JP2005283911A - Electroluminescence display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion type electroluminescence display panel having a new structure which allows long-time light emission with high luminance by suppressing deterioration due to heat generation without spoiling lightweight and flexible constitution and the degree of freedom of an installation place. <P>SOLUTION: Disclosed is the dispersion type electroluminescence display panel characterized in that a surface body or linear body with good heat conductivity is arranged on the back side of a display panel having a back electrode and a transparent electrode opposite each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electroluminescence display panel.

  An electroluminescence (hereinafter also referred to as “EL”) phosphor is a voltage excitation type phosphor, and a dispersion type EL panel is known in which a phosphor powder is sandwiched between electrodes to form a light-emitting panel. The general shape of a dispersion-type EL panel consists of a structure in which phosphor powder is dispersed in a binder with a high dielectric constant, and at least one is sandwiched between two transparent electrodes. Light is emitted by applying an electric field. The light-emitting panel made using phosphor powder can be several millimeters or less in thickness, is a surface light emitter, and has many advantages such as low heat generation, so it can be used for road signs, various interiors and exteriors. Applications include light sources for flat panel displays such as lighting and liquid crystal displays, and illumination light sources for large-area advertisements.

  Dispersion-type EL panels do not use high-temperature processes, so it is possible to form flexible panels using plastic as a substrate, and they can be manufactured at low cost with relatively simple processes without using vacuum equipment. In addition, it has a feature that the emission color of the panel can be easily adjusted by mixing a plurality of phosphor particles having different emission colors, and is applied to backlights and display panels such as LCDs. However, since the light emission luminance and efficiency are low, and a high voltage of 100 V or higher is required for high luminance light emission, the application range is limited. ) Could not be used.

On the other hand, the EL panel generally has a problem of generating heat when a voltage is applied. Also, heat is generated by outdoor sunlight. The EL panel is weak against heat, and heat generation can accelerate the deterioration of the heat-sensitive part (for example, the binder in which the phosphor powder is dispersed in the case of the dispersion type EL panel), so that it cannot emit light for a long time. .
In order to solve this problem, for example, as in Patent Document 1, it is possible to install a heat pipe on the back side of the EL display panel and suppress deterioration due to heat generation in the EL display panel. However, when such a method is adopted, the thickness of the EL display panel is increased by the amount of the heat pipe, and the heat pipe is not flexible. Therefore, the lightness, flexibility, and flexibility of the installation location are the advantages of the EL display panel. There is a problem that is damaged.
Therefore, the conventional EL display panel cannot emit light for a long time while suppressing deterioration due to heat generation without impairing lightness, flexibility, and freedom of installation location.
Japanese Unexamined Patent Publication No. 2000-105556 (Claims, FIGS. 1 to 3)

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to prevent deterioration due to heat generation without impairing lightness, flexibility, and freedom of installation, and to increase the brightness and length. An object of the present invention is to provide a dispersion type EL display panel having a novel structure capable of light emission for a long time.

  In the process of studying the means for achieving the above object, it is necessary to increase the applied voltage or increase the frequency of alternating current in order for the dispersed EL panel to emit light with high brightness. It became clear that the luminous efficiency in was low. For this reason, it has been clarified that in high-luminance light emission, most of the input power is consumed by heat generation, and in high-luminance light emission, heat generation becomes more remarkable.

In addition, in the conventional EL display panel, particularly when light is emitted with high luminance (for a long time), there is a problem in that the connection portion between the electrode and the lead for supplying electricity to the electrode remarkably generates heat, and the light emitter is locally heated. It has been found that light emission unevenness (non-uniform luminance within the light emitting surface) occurs due to deterioration due to. To solve this problem, for example, as disclosed in Patent Document 1, a method of installing a heat pipe on the back side of an EL display panel causes local heat generation at a connection portion between the electrode and a lead that supplies electricity to the electrode. It was impossible to reduce the unevenness of light emission by suppressing the deterioration due to.
The above knowledge has led to the following present invention.
(1) A dispersive electroluminescence display panel characterized in that a highly heat conductive planar body or linear body is disposed on the back side of a display panel having opposing back electrodes and transparent electrodes.
(2) The thermal conductivity of a sheet or linear body having good heat conductivity disposed on the back side of the display panel is 50 W / m · K or more, as described in (1) above Distributed electroluminescence display panel.
(3) The dispersive electroluminescence display as described in (1) or (2) above, wherein the heat-conductive sheet or linear member disposed on the back side of the display panel is a metal. panel.
(4) The dispersive electroluminescence display panel according to any one of (1) to (3), wherein the back electrode has a thermal conductivity of 100 W / m · K or more.
(5) The dispersive electroluminescence display panel as described in any one of (1) to (4) above, wherein the surface resistivity of the transparent electrode is 0.05Ω / □ to 50Ω / □.
(6) The dispersion type according to any one of the above (1) to (5), wherein the transparent electrode is made of a transparent conductive sheet and a transparent conductive sheet having a metal and / or alloy fine wire structure. Electroluminescence display panel.
(7) The dispersive electroluminescence display panel according to any one of (1) to (6), wherein a cooling fin is combined with the planar body or the linear body.
(8) The dispersive electroluminescence display panel according to any one of the above (1) to (7), wherein a planar body or a linear body is combined with an electronic cooling element.

  According to the present invention, it is possible to emit light with high brightness for a long time by suppressing heat generation without impairing lightness, flexibility, and flexibility of installation location, and it is possible to suppress light emission unevenness due to local heat generation. An EL display panel having a novel structure can be provided.

  Hereinafter, an EL display panel, an EL display device, and a manufacturing method thereof according to the present invention will be described in detail. In the present specification, “to” is used as a meaning including numerical values described before and after the lower limit value and the upper limit value.

  The particle-dispersed EL display panel of the present invention will be described below with reference to FIGS. FIG. 1 and FIG. 2 are examples of a dispersion type EL display panel having a sheet with good heat conductivity according to the present invention, FIG. 1 is a schematic plan view, and FIG. 2 is a schematic cross-sectional view.

  FIG. 1 and FIG. 2 show a dispersion type EL display panel of an embodiment in which the entire light emitting section 7 is covered with a moisture-proof film 6. The dispersion type EL display panel of the present invention has a light emitting portion 7 in which a dielectric layer 2, a light emitting layer 3, and a transparent electrode 4 are laminated in this order on a back electrode 1. In the light emitting unit 7, a conductive power supply unit (pass line) 5 is mounted in an electrically connected state in the vicinity of at least one side of the transparent electrode 4 on the side in contact with the light emitting layer 3. On the moisture-proof film 6 on the back electrode 1 side, a sheet body 10 having good heat conductivity is placed. Further, cooling fins 21 for air cooling are attached to the end portions of the sheet body 10 having good heat conductivity. The back electrode 1 and the power supply unit 5 are provided with lead pieces 12a and 12b connected to an AC power source, respectively.

The light emitting layer 3 included in the light emitting unit 7 is a layer formed by dispersing and containing EL phosphor particles. The EL phosphor particles used in the present invention preferably have an average sphere equivalent diameter of 0.1 to 15 μm, and more preferably 1 to 10 μm. Further, the variation coefficient of the equivalent sphere diameter is preferably 30% or less, and more preferably 5 to 20%.
Here, the “sphere equivalent diameter” means the diameter of the sphere when the EL phosphor particle size is converted to a sphere having the same volume as the EL phosphor particle size.

  As a method for preparing the EL phosphor particles, a firing method, a urea melting method, a spray pyrolysis method, or a hydrothermal synthesis method (Hydrothermal method) can be preferably used. The prepared EL phosphor particles preferably have a multiple twin structure. For example, when the EL phosphor particles are zinc sulfide, the plane spacing of the multiple twins (stacking defect structure) is preferably 1 to 10 nm, and more preferably 2 to 5 nm.

  The EL phosphor particles used in the present invention can be prepared by a firing method (solid phase method) widely used in the industry. For example, in the case of zinc sulfide, a 10-50 nm particle powder (usually called raw powder) is prepared by a liquid phase method, and this is used as a primary particle, and an impurity called an activator is mixed into the powder together with a flux. First baking is performed in a crucible at a high temperature of 900 to 1300 ° C. for 30 minutes to 10 hours to obtain an intermediate fluorescent powder. Next, the obtained intermediate phosphor powder is repeatedly washed with ion-exchanged water to remove the alkali metal or alkaline earth metal, excess activator and coactivator. Next, second baking is performed on the obtained intermediate phosphor powder. The second baking is performed at a temperature of 500 to 800 ° C., which is lower than that of the first baking, and the baking time is 30 minutes to 12 hours and heating (annealing) is performed for a short time.

  Although many stacking faults are generated in the intermediate phosphor particles by the first and second firings, the first firing and the second firing are performed so that the particle size is smaller and more stacking faults are included in the particles. It is preferable to appropriately select the firing conditions.

  Further, by applying an impact force in a certain range to the first fired product, the density of stacking faults can be greatly increased without destroying the particles. As a method of applying impact force, a method of contacting and mixing intermediate fluorescent particles, a method of mixing and mixing spheres such as alumina (ball mill), a method of accelerating and colliding intermediate phosphor particles, a method of irradiating ultrasonic waves, etc. Can be preferably used.

According to the above method, in the present invention, particles having 10 or more stacking faults having a stacking fault density of 5 nm or less can be formed. As a method for evaluating the frequency, when the particles are ground with a mortar and crushed into pieces having a thickness of about 0.2 μm or less and observed with an electron microscope with an acceleration voltage of 200 KV, 10 or more layers of stacking faults of 5 nm or less are observed. It can be evaluated by the frequency of the fragment particles it contains. In addition, the said crushing is unnecessary when a particle size is less than 0.2 micrometer.
In the present invention, the above frequency is preferably more than 50%, more preferably more than 70%. The higher the frequency, the better.

  Thereafter, the intermediate phosphor particles are etched with an acid such as HCl to remove the metal oxide adhering to the surface, and the copper sulfide adhering to the surface is removed by washing with a KCN solution. Subsequently, the intermediate phosphor is dried to obtain EL phosphor particles.

  In the case of zinc sulfide and the like, it is preferable to use a hydrothermal synthesis method as a method for forming phosphor particles because a multiple twin structure is introduced into the phosphor crystal. In the hydrothermal synthesis system, the particles are dispersed in a well-stirred aqueous solvent, and the zinc ions and / or sulfur ions that cause particle growth are determined from the outside of the reaction vessel at a controlled flow rate with an aqueous solution. Added for hours. Therefore, in this system, particles can move freely in an aqueous solvent, and added ions can diffuse in water and cause particle growth uniformly. For this reason, according to the hydrothermal synthesis method, the concentration distribution of the activator or the coactivator inside the particles can be changed, and particles that cannot be obtained by the firing method can be obtained. In the adjustment of the particle size distribution, the nucleation process and the growth process can be clearly separated, and the particle size distribution can be adjusted by freely controlling the degree of supersaturation during particle growth. Zinc sulfide particles can be obtained. It is preferable to insert an Ostwald ripening step between the nucleation process and the growth process in order to adjust the grain size and realize a multiple twin structure.

  For example, zinc sulfide crystals have very low solubility in water, which is very disadvantageous when growing particles by ionic reaction in aqueous solution. The solubility of zinc sulfide crystals in water increases as the temperature rises, but at 375 ° C. or higher, water becomes supercritical and the solubility of ions drastically decreases. Therefore, the particle preparation temperature is preferably 100 to 375 ° C, and more preferably 200 to 375 ° C. The time required for particle size adjustment is preferably within 100 hours, more preferably 5 minutes to 12 hours.

  As another method for increasing the solubility of zinc sulfide in water, a chelating agent is preferably used in the present invention. As the chelating agent for Zn ions, those having an amino group or a carboxyl group are preferable. Specifically, ethylenediaminetetraacetic acid (EDTA), N-2-hydroxyethylethylenediaminetriacetic acid (EDTA-OH), diethylenetriaminepentaacetic acid. 2-aminoethylethylene glycol tetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid, nitrilotriacetic acid, 2-hydroxyethyliminodiacetic acid, iminodiacetic acid, 2-hydroxyethylglycine, ammonia, methylamine, Examples include ethylamine, propylamine, diethylamine, diethylenetriamine, triaminotriethylamine, allylamine, and ethanolamine.

  In addition, in the case where the constituent metal ions and the cargoogen anion are directly precipitated by the precipitation reaction without using the precursors of the constituent elements, it is necessary to rapidly mix the solutions of both, and it is preferable to use a double jet mixer. .

  Moreover, it is preferable to use the urea melting method as a method for preparing the phosphor particles used in the present invention. The urea melting method is a method using molten urea as a medium for synthesizing phosphor particles. A substance containing an element that forms a phosphor matrix or an activator is dissolved in a solution in which urea is maintained at a temperature equal to or higher than the melting point to be in a molten state. Add reactants as needed. For example, when a sulfide phosphor is synthesized, a sulfur source such as ammonium sulfate, thiourea or thioacetamide is added to cause a precipitation reaction. When the temperature of the melt is gradually raised to about 450 ° C., a solid in which phosphor particles and phosphor intermediates are uniformly dispersed in a resin derived from urea is obtained. After this solid is finely pulverized, it is fired while thermally decomposing the resin in an electric furnace. By selecting an inert atmosphere, an oxidizing atmosphere, a reducing atmosphere, an ammonia atmosphere, or a vacuum atmosphere as the firing atmosphere, phosphor particles based on oxides, sulfides, and nitrides can be synthesized.

  It is also preferable to use a spray pyrolysis method as a method for preparing the phosphor used in the present invention. By spray pyrolysis, the phosphor precursor solution is atomized using an atomizer, and the phosphor particles or the chemical reaction with the atmospheric gas around the droplet or chemical reaction or chemical reaction inside the droplet. A phosphor intermediate product can be synthesized. By making the conditions for droplet formation suitable, particles having a fine particle size, a uniform amount of impurities, a spherical shape, and a narrow particle size distribution can be obtained. As an atomizer that generates fine droplets, it is preferable to use a two-fluid nozzle, an ultrasonic atomizer, or an electrostatic atomizer. The fine droplets generated by the atomizer are introduced into an electric furnace with a carrier gas and heated to dehydrate and condense, and the chemical reaction and sintering of the substances in the droplets, or the chemistry with the atmosphere gas The target phosphor particles or phosphor intermediate product is obtained by the reaction. The obtained particles are additionally fired as necessary.

  For example, when synthesizing a zinc sulfide phosphor, a mixed solution of zinc nitrate and thiourea is atomized and thermally decomposed in an inert gas (for example, nitrogen) at a temperature of about 800 ° C., and a spherical zinc sulfide phosphor is formed. obtain. If trace impurities such as Mn, Cu and rare earth are dissolved in the starting mixed solution, it acts as a luminescent center. Further, starting from a mixed solution of yttrium nitrate and europium nitrate at about 1000 ° C. in an oxygen atmosphere, an yttrium oxide phosphor activated with europium is obtained. It is not necessary that all the components in the droplet are dissolved, and ultrafine particles of silicon dioxide may be contained. Zinc silicate phosphor particles can be obtained by thermal decomposition of microdroplets containing zinc solution and silicon dioxide ultrafine particles.

  In addition, as a method for preparing the phosphor particles used in the present invention, a laser ablation method, a CVD method, a plasma CVD method, a sputtering or resistance heating, an electron beam method, a method combining fluid oil surface deposition, and the like, A metathesis method, a method using a thermal decomposition reaction of a precursor, a reverse micelle method, a method combining these methods with high-temperature firing, a liquid phase method such as a freeze-drying method, and the like can also be used. In these methods, phosphor particles having a size of 0.1 to 10 μm that are preferable for the present invention can be obtained by controlling the preparation conditions of the particles.

  As described in Japanese Patent No. 2756044 and US Pat. No. 6,458,512, the phosphor particles are coated with a non-light emitting shell layer composed of a metal oxide or metal nitride of 0.01 μm or more. Good waterproofness and water resistance can be imparted. Further, as described in WO020080626, a technique for increasing light extraction efficiency by forming a double structure including a core portion including a light emission center and a non-light emitting shell portion can be preferably used.

  The phosphor particles used in the present invention more preferably have a non-light emitting shell layer on the surface of the particles. This non-light-emitting shell layer may be formed with a thickness of 0.01 μm or more, preferably 0.01 to 1.0 μm, using a chemical method following the preparation of the semiconductor fine particles serving as the core of the EL phosphor particles. desirable.

  The non-light-emitting shell layer can be made of an oxide, nitride, oxynitride, or a material that has the same composition formed on the base phosphor particles and does not contain an emission center. Moreover, it can produce from the substance of a different composition grown epitaxially on the base | substrate fluorescent substance particle material.

  Non-light emitting shell layer forming methods include laser ablation, CVD, plasma CVD, gas phase methods such as sputtering, resistance heating, electron beam method combined with fluid oil surface deposition, metathesis method, sol gel Method, ultrasonic chemistry method, precursor thermal decomposition method, reverse micelle method or combination of these methods with high temperature firing, hydrothermal synthesis method, urea melting method, freeze drying method, etc. A decomposition method or the like can also be used. In particular, the hydrothermal synthesis method, the urea melting method, and the spray pyrolysis method, which are preferably used in the formation of phosphor particles, are also suitable for the synthesis of a non-luminescent shell layer.

  For example, when a non-light-emitting shell layer is formed on the surface of zinc sulfide phosphor particles using a hydrothermal synthesis method, a zinc sulfide phosphor serving as core particles is added and suspended in a solvent. As in the case of particle formation, a solution containing a metal ion to be a non-light emitting shell layer material and an anion as necessary is added from the outside of the reaction vessel at a controlled flow rate for a predetermined time. By sufficiently agitating the inside of the reaction vessel, the particles can move freely in the solvent, and the added ions can diffuse in the solvent and cause particle growth uniformly. The non-light emitting shell layer can be uniformly formed. By firing the particles as necessary, zinc sulfide phosphor particles having a non-light emitting shell layer on the surface can be synthesized.

  In addition, when a non-light emitting shell layer is formed on the surface of zinc sulfide phosphor particles using the urea melting method, the zinc sulfide phosphor particles are placed in a urea solution in which a metal salt as a non-light emitting shell layer material is dissolved and melted. Added. Since zinc sulfide does not dissolve in urea, the temperature of the solution is raised as in the case of particle formation to obtain a solid in which the zinc sulfide phosphor and the non-light emitting shell layer material are uniformly dispersed in the urea-derived resin. After this solid is finely pulverized, it is fired while thermally decomposing the resin in an electric furnace. Zinc sulfide phosphor particles having a non-light emitting shell layer made of oxide, sulfide, or nitride on the surface by selecting an inert atmosphere, an oxidizing atmosphere, a reducing atmosphere, an ammonia atmosphere, or a vacuum atmosphere as a firing atmosphere Can be synthesized.

  In addition, when a non-light emitting shell layer is formed on the surface of zinc sulfide phosphor particles by spray pyrolysis, the zinc sulfide phosphor is added to a solution in which the metal salt that is the non-light emitting shell layer material is dissolved. To do. By atomizing and thermally decomposing this solution, a non-light emitting shell layer is generated on the surface of the zinc sulfide phosphor particles. By selecting a pyrolysis atmosphere or an additional firing atmosphere, zinc sulfide phosphor particles having a non-light emitting shell layer made of an oxide, sulfide, or nitride on the surface can be synthesized.

  Specifically, the matrix material of the EL phosphor particles preferably used in the present invention includes one or more elements selected from the group consisting of Group II elements and Group VI elements, Group III elements and Group V elements. These are semiconductor fine particles composed of one or more elements selected from the group consisting of group elements, and are arbitrarily selected depending on the necessary emission wavelength region. Examples thereof include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, CaS, MgS, SrS, GaP, GaAs, and mixed crystals thereof. ZnS, CdS, CaS, and the like can be preferably used.

Furthermore, as the base material of the EL phosphor particles, BaAl ