid shape that is a circle, an ellipse and a polygon, and an upper surface is an ellipse, a circle, and a polygon. A prism array sheet formed as described above may be used. In the present invention, the most preferable concavo-convex structure is a prism array sheet having a truncated cone-shaped convex portion shown in FIG.

  As a manufacturing method of the concavo-convex structure of the prism array sheet, there are a method of manufacturing a mold having concavo-convex shape as a molded product, a method of printing a concavo-convex surface by flexographic printing, a method of attaching a convex portion by an inkjet method, etc. In view of reproducibility and productivity, a method using a mold is preferable. Although the manufacturing method of the prism array sheet 10A using a metal mold | die is shown below, this invention is not limited to this.

  In order to form the concavo-convex structure, a mold having a desired recess is produced by etching by hydrofluoric acid treatment or solvent treatment, hot pressing, injection molding, extrusion molding, etc., and the curable resin is used with this mold. In general, a mold is formed by pouring or pressing, followed by peeling. For example, a mold is pressed against the translucent substrate 11 on which the curable resin layer is coated with a predetermined thickness, and then the active beam is irradiated from the translucent substrate side or heated to cure the curable resin layer. It is preferable that the prism array sheet 10A is manufactured by peeling from the mold.

  As a material for the light-transmitting substrate 11, a material that is substantially transparent in the visible light region is preferably used. Specifically, the visible light transmittance of the light extraction film and the curable resin is preferably 75% or more in order to develop good light extraction efficiency. The visible light transmittance (%) can be calculated by measuring a reflection spectrum based on JIS R5756 using a Hitachi U-4000 spectrophotometer.

Specific examples of the translucent substrate material include cellulose ester resins such as triacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate, polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, cycloolefin polymer, Amorphous thermoplastic resins such as cross-linked polyethylene resin, polyvinyl chloride resin, polyarylate resin, polyphenylene ether resin, modified polyphenylene ether resin, polyetherimide resin, polysulfone resin, polyether ketone resin, polyethylene terephthalate, polyethylene resin, It is preferable to use crystalline thermoplastic resins such as polypropylene resin, polybutylene terephthalate, aromatic polyester resin, polyacetal resin, and polyamide resin. Arbitrariness. Moreover, a commercially available optical film can also be used,
For example, Konica Minolta Op K.K. Preferably used. In addition, cycloolefin polymer films such as ZEONOR (manufactured by ZEON CORPORATION) and ARTON (manufactured by JSR Corporation) are also preferably used.

  The translucent substrate of the present invention is preferably formed into a film, and is formed into a long film by a known solution casting method or melt casting method.

  The light extraction film may or may not contain particles, but as a refractive index adjusting agent so as to have a refractive index difference of 0.0 or more and 0.3 or less with respect to the refractive index of the sealing film optically. It is preferred to add particles.

  The particles preferably have a volume average dispersed particle diameter of 1 nm or more and less than 100 nm, more preferably 1 nm or more and 70 nm or less, and still more preferably 1 nm or more and 50 nm or less.

  The shape of the particles is not particularly limited, but spherical fine particles are preferably used. Further, the particle size distribution is not particularly limited, but in order to achieve the effect of the present invention more efficiently, a material having a relatively narrow distribution is preferable to a material having a wide distribution. Used. The shape and distribution of the particles can be confirmed using SEM and TEM.

  The particles are preferably inorganic particles, and examples of the inorganic particles include oxide fine particles. More specifically, for example, silica, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, yttrium oxide, lanthanum oxide, oxidation Examples include cerium, indium oxide, tin oxide, lead oxide, double oxides composed of these oxides, such as lithium niobate, potassium niobate, lithium tantalate, etc., or phosphates, sulfates, etc. it can.

  In the light extraction film preparation process and molding process according to the present invention, various additives (also referred to as compounding agents) can be added as necessary. There are no particular restrictions on the additives, but stabilizers such as antioxidants, heat stabilizers, light stabilizers, weather stabilizers, UV absorbers and near infrared absorbers; resin modifiers such as lubricants and plasticizers An anti-clouding agent such as a soft polymer or an alcohol compound; a colorant such as a dye or a pigment; an antistatic agent or a flame retardant; These compounding agents can be used alone or in combination of two or more, and the compounding amount is appropriately selected within a range not impairing the effects described in the present invention. In the present invention, in particular, the light extraction film preferably contains a plasticizer or an antioxidant in order to avoid handling and coloring due to long-term use.

  The plasticizer is not particularly limited, however, phosphate ester plasticizer, phthalate ester plasticizer, trimellitic ester plasticizer, pyromellitic acid plasticizer, glycolate plasticizer, citrate ester A plasticizer, a polyester plasticizer, etc. can be mentioned.

  In the phosphate ester plasticizer, for example, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc. Trimellitic plasticizers such as diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, diphenyl phthalate, dicyclohexyl phthalate, etc. For pyromellitic acid ester plasticizers such as phenyl trimellitate, triethyl trimellitate, etc. Examples of glycolate plasticizers such as tilpyromelitate, tetraphenylpyromellitate, and tetraethylpyromellitate include triacetin, tributyrin, ethylphthalylethyl glycolate, methylphthalylethyl glycolate, and butylphthalylbutyl glycolate. In the citrate plasticizer, for example, triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate, etc. Can be mentioned. Furthermore, when it is necessary to prevent coloring due to handling at high temperatures, it is also preferable to use high-purity amide waxes or fatty acid esters. For example, amides such as ethylenebisstearic acid amide, erucic acid, oleic acid, monoesters such as methyl laurate, butyl stearate, behenyl behenate, neopentyl polyol long chain fatty acid ester and dipentaerythritol long chain fatty acid ester It is preferable to use an ester of a polyol.

  Examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. Among these, phenolic antioxidants, particularly alkyl-substituted phenolic antioxidants are preferred. By blending these antioxidants, it is possible to prevent lens coloring and strength reduction due to oxidative degradation during molding without lowering transparency, heat resistance and the like. These antioxidants can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within a range not impairing the object of the present invention, but the thermoplastic composite material of the present invention. Preferably it is 0.001-20 mass parts with respect to 100 mass parts, More preferably, it is 0.01-10 mass parts.

  A conventionally well-known thing can be used as a phenolic antioxidant, for example, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2 , 4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate and the like, and JP-A Nos. 63-179953 and 1-168643. Acrylate compounds described in Japanese Patent Publication No. 1; octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis (4-methyl-6-tert-butylphenol) ), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5 Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenylpropionate)) methane [ie pentaerythrmethyl- Tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenylpropionate))], triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate) Alkyl-substituted phenolic compounds such as 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1, 3,5-triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine What triazine group-containing phenol compound; and the like.

  The phosphorus antioxidant is not particularly limited as long as it is usually used in the general resin industry. For example, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) Phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10 Monophosphite compounds such as -dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4'-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite ), 4,4'-isopropylidene-bis (phenyl-di-alkyl (C12-C15) phosphite) Like diphosphite compounds such as. Among these, monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.

  Examples of the sulfur-based antioxidant include dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3-thiodiprote. Pionate, pentaerythritol-tetrakis- (β-lauryl-thio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, etc. Can be mentioned.

  In addition, amine-based antioxidants such as diphenylamine derivatives, nickel and zinc thiocarbamates, and the like can also be used as antioxidants.

  Examples of the light-resistant stabilizer include benzophenone-based light-resistant stabilizer, benzotriazole-based light-resistant stabilizer, hindered amine-based light-resistant stabilizer, etc., but in the present invention, from the viewpoint of lens transparency, color resistance, etc., hindered amine-based It is preferable to use a light stabilizer (HALS). As specific examples of such HALS, those having a low molecular weight, medium molecular weight and high molecular weight can be selected.

  For example, LA-77 (manufactured by ADEKA), Tinuvin 765 (manufactured by Ciba Japan), Tinuvin 123 (manufactured by Ciba Japan), Tinuvin 440 (manufactured by Ciba Japan), Tinuvin 144 ( Ciba Japan), Hostavin N20 (Hoechst) medium molecular weight LA-57 (made by ADEKA), LA-52 (made by ADEKA), LA-67 (made by ADEKA) ), LA-62 (manufactured by ADEKA Corporation), and those having a larger molecular weight, LA-68 (manufactured by ADEKA Corporation), LA-63 (manufactured by ADEKA Corporation), Hostavin N30 (manufactured by Hoechst), Chimassorb 944 (Ciba Japan Co., Ltd.), Chimassorb 2020 ( (Ba Japan), Chimassorb 119 (Ciba Japan), Tinuvin 622 (Ciba Japan), CyasorbUV-3346 (Cytec), CyasorbUV-3529 (Cytec), Uvasil 299 (GLC), and the like. .

  The compounding amount of the compounding agent with respect to the light extraction film according to the present invention is preferably 0.01 to 20 parts by mass, more preferably 0.02 to 15 parts by mass, and particularly preferably 0.0 to 15 parts by mass with respect to 100 parts by mass of the resin. 05 to 10 parts by mass. If the amount added is too small, the effect of improving light resistance cannot be obtained sufficiently, and coloring occurs when used outdoors for a long time. On the other hand, if the blending amount of HALS is too large, haze is likely to occur and transparency is deteriorated.

  Next, the structure of the organic EL surface light emitter according to the present invention will be described with reference to the drawings.

  As shown in FIG. 3, an organic EL light emitting element 20 composed of a transparent electrode 22, a counter electrode 24, and a sealing film 21 provided on the transparent electrode 22 with an organic EL light emitting layer 23 interposed therebetween is used. The tip surface 12a of the concavo-convex structure 12 having a truncated cone shape in the prism array sheet 10A is adhered to and adhered to the light emission surface 21a of the light emitted from the organic EL light emitting element 20, and the organic EL surface light emitting body 30 is adhered. Formed.

  As described above, when the tip surface 12a of the concavo-convex structure 12 having a truncated cone shape in the prism array sheet 10A is brought into close contact with the emission surface 21a of the organic EL light emitting element 20, the concavo-convex structure 12 of the prism array sheet 10A is organic. While the shape is contracted toward the emission surface 21a of the EL light emitting element 20, the space 13 between the concavo-convex structure 12 of the prism array sheet 10A and the emission surface 21a of the organic EL light emitting element 20 becomes an air layer. .

  Then, the organic EL light emitting element 20 is caused to emit light by adhering the tip surface 12a of the concavo-convex structure 12 having a truncated cone shape in the prism array sheet 10A to the emission surface 21a of the organic EL light emitting element 20 in this way. As shown in FIG. 4, when the prism array sheet is not provided, the light totally reflected on the emission surface 21a of the organic EL light emitting element 20 is bonded to the tip surface 12a of the concavo-convex structure 12 of the prism array sheet 10A. In the portion thus formed, the light is guided into the prism array sheet 10A without being totally reflected.

  Then, most of the light guided into the prism array sheet 10A in this way is the concavo-convex structure 12 which is an interface between the concavo-convex structure 12 contracted toward the emission surface 21a of the organic EL light emitting element 20 and the space portion 13. The reflected light is reflected on the inclined surface 12b, and the reflected light is guided to the emission surface 14 of the prism array sheet 10A and emitted. Further, as shown in FIG. 4, even if the light is emitted from the part of the emission surface 21a where the tip surface 12a of the concavo-convex structure 12 of the prism array sheet 10A is not bonded, the light is emitted in the vertical direction from the emission surface 21a. Although the traveling direction of the light is slightly changed on the inclined surface 12b of the concavo-convex structure 12, it is emitted to the front side of the prism array sheet 10A, and the concavo-convex structure in the prism array sheet 10A from the emission surface 21a. Light emitted in a direction orthogonal to the inclined surface 12b of the body 12 is guided into the concavo-convex structure 12 from the inclined surface 12b, and is reflected by the inclined surface 12b on the opposite side of the concavo-convex structure 12 to be a prism. The light is emitted to the front side of the array sheet 10A.

