JP2008021575A - Organic electroluminescent element and manufacturing method of same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element allowing service life extension, flexibility provision, impact resistance provision, heat resistance provision, dimensional stability provision, luminance irregularity reduction, and yield improvement in a practical emission area, and having an aptitude for a backlight. <P>SOLUTION: This organic electroluminescent element has, on a substrate formed of a plastic film having a gas shielding layer, a transparent electrode layer, an organic layer including at least a luminescent layer, and a counter electrode. The organic electroluminescent element is characterized in that the plastic film contains a cross-linked resin and a glass fiber; the linear expansion coefficient of the plastic film at 30-150°C is 0-40 ppm/°C; and the luminescent layer comprises a luminescent layer host and a phosphorescent material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element (hereinafter abbreviated as an organic EL element) and a method for manufacturing the element, and more specifically, can be driven with lower power, has excellent durability as an organic EL element, The present invention relates to a highly stable organic EL element that is not easily affected by temperature changes and a method for manufacturing the element.

  The organic EL element is driven by a DC power supply, can be lowered by a battery of about several volts, has no viewing angle dependency due to self-emission, and has a quick response. As a white light source (backlight) for this purpose, research has been advanced as an organic EL display that has evolved further than a liquid crystal display, and a part has been commercialized.

  However, as a high-intensity white light source for self-luminous flat panel displays and non-self-luminous liquid crystal displays to meet the more stringent demands of portability and thinning, it is a light-weight, light-emitting efficiency, long-life organic EL There is a need for an element.

  A thin, impact-resistant planar light source that achieves uniform light emission has not been realized in the prior art.

  The most important reason is that the base material of the conventional organic EL element is glass, and the base material for sealing is a plate in which a part of a glass plate or a metal plate is dug. The larger the light emitting surface is, the more difficult it is to make it thin when glass is used, and it is difficult not only to handle in the process but also to maintain the strength that can withstand normal use by general consumers.

  The light-emitting function of organic EL elements is hindered by water molecules and oxygen molecules due to their electrochemical properties. Therefore, even if a flexible plastic film or sheet-like substrate is used, practical light emission is possible. It was difficult to form an element and emit light for a long time.

  The reason why plastic films and plastic sheets could not be used as the base material for organic EL elements is that (1) the plastic film does not have the same heat resistance as glass, so it can withstand the heat when forming transparent electrodes by sputtering. Inability to form transparent electrodes with good electrical conductivity, (2) Adhesive performance even when an adhesive that cures by ultraviolet light or heat is used when bonding plastic films to other materials or components (3) When a fine light-emitting region is continuously formed under heating conditions, dimensional accuracy equivalent to that of a glass substrate cannot be obtained. (4) Gas permeation of moisture and oxygen of the plastic material Because the properties are much higher than glass, an excellent gas barrier film without pinholes is needed to ensure a sufficiently long emission life of organic EL elements. It is necessary to be formed on the click film, and the like.

  In order to solve these problems, for example, Patent Document 1 discloses that a plastic film is multilayered, a hygroscopic material is kneaded into the plastic film, inorganic particles are contained, and the surface roughness is controlled. There is still not enough.

  Furthermore, in order to achieve the light emitting surface on the curved surface, supply the base film at the time of production in the original roll, or take up after processing, so-called roll-to-roll processing, of course, glass substrate, With conventional plastic films, it has been difficult to achieve the required level of the present invention.

  In the practical application, there is a demand for shape workability that can be reduced in weight and thickness, and can be curved, and it is proposed to use a substrate made of a flexible material such as a polymer film. (For example, Patent Document 2 and Patent Document 3).

  Another reason why application to a white light source with a large area using an organic EL element is strongly expected is that the disadvantages of incandescent lamps and fluorescent lamps that are widely used at present can be improved. That is, an incandescent lamp is a light source that has a light spectrum close to that of sunlight and close to natural light, but is not suitable for uniformly brightening the entire wall surface, and it is difficult to change the emission spectrum. Also, the efficiency of converting electrical energy into light energy is low. Fluorescent lamps are more frequently used at present because they are more efficient at converting electrical energy into light energy than incandescent lamps, but fluorescent lamps also have some drawbacks.

  Since the fluorescent lamp uses the glow discharge of mercury vapor, the lighting time is delayed and the discharge is unstable immediately after the lighting and the light quantity is not stable. In addition, a decrease in the amount of light in a low temperature environment is a problem. Furthermore, since the fluorescent lamp has mercury vapor sealed in a glass tube, it is difficult to reduce the size and environmental pollution due to mercury is also a problem.

  On the other hand, an organic EL element is a structure in which a light emitting layer made of a thin organic compound is held by electrodes, and emits light when a current is supplied between the electrodes. When the organic EL element that is a thin film is used as a light source, In addition, the lighting device can be easily reduced in size and weight, has a faster light emission response speed than a fluorescent lamp, and has a relatively stable light amount immediately after lighting.

  Accordingly, it would be very useful to replace easily fragile glass with a plastic having excellent impact resistance and to produce a plastic type organic EL element that does not use mercury.

  As described above, substrates such as glass are usually used for display devices and electro-optical devices provided in portable information terminal devices such as mobile phones in recent years, and glass is excellent in that it has low moisture permeability. However, since it is heavy and does not have flexibility (flexibility), it has drawbacks such as being easily broken by dropping.

  For this reason, a flexible element (for example, using a plastic substrate) which is strong against bending is demanded with the spread of these, and a flexible and flexible light emitting light source such as an illumination instead of a fluorescent lamp is also required. There is also a great demand for forming an organic EL element as a light emitting light source on a supporting member and using it for illumination.

  Actually, a method for forming an organic EL element on a plastic film as disclosed in Patent Documents 4 and 5 is known. Conventionally, one of the reasons why glass substrates could not be easily replaced with plastic substrates is that the coefficient of thermal expansion differs greatly between glass and plastic. Even when light is emitted evenly in a planar shape, the gas shielding layer and electrode layer on the plastic are mostly metal oxides, and are damaged or deformed due to differences in the thermal expansion coefficient from the plastic substrate. Occurs in the manufacturing heating process.

  Furthermore, in order to divide the transmitted light into the three primary colors of light, green, blue, and red, it is often a necessary process for display devices and electro-optical devices to form fine pixels on the substrate on the substrate. When the three primary colors are separately applied, the dimensional change of the substrate is required to be much smaller than the size of the pixel to be formed.

  Further, the larger the screen to be displayed, the larger the positional deviation at both ends, and the larger the deviation from the pixel formation mask pattern, so it was very difficult to increase the area of the plastic substrate. For example, organic EL light-emitting pixels can be formed regularly by moving a certain amount of mask, but the substrate can be bent and displaced during processes such as vapor deposition and transport, and high-definition can be achieved with a large plastic substrate. It is difficult to form a simple pixel pattern. In addition, there are problems that the plastic substrate is deformed by heat generated during energization, the element on the substrate is peeled off, becomes defective, and does not emit light.

  In particular, when used as a substrate for an organic EL device, it is required to have water vapor permeability and oxygen permeability as low as glass, and a gas shielding layer (barrier layer) made of an inorganic material is often formed on the plastic surface. Although it is performed, it is difficult to form a good gas shielding layer with a plastic having low heat resistance.

  Patent Document 6 discloses an attempt to improve gas permeability by multilayering a barrier layer. However, when the substrate itself is an existing plastic, heat resistance and low thermal expansion cannot be ensured, and cracks ( There are problems such as generation of fine cracks in the barrier layer) and generation of pinholes, deformation of the substrate due to inability to withstand the heat history during the above-described process and heat generation during light emission.

  In addition, when the substrate itself is processed into small pieces or cut into an arbitrary shape, fine fragments at the edges become foreign matters when the light emitting layer is formed, and a high yield cannot be obtained.

  For example, Patent Document 7 discloses an example of a liquid crystal display device using a synthetic resin substrate, which is formed by transferring a thin film device formed on a heat-resistant substrate onto a plastic substrate. This complicates the process and causes problems due to pixel defects and transfer deviation.

