JP2015088323A - Organic electroluminescent device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent device which is excellent in durability and luminous efficiency and in which deterioration in display performance due to curling of a substrate is suppressed.SOLUTION: The organic electroluminescent device has a first optical layer containing first particles and a binder, a flexible substrate, a barrier layer, a second optical layer containing second particles and a binder, a first electrode, an organic layer including an organic light-emitting layer, and a second electrode in this order. The first particles and the second particles are made of an organic material. The average particle diameter of the first particles is larger than that of the second particles.

Description

  The present invention relates to an organic electroluminescent device.

An organic electroluminescent device is a self-luminous light emitting device having a pair of electrodes consisting of an anode and a cathode on a substrate and an organic layer including a light emitting layer between the pair of electrodes, and is applicable to various uses. Is expected.
In an organic electroluminescent device, in order to improve the extraction efficiency of the light generated in the light emitting layer, a light diffusing layer having a function of scattering light is provided, or a barrier layer for preventing intrusion of gas such as water vapor or oxygen is provided. It is known to do.
In addition to the advantages that the organic electric field emission device can be reduced in weight and thickness, it is possible to realize illumination of a shape that could not be realized by using a flexible substrate such as a resin film. It has sex.

  For example, Patent Document 1 describes an organic electroluminescent device having a fine particle layer containing fine particles, a PET substrate, a barrier layer, a first electrode (ITO), a light emitting layer, and a second electrode (Al) in this order. Yes.

JP 2012-69507 A

  However, when patterning a transparent electrode such as ITO on a base material having a barrier layer formed on the substrate using a flexible substrate, a developer, an etchant, or a release agent soaks in the barrier layer. In some cases, the inorganic layer or the organic layer is dissolved to lower the barrier performance. When the barrier performance is lowered, the durability of the organic electroluminescent device is lowered. In addition, since flexible substrates expand and contract due to heat, etc., when layers with different coefficients of thermal expansion are stacked on the flexible substrate, curling occurs due to the difference in expansion coefficient, and the display performance of the organic electroluminescent device May decrease.

  An object of the present invention is to provide an organic electroluminescent device that is excellent in durability and luminous efficiency, and that suppresses a decrease in display performance due to curling of a substrate.

The present inventors have intensively studied to solve the above-mentioned problems, and are provided in an optical layer on the side having a barrier layer with respect to the flexible substrate provided with an optical layer containing particles made of organic matter on both sides of the flexible substrate. Development when patterning translucent electrodes such as ITO by increasing the average particle size of organic particles contained in the optical layer opposite to the barrier layer than the average particle size of organic particles It has been found that the penetration of liquids, etchants, and release agents can be prevented, and the deterioration of barrier performance can be suppressed.
That is, the means for solving the above problems are as follows.

[1]
A first optical layer containing first particles and a binder, a flexible substrate, a barrier layer, a second optical layer containing second particles and a binder, a first electrode, an organic layer comprising an organic light emitting layer, And a second electrode in this order,
The first particles and the second particles are particles made of organic matter,
The average particle size of the first particles is larger than the average particle size of the second particles;
Organic electroluminescent device.
[2]
The ratio of the average particle diameter of the first particles to the average particle diameter of the second particles (average particle diameter of the first particles / average particle diameter of the second particles) is 10 or more and 100 or less [1] The organic electroluminescent device as described.
[3]
The organic electroluminescent device according to [1] or [2], wherein the average thickness of the first optical layer is 5 μm or more and 50 μm or less.
[4]
The organic electroluminescent device according to any one of [1] to [3], wherein the average thickness of the second optical layer is 1 μm or more and 6 μm or less.
[5]
The organic electroluminescence device according to any one of [1] to [4], wherein the content of the first particles in the first optical layer is 30 to 80% by volume.
[6]
The organic electroluminescence device according to any one of [1] to [5], wherein the content ratio of the second particles in the second optical layer is 30 to 80% by volume.
[7]
[1] to [6], wherein the first optical layer further contains particles having a refractive index difference of 0.3 to 1.5 with respect to the first particles. Organic electroluminescent device.
[8]
The second optical layer further contains particles having a refractive index of 0.3 or more and 1.5 or less with respect to the second particles according to any one of [1] to [7]. Organic electroluminescent device.
[9]
The organic electroluminescence device according to any one of [1] to [8], wherein a planarization layer is provided between the second optical layer and the first electrode.
[10]
The organic electroluminescent device according to any one of [1] to [9], wherein the barrier layer has a multilayer structure in which an organic layer made of an organic material and an inorganic layer made of an inorganic material are stacked.

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent apparatus which was excellent in durability and luminous efficiency, and the fall of the display performance by the curl of a board | substrate was suppressed can be provided.

It is a schematic diagram which shows an example of the organic electroluminescent apparatus of this invention. It is a schematic diagram which shows an example of the organic electroluminescent apparatus of this invention.

[Organic electroluminescence device]
The organic electroluminescent device of the present invention includes a first optical layer containing first particles and a binder, a flexible substrate, a barrier layer, a second optical layer containing second particles and a binder, and a first electrode. , An organic layer including an organic light emitting layer, and a second electrode in this order, the first particle and the second particle are particles made of an organic substance, and the average particle diameter of the first particle is that of the second particle It is an organic electroluminescent device larger than the average particle size.

FIG. 1 is a schematic diagram showing a cross section of an example of the organic electroluminescent device of the present invention. The organic electroluminescent device 100 shown in FIG. 1 contains the first optical layer 2 containing the first particles 5 and the binder, the flexible substrate 1, the barrier layer 3, the second particles 6 and the binder. It has the 2nd optical layer 4, the 1st electrode 11, the organic layer 12 containing an organic light emitting layer, and the 2nd electrode 13 in this order.
In the present invention, the first optical layer and the second optical layer include the first particle and the second particle, respectively, and the average particle size of the first particle is larger than the average particle size of the second particle. . Thereby, it is possible to prevent the developer, the etchant, and the stripper from entering when forming the electrode. By mixing the particles together with the binder, the optical layer is reduced in the unpolymerized region of the binder-forming compound (monomer) and becomes a stronger film against the liquid that can enter. Here, since the liquid intrusion is more likely to occur from the flexible substrate side than the barrier layer side, the first optical layer particles are made larger and the second optical layer particles are made smaller, In the optical layer, unpolymerized portions are reduced and a strong film is obtained. In addition, since the second optical layer is on the side on which the electrode is formed, it is difficult to form the electrode if the average particle size of the second particles is too large. On the other hand, the average particle diameter of the first particles contained in the first optical layer can be increased, and the unpolymerized region of the binder-forming compound can be further reduced.
When the surface of the optical layer has a concavo-convex shape, the total reflection of light generated in the light emitting layer is suppressed, so that the light emission efficiency is improved. In the optical layer, when the refractive index of the binder is different from that of the particles, light scattering occurs, the angle of light incident on the refractive index interface changes, and total reflection is suppressed to improve luminous efficiency.
In addition, since the organic electroluminescent device of the present invention has optical layers on both sides of the flexible substrate, curling can be suppressed as compared with the case of having an optical layer only on one side, and an organic electroluminescent device substrate including an optical layer is provided. When produced by roll-to-roll, sticking is suppressed, which is preferable.

<First optical layer>
The first optical layer contains first particles and a binder.
The first optical layer is preferably a light diffusion layer having a function of diffusing light incident on the layer.

(binder)
It is preferable that the binder contained in the first optical layer contains an organic resin.
The organic resin is not particularly limited and may be appropriately selected depending on the purpose. For example, (1) a thermoplastic resin, (2) a combination of a reactive curable resin and a curing agent, or (3) a binder. Examples thereof include a polymer obtained from a combination of a precursor (a curable polyfunctional monomer or polyfunctional oligomer described below) and a polymerization initiator. From the viewpoint of productivity, it is a polymer obtained from a combination of (3) a binder precursor (a curable compound, preferably a curable polyfunctional monomer or polyfunctional oligomer described later) and a polymerization initiator. Preferably there is. That is, the binder containing the organic resin of the first optical layer is preferably obtained by curing a composition containing a curable compound and a polymerization initiator.

(1) Thermoplastic resin There is no restriction | limiting in particular as a thermoplastic resin, According to the objective, it can select suitably, For example, a polystyrene resin, a polyester resin, a cellulose resin, a polyether resin, a vinyl chloride resin, a vinyl acetate resin , Vinyl-vinyl chloride copolymer resin, polyacrylic resin, polymethacrylic resin, polyolefin resin, urethane resin, silicone resin, imide resin, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, polyacrylic resins and polymethacrylic resins are preferable, polyacrylic resins derived from acrylic or methacrylic having a fluorene structure and polymethacrylic resins are more preferable, and polyacrylic resins having a fluorene structure are particularly preferable.

(2) Combination of reactive curable resin and curing agent It is preferable to use a thermosetting resin and / or an ionizing radiation curable resin as the reactive curable resin.
There is no restriction | limiting in particular as a thermosetting resin, According to the objective, it can select suitably, For example, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin Aminoalkyd resin, melamine-urea cocondensation resin, silicon resin, polysiloxane resin and the like.
The ionizing radiation curable resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a radical polymerizable unsaturated group {(meth) acryloyloxy group, vinyloxy group, styryl group, vinyl group, etc. } And / or a resin having a functional group such as a cationic polymerizable group (epoxy group, thioepoxy group, vinyloxy group, oxetanyl group, etc.), for example, a relatively low molecular weight polyester resin, polyether resin, (meth) acrylic resin, Examples thereof include epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiol polyene resins. These may be used individually by 1 type and may use 2 or more types together.

  As necessary for these reactive curable resins, a crosslinking agent (epoxy compound, polyisocyanate compound, polyol compound, polyamine compound, melamine compound, etc.), polymerization initiator (azobis compound, organic peroxide compound, organic halogen compound, Conventionally known compounds such as curing agents such as onium salt compounds and UV photoinitiators such as ketone compounds) and polymerization accelerators (organic metal compounds, acid compounds, basic compounds, etc.) are used. Specific examples include compounds described by Fuzo Yamashita and Tosuke Kaneko “Crosslinking Agent Handbook” (Taiseisha, published in 1981).

(3) Polymer obtained from a combination of a binder precursor and a polymerization initiator Hereinafter, a curable compound is crosslinked or polymerized by light irradiation using the combination of (3), which is a preferable method for forming a cured binder. The method for forming the cured binder will be mainly described.

  The functional group of the photocurable polyfunctional monomer or polyfunctional oligomer that is the precursor of the binder may be any of a radical polymerizable functional group and a cationic polymerizable functional group.

  Examples of the radical polymerizable functional group include ethylenically unsaturated groups such as a (meth) acryloyl group, a vinyloxy group, a styryl group, and an allyl group. Among these, a (meth) acryloyl group is particularly preferable, and a polyfunctional monomer containing two or more radically polymerizable groups in the molecule is particularly preferable.

  The radical polymerizable polyfunctional monomer is preferably selected from compounds having at least two terminal ethylenically unsaturated bonds. Preferably, it is a compound having 2 to 6 terminal ethylenically unsaturated bonds in the molecule. Such a compound group is widely known in the polymer material field, and these can be used without particular limitation in the present invention. These can have chemical forms such as monomers, prepolymers (ie, dimers, trimers and oligomers) or mixtures thereof, and copolymers thereof.

  Examples of the radical polymerizable monomer include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters thereof, amides, and the like. Among these, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are particularly preferable.

  Also, addition reaction products of unsaturated carboxylic acid esters and amides having a nucleophilic substituent such as hydroxyl group, amino group and mercapto group with monofunctional or polyfunctional isocyanates and epoxies, polyfunctional carboxylic acids. A dehydration condensation reaction product with an acid or the like is also preferably used. A reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As yet another example, a compound group in which an unsaturated phosphonic acid, styrene, or the like is substituted for the above unsaturated carboxylic acid can be used.

  Examples of the aliphatic polyhydric alcohol compound include alkanediol, alkanetriol, cyclohexanediol, cyclohexanetriol, inositol, cyclohexanedimethanol, pentaerythritol, sorbitol, dipentaerythritol, tripentaerythritol, glycerin, diglycerin and the like. Examples of polymerizable ester compounds (monoesters or polyesters) of these aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids include those described in paragraph numbers [0026] to [0027] of JP-A No. 2001-139663. Compounds.

  Examples of other polymerizable esters include, for example, vinyl alcohol, allyl methacrylate, allyl acrylate, aliphatic alcohols described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, and the like. Those having an ester group, those having an aromatic skeleton described in JP-A-2-226149 and those having an amino group described in JP-A-1-165613 are also preferably used.

  Specific examples of polymerizable amides formed from aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis (meth) acrylamide, 1,6-hexamethylene bis (meth) acrylamide, and diethylenetriamine tris (meth) acrylamide. And xylylene bis (meth) acrylamide, and those having a cyclohexylene structure described in JP-B No. 54-21726.

  Furthermore, vinylurethane compounds containing two or more polymerizable vinyl groups in one molecule (Japanese Patent Publication No. 48-41708, etc.), urethane acrylates (Japanese Patent Publication No. 2-16765, etc.), ethylene oxide skeleton A urethane compound having a diol (Japanese Examined Patent Publication No. Sho 62-39418), polyester acrylates (Japanese Examined Patent Publication No. Sho 52-30490, etc.), and further described in Journal of Japan Adhesion Association Vol. Photocurable monomers and oligomers can also be used. Two or more kinds of these radical polymerizable polyfunctional monomers may be used in combination.

  Next, a cationically polymerizable group-containing compound (hereinafter also referred to as “cationic polymerizable compound” or “cationic polymerizable organic compound”) that can be used for forming the binder of the first optical layer will be described.

  As the cationic polymerizable compound, any compound that causes a polymerization reaction and / or a crosslinking reaction when irradiated with an active energy ray in the presence of an active energy ray-sensitive cationic polymerization initiator can be used. , Cyclic thioether compounds, cyclic ether compounds, spiro orthoester compounds, vinyl hydrocarbon compounds, vinyl ether compounds, and the like. One or more of the above cationic polymerizable organic compounds may be used.

  As the cationically polymerizable group-containing compound, the number of cationically polymerizable groups in one molecule is preferably 2 to 10, and more preferably 2 to 5. The weight average molecular weight of the compound is preferably 3,000 or less, more preferably 200 to 2,000, and still more preferably 400 to 1,500. If the weight average molecular weight is not less than the above lower limit, there is no inconvenience such as a problem of volatilization in the film formation process, and if it is not more than the above upper limit, the first optical layer forming material This is preferable because it does not cause problems such as poor compatibility.

  Examples of the epoxy compound include an aliphatic epoxy compound and an aromatic epoxy compound.

  Examples of the aliphatic epoxy compound include polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers and copolymers of glycidyl acrylate and glycidyl methacrylate, and the like. Can do. In addition to the above epoxy compounds, for example, monoglycidyl ethers of higher aliphatic alcohols, glycidyl esters of higher fatty acids, epoxidized soybean oil, butyl epoxy stearate, octyl epoxy stearate, epoxidized linseed oil, epoxidized polybutadiene And so on. Examples of the alicyclic epoxy compound include polyglycidyl ethers of polyhydric alcohols having at least one alicyclic ring, or unsaturated alicyclic rings (for example, cyclohexene, cyclopentene, dicyclooctene, tricyclodecene, etc. ) Cyclohexene oxide or cyclopentene oxide-containing compound obtained by epoxidizing the containing compound with a suitable oxidizing agent such as hydrogen peroxide or peracid.

  Examples of the aromatic epoxy compound include mono- or polyglycidyl ethers of monovalent or polyvalent phenols having at least one aromatic nucleus, or alkylene oxide adducts thereof. Examples of these epoxy compounds include compounds described in paragraphs [0084] to [0086] of JP-A-11-242101, and paragraphs [0044] to [0046] of JP-A-10-158385. And the compounds described.

  Of these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable, and alicyclic epoxides are more preferable in view of fast curability. One of the above epoxy compounds may be used alone, or two or more may be used in appropriate combination.

  Examples of the cyclic thioether compound include compounds having a thioepoxy ring instead of the epoxy ring of the epoxy compound.

  Specific examples of the compound containing an oxetanyl group as the cyclic ether compound include compounds described in paragraphs [0024] to [0025] of JP-A No. 2000-239309. These compounds are preferably used in combination with an epoxy group-containing compound.

  Examples of the spiro orthoester compound include compounds described in JP 2000-506908 A.