  Here, when the prism array sheet is not provided as described above, the light totally reflected on the emission surface 21a of the organic EL light emitting element 20 is reflected from the front end surface 12a of the concavo-convex structure 12 to the prism array sheet 10A. In order to be guided appropriately inside, the difference between the refractive index of the prism array sheet 10A and the refractive index of the sealing film 21 of the organic EL light emitting element 20 is 0.0 or more and 0.3 or less. It is preferable to make it.

  In addition, when providing the prism array sheet 10A with the concavo-convex structure body 12 having a frustum shape as described above, the apex angle θ at which the inclined surfaces 12b of the concavo-convex structure body 12 cross each other increases, and the above organic When the inclination angle α of the inclined surface 12b of the concavo-convex structure 12 with respect to the emission surface 21a of the EL light emitting element 20 becomes too small, the light totally reflected on the emission surface 21a of the organic EL light emitting element 20 when no prism array sheet is provided. Even if the light is guided into the prism array sheet 10A, the light is not incident on the inclined surface 12b of the concavo-convex structure 12, but is guided to the output surface 14 of the prism array sheet 10A, and the light is emitted from the prism array sheet 10A. The intensity of the light that is totally reflected on the surface 14 and returned from the output surface 14 of the prism array sheet 10A. Decreases.

  On the other hand, when the apex angle θ at which the inclined surfaces 12b of the concavo-convex structure 12 intersect each other becomes small, and the inclination angle α of the inclined surface 12b of the concavo-convex structure 12 with respect to the emission surface 21a of the organic EL light emitting element 20 becomes too large. The light guided into the prism array sheet 10A as described above is not reflected by the inclined surface 12b of the concavo-convex structure 12, passes through the concavo-convex structure 12, and is guided to the space 13, and further The light passes through the space 13 and is guided again into the prism array sheet 10A, and this light is totally reflected and returned by the exit surface 14 of the prism array sheet 10A as described above. The intensity of the light emitted from the exit surface 14 of 10A decreases.

  For this reason, the apex angle θ at which the inclined surfaces 12b of the concavo-convex structure 12 intersect each other is (1 / n−0.35) when the refractive index for light having a wavelength of 550 nm in the prism array sheet 10A is n. ) <Sin θ <(1 / n + 0.3), and more preferably 1 / n <sin θ <(1 / n + 0.25). Further, when the inclination angle α is in the range of 45 ° ≦ α ≦ 70 °, the light extraction efficiency is high and preferable.

  FIG. 5 shows an enlarged schematic view of a portion where the prism array sheet 10 </ b> A is bonded to the emission surface of the organic EL light emitting element 20.

  The leading end surface 12a of the concavo-convex structure 12 of the prism array sheet 10A is finally cured and bonded to the emission surface 21a of the organic EL light emitting element 20 via a curable resin.

  Further, the possible range of the optical height h of the concavo-convex structure 12 shown in FIG. 5 varies depending on the apex angle θ in the concavo-convex structure 12 and the pitch p of the concavo-convex structure 12, but generally If the optical height h of the concavo-convex structure 12 is too low, light that is totally reflected when no prism array sheet is provided on the emission surface 21a of the organic EL light-emitting element 20 enters the prism array sheet 10A. Even if the light is guided, the light does not strike the inclined surface 12b of the concavo-convex structure 12, but is guided to the exit surface 14 of the prism array sheet 10A, and is totally reflected and returned by the exit surface 14 of the prism array sheet 10A. It becomes like this. On the other hand, when the optical height h of the concavo-convex structure 12 becomes too high, a portion that is not used for light reflection is generated on the inclined surface 12b of the concavo-convex structure 12, and the pitch p of the concavo-convex structure 12 is the same. In this case, the area of the front end surface 12a of the concavo-convex structure 12 bonded to the emission surface 21a of the organic EL light emitting element 20 is reduced, and the amount of light guided into the prism array sheet 10A is reduced. For this reason, it is preferable that the optical height h of the concavo-convex structure 12 satisfies the condition of 0.28 p ≦ h ≦ 1.1 p with respect to the pitch p of the concavo-convex structure 12. Here, the pitch p of the convex portions refers to the distance between the centers of adjacent convex portions. In the case of a display application, the pitch p of the protrusions is preferably in the range of half the size of one pixel of the display to 1 μm. The pitch of the protrusions depends on the resolution of the display to be used, but is generally in the range of 67 μm to 1 μm from the resolution of a commercially available display. The size of a pixel represents the size of one side when a square pixel is assumed. In addition, when the shape of a pixel is another shape, it means the minimum length when a straight line passing through the center of one pixel is drawn. Unlike the case of the light extraction film for illumination, when used for display applications, if the pitch is larger than 50% of the pixel size of the display used, sufficient light extraction efficiency may not be obtained or the resolution may be reduced. May cause. Therefore, it is preferably 50% or less of the size of the pixel to be used, and more preferably 1/3 or less of the pixel.

  In addition, if the pitch of the projections is in a range smaller than 1 μm, a light interference phenomenon or the like may be caused, leading to a decrease in image quality, and if the pitch is equal or smaller than the wavelength, the light extraction effect is sufficiently obtained. As a result, the pitch of the convex portions is preferably 1 μm or more.

  Hereinafter, a specific configuration of the organic EL surface light emitter having the sealing film will be described in detail.

(Cross-section structure)
With reference to FIG. 6, the cross-sectional structure of the organic EL light emitting device 100 will be described. However, the following description is an example, and the present invention is not limited to this.

  The organic EL light emitting device 100 is a so-called “top emission structure” organic EL light emitting device. In the top emission structure, light is extracted not from the element substrate side but from the sealing film side, so that there is an effect that a large light emission area can be secured without being affected by the size of various circuits arranged on the element substrate. Therefore, luminance can be secured while suppressing voltage and current, and the lifetime of the light-emitting element can be maintained long.

  The organic EL light emitting device 100 includes a plurality of light emitting devices 121 each having a light emitting layer 112 (organic light emitting layer) sandwiched between an anode 110 and a cathode 111 (a pair of electrodes), and a pixel partition wall 113 separating the light emitting devices 121. 120A and a sealing film 119 disposed opposite to the element substrate 120A are provided.

(Element board)
As shown in FIG. 6, in the organic EL light emitting device 100, an inorganic insulating layer 114 made of silicon nitride or the like is coated on an element substrate 120A on which various wirings (for example, TFTs) are formed. In addition, a contact hole (not shown) is formed in the inorganic insulating layer 114, and the above-described anode 110 is connected to the driving TFT 123. On the inorganic insulating layer 114, a planarizing layer 116 is formed, in which a metal reflector 115 made of an aluminum alloy or the like is provided.

  On the planarizing layer 116, an anode 110 and a cathode 111 are formed with a light emitting layer 112 interposed therebetween, and the light emitting element 121 is configured. Insulating pixel partition walls 113 are arranged so as to divide the light emitting elements 121.

  In this embodiment, the anode 110 is a metal oxide conductive film such as ITO (Indium Thin Oxide) having a high hole injection layer having a work function of 5 eV or more.

  In the present embodiment, because of the top emission structure, the anode 110 does not necessarily need to use a light-transmitting material, and a metal electrode made of aluminum or the like may be used. When this configuration is adopted, the above-described metal reflector 115 need not be provided.

  As a material for forming the cathode 111, since this embodiment has a top emission structure, it needs to be a light-transmitting material, and thus a transparent conductive material is used. As the transparent conductive material, ITO is suitable, but other than this, for example, an indium oxide / zinc oxide based amorphous transparent conductive film (Indium Zinc Oxide: IZO) is used. be able to. In this embodiment, ITO is used.

  For the cathode 111, a material having a large electron injection effect (a work function of 4 eV or less) is preferably used. For example, calcium, magnesium, sodium, lithium metal, or a metal compound thereof. Examples of the metal compound include metal fluorides such as calcium fluoride, metal oxides such as lithium oxide, and organometallic complexes such as acetylacetonato calcium. In addition, these materials alone have high electrical resistance and do not function as electrodes, so patterning a metal layer such as aluminum, gold, silver, or copper to avoid the light emitting part, or transparent metals such as ITO or tin oxide You may use in combination with the laminated body with an oxide conductive layer.

  In the present embodiment, a laminate of lithium fluoride, magnesium-silver alloy, and ITO is used by adjusting the film thickness to obtain transparency.

  As a material used for the organic EL light emitting layer, for example, a red light emitting element in which a naphthacene or pentacene derivative described in JP-A-8-311442 is added to the light emitting layer can be given. Examples of light emitting materials include chelate complexes such as tris (8-quinolinolato) aluminum complex, coumarin derivatives, tetraphenylbutadiene derivatives, bisstyrylarylene derivatives, oxadiazole derivatives, and the like as light emitting materials in the visible region from blue to red. In particular, a device using a phenylanthracene derivative as a blue light emitting material is disclosed. Furthermore, Japanese Patent Application Laid-Open No. 2001-160489 discloses the use of an azafluorante compound in a yellow to green light emitting layer.

  The light emitting layer 112 employs a white light emitting layer that emits white light. The white light emitting layer is formed on the entire surface of the element substrate 120A using a vacuum deposition process. As the white luminescent material, a styrylamine-based luminescent material, anthracene-based dopamine (blue), or a styrylamine-based luminescent material, rubrene-based dopamine (yellow) is used.

A triarylamine (ATP) multimer hole injection layer, a TDP (triphenyldiamine) hole transport layer, and an aluminum quinolinol (Alq ₃ ) layer (electron transport layer) are formed on the lower layer or the upper layer of the light emitting layer 112. It is preferable to form a film.

  An electrode protective layer 117 is formed on the element substrate 120A to cover the light emitting element 121 and the pixel partition 113.

  The electrode protective layer 117 is preferably composed of a silicon compound such as silicon oxynitride in consideration of transparency, adhesion, water resistance, and gas barrier properties. The film thickness of the electrode protective layer 117 is preferably 100 nm or more, and the upper limit of the film thickness is preferably set to 200 nm or less in order to prevent generation of cracks due to stress generated by covering the pixel partition wall 113.

  In the present embodiment, the electrode protective layer 117 is formed as a single layer, but may be stacked as a plurality of layers. For example, the electrode protective layer 117 may be composed of a low elastic modulus lower layer and a high water resistance upper layer.

  An organic buffer layer 118 is formed on the electrode protective layer 117 and covers the electrode protective layer 117. The organic buffer layer 118 is disposed so as to fill the uneven portion of the electrode protection layer 117 formed in a concavo-convex shape due to the influence of the shape of the pixel partition 113, and the upper surface thereof is formed substantially flat. The organic buffer layer 118 has a function of relieving stress generated by warping and volume expansion of the element substrate 120A and preventing the electrode protective layer 117 from peeling from the pixel partition 113 having an unstable shape. Further, since the upper surface of the organic buffer layer 118 is substantially flattened, a sealing film 119 described later, which is a hard film formed on the organic buffer layer 118, is also flattened. Therefore, there is no portion where stress is concentrated, and this prevents the occurrence of cracks in the sealing film 119.

  Since the organic buffer layer 118 is formed by a screen printing method under a vacuum under reduced pressure as a raw material main component before curing, all of the organic buffer layer 118 having excellent fluidity and having no solvent or volatile component is a raw material of a polymer skeleton. It is necessary to be an organic compound material, and an epoxy monomer / oligomer having an epoxy group and a molecular weight of 3000 or less is preferably used (monomer definition: molecular weight 1000 or less, oligomer definition: molecular weight 1000 to 3000). For example, bisphenol A type epoxy oligomer, bisphenol F type epoxy oligomer, phenol novolac type epoxy oligomer, polyethylene glycol diglycidyl ether, alkyl glycidyl ether, 3,4-epoxycyclohexenylmethyl-3,4'-epoxycyclohexene carboxylate, ε -Caprolactone-modified 3,4-epoxycyclohexylmethyl 3 ', 4'-epoxycyclohexanecarbochelate, etc., and these may be used alone or in combination.

  Moreover, as the curing agent that reacts with the epoxy monomer / oligomer, one that forms a cured film with excellent electrical insulation and adhesiveness, high hardness, toughness, and excellent heat resistance, excellent transparency, and curing properties. An addition polymerization type with little variation is preferable. For example, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, methyl-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride, 1,2,4,5-benzene Acid anhydride curing agents such as tetracarboxylic dianhydride and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride are preferred. Furthermore, it is easy to cure at low temperature by adding a trace amount of amine compounds such as alcohols and aminophenols that have high molecular weight and are not easily volatilized as reaction accelerators that promote the reaction (ring opening) of acid anhydrides. Become. These curings are performed by heating in the range of 60 to 100 ° C., and the cured film becomes a polymer having an ester bond.

  In order to shorten the curing time, a cation-releasing type photopolymerization initiator may be used, but it is preferable that the reaction is slow so that the curing shrinkage does not rapidly proceed, and the viscosity decreases due to heating after coating. It is preferable that the cured product is finally formed by thermosetting so as to advance the process.

  Furthermore, even if an additive such as a silane coupling agent that improves the adhesion to the electrode protective layer 117 or a sealing film 119 described later, a water capturing agent such as an isocyanate compound, or a fine particle that prevents shrinkage during curing is mixed. good. In addition, since the printing is performed under a reduced pressure atmosphere, the water content is adjusted to 0.01% by mass (100 ppm) or less in order to make it difficult for bubbles to be generated when applied.

  The viscosity of each raw material is preferably 1000 mPa · s (room temperature: 25 ° C.) or more. This is because it does not penetrate into the light emitting layer 112 immediately after coating and a non-light emitting region called a dark spot is not generated. Moreover, as a viscosity of the buffer layer forming material which mixed these raw materials, 500-20000 mPa * s, especially 2000-10000 mPa * s (room temperature) are preferable.

  Moreover, as an optimal film thickness of the organic buffer layer 118, 3-10 micrometers is preferable. When the organic buffer layer 118 is thicker, foreign matter is mixed in to prevent defects in the sealing film 119. However, if the combined thickness of the organic buffer layer 118 exceeds 10 μm, light that diffuses to the side surface increases. Therefore, the efficiency of extracting light is reduced.

  Moreover, as a characteristic after hardening, it is preferable that the elastic modulus of the organic buffer layer 118 is 1 to 10 GPa. If it is 10 GPa or more, the stress at the time of planarizing the pixel partition wall 113 cannot be absorbed, and if it is 1 GPa or less, wear resistance, heat resistance and the like are insufficient.

  On the organic buffer layer 118, a sealing film 119 is formed in a wide range so as to cover the organic buffer layer 118 and cover the terminal portion of the electrode protection layer 117.

The sealing film 119 is for preventing oxygen and moisture from entering, and thus, deterioration of the light-emitting element 121 due to oxygen and moisture can be suppressed. As long as the sealing film is a layer that prevents permeation of oxygen and moisture, the composition and the like are not particularly limited. The oxygen permeability is preferably 0.005 ml / m ² / day or less at 23 ° C. and 0% RH, and the water vapor permeability measured according to the JIS K7129 B method is preferably 0.1 g / m ² / day or less. In consideration of transparency, gas barrier properties, and water resistance, the sealing film is preferably formed of a silicon compound containing nitrogen, that is, silicon nitride or silicon oxynitride. Specifically, inorganic oxides are preferable, and examples include silicon oxide, aluminum oxide, silicon oxynitride, aluminum oxynitride, magnesium oxide, zinc oxide, indium oxide, and tin oxide, and silicon oxide is particularly preferable.

  The elastic modulus of the sealing film 119 is preferably 100 GPa or more, specifically about 200 to 250 GPa. The film thickness of the sealing film 119 is preferably about 200 to 600 nm. This is because if it is less than 200 nm, the coverage with respect to foreign matter is insufficient and a through-hole is partially formed, and the gas barrier property may be impaired. If it exceeds 600 nm, a crack due to stress occurs. Because there is a fear.

  Further, the sealing film 119 may have a laminated structure, or may have a configuration in which the composition is not uniform, and the oxygen concentration particularly changes continuously or discontinuously. In addition, as for the film thickness at the time of setting it as a laminated structure, 200-400 nm is preferable as a 1st sealing film, and if it is less than 200 nm, the surface and side surface coating | cover of the organic buffer layer 118 will run short. As a 2nd sealing film which improves the coating | covering property, such as a foreign material, 200-800 nm is preferable. When the total thickness exceeds 1000 nm, the occurrence frequency of cracks is increased, and this is not preferable from the economical viewpoint.