Moreover, in order to reduce the coefficient of thermal expansion, a method of adding an organic or inorganic filler having a small thermal expansion to a plastic is disclosed, but even if these substrates are simply used as an organic EL substrate, they are cut. Since the organic EL element was adversely affected by the permeability of water and oxygen during processing, it was not possible to use at all, and the required level of the present invention could not be met.
JP-A-2005-38661 JP-A-2-251429 JP-A-6-124785 JP 2002-175875 A JP 2002-190384 A JP 2003-17244 A JP 2001-166300 A

  Therefore, the present invention has been made in view of such problems, and has a long life, flexibility, impact resistance, heat resistance, dimensional stability, luminance unevenness reduction, and practical light emission. It is an object of the present invention to provide an organic EL element having improved yield in area and suitability for backlight and a method for manufacturing the element.

  The other subject of this invention becomes clear by the following description.

  The above-described problems of the present invention are solved by the following inventions.

(Claim 1)
In an organic electroluminescence device having a transparent electrode layer, an organic layer including at least a light emitting layer, and a counter electrode on a substrate made of a plastic film having a gas shielding layer,
The plastic film includes a crosslinked resin and glass fiber, and the linear expansion coefficient of the plastic film at 30 ° C. to 150 ° C. is 0 ppm / ° C. or more and 40 ppm / ° C. or less, and the light emitting layer is a light emitting layer host. An organic electroluminescence device comprising a phosphorescent material.

(Claim 2)
2. The organic electroluminescence device according to claim 1, wherein the glass fiber is blended in an amount of 1 to 90% by weight based on the plastic film composition.

(Claim 3)
The organic electroluminescence element according to claim 1, wherein the gas shielding layer has at least a gas barrier layer.

(Claim 4)
The water vapor permeability of the plastic film having the gas shielding layer is 0.01 g / m ² · 24 hr or less (measured value at 40 ° C. and 90% RH based on JIS K7129B method). The organic electroluminescent element in any one of 1-3.

(Claim 5)
Forming a plastic film substrate containing a crosslinked resin and glass fiber;
Forming a gas shielding layer on the plastic film substrate;
Providing a transparent electrode layer on the gas-shielding layer to form a substrate with a transparent electrode;
Forming an organic layer including at least a light emitting layer on the transparent electrode layer;
Forming a counter electrode on the organic layer, and a method of manufacturing an organic electroluminescence element,
The method for producing an organic electroluminescent element, wherein the plastic film substrate has a linear expansion coefficient at 30 ° C. to 150 ° C. of not less than 0 ppm / ° C. and not more than 40 ppm / ° C.

(Claim 6)
6. The method of manufacturing an organic electroluminescent element according to claim 5, further comprising a step of cutting the substrate into a desired shape with a laser cutter after forming the substrate with a transparent electrode.

(Claim 7)
After passing through the step of cutting the substrate with a transparent electrode into a desired shape with a laser cutter, the organic layer is formed after passing through a cleaning step with an organic solvent and a deaeration step under vacuum of the substrate. The manufacturing method of the organic electroluminescent element of Claim 5 or 6.

(Claim 8)
8. The method according to claim 5, further comprising a step of forming a conductive planarization layer on the transparent electrode layer after the step of forming the substrate with a transparent electrode, and then forming an organic layer. The manufacturing method of the organic electroluminescent element of description.

(Claim 9)
The said glass fiber is mix | blended 1 to 90 weight% with respect to a plastic film composition, The manufacturing method of the organic electroluminescent element in any one of Claims 5-8 characterized by the above-mentioned.

(Claim 10)
The method for producing an organic electroluminescent element according to claim 5, wherein the step of forming the gas shielding layer includes at least a step of forming a gas barrier layer.

(Claim 11)
6. The water vapor permeability of the plastic film having the gas shielding layer is 0.01 g / m ² · 24 hr or less (measured value at 40 ° C. and 90% RH based on JISK7129B method). The manufacturing method of the organic electroluminescent element in any one of -10.

(Claim 12)
The method for producing an organic electroluminescent element according to claim 5, wherein the light emitting layer comprises a light emitting layer host and a phosphorescent material.

  According to the present invention, an organic EL device having long life, flexibility, impact resistance, heat resistance, dimensional stability, luminance unevenness reduction, yield improvement in a practical light emitting area, and backlight suitability A method for manufacturing the element can be provided.

  Embodiments of the present invention will be described below.

  The method for producing an organic EL device according to the present invention includes a step of forming a plastic film substrate containing a crosslinked resin and glass fiber, a step of forming a gas shielding layer on the plastic film substrate, and the gas shielding property. Forming a transparent electrode layer on the layer, forming a substrate with a transparent electrode, forming an organic layer including at least a light emitting layer on the transparent electrode layer, and a counter electrode on the organic layer In the method of manufacturing an organic electroluminescence element having a step of forming a film, the plastic film substrate has a linear expansion coefficient at 30 ° C. to 150 ° C. of 0 ppm / ° C. or more and 40 ppm / ° C. or less.

  Hereinafter, each process will be described in detail.

[Step of forming a plastic film substrate containing a crosslinked resin and glass fiber]
Examples of the crosslinked resin used for producing the plastic film of the present invention include (A) a resin obtained by crosslinking a reactive monomer such as acrylate with active energy rays and / or heat, or (B) an epoxy resin.

  In the present invention, the crosslinking is preferably performed after glass fibers described later are contained.

  A preferable cross-linked resin (A) is a transparent resin obtained by cross-linking of an acrylate (a1) having an alicyclic structure and at least one acrylate (a2) selected from a sulfur-containing acrylate and an acrylate having a fluorene skeleton. Resin. (A1) is a low refractive index monomer having a lower refractive index than glass fiber, and (a2) is a monomer having a higher refractive index than glass fiber. Both are described in detail below.

(A1) Low refractive index monomer As the reactive monomer having a refractive index lower than that of the glass fiber, various (meth) acrylates containing an alicyclic structure or an aliphatic chain can be used. A (meth) acrylate having an alicyclic structure is preferred from the surface.

  As the (meth) acrylate having an alicyclic structure, any (meth) acrylate having an alicyclic structure and having two or more functional groups may be used, and the following formula ( At least one (meth) acrylate selected from 1) and (2) is preferred.

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group. A represents 1 or 2, and b represents 0 or 1.)

(Wherein X represents a hydrogen atom, —CH ₃ , —CH ₂ OH, NH ₂ , R ₃ and R ₄ are H or —CH ₃ , and p is 0 or 1)

In formula (1), dicyclopentadienyl diacrylate having a structure in which R ₁ and R ₂ are hydrogen, a is 1 and b is 0 is particularly preferred from the viewpoint of physical properties such as viscosity.

Further, in the formula (2), perhydro-1,4,5,8-dimethananaphthalene having a structure in which X is —CH ₂ OCOCH═CH ₂ , R ₃ , R ₄ is hydrogen and p is 1. At least one acrylate selected from acrylates having a structure in which -2,3,7- (oxymethyl) triacrylate, X, R ₃ , and R ₄ are all hydrogen and p is 0 or 1 is preferable. In particular, in view of viscosity and the like, norbornane dimethylol diacrylate having a structure in which X, R ₃ and R ₄ are all hydrogen and p is 0 is most preferable. The (meth) acrylate of the formula (2) can be obtained by the method disclosed in JP-A-5-70523.

  As the reactive monomer having a refractive index lower than that of the glass fiber, the cyclic ether (meth) acrylate represented by the following formula (6) is also desirable because of its high transparency and heat resistance.

(In the formula, R ₁₈ and R ₁₉ each independently represent a hydrogen atom or a methyl group.)

(A2) High Refractive Index Monomer As the reactive monomer having a higher refractive index than glass fiber, various (meth) acrylates containing sulfur and aromatic rings can be used. A (meth) acrylate or a (meth) acrylate having a fluorene skeleton is preferred.

  The sulfur-containing (meth) acrylate used in the present invention may be a (meth) acrylate having two or more functional groups containing sulfur, and is represented by the following formula (3) from the viewpoint of heat resistance and transparency ( (Meth) acrylate is preferred.

(Wherein, X represents a sulfur or SO _2, Y is .n and m _.R 5 _{to R 10} showing the oxygen or sulfur each independently represent a hydrogen atom or a methyl group is 0-2.)

Among the (meth) acrylates represented by formula (3), X is sulfur, Y is oxygen, R _{5 to} R ₁₀ are all hydrogen, and n and m are both 1 because of reactivity, heat resistance and ease of handling. [4- (acryloyloxyethoxy) phenyl] sulfide is most preferred.

  The (meth) acrylate having a fluorene skeleton used in the present invention is not particularly limited as long as it is a (meth) acrylate having a fluorene skeleton and having two or more functional groups, but the following from the viewpoint of heat resistance and transparency. At least one (meth) acrylate selected from the formulas (4) and (5) is preferred.

(In the formula, R _{11 to} R ₁₄ each independently represents a hydrogen atom or a methyl group. R and s are 0 to 2.)

(In the formula, R _{15 to} R ₁₇ each independently represent a hydrogen atom or a methyl group.)

Among these, bis [4- (acryloyloxyethoxy) phenyl] fluorene in which R _{11 to} R ₁₄ are all hydrogen and r and s are 1 in the formula (4) is most preferable.

  These low-refractive index monomer and high-refractive index monomer can be mixed and crosslinked at an appropriate blending ratio according to the target refractive index, and the refractive index of the transparent resin is combined with the refractive index of the glass fiber. Can be adapted to

  In order to impart flexibility to the (meth) acrylate having two or more functional groups used in the present invention, a monofunctional (meth) acrylate may be used in combination as long as desired properties are not impaired. In this case, the blending amount is adjusted so that the refractive index of the entire resin component matches the refractive index of the glass fiber.

(Polymerization initiator)
In order to crosslink and cure the reactive monomer with active energy rays such as ultraviolet rays, it is preferable to add a photopolymerization initiator that generates radicals in the resin composition. Examples of such photopolymerization initiators include benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,6-dimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl. Examples thereof include diphenylphosphine oxide. Two or more of these photopolymerization initiators may be used in combination.

  The content of the photopolymerization initiator in the resin composition may be an appropriate amount to be cured, and 0.01 to 2 weights with respect to a total of 100 parts by weight of (meth) acrylate having two or more functional groups. Part, preferably 0.02 to 1 part by weight, and most preferably 0.1 to 0.5 part by weight. When the amount of the photopolymerization initiator added is too large, the polymerization proceeds rapidly, and problems such as increased birefringence, coloring, and cracks during curing occur. On the other hand, if the amount is too small, the composition cannot be sufficiently cured, and there is a possibility that problems such as adhesion to the mold after crosslinking and removal cannot occur.

  When heat treatment is performed at a high temperature after curing by active energy rays and / or crosslinking by thermal polymerization, 250 to 300 ° C. in a nitrogen atmosphere or in a vacuum state for the purpose of reducing the linear expansion coefficient during the heat treatment step. It is preferable to add a heat treatment step for 1 to 24 hours.

  The epoxy resin (B) has a different refractive index of the cured epoxy resin depending on the curing agent used. In the present invention, the refractive index after curing is lower than the refractive index of the glass fiber used. Or it will not be specifically limited if it becomes high.

  As an epoxy resin having a low refractive index or a high epoxy resin, when glass fiber having a refractive index of 1.52 or more such as E glass or S glass is used as a glass fiber, an acid anhydride is used as a curing agent, and (i) comparison At least one selected from alicyclic epoxy resins having a low refractive index (such as the following formulas (3) to (8)) and triglycidyl isocyanurate having a moderate refractive index (the following formula (9)) A combination of an epoxy resin and (ii) at least one epoxy resin selected from a sulfur-containing epoxy resin having a relatively high refractive index (the following formula (1)) and a fluorene skeleton-containing epoxy resin (the following formula (2)) Is preferred.

  Among them, triglycidyl isocyanurate is more preferable as the component (i) from the viewpoint of heat resistance.

  On the other hand, when glass fibers having a refractive index of less than 1.52, such as NE glass, are used, (i) an alicyclic epoxy resin having a relatively low refractive index (the following formulas (3) to (8) )) And at least one epoxy resin selected from (ii) triglycidyl isocyanurate having a medium refractive index (the following formula (9)), and a sulfur-containing epoxy resin having a relatively high refractive index (below) A combination of at least one epoxy resin selected from the formula (1)) and a fluorene skeleton-containing epoxy resin (the following formula (2)) is preferable.

  Examples of the epoxy resin having a relatively low refractive index include alicyclic epoxy resins represented by the following formulas (3) to (8).

(In the formula, R ₆ represents an alkyl group or a trimethylolpropane residue, and q is 1 to 20.)

(Wherein R ₇ and R ₈ each independently represent a hydrogen atom or a methyl group, and r is 0 to 2).

  (In the formula, s is 0 to 2.)

  The triglycidyl isocyanurate having a medium refractive index is represented by the following formula (9).

  The sulfur-containing epoxy resin having a relatively high refractive index is not particularly limited as long as it contains sulfur and has two or more epoxy groups. From the viewpoint of heat resistance and transparency, the following formula (1 The epoxy resin shown in FIG.

(In the formula, X represents S or SO ₂ , Y represents O or S. R _{1 to} R ₄ each independently represents a hydrogen atom or a methyl group, and n is 0 to 2.)

Among the epoxy resins represented by the formula (1), bisphenol S in which X is SO ₂ , Y is oxygen, R _{5 to} R ₁₀ are all hydrogen, and n is 0 to 1 because of reactivity, heat resistance and ease of handling. Is most preferred.

  The fluorene skeleton-containing epoxy resin having a relatively high refractive index is not particularly limited as long as it contains an fluorene skeleton and has two or more epoxy groups, but the following formula is used from the viewpoint of heat resistance and transparency. The epoxy resin represented by (2) is preferred.

(In the formula, R ₅ represents hydrogen or a methyl group, and m is 0 to 2.)

  Epoxy resins having different refractive indexes after curing can be mixed and cured at an appropriate blending ratio according to the target refractive index, and the refractive index of the epoxy resin can be adjusted to the refractive index of the glass fiber.

  The epoxy resin used in the present invention may be used in combination with a monofunctional epoxy compound as long as desired properties are not impaired, for example, to impart flexibility. In this case, the blending amount is adjusted so that the refractive index of the entire resin matches the refractive index of the glass fiber.

  The epoxy resin used in the present invention is used after being cured by heating or irradiation with active energy rays in the presence of a curing agent or a polymerization initiator. The curing agent is not particularly limited, but an acid anhydride-based curing agent or a cationic catalyst is preferable because an excellent transparent cured product can be easily obtained.

  Examples of acid anhydride curing agents include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, glutaric anhydride, Examples include methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl hydrogenated nadic acid anhydride, and hydrogenated nadic acid anhydride. Among them, methyl hexahydrophthalic anhydride and methyl hydrogenated anhydrous Acid is preferred.

  When using an acid anhydride curing agent, it is preferable to use a curing accelerator in combination. Examples of the curing accelerator include 1,8-diaza-bicyclo (5,4,0) undecene-7, tertiary amines such as triethylenediamine, imidazoles such as 2-ethyl-4-methylimidazole, and triphenylphosphine. And phosphorus compounds such as tetraphenylphosphonium tetraphenylborate, quaternary ammonium salts, organometallic salts, and derivatives thereof, among which phosphorus compounds are preferred. These curing accelerators may be used alone or in combination of two or more.

  The amount of the acid anhydride curing agent used is preferably set to 0.5 to 1.5 equivalents of the acid anhydride group in the acid anhydride curing agent with respect to 1 equivalent of the epoxy group in the epoxy resin. 0.7-1.2 equivalent is more preferable.

  Cationic catalysts include acetic acid, benzoic acid, salicylic acid, p-toluenesulfonic acid and other organic acids, boron trifluoride amine complexes, boron trifluoride ammonium salt, aromatic diazonium salt, aromatic sulfonium salt, aromatic Examples thereof include cationic catalysts containing a group iodonium salt and an aluminum complex, and among these, a cationic catalyst containing an aluminum complex is preferred.

  Although the refractive index of the glass fiber mix | blended with the plastic film of this invention is not specifically limited, It is preferable to exist in the range of 1.50-1.57 so that adjustment of the refractive index of resin to combine is easy. In particular, when the refractive index of the glass fiber is 1.50 to 1.54, a resin close to the Abbe number of the glass can be selected, which is preferable. When the Abbe numbers of the resin and glass are close, the refractive indexes of the two coincide in a wide wavelength region, and a high light transmittance is obtained in a wide wavelength region.

  The glass fibers used in the present invention may be any of glass fiber filaments (short fibers or long fibers), glass fiber woven fabrics, glass fiber nonwoven fabrics, etc., among which glass fiber woven fabrics are preferred. In the present invention, glass fiber does not include glass powder, glass beads, or 1 mm or less glass fiber (short fiber).

  Examples of the glass include E glass, C glass, A glass, S glass, D glass, NE glass, T glass, quartz, low inductivity glass, and high inductivity glass. E glass, S glass, T glass, and NE glass, which have few impurities and are easily available, are preferred.

  When a glass fiber woven fabric is used as the glass fiber, the method of weaving the filament is not limited, and plain weave, Nanako weave, satin weave, twill weave, etc. can be applied, and plain weave is preferred.

  In general, the thickness of the glass fiber woven fabric is preferably 30 to 200 μm, and more preferably 40 to 150 μm.

  Only one glass fiber cloth such as a glass fiber woven cloth or a glass non-woven cloth may be used, or a plurality of glass fiber cloths may be used.

  The blending amount of the glass fiber in the plastic film composition is preferably 1 to 90% by weight, more preferably 10 to 80% by weight, and still more preferably 30 to 70% by weight. When the blending amount of the glass fiber is less than this, the linear expansion coefficient does not fall within the scope of the present invention. On the other hand, when the blending amount is larger than this, the molded appearance tends to be lowered.

  The plastic film substrate thus obtained has a linear expansion coefficient at 30 ° C. to 150 ° C. of 0 ppm / ° C. or more and 40 ppm / ° C. or less, preferably 0 ppm / ° C. or more and 30 ppm / ° C. or less. is there. In the present invention, the linear expansion coefficient is measured by the following method.

  According to JIS K7197, it measured using the TMA / Ss120C type | mold thermal stress strain measuring device by Seiko Electronics Co., Ltd.

[Process for forming a gas shielding layer on a plastic film substrate]
In the present invention, the step of forming a gas shielding layer preferably includes at least a step of forming a gas barrier layer.

  When the gas barrier layer is provided, the gas permeability of the plastic film is significantly reduced. Therefore, the light emission life can be extended by suppressing damage to the organic EL element caused by water vapor and oxygen contained in the outside air. In addition, expansion of the non-lighting area that increases with time during light emission can be suppressed.

  As another preferable aspect of the present invention, it is preferable to have a step of sequentially forming a plastic film substrate / gas barrier layer / intermediate coat layer / gas barrier layer on the transparent electrode side of the plastic film substrate.

  Moreover, it is preferable to have the process of forming a plastic film board | substrate / gas barrier layer / overcoat layer on the opposite side to the transparent electrode side of a plastic film board | substrate.

  Therefore, as a preferable layer structure, an embodiment in which an overcoat layer / gas barrier layer / plastic film substrate / gas barrier layer / intermediate coat layer / gas barrier layer / transparent electrode is used.

  As the gas barrier layer, an inorganic oxide film having transparency is preferably provided. This inorganic oxide film is composed of silicon oxide, aluminum oxide, titanium oxide, yttrium oxide, germanium oxide, zinc oxide, magnesium oxide, calcium oxide, boron oxide, strontium oxide, barium oxide, lead oxide, zirconium oxide, sodium oxide, oxide It can be formed using one kind or two or more kinds of oxides such as lithium and potassium oxide. In particular, silicon oxide, aluminum oxide, and titanium oxide can be preferably used.

  When silicon oxide is used as the inorganic oxide film, it can be loaded into a sputtering roll coater, and a SiOx film can be formed by DC magnetron sputtering using Si as a target by reactive sputtering using oxygen as a reactive gas. Can be appropriately set in the range of 10 nm to 500 nm in consideration of barrier properties and transparency. Such an inorganic oxide film may have a multilayer structure of two or more layers, or may contain a nitride such as silicon nitride as a subcomponent.

  The overcoat layer is made of thermoplastic resin, thermosetting resin, UV curable resin, etc. in solution, latex, or solvent-free, wire bar, extrusion, micro gravure, reverse roll, etc. coating method, vapor deposition method, sputtering method, etc. It can form by the method of.

  The thickness is preferably in the range of 0.5 μm to 5 μm.

  The intermediate coating layer can be formed by a method such as wire bar, extrusion, microgravure, reverse roll, etc. with a thermoplastic resin, thermosetting resin, ultraviolet curable resin, etc. in a solution, latex, or no solvent.

  The thickness is preferably in the range of 0.5 μm to 5 μm.

In the present invention, the water vapor permeability of the plastic film substrate having the gas shielding layer is preferably 0.01 g / m ² · 24 hr or less (measured value at 40 ° C. and 90% RH based on JIS K7129B method). .

If it is 0.01 g / m ² · 24 hr or less, the light emission lifetime of the organic EL element can be secured in a practical time, and the growth of the non-light-emitting region (dark spot) can be suppressed to an inconspicuous level.

[Step of providing a transparent electrode layer on a gas shielding layer to form a substrate with a transparent electrode]
The transparent electrode layer normally functions as an anode in an organic EL device, and the anode is preferably a material having a work function (4 eV or more) of a metal, an alloy, an electrically conductive compound and a mixture thereof as an electrode material.

Specific examples of such electrode materials include metals such as Au, conductive transparent materials such as Cul, indium tin oxide (ITO), SnO ₂ , and ZnO.

  The anode may be formed by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithographic method, or when pattern accuracy is not required so much (about 100 μm or more) ) May form a pattern through a mask having a desired shape at the time of vapor deposition or spucking of the electrode material.

  When light emission is extracted from the anode, it is desirable that the transmittance is greater than 10%, or the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1 μm, preferably 10 nm to 200 nm.

  In this invention, after forming the said board | substrate with a transparent electrode, it is preferable to have the process of cut | disconnecting this board | substrate into a desired shape using a laser cutter. There are cases where the substrate itself is processed into small pieces or cut into an arbitrary shape, but in that case, there is a problem that fine fragments at the edges become foreign matters when the light emitting layer is formed, and high yield cannot be obtained. In such cutting, chips are generated with a normal cutting knife, scissors, etc. In particular, since glass fibers are loaded in the present invention, fine glass pieces of the glass fibers are generated, and foreign substances are generated on the surface of the substrate after cleaning. However, there is no unevenness of the cut surface when cutting with a laser cutter, and there is an effect that chips are not generated. When a plastic film substrate not mixed with glass fiber is cut with a laser cutter, it is carbonized to produce powder. However, in the case of the substrate of the present invention mixed with glass fiber, the powder is not carbonized. Does not occur.

  The laser is preferably a carbon dioxide laser, and the energy is preferably in the range of 20W to 50W.

  Next, in the present invention, after passing through the step of cutting the substrate with a transparent electrode into a desired shape using a laser cutter, the substrate was subjected to a cleaning step with an organic solvent and a deaeration step under vacuum of the substrate. Thereafter, it is preferable to form an organic layer. By cleaning, it is possible to remove the cutting chips at the edge of the substrate and to clean by removing the plastic oligomer at the cutting portion, and to remove organic solvent, moisture and oxygen gas diffused in the plastic substrate by degassing. This is because the lifetime of the organic EL element can be extended.

  As the organic solvent used in the washing step with an organic solvent, alcohol solvents such as isopropyl alcohol and ethanol are preferable. Of these, isopropyl alcohol is preferred.

The degree of vacuum in the degassing step of the substrate under vacuum is preferably in the range of 10 ⁻³ Pa to 10 ⁻⁷ Pa. In addition, since gas components such as moisture and air that exist inside the substrate move by diffusion in the substrate, the display pressure of the vacuum chamber and the substrate of the present invention that has been exhausted sufficiently are installed when there is no substrate. Usually, the ultimate pressure varies. It is important to allow sufficient evacuation time so that the pressure increase due to the gas released from the substrate becomes a pressure difference that is substantially negligible, as in the case where the substrate does not exist. Therefore, the film formation of each layer of the organic EL element is not started immediately after reaching a predetermined degree of vacuum, but the film is formed with almost no change in pressure in the vacuum chamber over time to form the organic EL element. It is important to do.

[Step of forming an organic layer including at least a light emitting layer on the transparent electrode layer]
In this invention, it is preferable to have the process of forming a planarization layer on this transparent electrode layer after the process of providing the said transparent electrode layer and forming a board | substrate with a transparent electrode, and then forming an organic layer.

  When the planarization layer is formed, steep unevenness that may exist on the substrate surface becomes gentle, and leakage current due to concentration of the electric field between the anode and the cathode after the element formation is suppressed. When a voltage is applied to the organic EL element and gradually raised, the first short-circuited part is the part where the electric field concentrates. Therefore, when the planarization layer is formed, the element is not easily burned even if the area is increased. The yield of light emission is improved.

  As the planarization layer, a conductive material can be widely used. However, a material in which charges are easily injected from an electrode and a molecule having a flat plate shape and easy to stack is preferable. Phthalocyanine-based materials are preferable, and copper phthalocyanines (CuPC) are particularly preferable. The planarization layer can be formed by a method such as vapor deposition, sputtering, or chemical vapor deposition (CVD) in vacuum.

  The thickness of the planarization layer is preferably 1 nm to 50 nm, but if it is too thick, the light emission voltage increases and the power efficiency decreases. If the thickness is less than 1 nm, the unevenness of the surface of the substrate cannot be sufficiently hidden, and when a voltage is applied to the completed device, the leakage current increases and the possibility of damage due to current concentration increases.

  In addition, since it demonstrates in detail later about the organic layer in this invention, it abbreviate | omits here.

[Step of forming counter electrode on organic layer]
The counter electrode normally functions as a cathode. As the cathode, a material having a small work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used. Preferably used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.

Among these, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this from the viewpoint of durability against electron injecting and oxidation, for example, a magnesium / silver mixture, magnesium / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures and the like are preferred.

  The cathode can be produced by forming a thin film from these electrode materials by a method such as vapor deposition or sputtering. Alternatively, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 1 μm, preferably 50 nm to 200 nm. In order to transmit light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission efficiency is improved, which is convenient.

[Sealing process]
In this invention, it seals on each layer (on a counter electrode) which comprises the said organic EL element formed on the translucent board | substrate in this way using another sealing member.

The sealing member may be formed of glass, resin, ceramic, metal, metal compound, or a composite thereof. In a test based on JIS Z-0208, the thickness is 1 μm or more and the water vapor transmission rate. Is 1 g / m ² · 24 hr (1.013 × 10 ⁻¹ MPa, 25 ° C.) or less.

  Moreover, it is also preferable to use the light-transmitting plastic film substrate according to the present invention. By making both the substrates low in moisture permeability and highly flexible, an organic EL element resistant to impact can be formed. The present invention can also be applied to a surface light source whose light emitting surface is a curved surface.

  In addition, the sealing member (glass, film, etc.) on the counter electrode side (cathode, eg, Al, Mg electrode side) is sealed in order to prevent electroluminescence from being absorbed or light from diffusing to the back side. It is preferable to form a pigment layer filled with white titanium oxide on the surface of the member facing the cathode (Al, Mg, etc.) side.

  Sealing is performed through a substantially frame-shaped adhesive layer (or sealing material) provided by a coating method, a transfer method, or the like on the periphery of the surface of the sealing member facing, for example, the counter cathode (upper electrode) side. This is performed by pasting together the transparent substrates on which the respective layers of the organic EL elements facing each other are formed.

For the adhesive layer, a thermosetting epoxy resin, an ultraviolet curable epoxy resin, or a room temperature curable epoxy resin in which a reaction starts by microencapsulating and pressurizing a reaction initiator can be used. In this case, an air escape opening or the like is provided at a predetermined portion of the adhesive layer (not shown) to complete the sealing. The air escape opening is one of the above curable epoxy resins in a reduced pressure atmosphere (preferably a degree of vacuum of 1.33 × 10 ⁻² MPa or less) in a vacuum apparatus, or in a nitrogen gas or inert gas atmosphere, or Sealed with an ultraviolet curable resin or the like.

  Examples of epoxy resins include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, xylenol, phenol novolac, cresol novolac, polyfunctional, tetraphenylolmethane, polyethylene glycol, polypropylene A glycol type, hexanediol type, trimethylolpropane type, propylene oxide bisphenol A type, hydrogenated bisphenol A type, or a mixture thereof is mainly used.

  In the present invention, a material that absorbs moisture or reacts with moisture (for example, barium oxide) can be formed in a layer on the substrate and sealed.

<< Component layer and dopant of organic EL element >>
In the present invention, the organic layer only needs to have at least a light emitting layer, and in the broad sense, the light emitting layer is a layer that emits light when a current is passed through an electrode composed of a cathode and an anode. Specifically, it refers to a layer containing a compound that emits light when an electric current is passed through an electrode composed of a cathode and an anode.

In the present invention, the light emitting layer is obtained by adding a phosphorescent material (hereinafter also referred to as a phosphorescent compound) as a dopant to a light emitting layer host (hereinafter also referred to as a host compound) which is a main material of the light emitting layer.

  In the present invention, a preferable organic layer is one in which a light emitting layer is provided between the first layer and the second layer having different functions such as hole transport property and electron transport property.

  In general, when there are two or more materials constituting the light emitting layer, the main component is called a host compound and the other components are called dopants. In the present invention, the phosphorescent dopant is used as described above.

  In that case, the mixing ratio of the dopant to the host compound as the main component is preferably 0.1% by mass to less than 15% by mass.

(Host compound)
In the organic electroluminescent device of the present invention, as the host compound, any known compound used for the organic EL device may be selected and used. Most of the above hole transport materials and electron transport materials can also be used as the light emitting layer host compound.

  The host compound is preferably an organic compound or a complex. For example, a polymer material may be used, and a polymer material in which the host compound is introduced into a polymer chain or the host compound is a polymer main chain may be used.

  Examples of the light-emitting host (host compound) include a material including a partial structure such as a carbazole derivative, a biphenyl derivative, a styryl derivative, a benzofuran derivative, a thiophene derivative, or an arylsilane derivative as a unit. Of these, a carbazole derivative and a biphenyl derivative are preferable light emitting materials exhibiting high light emission efficiency. As the host compound, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

(Dopant)
In recent years, Princeton University has reported an organic EL device using phosphorescence emission from excited triplets (MABaldo et al., Nature, 395, 151-154 (1998)), and fluorescence emission from excited singlets. Compared with organic EL elements using the above, the luminous efficiency is four times as much in principle and has been attracting attention. Also in this invention, it is preferable from the point of luminous efficiency to contain a phosphorescent compound (dopant).

  The phosphorescent compound in the present invention is a compound in which light emission from an excited triplet is observed, and is a compound having a phosphorescence quantum yield of 0.001 or more at 25 ° C. The phosphorescence quantum yield is preferably 0.01 or more, more preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the 4th edition Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence compound used in the present invention only needs to achieve the above phosphorescence quantum yield in any solvent.

  There are two types of principle of the dopant. One is the recombination of the carrier on the host where the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the dopant to emit light from the dopant. The other is a carrier trap type in which the dopant becomes a carrier trap, and carrier recombination occurs on the dopant compound, and light emission from the dopant is obtained. The condition is that the excited state energy of is lower than the excited state energy of the host compound.

  In the organic electroluminescence device of the present invention, the phosphorescent compound used as a dopant is preferably a complex compound containing a Group VIII metal in the periodic table of elements, more preferably an iridium compound or an osmium compound. Or a platinum compound (platinum complex compound), and most preferred is an iridium compound.

  Specific examples of the phosphorescent compound used in the present invention are shown below, but are not limited thereto. These compounds can be synthesized, for example, by the method described in Inorg. Chem. 40, 1704-1711. The phosphorescent compound to be contained may or may not have a polymerizable functional group or a reactive functional group.

  The organic layer of the present invention preferably has a hole transport layer, an electron transport layer, an anode buffer layer, a cathode buffer layer, and the like in addition to the light emitting layer, and is sandwiched between the cathode and the anode.

  Specific structures of the organic layer include the structures shown below.

(I) Anode / hole transport layer / light emitting layer / cathode (ii) Anode / light emitting layer / electron transport layer / cathode
(Iii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iv) Anode / anode buffer layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode

<Light emitting layer>
The light emitting layer according to the organic EL device of the present invention will be described.

  The light-emitting layer is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer. It may be an interface with an adjacent layer.

  As the formation method, for example, a thin film can be formed by a known method such as a vapor deposition method, a spin coating method, a casting method, or an LB method. In the present invention, the vapor deposition method is particularly preferable.

  In general, it is preferable that the light emitting layer is disposed on the cathode side of the hole transport layer from the viewpoint of the performance of the device. Therefore, compared with the hole transport material, all the materials used for the light emitting layer are relatively (definition of the present invention). So it becomes an electron transport material.

  In the present invention, when referring to a hole transport material and an electron transport material, a material having a higher highest occupied molecular orbital (HOMO) level (close to the vacuum order) is the hole transport. The material is defined as the electron transport material.

(Film thickness of the light emitting layer)
There is no restriction | limiting in particular about the film thickness of the light emitting layer formed in this way, Although it can select suitably according to a condition, It is preferable to adjust film thickness in the range of 5 nm-5 micrometers.

  Next, other layers constituting the organic EL element in combination with the light emitting layer, such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer, will be described.

<< Hole injection layer, hole transport layer, electron injection layer, electron transport layer >>
The hole injection layer and hole transport layer used in the present invention have a function of transmitting holes injected from the anode to the light emitting layer, and the hole injection layer and hole transport layer serve as the anode and the light emitting layer. In addition, a large number of holes are injected into the light emitting layer with a lower electric field, and electrons injected from the cathode, the electron injection layer, or the electron transport layer into the light emitting layer are separated from the light emitting layer. Due to an electron barrier existing at the interface of the hole injection layer or the hole transport layer, it is accumulated at the interface in the light emitting layer, and the light emitting efficiency is improved.

《Hole injection material, hole transport material》
The material of the hole injection layer and hole transport layer (hereinafter referred to as hole injection material and hole transport material) has the property of transmitting holes injected from the anode to the light emitting layer. If it is a thing, there will be no restriction | limiting in particular, In a photoconductive material, what is conventionally used as a charge injection transport material of a hole, and the well-known thing used for the hole injection layer of a EL element, a hole transport layer are used. Any one can be selected and used.

  The hole injection material and the hole transport material have any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. Examples of the hole injection material and hole transport material include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, virazoline derivatives and virazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazoles. Derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, or conductive polymer oligomers, particularly thiophene oligomers. As the hole injecting material and the hole transporting material, those described above can be used, and porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds, particularly aromatic tertiary amine compounds can be used. preferable.

Representative examples of the aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N ′ monotetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N ′. -Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD); 2,2-bis (4-di-P-tolylaminophenyl) propane; Bis (4-di-P-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-P-tolyl 4,4′-diaminobiphenyl; 1,1-bis (4-di-P -Tolylaminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-P-tolylaminophenyl) phenylmethane; N, N'-diphenyl- N, N'-di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di- P-tolylamino) -4 '-[4- (di-P-tolylamino) styryl] stilpene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenyl Aminostilbenzene; N-phenylcarbazole, and those having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule, such as 4,4′-bis [ N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), 4,4 ′ in which three triphenylamine units described in JP-A-4-308688 are linked in a star-perst type , 4〃-Tris [N- (3-methylpheny ) -N-phenylamino] triphenylamine (MTDATA).

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Alternatively, inorganic compounds such as P-type-Si and P-type-SiC can also be used as the hole injection material and the hole transport material. The hole injection layer and the hole transport layer are formed by thinning the hole injection material and the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method. Can be formed.

(Hole injection layer thickness, hole transport layer thickness)
Although there is no restriction | limiting in particular about the film thickness of a positive hole injection layer and a positive hole transport layer, It is preferable to adjust to the range about 5 nm-5 micrometers. The hole injection layer and hole transport layer may have a single layer structure composed of one or more of the above materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.

<< Electron transport layer, electron transport material >>
The electron transport layer according to the present invention is only required to have a function of transmitting electrons injected from the cathode to the light emitting layer, and as the material thereof, any one of conventionally known compounds can be selected and used. Can do.

  Examples of materials used for this electron transport layer (hereinafter referred to as electron transport materials) include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiobilane dioxide derivatives, heterocyclic tetracarponic anhydrides such as naphthalene perylene, carposimide, fluoreni Examples include redenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and organometallic complexes. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Or metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, tris (2-Methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu, Metal complexes replaced with Ca, Sn, Ga, or Pb can also be used as the electron transport material.

  In addition, metal-free or metal phthalocyanine, and those having the terminal substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. Alternatively, the distyrylvirazine derivative exemplified as the material for the light-emitting layer can also be used as an electron transport material, and like the hole injection layer and the hole transport layer, n-type-Si, n-type-SiC, and the like can be used. Inorganic semiconductors can also be used as electron transport materials.

  This electron transport layer can be formed by forming the above compound by a known thin film forming method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method.

(Film thickness of electron transport layer)
Although the film thickness of an electron carrying layer does not have a restriction | limiting in particular, It is preferable to adjust to the range of 5 nm-5 micrometers. This electron transport layer may have a single layer structure composed of one or two or more of these electron transport materials, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions.

  Further, in the present invention, the fluorescent compound is not limited to the light emitting layer, and the hole transport layer adjacent to the light emitting layer, or the fluorescent compound serving as a host compound of the phosphorescent compound in the electron transport layer; At least one fluorescent compound having a fluorescent maximum wavelength may be contained in the same region, whereby the luminous efficiency of the EL element can be further increased. As the fluorescent compound contained in these hole transport layer and electron transport layer, the fluorescent compound having a fluorescence maximum wavelength in the range of 350 nm to 440 nm, more preferably 390 nm to 410 nm, as in the light emitting layer. A compound is used.

  Next, a suitable example for producing an organic EL element having an organic layer will be described. As an example, a method for manufacturing an EL element composed of the anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode will be described.

  First, a thin film made of a desired electrode material, for example, an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. An anode is produced. Next, a thin film comprising a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer / electron injection layer, which is a device material, is formed thereon.

  Further, a buffer layer (electrode interface layer) may be present between the anode and the light emitting layer or hole injection layer and between the cathode and the light emitting layer or electron injection layer.

  The buffer layer is a layer provided on the electrode and the organic layer in order to lower the driving voltage and improve the luminous efficiency. “The organic EL element and its forefront of industrialization (November 30, 1998, NTS Corporation) Issue) ”, Chapter 2,“ Electrode Materials ”(pages 123 to 166) in detail, and includes an anode buffer layer and a cathode buffer layer.

  The details of the anode buffer layer are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, a phthalocyanine buffer layer represented by copper phthalocyanine Examples thereof include an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, specifically, metals represented by strontium, aluminum, and the like. Examples include a buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, an oxide buffer layer typified by aluminum oxide and lithium oxide, and the like.

  The buffer layer is preferably a very thin film, and depending on the material, the film thickness is preferably in the range of 0.1 to 100 nm.

  Furthermore, in addition to the above basic constituent layers, layers having other functions may be laminated as required. For example, JP-A-11-204258, JP-A-11-204359, and “Organic EL devices and their industrialization most recently”. It may have a functional layer such as a hole blocking layer described on page 237 of the front line (published on November 30, 1998 by NTT).

  Although the manufacturing method of the organic EL element according to the present invention has been described above, a supplementary explanation will be given below.

As the thinning method, there are a spin coating method, a casting method, a vapor deposition method and the like as described above, but a vacuum vapor deposition method is preferable because a homogeneous film can be easily obtained and pinholes are hardly generated. When the vacuum deposition method is adopted for thinning, the deposition conditions vary depending on the type of compound used, the target crystal structure of the molecular deposition film, the association structure, etc., but generally the boat heating temperature is 50 to 450 ° C., the degree of vacuum It is desirable to select appropriately within a range of 10 ⁻⁶ to 10 ⁻³ Pa, a deposition rate of 0.01 nm / second to 50 nm / second, a substrate temperature of −50 ° C. to 300 ° C., and a film thickness of 5 nm to 5 μm.

  As described above, a desired electrode material, for example, a thin film made of an anode material is formed on the plastic film substrate by a method such as vapor deposition or sputtering, and then an anode is prepared. Then, holes are injected onto the anode as described above. After forming each layer thin film composed of a layer, a hole transport layer, a light emitting layer, an electron transport layer / electron injection layer, a thin film composed of a cathode material is formed thereon by a method such as vapor deposition or sputtering, for example. A desired organic EL element can be obtained.

  The organic EL device is preferably produced from the hole injection layer to the cathode in this manner consistently by a single evacuation. However, the production order is reversed so that the cathode, the electron injection layer, the light emitting layer, It is also possible to produce the hole injection layer and the anode in this order. In the case of applying a DC voltage to the organic EL device thus obtained, light emission can be observed by applying a voltage of about 5 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Or even if 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.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
<Production of glass sheet containing glass fiber-containing crosslinked resin>
The following glass fiber is impregnated with the following polyfunctional acrylate resin (refractive index after cross-linking: 1.560), and then continuously cured by an ultraviolet curing device, resin 60% by weight, glass fiber 40% by weight, width 30 cm, length 100 m. A plastic film (1) having a thickness of 100 μm was obtained.

<Multifunctional acrylate resin>
Dicyclopentadienyl diacrylate (Formula 1)
(M-203 manufactured by Toagosei Co., Ltd., refractive index 1.527 after crosslinking) 58 parts by weight Bis [4- (acryloyloxyethoxy) phenyl] sulfide (Formula 3)
(Toagosei Co., Ltd. prototype TO-2066, refractive index after crosslinking 1.606) 42 parts by weight Photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) 0.5 Parts by weight

<Glass fiber>
E glass-based glass cloth (thickness 50 μm, refractive index 1.560, Unitika cloth E06B (# 1080))

  The obtained plastic film (1) had a linear expansion coefficient of 18 ppm at 30 ° C. to 150 ° C.

  Further, the glass transition temperature of this plastic film (1) was 300 ° C. or higher as evaluated by tan δmax. The total light transmittance of this plastic film (1) was 90%.

  Next, as shown in FIG. 1, this plastic film (reference numeral 1) is loaded into a sputtering roll coater, and DC magnetron sputtering is used to perform reactive sputtering using oxygen as a reactive gas, using Si as a target. Then, a 60 nm-thick SiOx film (x = 1.8, based on XPS) was formed on a plastic film (reference numeral 1) to form a gas barrier layer (reference numeral 2).

  Next, 100 parts by weight of an epoxy acrylate prepolymer in a continuous coating machine provided with a roll unwinding device, a micro gravure coater, a drying furnace, a UV irradiation device, and a roll winding device on the gas barrier layer (reference numeral 2), Apply a homogeneous mixed solution of 200 parts by weight of diethylene glycol, 100 parts by weight of ethyl acetate, 2 parts by weight of benzene ethyl ether, and 1 part by weight of silane coupling agent with a micro gravure coater of a continuous coating machine, and pass through a 120 ° C drying zone. Then, an ultraviolet ray was irradiated to form an overcoat layer (reference numeral 3) having a thickness of 2 μm.

  Next, in order to form a gas barrier layer (symbol 4) on the surface opposite to the overcoat layer (symbol 3) on the plastic film (symbol 1) on which the overcoat layer (symbol 3) is formed, a sputter roll coater is used. And 60 m thick SiOx (x = 1.8, XPS) on the opposite side of the gas barrier layer 1 by DC magnetron sputtering, using Si as a target by reactive sputtering using oxygen as a reactive gas. Film formation was performed to form a gas barrier layer (reference numeral 4).

  Next, 2 μm of an intermediate coat layer (reference numeral 5) was formed on the gas barrier layer (reference numeral 4) in the same manner as the overcoat layer (reference numeral 3), and this was used as an intermediate coat layer (reference numeral 5).

  Finally, a SiOx film (x = 1.8, based on XPS) having a film thickness of 60 nm is formed on the intermediate coat layer (reference numeral 5) in the same manner as the barrier layers (reference numeral 2) and (reference numeral 4). A layer (symbol 6) was formed.

When the water vapor permeability at 40 ° C. and 90% RH was measured on the plastic film substrate (reference numeral 10) formed up to the gas barrier layer (reference numeral 6) as described above according to the JISK7129B method, it was 0.01 g / (m ² · 24 hr). It was the following.

《ITO film formation and substrate cutting and cleaning》
A transparent electrode (symbol 7) of indium tin oxide (ITO) was formed on the barrier layer (symbol 6) of the substrate so as to have a thickness of 100 nm by sputtering.

  At this time, a portion where ITO was not sputtered was simultaneously formed using a shadow mask, and the shape of the electrode when energized was created on the substrate.

  This was cut into 30 mm square pieces using a laser cutter (carbon dioxide laser: energy 30 W).

  This plastic substrate with an ITO pattern was sequentially washed with pure water, a 5% surfactant aqueous solution, ammoniacal hydrogen peroxide solution, and isopropyl alcohol (IPA), and dried in a clean nitrogen atmosphere. (Substrate 1)

<Preparation of the organic electroluminescence device of the present invention>
<Green phosphorescence standard configuration>
Next, 20 nm of copper phthalocyanines (CuPC) was vapor-deposited as a planarizing layer (not shown) on the substrate with ITO electrodes (substrate 1) of the present invention, and an organic layer (reference numeral 8) was formed thereon.

As the organic layer, a hole transport material NPD was first vacuum-deposited on the planarizing layer, and then a light emitting layer host CBP and a light emitting layer dopant Ir (ppy) ₃ (illustration Ir-1) were formed by co-evaporation. Then BAlq as the hole blocking material, was deposited to the electron transporting material Alq ₃ becomes each 10 nm, a 40nm thick.

  On top of this, LiF was deposited to 0.5 nm and aluminum was deposited to 150 nm as a counter electrode (symbol 9) to form a multilayer element.

  This element was bonded using a stainless steel sealing can (symbol 10) and an ultraviolet curable adhesive (symbol 11) in a nitrogen atmosphere.

  Barium oxide was added as a dehydrating agent between the sealing can and the element. When a voltage of 10 V was applied to this device with the indium tin oxide side being positive and the aluminum side being negative, green light emission having a peak wavelength of 510 nm was observed. This element is referred to as OLED1-1.

Comparative Example 1
<PET ITO substrate>
A transparent electrode of indium tin oxide (ITO) was formed on a commercially available 0.2 mm thick polyethylene terephthalate substrate by sputtering so as to have a thickness of 100 nm. At this time, a portion where ITO was not sputtered was simultaneously formed using a shadow mask, and the shape of the electrode when energized was formed on a polyethylene terephthalate substrate.

  The linear expansion coefficient of the polyethylene terephthalate substrate at 30 ° C. to 150 ° C. is 60 ppm / ° C.

  Next, each pattern was cut into 30 × 30 mm pieces with a knife cutter, and the polyethylene terephthalate substrate with the ITO pattern was sequentially washed with pure water, 5% surfactant aqueous solution, ammoniacal hydrogen peroxide solution, isopropyl alcohol, Dry under a clean nitrogen atmosphere. This is called substrate 2.

<Production of comparative organic electroluminescence device>
On the substrate 2 (washed polyethylene terephthalate substrate having an indium tin oxide transparent electrode (ITO electrode)), CuPC is deposited as a planarizing layer to a thickness of 20 nm, the hole transport material NPD is vacuum deposited, and then the light emitting layer host CBP and the light emitting layer dopant are deposited. Ir (ppy) ₃ was deposited by co-evaporation, then BAlq as the hole blocking material and electron transporting material Alq ₃ were deposited to a thickness of 10 nm and 40 nm, respectively, and then LiF was 0.5 nm and Al was vapor-deposited with a film thickness of 150 nm to form a cathode to produce an organic EL device.

  This element was bonded using a stainless steel sealing can and an ultraviolet curable adhesive in a nitrogen atmosphere. Barium oxide was added as a dehydrating agent between the sealing can and the element.

  Thus, it was set as the organic EL element OLED2-1 produced.

Example 2
The same procedure as in Example 1 was performed except that the glass fiber-containing resin substrate with electrode of Example 1 (Substrate 1) was cleaned with pure water instead of isopropyl alcohol for cleaning the substrate after laser cutting in Example 1. Thus, a multilayer element was formed. Sealing was performed in the same manner as in Example 1 to obtain element OLED1-2.

Example 3
Using the glass fiber-containing resin substrate with an electrode of Example 1 (substrate 1), vacuum evacuation was prototyped at a pressure of 5 × 10 ⁻⁴ Pa, sealing was performed in the same manner as in Example 1, and the element OLED1- 2 was produced.

Example 4
In Example 1, the element OLED1-4 was produced similarly except having adopted the knife cut instead of the laser cut.

Example 5
In Example 1, instead of laser cutting, knife cutting was adopted, IPA cleaning was omitted, a flattening layer was not provided, and the element OLED1-5 was similarly made except that the vacuum exhaust pressure was increased as shown in Table 1. Was made.

Comparative Example 2
In Comparative Example 1, the laminated type was cut in the same manner as in Comparative Example 1, except that the cutting process after ITO patterning of the substrate 2 was performed using a laser cutter and the vacuum evacuation was performed at 5 × 10 ⁻³ Pa. An element was formed to prepare an element OLED2-2.

Comparative Example 3
In Comparative Example 1, an ITO patterned substrate 3 was produced in the same manner as the substrate 2 using a 0.2 mm thick polycarbonate (linear expansion coefficient is 70 ppm / ° C.). In exactly the same manner as in Comparative Example 1, a multilayer element was formed to produce an element OLED3-1.

<Evaluation of organic electroluminescence device>
The organic EL device obtained as described below was evaluated, and the results are shown in Table 1.

(Luminance brightness)
In the organic EL element OLED1-1, a current started to flow at an initial driving voltage of 4 V, and green light emission was displayed. The light emission luminance (cd / m ² ) and light emission efficiency (lm / W) when a temperature of 23 ° C. and a 10 V DC voltage were applied to the organic EL element OLED1-1 were measured.

  Luminance and luminous efficiency were expressed as relative values when the organic electroluminescence element OLED1-1 was 100. The light emission luminance was measured using CS-1000 (Minolta).

(Durability / Dark spot growth)
After driving for 200 hours at a constant current of 10 mA / cm ² , the area of the non-emission point (dark spot) that can be visually confirmed in the range of 6 mm × 15 mm square was measured.

(Luminance unevenness)
After dividing the 6 mm × 15 mm light emitting surface into 10 3 mm × 3 mm regions and measuring the luminance of the central part of each region by the above-mentioned light emission luminance measurement method, the luminance variation is the maximum luminance of the ten measured values. The difference in minimum luminance was divided by 10 average luminances to obtain a variation rate (luminance variation).

(Luminescence yield)
10 elements of each example and comparative example were produced in the same way, and they were selected as non-defective products except those that did not emit light even though current flowed at the first energization immediately after the trial production. It was used as an index of frequency.

  As is apparent from Table 1, dark spots are greatly reduced in the organic electroluminescence device using the substrate of the present invention, and the yield (yield) of non-defective products is also improved by improving the cutting process and the cleaning process. Became clear.

  It turns out that there exists an effect which improves the light emission yield by using the board | substrate of this invention (Example 1-5 and Comparative Example 2). Moreover, since the laser cutter is used in Example 1-3, the light emission yield is improved as compared with Example 4-5 using a knife, and by combining the substrate unique to the present invention and the laser cutter. It turns out that a synergistic effect is acquired.

  Moreover, it turns out that brightness nonuniformity can be reduced by using together the washing | cleaning with an organic solvent in the board | substrate of this invention (Example 1-4 and Example 5). Further, when Example 2 and Example 1 are compared, it can be seen that the organic solvent has a higher luminance unevenness reducing effect than pure water.

  Further, when the substrate of the present invention and the planarization layer are used in combination, as is clear from the comparison between Example 5 and Example 1-4, the light emission yield is improved. From the comparison, it can be seen that the lifetime is increased, that is, the dark spot growth is suppressed by setting the vacuum exhaust pressure at the time of vapor deposition to a higher vacuum. Therefore, the yield of light emission is improved, the unevenness of brightness is reduced, and the growth of dark spots is suppressed, so that a flexible and impact-resistant plastic backlight can be obtained as a combined effect. It is done.

  In addition, in the organic electroluminescence device using a plastic substrate having a small linear expansion coefficient at 30 ° C. to 150 ° C. of the present invention, even when the emission luminance is high, it is difficult to cause deformation due to heat generation or turn off due to short circuit. confirmed.

  The organic EL device of 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 display that directly celebrates a still image or a moving image. It may be used as a device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full color display device can be produced by using two or more organic EL elements of the present invention having different emission colors.

Schematic sectional view showing an example of the organic EL device of the present invention

Explanation of symbols

1: Plastic film 2: Gas barrier layer 3: Overcoat layer 4: Barrier layer 5: Intermediate coat layer 6: Gas barrier layer 7: Transparent electrode 8: Organic layer 9: Counter electrode 10: Stainless steel sealing can 11: Adhesive

Claims (12)

In an organic electroluminescence device having a transparent electrode layer, an organic layer including at least a light emitting layer, and a counter electrode on a substrate made of a plastic film having a gas shielding layer,
The plastic film includes a crosslinked resin and glass fiber, and the linear expansion coefficient of the plastic film at 30 ° C. to 150 ° C. is 0 ppm / ° C. or more and 40 ppm / ° C. or less, and the light emitting layer is a light emitting layer host. An organic electroluminescence device comprising a phosphorescent material.   2. The organic electroluminescence device according to claim 1, wherein the glass fiber is blended in an amount of 1 to 90% by weight based on the plastic film composition.   The organic electroluminescence element according to claim 1, wherein the gas shielding layer has at least a gas barrier layer. The water vapor permeability of the plastic film having the gas shielding layer is 0.01 g / m ² · 24 hr or less (measured value at 40 ° C. and 90% RH based on JIS K7129B method). The organic electroluminescent element in any one of 1-3. Forming a plastic film substrate containing a crosslinked resin and glass fiber;
Forming a gas shielding layer on the plastic film substrate;
Providing a transparent electrode layer on the gas-shielding layer to form a substrate with a transparent electrode;
Forming an organic layer including at least a light emitting layer on the transparent electrode layer;
Forming a counter electrode on the organic layer, and a method of manufacturing an organic electroluminescence element,
The method for producing an organic electroluminescent element, wherein the plastic film substrate has a linear expansion coefficient at 30 ° C. to 150 ° C. of not less than 0 ppm / ° C. and not more than 40 ppm / ° C.   6. The method of manufacturing an organic electroluminescent element according to claim 5, further comprising a step of cutting the substrate into a desired shape with a laser cutter after forming the substrate with a transparent electrode.   After passing through the step of cutting the substrate with a transparent electrode into a desired shape with a laser cutter, the organic layer is formed after passing through a cleaning step with an organic solvent and a deaeration step under vacuum of the substrate. The manufacturing method of the organic electroluminescent element of Claim 5 or 6.   8. The method according to claim 5, further comprising a step of forming a conductive flattening layer on the transparent electrode layer after the step of forming the substrate with a transparent electrode, and then forming an organic layer. The manufacturing method of the organic electroluminescent element of description.   The said glass fiber is mix | blended 1 to 90 weight% with respect to a plastic film composition, The manufacturing method of the organic electroluminescent element in any one of Claims 5-8 characterized by the above-mentioned.   The method for producing an organic electroluminescent element according to claim 5, wherein the step of forming the gas shielding layer includes at least a step of forming a gas barrier layer. 6. The water vapor permeability of the plastic film having the gas shielding layer is 0.01 g / m ² · 24 hr or less (measured value at 40 ° C. and 90% RH based on JISK7129B method). The manufacturing method of the organic electroluminescent element in any one of -10. The method for producing an organic electroluminescent element according to claim 5, wherein the light emitting layer comprises a light emitting layer host and a phosphorescent material.

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