  Examples of vinyl hydrocarbon compounds include styrene compounds, vinyl group-substituted alicyclic hydrocarbon compounds (vinyl cyclohexane, vinyl bicycloheptene, etc.), compounds described in the above radical polymerizable monomers, propenyl compounds {"J. Polymer Science: Part". A: Polymer Chemistry ”, vol. 32, p. 2895 (1994) etc.}, alkoxy allene compound {“ J. Polymer Science: Part A: Polymer Chemistry ”, vol. 33, p. 2493 (1995) etc.}, vinyl compound { “J. Polymer Science: Part A: Polymer Chemistry”, 34, 1015 (1996), JP-A-2002-29162, etc.}, isopropenyl compound {J. Polymer Science: Part A: Polymer Chemistry ”, Vol. 34, page 2051 (1996), etc.}, etc. These may be used in appropriate combination of two or more.

  Moreover, it is preferable to use the compound which contains at least each 1 type chosen from a radically polymerizable group and a cationically polymerizable group in a molecule | numerator at least as a polyfunctional compound. Examples thereof include compounds described in paragraph numbers [0031] to [0052] in JP-A-8-277320, compounds described in paragraph number [0015] in JP-A 2000-191737, and the like. The compounds used in the present invention are not limited to these.

  The radical polymerizable compound and the cationic polymerizable compound described above are preferably contained in a mass ratio of radical polymerizable compound: cation polymerizable compound in a ratio of 90:10 to 20:80, and 80:20 It is more preferable to contain in the ratio of -30: 70.

-Polymerization initiator-
The binder preferably contains a polymerization initiator. Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator.
The polymerization initiator is preferably a compound that generates radicals or acids upon irradiation with light and / or heat. The photopolymerization initiator preferably has a maximum absorption wavelength of 400 nm or less. Thus, the handling can be performed under a white light by setting the absorption wavelength to the ultraviolet region. A compound having a maximum absorption wavelength in the near infrared region can also be used.

  The compound that generates radicals refers to a compound that generates radicals by irradiation with light and / or heat, and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. A known polymerization initiator or a compound having a bond with a small bond dissociation energy can be appropriately selected and used. Moreover, the compound which generate | occur | produces a radical can be used individually or in combination of 2 or more types.

  Examples of the compound that generates radicals include conventionally known organic peroxide compounds, thermal radical polymerization initiators such as azo polymerization initiators, organic peroxide compounds (JP 2001-139663 A, etc.), amine compounds (special No. 44-20189), metallocene compounds (JP-A-5-83588, JP-A-1-304453, etc.), hexaarylbiimidazole compounds (US Pat. No. 3,479,185, etc.) ), Disulfone compounds (JP-A-5-239015, JP-A-61-166544, etc.), organic halogenated compounds, carbonyl compounds, organic boric acid compounds, phosphine oxide compounds, phosphonate compounds, etc. Is mentioned. The radical generator is more preferably a phosphine oxide compound or a phosphonate compound, particularly preferably an acyl phosphine oxide, an acyl phosphonate, or the like. Specifically, bis (2,4,6-trimethylbenzoyl)- It is phenylphosphine oxide.

  Specific examples of the organic halogenated compound include Wakabayashi et al., “Bull. Chem. Soc Japan”, 42, 2924 (1969), US Pat. No. 3,905,815, and JP-A-5-27830. No., M.C. P. Hutt, “J. Heterocyclic Chemistry”, Vol. 1 (No. 3), (1970) ”and the like, and in particular, an oxazole compound substituted with a trihalomethyl group: an s-triazine compound. More preferable examples include s-triazine derivatives in which at least one mono, di, or trihalogen-substituted methyl group is bonded to the s-triazine ring.

  Examples of the carbonyl compound include, for example, “Latest UV Curing Technology”, pages 60 to 62 [published by Technical Information Association, 1991], paragraph numbers [0015] to [0016] of JP-A-8-134404, And the compounds described in paragraphs [0029] to [0031] of JP-A No. 11-217518. Further, benzoin compounds such as acetophenone, hydroxyacetophenone, benzophenone, thioxan, benzoin ethyl ether, benzoin isobutyl ether, benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate, ethyl p-diethylaminobenzoate, benzyldimethyl Examples include ketal and acylphosphine oxide.

  Examples of the organic borate compound include Japanese Patent Nos. 2764769 and 2002-116539, and Kunz, Martin, “Rad. Tech'98. Proceeding April 19-22, 1998, Chicago”. And the organic borates described in 1. For example, the compounds described in paragraphs [0022] to [0027] of JP-A-2002-116539 can be mentioned. Examples of other organic boron compounds include JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, JP-A-7-306527, and JP-A-7-292014. Specific examples include organoboron transition metal coordination complexes.

  These radical generating compounds may be added alone or in combination of two or more. As addition amount, 0.1 mass%-30 mass% are preferable with respect to radical polymerization monomer whole quantity, 0.5 mass%-25 mass% are more preferable, 1 mass%-20 mass% are still more preferable. Within the above range of addition amount, the temporal stability of the binder-forming material becomes highly polymerizable without problems.

Next, a photoacid generator that can be used as a photopolymerization initiator will be described in detail.
Photoacid generators include known compounds such as photoinitiators for photocationic polymerization, photodecolorants for dyes, photochromic agents, known photoacid generators used in microresists, etc. and their compounds A mixture etc. are mentioned. Examples of the photoacid generator include organic halogenated compounds, disulfone compounds, onium compounds, and the like. Among these, organic halogenated compounds and disulfone compounds are particularly preferable. Specific examples of the organic halogen compound and disulfone compound are the same as those described for the compound generating a radical.

  Examples of the onium compound include diazonium salts, ammonium salts, iminium salts, phosphonium salts, iodonium salts, sulfonium salts, arsonium salts, selenonium salts, and the like, for example, paragraph numbers [0058] to [0058] of [JP-A-2002-29162]. And the like, and the like.

  As the acid generator, an onium salt is particularly preferably used, and among them, a diazonium salt, an iodonium salt, a sulfonium salt, and an iminium salt are preferable from the viewpoint of photosensitivity at the start of photopolymerization, material stability of the compound, and the like.

  Specific examples of the onium salt include, for example, an amylated sulfonium salt described in paragraph [0035] of JP-A-9-268205, and paragraphs [0010] to [0011] of JP-A-2000-71366. A diaryl iodonium salt or a triarylsulfonium salt described in JP-A-2001-288205, a sulfonium salt of thiobenzoic acid S-phenyl ester described in JP-A-2001-288205, and a paragraph number of JP-A-2001-133696 [ The onium salts described in [0030] to [0033].

  Other examples of the photoacid generator include photoacid generators having organometallic / organic halides and o-nitrobenzyl type protecting groups described in paragraphs [0059] to [0062] of JP-A-2002-29162. And compounds such as compounds (iminosulfonate, etc.) that generate sulfonic acid upon photolysis.

  These acid generators may be used alone or in combination of two or more. The addition amount of the acid generator is preferably 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, and more preferably 1% by mass to 10% by mass with respect to the total mass of the total cationic polymerizable monomer. Is more preferable. The addition amount is preferably in the above range from the viewpoint of stability of the binder forming material, polymerization reactivity, and the like.

  The binder-forming material is a proportion of 0.5% by mass to 10% by mass of the radical polymerization initiator or 1% by mass to 10% by mass of the cationic polymerization initiator with respect to the total mass of the radical polymerizable compound or the cationic polymerizable compound. The radical polymerization initiator is preferably contained in an amount of 1% by mass to 5% by mass, or the cationic polymerization initiator is contained in an amount of 2% by mass to 6% by mass.

The refractive index of the binder in the first optical layer is preferably 1.7 or more and 2.2 or less, more preferably 1.7 or more and 2.1 or less, from the viewpoint of light extraction efficiency, and 1.7 or more and 2.0 or less. The following is more preferable.
The refractive index of the binder in the first optical layer is preferably equal to or higher than the refractive index of the light emitting layer.

(First particle)
The first particles contained in the first optical layer will be described.
Only 1 type may be sufficient as the 1st particle | grains contained in a 1st optical layer, and 2 or more types may be used for it.
The first particles are particles made of an organic substance, and are preferably light diffusion particles capable of diffusing light.
There is no restriction | limiting in particular as 1st particle | grains, According to the objective, it can select suitably, You may contain 2 or more types of particle | grains.
Examples of organic particles include polymethyl methacrylate particles, cross-linked polymethyl methacrylate particles, acrylic-styrene copolymer particles, melamine particles, polycarbonate particles, polystyrene particles, cross-linked polystyrene particles, polyvinyl chloride particles, benzoguanamine-melamine formaldehyde particles, and the like. Is mentioned.

Among these, as the first particles, crosslinked resin particles are preferable in view of solvent resistance and dispersibility in the binder, and crosslinked polymethyl methacrylate particles are particularly preferable.
It can be confirmed that the first particles are crosslinked resin particles by dispersing in a solvent, for example, toluene, and seeing the difficulty of dissolving the resin particles.

The refractive index of the first particles is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 1.0 or more and 3.0 or less, more preferably 1.2 or more and 2.0 or less. More preferably, it is 3 or more and 1.8 or less. When the refractive index is 1.0 or more and 3.0 or less, light diffusion (scattering) does not become too strong, and thus light extraction efficiency is likely to be improved.
The refractive index of the first particles is determined by measuring the refractive index of the refractive liquid using, for example, an automatic refractive index measuring device (KPR-2000, manufactured by Shimadzu Corporation), and then using a precision spectrometer (GMR-1DA, Inc.). (Manufactured by Shimadzu Corporation).

The average particle size of the first particles is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less, and even more preferably 7 μm or more and 20 μm or less.
When the average particle size of the first particles is 3 μm or more, the ratio of the binder portion on the outermost surface of the first optical layer is reduced, and the number of unpolymerized portions of the binder is reduced, so that it is strong against liquid penetration during the etching process. When the average particle size of the first particles is 100 μm or less, the optical layer can be uniformly applied while maintaining good dispersibility in the first optical layer forming material (preferably coating solution). Therefore, it is strong against liquid intrusion and can maintain a barrier property.
The average particle diameter of the first particles can be measured, for example, by an apparatus using a dynamic light scattering method such as Nanotrack UPA-EX150 manufactured by Nikkiso Co., Ltd., or by image processing of an electron micrograph.

  The content of the first particles in the first optical layer is preferably 30% to 80% by volume, more preferably 40% to 60% by volume, and particularly preferably 45% to 55% by volume. If the content is 30% by volume or more, the probability that the light incident on the first optical layer is scattered by the first particles is high, and the ability to convert the light angle of the first optical layer is large. The light extraction efficiency can be improved without increasing the thickness of the first optical layer. Moreover, since it is not necessary to increase the thickness of the first optical layer, the cost is reduced, the variation in the thickness of the first optical layer is reduced, and the scattering effect in the light emitting surface is less likely to occur. On the other hand, when the content is 66% by volume or less, the surface of the first optical layer is not excessively roughened, and cavities are not easily generated inside, so that the physical strength of the first optical layer is hardly lowered.

(Metal oxide particles)
In addition to the first particles, the first optical layer preferably further contains particles having a refractive index difference of 0.3 or more and 1.5 or less with respect to the first particles. Such particles are preferably metal oxide particles. In particular, by containing particles having an average particle size smaller than the average particle size of the first particles, the dispersibility of the first particles in the first optical layer forming material (preferably coating solution) is improved. Since a more homogeneous film can be obtained, defects are less likely to occur and the liquid is more resistant to intrusion.

  The average particle size of the metal oxide particles is preferably 1 nm to 200 nm, more preferably 3 nm to 100 nm, and still more preferably 5 nm to 50 nm.

Examples of the metal oxide particles include titanium oxide fine particles, zirconia oxide fine particles, and aluminum oxide fine particles.
The titanium oxide fine particles are not particularly limited and can be appropriately selected depending on the purpose. The crystal structure is preferably mainly composed of rutile, a mixed crystal of rutile / anatase, and anatase. Preferably it is a component.
The titanium oxide fine particles may be combined by adding a metal oxide other than titanium oxide.
The metal oxide that can be combined with the titanium oxide fine particles is preferably at least one metal oxide selected from Sn, Zr, Si, Zn, and Al.
The amount of metal oxide added to titanium is preferably 1 mol% to 40 mol%, more preferably 2 mol% to 35 mol%, still more preferably 3 mol% to 30 mol%.

  The content of the metal oxide particles is preferably 10% by volume to 50% by volume, more preferably 10% by volume to 40% by volume, and still more preferably 20% by volume to 40% by volume with respect to the binder. . When the content is 10% by volume or more, the effect of increasing the refractive index of the binder is excellent, and the light extraction effect is improved. When the content is 50% by volume or less, Rayleigh scattering does not increase and the light extraction effect is suppressed. Hateful.

  The titanium oxide fine particles are more preferably titanium oxide fine particles subjected to photocatalytic inactivation treatment.

(solvent)
The first optical layer may be formed of a first optical layer forming material containing a binder or a binder forming material, first particles, and, if necessary, a polymerization initiator and metal oxide particles. it can. The first optical layer forming material may further contain a solvent.
The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, alcohols, ketones, esters, amides, ethers, ether esters, aliphatic hydrocarbons, halogenated hydrocarbons And the like. Specifically, alcohol (for example, methanol, ethanol, propanol, butanol, benzyl alcohol, ethylene glycol, propylene glycol, ethylene glycol monoacetate, etc.), ketone (for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, etc.), ester ( For example, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl formate, propyl formate, butyl formate, ethyl lactate, etc.), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methyl chloroform), aromatic Group hydrocarbons (eg benzene, toluene, xylene, ethylbenzene etc.), amides (eg dimethylformamide, dimethylacetamide, n-methylpyrrolidone etc.), ether (E.g. dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, etc.), ether alcohols (such as 1-methoxy-2-propanol, ethyl cellosolve, methyl carbinol and the like) and the. These may be used individually by 1 type and may use 2 or more types together. Among these, aromatic hydrocarbons and ketones are preferable, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone are more preferable, and toluene and xylene are particularly preferable.

The average film thickness of the first optical layer is preferably 5 μm or more and 50 μm or less, more preferably 7 μm or more and 25 μm or less, and even more preferably 8 μm or more and 15 μm or less. When the average film thickness is 50 μm or less, it is preferable that separation from the substrate due to shrinkage during polymerization does not occur and the barrier property can be maintained. When the thickness is 5 μm or more, liquid penetration due to the thin film thickness hardly occurs and the barrier property can be maintained, which is preferable.
The average film thickness of the first optical layer can be determined, for example, by cutting out a part of the first optical layer and measuring it with a scanning electron microscope (S-3400N, manufactured by Hitachi High-Tech Co., Ltd.). The first optical layer may have an uneven shape on the surface depending on the particle size of the first particles and the amount of the binder. In that case, in the present invention, the thickness of the first optical layer is , Defined as the thickness of the layer consisting of the binder.

  The first optical layer is a first optical layer forming material containing the above-mentioned various components, for example, dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, microgravure It is preferable to produce by applying by a known thin film forming method such as a coating method or an extrusion coating method, followed by drying, light and / or heat irradiation. More preferably, curing by light irradiation is advantageous from the viewpoint of rapid curing. Furthermore, after the photocuring treatment, it is also preferable to perform a heat treatment to stop the curing of the binder (polymerization reaction) by the photopolymerization initiator. In this case, the heating temperature is preferably 60 ° C to 105 ° C, more preferably 70 ° C to 100 ° C, and still more preferably 70 ° C to 90 ° C.

  The light source for light irradiation may be any wavelength near the wavelength (absorption wavelength) at which the photopolymerization initiator reacts. When the absorption wavelength is in the ultraviolet region, each light source can be an ultrahigh pressure, high pressure, medium pressure, low pressure mercury lamp, A chemical lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, sunlight, etc. are mentioned. Various available laser light sources having a wavelength of 350 nm to 420 nm may be irradiated as a multi-beam. When the absorption wavelength is in the infrared region, examples of the light source include a halogen lamp, a xenon lamp, and a high-pressure sodium lamp. Various available laser light sources having a wavelength of 750 nm to 1,400 nm may be converted into multi-beams for irradiation. .

In the case of radical photopolymerization by light irradiation, it can be carried out in air or in an inert gas, but in order to shorten the polymerization induction period of the radically polymerizable monomer or sufficiently increase the polymerization rate, etc. It is preferable that the atmosphere has a reduced oxygen concentration. The oxygen concentration range is preferably 0 to 1,000 ppm, more preferably 0 to 800 ppm, and still more preferably 0 to 600 ppm. Irradiation intensity of ultraviolet irradiation is ^preferably from ^{0.1mW / cm 2 ~100mW / cm 2} , irradiation amount on the coating film ^{surface, 100mJ / cm 2 ~10,000mJ / cm} 2 are preferred, 100 mJ / cm ^{2 to} 5,000 mJ / cm ² is more preferable, and 100 mJ / cm ^{2 to} 1,000 mJ / cm ² is particularly preferable. Moreover, 15 to 70 degreeC is preferable, as for the temperature in a light irradiation process, 20 to 60 degreeC is more preferable, and 25 to 50 degreeC is especially preferable.

<Second optical layer>
The second optical layer contains second particles and a binder.
Specific examples and preferred ranges of the binder of the second optical layer are the same as those of the binder of the first optical layer.

Specific examples and preferred ranges of the material of the second particles of the second optical layer are the same as those of the first particles of the first optical layer.
The average particle size of the second particles is preferably from 0.1 μm to 10 μm, more preferably from 0.2 μm to 8 μm, still more preferably from 0.3 μm to 5 μm. When the average particle size of the second particles is 0.1 μm or more, the particles are less likely to aggregate, and a homogeneous film can be formed and barrier properties can be ensured. When the average particle size of the second particles is 10 μm or less, the dispersibility of the particles in the second optical layer forming material (preferably coating solution) is particularly improved, and a homogeneous film can be formed.
The average particle diameter of the second particles can be measured by an apparatus using a dynamic light scattering method such as Nanotrack UPA-EX150 manufactured by Nikkiso Co., Ltd., or by image processing of an electron micrograph.
The content of the second particles in the second optical layer is preferably 30% by volume to 80% by volume, more preferably 40% by volume to 60% by volume, and particularly preferably 45% by volume to 55% by volume. If the content is 30% by volume or more, there is a high probability that the light incident on the second optical layer is scattered by the second particles, and the ability to convert the light angle of the second optical layer is large. preferable. When the content is 80% by volume or less, the surface of the second optical layer is not excessively rough, and element leakage due to the rough surface can be prevented.

In addition to the second particles, the second optical layer preferably further contains particles having a refractive index difference of 0.3 or more and 1.5 or less with respect to the second particles. As such particles, metal oxide particles are preferable. In particular, by containing metal oxide particles having an average particle size smaller than the average particle size of the second particles, the dispersibility of the second particles in the second optical layer forming material (preferably coating solution). As a result, the film can be made more homogeneous, and defects are less likely to occur, making it more resistant to liquid penetration.
Specific examples and preferred ranges of the material, average particle diameter, and content of the metal oxide particles are the same as those of the metal oxide particles that may be added to the first optical layer.

  The second optical layer is formed of the second optical layer forming material containing the binder or the binder forming material, the second particles, and, if necessary, a polymerization initiator and metal oxide particles. Can do. Further, the second optical layer forming material may further contain a solvent. Specific examples and preferred ranges of the solvent are the same as the solvent that the first optical layer forming material may contain.

The average film thickness of the second optical layer is preferably from 1 μm to 6 μm, more preferably from 1.5 μm to 5.5 μm, and even more preferably from 2 μm to 5 μm. When the average film thickness of the second optical layer is 1 μm or more, the film is thick and strong against liquid penetration. When the average film thickness of the second optical layer is 6 μm or less, peeling from the barrier layer hardly occurs due to shrinkage during polymerization, and the barrier property can be maintained.
The average film thickness of the second optical layer can be determined, for example, by cutting a part of the second optical layer and measuring it with a scanning electron microscope (S-3400N, manufactured by Hitachi High-Tech Co., Ltd.). The second optical layer may have a concavo-convex shape on the surface depending on the particle size of the second particles and the amount of the binder, but in that case, in the present invention, the thickness of the second optical layer is This is the same as the definition of the film thickness of the first optical layer, and is defined as the thickness of the layer made of the binder.

  The formation method and preferable conditions of the second optical layer are the same as those of the first optical layer.

<Flexible substrate>
As long as the flexible substrate in the present invention has flexibility, its shape, structure, size and the like are not particularly limited and can be appropriately selected according to the purpose. The structure may be a single-layer structure or a laminated structure, and the size can be appropriately selected according to the size of the organic electroluminescence device.
As a material for the flexible substrate, a resin is preferable. For example, polyester such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate, polyimide (PI), polyethylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, styrene- Examples include acrylonitrile copolymer and polyethersulfone (PES). These may be used individually by 1 type and may use 2 or more types together. Among these, polyester and polyethersulfone (PES) are preferable, and polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES) are particularly preferable from the viewpoint of applicability with a roll.
The flexible substrate preferably has translucency, and the visible light transmittance is preferably 70% or more, and more preferably 80% or more.
The surface of the flexible substrate may be subjected to surface activation treatment in order to improve adhesion with a layer provided thereon. Examples of the surface activation treatment include glow discharge treatment and corona discharge treatment.
There is no restriction | limiting in particular as thickness of a flexible substrate, Although it can select suitably according to the objective, Usually, 10 micrometers or more and 500 micrometers or less are preferable, and 50 micrometers or more and 300 micrometers or less are more preferable.

<Barrier layer>
There is no restriction | limiting in particular as a barrier layer in this invention, What is necessary is just to select suitably according to the objective, The organic layer consisting of an organic material may be individual, and the inorganic layer consisting of an inorganic material may be independent. A multilayer structure in which an organic layer made of an organic material and an inorganic layer made of an inorganic material are laminated may be used. From the viewpoint of barrier properties, the barrier layer preferably has a multilayer structure in which an organic layer made of an organic material and an inorganic layer made of an inorganic material are laminated.
As the inorganic materials, for example _{SiNx, SiON, SiO 2, Al} 2 O 3, etc. TiO ₂ and the like.
Examples of organic materials include silicone polymers, epoxy polymers, acrylic polymers, urethane polymers, and the like.
There is no restriction | limiting in particular as a formation method of a barrier layer, According to material, it can select suitably, For example, the apply | coating method, CVD method, a vacuum evaporation method, a sputtering method etc. are mentioned.
The refractive index of the barrier layer (in the case of a multilayer structure, the average refractive index) is preferably 1.7 or more, and more preferably 1.8 to 2.2.
The optical properties of the barrier layer are preferably such that the visible light transmittance is 80% or more, more preferably 85% or more, and still more preferably 90% or more.
There is no restriction | limiting in particular in the average thickness of a barrier layer, Although it can select suitably according to the objective, 0.1 micrometer-10 micrometers are preferable, 0.1 micrometer-5 micrometers are more preferable, 0.2 micrometer-3 micrometers are still more preferable. When the average thickness of the barrier layer is 0.1 μm or more, a sealing function for preventing the permeation of oxygen and moisture in the atmosphere is sufficient, and when it is 10 μm or less, the light transmittance is improved and the translucency is excellent. In addition, when an inorganic material is used in a single layer, cracking due to a stress difference, separation from an adjacent layer, and the like are suppressed, and barrier properties are improved.

<Planarization layer>
In the present invention, a planarizing layer may be provided when the surface of the first optical layer or the second optical layer has an uneven shape. In particular, it is preferable to provide a planarization layer between the second optical layer and the first electrode.
Although it does not specifically limit as a planarization layer, It is preferable that the binder containing an organic resin is included, it is preferable that it is a composition which does not contain the 1st particle in the 1st optical layer, and it does not contain the 1st particle. The binder precursor (3) described in the first optical layer (a curable compound, preferably a curable polyfunctional monomer) can be formed in the same manner as in the first optical layer. Or a polyfunctional oligomer) and a polymer obtained from a combination of a polymerization initiator. That is, it is preferable that the binder containing the organic resin of the planarizing layer is obtained by curing a composition containing a curable compound and a polymerization initiator.
There is no restriction | limiting in particular in the average film thickness of a planarization layer, Although it can select suitably according to the objective, 1 micrometer-10 micrometers are preferable, 2 micrometers-8 micrometers are more preferable, and 3 micrometers-7 micrometers are especially preferable. When the average film thickness of the planarizing layer is 1 μm or more, the surface of the protruding light diffusion layer can be planarized, and when it is 10 μm or less, the light extraction ability is unlikely to decrease due to light absorption of the planarizing layer. .
The refractive index of the planarization layer is preferably 1.7 or more, 2.2 or less, more preferably 1.7 or more and 2.1 or less, and even more preferably 1.7 or more and 2.0 or less, from the viewpoint of light extraction efficiency.
The refractive index of the planarizing layer is preferably equal to or higher than the refractive index of the light diffusion layer.

<First electrode>
The first electrode in the organic electroluminescent device of the present invention is preferably used as an anode.
The first electrode preferably has translucency, and preferred examples of the material of the translucent electrode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof. Specific examples include conductive oxides such as tin oxide (ATO, FTO) doped with antimony or fluorine, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), Metals such as gold, silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene and polypyrrole And a laminate of these and ITO. Among these, conductive metal oxides are preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.

  The first electrode is, for example, a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as a CVD method or a plasma CVD method. It can be formed on the light diffusion layer according to a method appropriately selected in consideration of suitability with the material constituting the photoelectrode. For example, when ITO is selected as the material of the translucent electrode, it can be performed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.

  The patterning for forming the first electrode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like. It may be performed by a lift-off method or a printing method.

  The thickness of the first electrode can be appropriately selected depending on the material constituting the translucent electrode and cannot be generally defined, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.

The resistance value of the first electrode is preferably 10 ³ Ω / □ (Ω / sq.) Or less, and more preferably 10 ² Ω / □ or less. The translucent electrode may be colorless and transparent or colored and transparent. In order to extract emitted light from the translucent electrode side, the visible light transmittance is preferably 60% or more, and more preferably 70% or more.

  The first electrode is described in detail in the book “New development of transparent conductive film” published by CMC (1999), supervised by Yutaka Sawada, and the matters described here can be applied to the present invention.

  There is no restriction | limiting in particular in the shape and magnitude | size of a 1st electrode, According to the use and objective of an organic electroluminescent apparatus, it can select suitably.

<Organic layer>
The organic layer of the organic electroluminescent device of the present invention includes at least a light emitting layer. Examples of the functional layer other than the light emitting layer include a hole transport layer, an electron transport layer, a hole block layer, an electron block layer, a hole injection layer, and an electron injection layer.

The organic layer preferably has a hole transport layer between the anode and the light emitting layer, and preferably has an electron transport layer between the cathode and the light emitting layer. Furthermore, a hole injection layer may be provided between the hole transport layer and the anode, or an electron injection layer may be provided between the electron transport layer and the cathode.
Further, a hole transporting intermediate layer (electron blocking layer) may be provided between the light emitting layer and the hole transporting layer, and an electron transporting intermediate layer (hole blocking layer) between the light emitting layer and the electron transporting layer. ) May be provided. Each functional layer may be divided into a plurality of secondary layers.

  These functional layers including the light emitting layer can be suitably formed by any of dry film forming methods such as vapor deposition and sputtering, wet coating methods, transfer methods, printing methods, and ink jet methods.

(Light emitting layer)
The light-emitting layer receives holes from the anode, the hole injection layer, or the hole transport layer when an electric field is applied, receives electrons from the cathode, the electron injection layer, or the electron transport layer, and recombines holes and electrons. It is a layer which has the function to provide and to emit light.
The light emitting layer includes a light emitting material. The light emitting layer may be composed of only a light emitting material, or may be a mixed layer of a host material and a light emitting material (in the latter case, the light emitting material may be referred to as “light emitting dopant” or “dopant”). The light emitting material may be a fluorescent light emitting material or a phosphorescent light emitting material, and two or more kinds may be mixed. The host material is preferably a charge transport material. The host material may be one type or two or more types. Furthermore, the light emitting layer may contain a material that does not have charge transporting properties and does not emit light.

  The thickness of the light emitting layer is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 2 nm to 500 nm, and more preferably 3 nm to 200 nm from the viewpoint of external quantum efficiency. More preferably, it is ˜100 nm. Further, the light emitting layer may be a single layer or two or more layers, and each layer may emit light in different emission colors.

As the light emitting material, any of a phosphorescent light emitting material, a fluorescent light emitting material and the like can be suitably used.
The luminescent material has a difference in ionization potential (ΔIp) and a difference in electron affinity (ΔEa) between the host compound and 1.2 eV>ΔIp> 0.2 eV and / or 1.2 eV>ΔEa> 0. A dopant satisfying the relationship of .2 eV is preferable from the viewpoint of driving durability.
The light emitting material in the light emitting layer is contained in an amount of 0.1% by mass to 50% by mass with respect to the total mass of the compound generally forming the light emitting layer in the light emitting layer, but from the viewpoint of durability and external quantum efficiency. The content is preferably 1% by mass to 50% by mass, and more preferably 2% by mass to 50% by mass.

  As the host material, a hole transporting host material having excellent hole transportability (may be described as a hole transportable host) and an electron transporting host compound having excellent electron transportability (in the case of being described as an electron transporting host) Can be used).

  The hole injection layer or the hole transport layer is a layer having a function of receiving holes from the anode or the layer on the anode side and transporting them to the cathode side. The hole injecting material and hole transporting material used for these layers may be a low molecular compound or a high molecular compound. Specifically, pyrrole derivatives, carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styryl Anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organosilane derivatives, carbon, Etc. are preferred.

The electron injection layer or the electron transport layer is a layer having a function of receiving electrons from the cathode or the layer on the cathode side and transporting them to the anode side. The electron injection material and the electron transport material used for these layers may be a low molecular compound or a high molecular compound.
Specifically, pyridine derivatives, quinoline derivatives, pyrimidine derivatives, pyrazine derivatives, phthalazine derivatives, phenanthroline derivatives, triazine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone Derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthalene, perylene and other aromatic ring tetracarboxylic acid anhydrides, phthalocyanine derivatives, 8-quinolinol derivative metal complexes, Metal phthalocyanines, various metal complexes represented by metal complexes with benzoxazole and benzothiazole as ligands, organosilane derivatives represented by siloles Body, the layer containing the like are preferable.

The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing to the cathode side, and is usually provided as an organic compound layer adjacent to the light emitting layer on the cathode side.
On the other hand, the electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side, and is usually provided as an organic compound layer adjacent to the light emitting layer on the anode side.
Examples of the compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like. As an example of the compound constituting the electron blocking layer, for example, those mentioned as the hole transport material described above can be used.
The thickness of the hole blocking layer and the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the hole blocking layer and the electron blocking layer may have a single-layer structure made of one or more of the materials described above, or may have a multilayer structure made up of a plurality of layers having the same composition or different compositions. Good.

<Second electrode>
The second electrode in the organic electroluminescent device of the present invention is preferably used as a cathode.
The second electrode (cathode) usually has a function as an electrode for injecting electrons into the organic compound layer, and there is no particular limitation on the shape, structure, size, etc. Depending on the purpose, it can be appropriately selected from known electrode materials.

  Examples of the material constituting the cathode include simple metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, Li, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium, ytterbium, and the like. These may be composed of one kind of material, but from the viewpoint of achieving both stability and electron injection properties, it is also possible to use a cathode composed of a suitable combination of two or more kinds of materials. it can.

Among these, as a material constituting the cathode, an alkali metal or an alkaline earth metal is preferable from the viewpoint of electron injecting property, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01 to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc.) Say.

  The materials for the cathode are described in detail in JP-A-2-15595 and JP-A-5-121172, and the materials described in these public relations can also be applied in the present invention.

  There is no restriction | limiting in particular about the formation method of a cathode, According to a well-known method, it can carry out. For example, the above-mentioned cathode is constructed from a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method. It can be formed according to a method appropriately selected in consideration of suitability with the material. For example, when a metal or the like is selected as the cathode material, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.

  Patterning when forming the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or by vacuum deposition or sputtering with the mask overlaid. It may be performed by a lift-off method or a printing method.

In the present invention, the cathode forming position is not particularly limited, and may be formed on the entire organic layer or a part thereof.
In addition, a dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the cathode and the organic layer with a thickness of 0.1 to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer. The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

The thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be generally defined, but is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm.
Moreover, the cathode may have translucency or may not have translucency. When it does not have translucency, it preferably functions as a reflective electrode. Note that the light-transmitting cathode can be formed by forming a thin film of the cathode material to a thickness of 1 to 10 nm and further stacking a light-transmitting conductive material such as ITO or IZO. .

(Sealing can)
The sealing can is not particularly limited as long as it has a size, shape, structure, etc. that can encapsulate the first electrode, organic layer, second electrode, planarization layer, optical layer, etc. You can choose. The organic electroluminescent device 100 of FIG. 2 shows an example in which the organic electroluminescent device of FIG.
A moisture absorbent or an inert liquid may be sealed in a space between the sealing can and the first electrode, the second electrode, the organic layer, the planarization layer, the optical layer, and the like.
The moisture absorbent is not particularly limited and can be appropriately selected depending on the purpose. For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, Examples thereof include calcium chloride, magnesium chloride, copper chloride, cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, and magnesium oxide.
The inert liquid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paraffins, liquid paraffins; fluorinated solvents such as perfluoroalkanes, perfluoroamines and perfluoroethers; chlorine System solvents, silicone oils and the like.

The organic electroluminescent device can be configured as a device capable of displaying in full color.
As a method for making the organic electroluminescent device of the full color type, for example, as described in “Monthly Display”, September 2000, pages 33-37, the three primary colors (blue (B), green (G), red color (R)), a three-color light emission method in which a layer structure that emits light corresponding to each color is disposed on a substrate, and a white method in which white light emission by a white light emission layer structure is divided into three primary colors through a color filter layer A color conversion method for converting blue light emission by a blue light emission layer structure into red (R) and green (G) through a fluorescent dye layer is known.
In this case, it is preferable to appropriately adjust the laser power and thickness for each pixel of blue (B), green (G), and red (R).
In addition, a planar light source having a desired emission color can be obtained by using a combination of a plurality of layer structures having different emission colors obtained by the above method. For example, a white light-emitting light source that combines blue and yellow light-emitting devices, a white light-emitting light source that combines blue (B), green (G), and red (R) organic electroluminescent devices.

  Organic electroluminescent devices include, for example, lighting equipment, computers, in-vehicle displays, outdoor displays, household equipment, commercial equipment, home appliances, traffic-related displays, clock displays, calendar displays, luminescent It can be suitably used in various fields including screens and audio equipment.

(Method for manufacturing organic electroluminescent device)
The organic electroluminescent device manufacturing method of the present invention includes a barrier layer forming step of forming a barrier layer by applying a barrier layer forming material on a flexible substrate;
A first optical layer forming step of forming a first optical layer by applying a first optical layer forming material on the opposite side of the flexible substrate from the barrier layer;
A second optical layer forming step of applying a second optical layer forming material on the barrier layer to form a second optical layer;
Forming a first electrode on the second optical layer;
Forming an organic layer including a light emitting layer on the first electrode;
It is preferable to include a step of forming a second electrode on the organic layer, and other steps may be included as necessary.
It is the first and second optical layer forming materials that the first and second optical layer forming steps are performed within 24 hours after the addition of the polymerization initiator to the first and second optical layer forming materials. As the polymerization proceeds, the viscosity gradually changes, which is preferable in that it can prevent abnormal film thickness after coating and insufficient curing.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Preparation of barrier film)
On the smooth surface of a polyethylene naphthalate (PEN) film (manufactured by Teijin DuPont, Teonex Q65FA, thickness 100 μm), an inorganic layer of silicon nitride was formed by plasma CVD (film thickness 50 nm). On the surface of this inorganic layer, a polymerizable composition having the following composition was applied to form a dry film thickness of 1000 nm, and irradiated with an ultraviolet ray irradiation amount of 0.5 J / cm ² under a nitrogen atmosphere having an oxygen content of 100 ppm or less. And cured to produce an organic layer. An inorganic layer was produced by laminating silicon nitride on the surface of the organic layer by a plasma CVD method. The inorganic layer was adjusted so that the film thickness was 50 nm.
This barrier film is a laminate of a polyethylene naphthalate (PEN) film, which is a flexible substrate, and a barrier layer.
(Composition of polymerizable composition)
-Polymerizable compound (acrylate 1) 50 g
・ Polymerization initiator (Lamberti, Esacure KTO46) 1g
・ Silane coupling agent (Shin-Etsu Silicone KBM-5013) 5g
・ 2-butanone 400g

(Surface treatment of barrier film)
The barrier film was adhered to a support (glass plate), placed in a cleaning container, ultrasonically cleaned in a neutral detergent, then ultrasonically cleaned in pure water, and heated and dried at 120 ° C. for 120 minutes. Then, the silane coupling process was performed on both surfaces. By this surface treatment, the adhesion between the optical layer and the barrier film can be enhanced. The optical layer is applied while the barrier film is adhered to the support. After apply | coating an optical layer to the single side | surface of a barrier film, it peels from a support body and a protective film is stuck on a coating surface. The optical layer is applied to the opposite surface by adhering the protective film side to the support.

(Preparation of first optical layer forming coating solution)
First coating liquids A1 to A5 for forming an optical layer were prepared as follows.

<Preparation of first optical layer forming coating solution A1>
Propylene glycol monomethyl ether (PGME) 400 volume% as a solvent, titanium oxide particles (refractive index n = 2.7, average particle diameter 15 nm) 15 volume%, polymethyl methacrylate (PMMA) particles (refractive index n = 1.5, average particle size 10 μm) is mixed with 50% by volume, organic resin material “material name: fluorene derivative (acrylate), trade name: Ogsol EA-0200, manufactured by Osaka Gas Chemical Co., Ltd.” at a ratio of 35% by volume. Further, 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Ogsol EA-0200 and stirred to obtain a first optical layer forming coating solution A1.

<Preparation of coating liquid A2 for forming the first optical layer>
To 400% by volume of PGME solvent, 15% by volume of titanium oxide particles (refractive index n = 2.7, average particle size 15 nm), 50% by volume of PMMA particles (refractive index n = 1.5, average particle size 20 μm), Oxol EA-0200 was mixed at a ratio of 35% by volume, and further 2% by mass polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Oxol EA-0200, and the mixture was stirred. It was set as coating liquid A2 for optical layer formation.

<Preparation of coating liquid A3 for forming the first optical layer>
15% by volume of titanium oxide particles (refractive index n = 2.7, average particle size 15 nm) and 50% by volume of melamine silica particles (refractive index n = 1.65, average particle size 2 μm) in 400% by volume of PGME solvent. Ogsol EA-0200 was mixed at a ratio of 35% by volume, and 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was further mixed with Ogsol EA-0200. The optical layer forming coating solution A3 was used.

<Preparation of first optical layer forming coating solution A4>
Propylene glycol monomethyl ether (PGME) 400 volume% as a solvent, titanium oxide particles (refractive index n = 2.7, average particle diameter 15 nm) 24 volume%, polymethyl methacrylate (PMMA) particles (refractive index n = 1.5, average particle size 10 μm) is mixed with 20% by volume, organic resin material “Material name: fluorene derivative (acrylate), trade name: Ogsol EA-0200, manufactured by Osaka Gas Chemical Co., Ltd.” at a ratio of 56% by volume. Further, 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Ogsol EA-0200 and stirred to obtain a first optical layer forming coating solution A4.

<Preparation of first optical layer forming coating solution A5>
400% by volume of propylene glycol monomethyl ether (PGME) as a solvent, 3% by volume of titanium oxide particles (refractive index n = 2.7, average particle size 15 nm), polymethyl methacrylate (PMMA) particles (refractive index n = 1.5, average particle size 10 μm) is mixed with 90% by volume, organic resin material “Material name: fluorene derivative (acrylate), trade name: Ogsol EA-0200, manufactured by Osaka Gas Chemical Co., Ltd.” at a ratio of 7% by volume. Furthermore, 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Oxol EA-0200 and stirred to obtain a first optical layer forming coating solution A5.

(Preparation of second optical layer forming coating solution)
Second coating solutions B1 to B6 for forming an optical layer were prepared as follows.

<Second coating liquid B1 for forming an optical layer>
15% by volume of titanium oxide particles (refractive index n = 2.7, particle size 15 nm) and 50% by volume of PMMA particles (refractive index n = 1.5, average particle size 0.5 μm) in 400% by volume of PGME solvent. Ogsol EA-0200 was mixed at a ratio of 35% by volume, and 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Ogsol EA-0200. The optical layer forming coating solution B1 was used.

<Second Optical Layer Forming Coating Liquid B2>
PGME solvent 400% by volume, titanium oxide particles (refractive index n = 2.7, average particle size 15 nm) 15% by volume, PMMA particles (refractive index n = 1.5, average particle size 0.3 μm) 50 volumes %, Ogsol EA-0200 was mixed at a ratio of 35% by volume, and further 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Ogsol EA-0200 and stirred. The second optical layer forming coating solution B2 was obtained.

<Second Optical Layer Forming Coating Liquid B3>
400% by volume of PGME solvent, 15% by volume of titanium oxide (refractive index n = 2.7, average particle size 15 nm), 50% by volume of PMMA particles (refractive index n = 1.5, average particle size 1.5 μm) Ogsol EA-0200 was mixed at a ratio of 35% by volume, and 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Ogsol EA-0200. The optical layer forming coating solution B3 was used.

<Second coating liquid B4 for forming an optical layer>
15% by volume of titanium oxide particles (refractive index n = 2.7, average particle size 15 nm) and 50% by volume of melamine silica particles (refractive index n = 1.65, average particle size 2 μm) in 400% by volume of PGME solvent. Ogsol EA-0200 was mixed at a ratio of 35% by volume, and 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was further mixed with Ogsol EA-0200. The optical layer forming coating solution B4 was used.

<Second coating liquid B5 for forming an optical layer>
24% by volume of titanium oxide particles (refractive index n = 2.7, particle size 15 nm), 20% by volume of PMMA particles (refractive index n = 1.5, average particle size 0.5 μm) in 400% by volume of PGME solvent Ogsol EA-0200 was mixed at a ratio of 56% by volume, and further 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Ogsol EA-0200. The optical layer forming coating solution B5 was used.

<Second coating liquid B6 for forming an optical layer>
400% by volume of PGME solvent, 3% by volume of titanium oxide particles (refractive index n = 2.7, particle size 15 nm), 90% by volume of PMMA particles (refractive index n = 1.5, average particle size 0.5 μm) Ogsol EA-0200 was mixed at a ratio of 7% by volume, and further 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed with Ogsol EA-0200. The optical layer forming coating solution B6 was used.

<Preparation of flattening layer forming coating solution>
Titanium oxide (refractive index n = 2.7, average particle diameter of 15 nm) is mixed with 400% by volume of PGME solvent at a ratio of 30% by volume and Oxol EA-0200 at a ratio of 70% by volume, and further with respect to Oxol EA-0200. 2% by mass of a polymerization initiator (Irgacure 819, manufactured by BASF) was mixed and stirred to obtain a coating solution for forming a flattening layer.

(Deposition of the first optical layer)
The first optical layer forming coating solution shown in Table 1 is applied to the surface of the barrier film subjected to the surface treatment on the side of the flexible substrate with a die coater, and the first optical layer is cured by irradiating with ultraviolet rays for 2 minutes. Formed. The coating amount was adjusted so that the average film thickness described in Table 1 (the average film thickness of the binder layer) was obtained.

(Deposition of second optical layer)
The second optical layer-forming coating liquid described in Table 1 was applied to the surface of the barrier layer with a die coater, and was irradiated with ultraviolet rays for 2 minutes to be cured to form a second optical layer. The coating amount was adjusted so that the average film thickness described in Table 1 (the average film thickness of the binder layer) was obtained.

(Formation of planarization layer)
A planarization layer forming coating solution was applied onto the second optical layer with a die coater, and irradiated with ultraviolet rays for 2 minutes to be cured to form a planarization layer. The coating amount was adjusted so that the average film thickness described in Table 1 was obtained.

(Deposition of the first electrode)
On the planarizing layer (Comparative Example 2 is a barrier layer), ITO was sputter-deposited to a thickness of 100 nm using a vacuum apparatus. After washing with ultrasonic waves, it was dried at 120 ° C. for 2 hours.

(Deposition of organic layer)
On the first electrode (translucent electrode) obtained as described above, a vacuum deposition apparatus was used to deposit 40 nm of luminescent material A using 10 nm of HAT-CN, 500 nm of α-NPD, 5 nm of organic material A, and mCP as a host material. A total of 30 nm of the light emitting layer doped with%, BAlq of 39 nm, and 1 nm of BCP were deposited in this order.

(Deposition of reflective electrode)
On the BCP layer, 1 nm of LiF and 200 nm of Al were evaporated.

(Sealing)
In the nitrogen gas atmosphere, the organic layer side was sealed with the sealing glass can which apply | coated the sealing material to the installation surface with a flexible substrate in the produced laminated body (structure of FIG. 2). In addition, the desiccant was previously stuck inside the sealing can.

<Evaluation>
[Barrier performance]
The barrier performance was evaluated by the durability of the organic electroluminescence device. Turned on at 5 mA for 500 hours, A with a dark spot total area of less than 3% with respect to the light emitting surface is A, 3% to 40% is B, 40% is over or no light is C .

[External quantum efficiency]
The external quantum yield was measured using an external quantum efficiency measurement device “C9920-12” manufactured by Hamamatsu Photonics Co., Ltd., by applying a constant DC current to each organic electroluminescence device to emit light.

〔curl〕
After the first and second optical layers and the planarizing layer are formed on a 10 cm × 10 cm barrier film, the resulting laminate is allowed to stand on a horizontal base. At this time, the lift of the end of the laminated body from the surface of the table was A, and A was 2-5 mm or less, B was 5 mm, and C was C.
The results are shown in Table 1.

In the organic electroluminescence devices of Examples 1 to 11, liquid infiltration from the flexible substrate side is suppressed more than the barrier layer by making the average particle size of the first particles larger than the average particle size of the second particles. The barrier performance was excellent. In addition, it has excellent luminous performance and display performance because curling of the substrate is suppressed.
On the other hand, the organic electroluminescence device of Comparative Example 1 has the same average particle diameter of the first particles and the average particle diameter of the second particles, so that liquid penetration occurs from the flexible substrate side, and the barrier performance is It was lower than the example. In Comparative Example 2, liquid intrusion from the barrier layer side also occurred, and in addition to a decrease in barrier performance, curling also occurred.

  The organic electroluminescent device of the present invention is, for example, various lighting, computer, in-vehicle display, outdoor display, household equipment, commercial equipment, home appliances, traffic display, clock display, calendar display, It can be suitably used in various fields including luminescent screens, audio equipment and the like.

DESCRIPTION OF SYMBOLS 1 Flexible substrate 2 1st optical layer 3 Barrier layer 4 2nd optical layer 5 1st particle 6 2nd particle 11 1st electrode 12 Organic layer 13 2nd electrode 14 Sealing can 100 Organic electroluminescent apparatus

Claims (10)

A first optical layer containing first particles and a binder, a flexible substrate, a barrier layer, a second optical layer containing second particles and a binder, a first electrode, an organic layer comprising an organic light emitting layer, And a second electrode in this order,
The first particles and the second particles are particles made of organic matter,
The average particle size of the first particles is larger than the average particle size of the second particles;
Organic electroluminescent device.   The ratio of the average particle diameter of the first particles to the average particle diameter of the second particles (average particle diameter of the first particles / average particle diameter of the second particles) is 10 or more and 100 or less. The organic electroluminescent device as described.   The organic electroluminescent device according to claim 1 or 2, wherein the average thickness of the first optical layer is 5 µm or more and 50 µm or less.   The organic electroluminescent device according to any one of claims 1 to 3, wherein an average film thickness of the second optical layer is 1 µm or more and 6 µm or less.   The organic electroluminescence device according to any one of claims 1 to 4, wherein the content of the first particles in the first optical layer is 30 to 80% by volume.   The organic electroluminescence device according to any one of claims 1 to 5, wherein the content ratio of the second particles in the second optical layer is 30 to 80% by volume.   The organic according to any one of claims 1 to 6, wherein the first optical layer further contains particles having a refractive index difference of 0.3 to 1.5 with respect to the first particles. Electroluminescent device.   The organic according to any one of claims 1 to 7, wherein the second optical layer further contains particles having a refractive index of 0.3 or more and 1.5 or less with respect to the second particles. Electroluminescent device.   The organic electroluminescent device according to any one of claims 1 to 8, further comprising a planarizing layer between the second optical layer and the first electrode.   The organic electroluminescent device according to claim 1, wherein the barrier layer has a multilayer structure in which an organic layer made of an organic material and an inorganic layer made of an inorganic material are laminated.

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