  Further, in the present embodiment, since the organic EL light emitting device 100 has a top emission structure, the sealing film 119 needs to have light transmittance. Therefore, by appropriately adjusting the material and film thickness, In the embodiment, the light transmittance in the visible light region is set to 80% or more, for example.

  The sealing film may be formed by applying the above-described raw materials by using a spray method, a spin coating method, a sputtering method, an ion assist method, a plasma CVD method, a plasma CVD method under a pressure near atmospheric pressure, or the like. it can.

  Further, the light extraction film 10A is adhered onto the sealing film 119, and the organic EL surface light emitter of the present invention is formed.

<< Display device, lighting device >>
The organic EL surface light emitter of the present invention can be used as a display device, a display, or various light sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Although not limited to this, it can be effectively used for backlights of various display devices combined with a color filter, a light diffusing plate, etc., and as a light source for illumination.

  A display and a lighting device to which the organic EL surface light emitter of the present invention is applied will be described.

  The organic EL surface light emitter of the present invention is used in a multicolor or white display device. In the case of a multicolor or white display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like. When patterning is performed only on the light-emitting layer, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  Moreover, it is also possible to produce the cathode, the electron transport layer, the hole blocking layer, the light emitting layer unit, the hole transport layer, and the anode in this order by reversing the production order. When a DC voltage is applied to the multicolor or white display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The organic EL surface light emitter according to the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a type that directly recognizes a still image or a moving image. It may be used as a display device (display). The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method.

  In the white organic EL surface light emitter used in the present invention, patterning may be performed by a metal mask, an inkjet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned. There is no restriction | limiting in particular as a light emission dopant used for a light emitting layer, For example, if it is a backlight in a liquid crystal display device, a platinum complex and a well-known light emission dopant will be adapted so that it may correspond to the wavelength range corresponding to CF (color filter) characteristic. Any one of them may be selected and combined, or combined with the light extraction film according to the present invention to be whitened.

  As described above, the white organic EL surface light emitter is taken out from the organic EL light emitting element by combining the CF (color filter) and arranging the element and the driving transistor circuit in accordance with the CF (color filter) pattern. By obtaining blue light, green light, and red light through a blue filter, a green filter, and a red filter using white light as a backlight, a full-color organic EL display with a low driving voltage and a long life can be formed.

  Further, the organic EL surface light emitter of the present invention can be applied as a backlight to various display devices. However, a reflective, transmissive, transflective LCD or TN, STN, OCB, HAN, VA It is also preferably used as a backlight of a liquid crystal display device having LCDs of various driving methods such as types (PVA type, MVA type) and IPS type. In particular, a large-screen display device having a screen of 30 or more types, particularly 30 to 54 types, has an effect of obtaining an image with high front luminance and high contrast.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
<Preparation of Organic EL Surface Emitter 101>
The organic EL light emitting device 20 shown in FIG. 3 was produced.

  The organic EL light-emitting element 20 includes a transparent electrode 22, a counter electrode 24, and a sealing film 21 provided on the transparent electrode 22 with an organic EL light-emitting layer 23 sandwiched between the following substrates.

  Here, the substrate of the organic EL light-emitting element 20 is made of a non-alkali glass having a metal reflector having a thickness of 0.7 mm and a size of 40 mm × 52 mm on one side, and the other surface is used as a counter electrode 24 by vacuum deposition. Thus, an electrode made of aluminum having a film thickness of 110 nm was provided.

Then, on the counter electrode 24, m-MTDATA was used as a hole injection material, and a hole injection layer having a thickness of 10 nm was formed by vacuum deposition. Next, α-NPD was used as a hole transport material on the hole injection layer, and a hole transport layer having a thickness of 30 nm was formed by a vacuum deposition method. Then, a CBP is used as a host material on this hole transport layer, and a light emitting material that emits white light is deposited by vacuum deposition so that Ir (ppy) ₃ is contained as a dopant material in an amount of 6% by mass. A light emitting layer having a thickness of 30 nm was formed.

On this light emitting layer, BAlq was vapor-deposited with a thickness of 10 nm by a vacuum vapor deposition method to form a hole blocking layer. Further, Alq ₃ was formed to 40 nm on the hole blocking layer by a vacuum deposition method to form an electron transport layer. Further, LiF was formed to 0.5 nm by a vacuum deposition method to form an electron injection layer. And on this electron injection layer, ITO was formed into a film having a thickness of 110 nm and patterned into an electrode shape by photolithography to form a transparent electrode 22 having a size of 35 × 46 mm.

  Further, a transparent sealing film (sealing film) was prepared by the following procedure, and adhered so as to seal the transparent electrode 22 and below.

<Preparation of transparent sealing film (sealing film)>
As a base material, a UV curable acrylic resin coating film having a thickness of 5 μm is provided on a polyethylene naphthalate film having a thickness of 125 μm (a film made by Teijin DuPont). A transparent sealing film having a refractive index of 1.48, in which two layers of silicon oxide films (SiO ₂ ) were laminated, was produced under the atmospheric pressure plasma discharge treatment apparatus and the following discharge conditions.

(Atmospheric pressure plasma discharge treatment equipment)
Using the atmospheric pressure plasma discharge treatment apparatus, plasma discharge was performed under the following conditions to form a layer 1 having a thickness of about 200 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 95.7% by volume
Thin film forming gas: hexamethyldisiloxane (mixed with nitrogen gas and vaporized by a vaporizer manufactured by Lintec Corporation) 0.3% by volume
Addition gas: 4.0% by volume of hydrogen gas
<Power supply conditions>
1st electrode side Power supply type
Frequency 80kHz
Output density 8W / cm ²
Second electrode side Power supply type High frequency power supply manufactured by Pearl Industrial Co., Ltd.
Frequency 13.56MHz
Output density 7W / cm ²
Next, plasma discharge was performed under the following conditions to form a layer 2 having a thickness of about 250 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 95.9 vol%
Thin film forming gas: Tetraethoxysilane (mixed with nitrogen gas and vaporized by a vaporizer manufactured by Lintec Corporation) 0.1% by volume
Addition gas: 4.0% by volume of hydrogen gas
<Power supply conditions>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
Second electrode side Power supply type High frequency power supply manufactured by Pearl Industrial Co., Ltd.
Frequency 13.56MHz
Output density 7W / cm ²
<Production of light extraction film>
In order to obtain a light extraction film having a plurality of truncated cone-shaped concavo-convex structures, a flat plate mold was cut to produce a truncated cone hole-shaped mold. A thermosetting resin (bisphenol A diglycidyl ether) is applied in a thickness of 20 μm on a TAC substrate (triacetyl cellulose film) that is a light-transmitting substrate, and a frustoconical hole-shaped mold is formed on the coating layer side. After pressing, and then heating from the TAC substrate side to 60 ° C. to cure the coating layer, it was peeled off to obtain a light extraction film (a) having a plurality of convex portions.

  When the following gel fraction was measured, the curable resin layer of the produced light extraction film (a) was 60% by mass and was half-cured (semi-cured).

<Gel fraction>
About 0.1 g of semi-cured curable resin was taken and weighed to measure the mass (W1). Next, this was wrapped in a microporous tetrafluoroethylene membrane (membrane mass W2), immersed in about 50 ml of ethyl acetate for 7 days, and then the soluble component was extracted. This was dried and the total mass (W3) was measured. From these measured values, the gel fraction (mass%) of the curable resin semi-cured by the following formula is obtained.

Gel fraction (mass%) = {(W3-W2) / W1} × 100
The light extraction film (a) has a refractive index of 1.5 with respect to light having a wavelength of 550 nm, an inclination angle α with respect to the bottom surface of the truncated cone-shaped concavo-convex structure 12 is 60 °, and has a height h of 30 convex portions. The average value was 25 μm, and the pitch of the convex portions was 30 μm. The refractive index was measured using an Abbe refractometer. Further, the visible light transmittance of the light extraction film was 90% and had good transparency. The visible light transmittance was calculated by measuring a reflection spectrum based on JIS R5756 using a Hitachi U-4000 spectrophotometer.

  Next, in the state of half cure, the light extraction film (a) was immediately brought into close contact with the sealing film of the organic EL element, and was heated at 80 ° C. to be fully cured to produce an organic EL surface light emitter 101.

<Preparation of organic EL surface light emitter 102>
Instead of the thermosetting resin (bisphenol A diglycidyl ether) used in the light extraction film (a), an ultraviolet curable resin pentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd.) is formed on a TAC substrate (triacetyl cellulose film). And Irgacure 184 (photopolymerization initiator: manufactured by Ciba Japan Co., Ltd.) with a thickness of 30 μm, and the above-mentioned frustoconical hole-shaped mold is pressed against the coating layer side, and then the TAC substrate side Then, the coating layer was cured by irradiating ultraviolet rays, and then peeled off to obtain a light extraction film (b) having a plurality of convex portions.

  When the gel fraction was measured, the curable resin layer of the produced light extraction film (b) was 50% by mass and was half-cured (semi-cured).

  In a state where the ultraviolet curable resin is in a semi-cured state, the organic EL surface light emitter 102 was produced by immediately adhering to the sealing film and irradiating with ultraviolet light to be fully cured.

<Preparation of Organic EL Surface Emitter 103>
The thermosetting resin used in the preparation of the organic EL surface light emitter and the ultraviolet curable resin were mixed at 4: 6, and the curable resin was semi-cured by adjusting the heating and ultraviolet irradiation conditions in the same manner. A light extraction film (c) in a state was prepared, immediately adhered to the sealing film, and heated and irradiated with ultraviolet rays to be fully cured to produce an organic EL surface light emitter 103.

  As a result of measuring the gel fraction, the curable resin of the light extraction film (c) was 50% by mass and confirmed to be semi-cured.

<Preparation of organic EL surface light emitters 104 and 105>
In the production of the concavo-convex structure of the light extraction film (b), ultraviolet irradiation was sufficiently performed to cure the gel fraction to 90% by mass to obtain a light extraction film (d). This is so that the convex end surface of the concavo-convex structure becomes a gap of 1 μm from the sealing film through an adhesive layer having a thickness of 10 μm coated on the sealing film using a thermosetting acrylic resin adhesive. The organic EL surface light-emitting body 104 was fabricated by being buried and bonded in an environment of 25 ° C. and a relative humidity of 55%.

  Similarly, the tip of the convex portion of the concavo-convex structure is formed through an adhesive layer having a thickness of 20 μm, in which the concavo-convex structure of the light extraction film (d) is coated on the sealing film using a UV curable epoxy resin adhesive. The organic EL surface light emitter 105 was manufactured by being buried and bonded in an environment of 25 ° C. and a relative humidity of 55% so that the surface became a gap of 10 μm from the sealing film, and solidified by irradiation with ultraviolet rays.

<Preparation of organic EL surface light emitters 106 and 107>
An acrylic base material (Mitsubishi Rayon Acrypet) was used in place of the TAC base material of the translucent base material. An ultraviolet curable resin pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) was used on an acrylic substrate. After that, the organic EL surface light emitter 106 was produced according to the procedure of the organic EL surface light emitter 102.

  Polycarbonate (Teijin Panlite) was used instead of the TAC substrate of the translucent substrate. For the curable resin and the like, the organic EL surface light emitter 107 was produced in the same procedure as the organic EL surface light emitter 106.

<Preparation of Organic EL Surface Emitter 108>
In the production of the organic EL surface light emitter 102, the organic EL surface light emitter 108 of the present invention was similarly produced except that the sealing film was subjected to a surface modification treatment by the following corona discharge treatment.

  The corona discharge treatment was carried out at 20 ° C. for 10 seconds using Shinko Electric Measurement Co., Ltd. Corona Master PS-1M (14 kV, 15 kHz, 100 V AC).

  Details of the configurations of the organic EL surface light emitters 101 to 108 are shown in Table 1.

<< Evaluation of organic EL surface emitter >>
The following evaluation was performed using the produced organic EL surface light emitters 101 to 108.

(Light extraction efficiency)
It measured using the organic EL luminous efficiency measuring device EL1003 of Precise Gauge Co., Ltd. Measurement conditions were such that a current and voltage of 4 V and 66 mA were applied so that the front luminance of the organic EL light emitting device without a light extraction film was 1000 cd / m ² . It was expressed as a relative value when the front luminance of the organic EL light emitting device without the light extraction film was 1.0.

◎: 1.7 to 1.9 times ○: 1.5 to 1.7 times △: 1.3 to 1.5 times ×: 1.0 to 1.3 times (peeling)
After the produced organic EL surface light emitter was left in an 85 ° C. environment for 200 hours, the adhesion state of the organic EL light emitting element and the light extraction film was visually evaluated. Those where the area of the peeled portion is less than 10% of the entire pasted portion, ◎ when it is 10% to 20% or less, ○ when it is greater than 20% and 50% or less, Δ, when it is 50% or more X. The smaller the area of the peeled portion, the better the peeling.

(Front brightness unevenness)
The organic EL surface light emitter was visually observed from the front, and the observation of luminance unevenness was evaluated according to the following criteria.

○: Brightness unevenness is not observed Δ: Some brightness unevenness is observed ×: Brightness unevenness is clearly observed Table 2 shows the above evaluation results.

  From Table 2, the organic EL surface light emitters 101 to 103, 106, and 107 of the present invention are organic EL surface light emitters that are superior to Comparative Examples 104 and 105 in terms of light extraction efficiency, peeling, and luminance unevenness. I understand that.

  Further, when the organic EL surface light emitters 102 and 108 were left in an 85 ° C. environment for 500 hours and the adhesion state between the organic EL light emitting element and the light extraction film was visually evaluated, the organic EL surface light emitter 102 was ○. However, it was found that the organic EL surface light emitter 108 was ◎, and the adhesion was further improved by the surface modification treatment of the sealing film.

Example 2
Next, the organic EL surface light emitters 101 to 108 are combined with a CF (color filter) and a CF (color filter) pattern, and an element and a driving transistor circuit are combined. When an organic EL display was produced by obtaining blue light, green light, and red light through a green filter and a red filter, the organic EL surface light emitters 101 to 103, 106, 107, and 108 of the present invention were used. It was found that a long-life organic EL display having excellent luminance can be obtained.

Example 3
Next, when the organic EL surface light emitters 101 to 108 were used in place of the backlight incorporated in advance in the 15-inch display VL-150SD manufactured by Fujitsu, which is a VA liquid crystal display device, the organic EL surface light emitter 101 of the present invention was used. It was found that a liquid crystal display device having excellent luminance can be obtained by using ˜103, 106, 107, and 108.

Example 4
Next, the non-light emitting surface of the organic EL surface light emitters 101 to 108 is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (Toagosei Co., Ltd.) is used as a sealing material. Application of LUX TRACK LC0629B), irradiation with UV light from the glass substrate side and curing to form an illumination device, the organic EL surface light emitters 101 to 103, 106, 107, 108 of the present invention are used. It was found that a lighting device having excellent brightness was obtained.

It is a schematic diagram of the light extraction film which has the convex part of the shape which the front end side shrunk. It is a schematic diagram of another light extraction film which has the convex part of the shape which the front end side shrunk. It is a schematic diagram of the organic EL surface light emitter of the present invention. It is a schematic diagram which shows light emission in the organic EL surface light emitter of the present invention. It is the schematic diagram which expanded the mode that the convex part of the light extraction film was adhere | attached. It is a block diagram of the organic EL surface light emitter in the top emission method. It is a schematic diagram which shows the formation process of an uneven structure body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10A Prism array sheet 11 Translucent board | substrate 12 Uneven structure 13 Space part 14 Outgoing surface 20 Organic EL light emitting element 21 Sealing film 21a Outgoing surface 22 Transparent electrode 23 Organic EL light emitting layer 24 Counter electrode 30 Organic EL surface light emitting body 100 Organic EL light emitting device 110 anode (a pair of electrodes)
111 Cathode (a pair of electrodes)
112 Light emitting layer (organic light emitting layer)
117 Electrode protective layer 118 Organic buffer layer 119 Sealing film 120A Element substrate 121 Light emitting element

Claims (6)

Organic electroluminescence surface emission in which a light extraction film having a plurality of concavo-convex structures is bonded onto a sealing film laminated on a light emitting side electrode of a light emitting element having an organic light emitting layer sandwiched between a pair of electrodes A method for producing a body, wherein after the concave-convex structure of the light extraction film is formed of a curable resin, the concave-convex structure is adhered to the sealing film in a half-cured state and cured by a curing means. A method for producing an organic electroluminescent surface light emitter, which is bonded. The method for producing an organic electroluminescence surface-emitting body according to claim 1, wherein the curing means is at least one of heating and actinic ray irradiation. The method for producing an organic electroluminescent surface-emitting body according to claim 1, wherein the light extraction film or the sealing film is subjected to a surface modification treatment. An organic electroluminescent surface light emitter manufactured by the method for manufacturing an organic electroluminescent surface light emitter according to claim 1. A display device comprising the organic electroluminescent surface light emitter according to claim 4. An illuminating device using the organic electroluminescent surface light emitter according to claim 4.

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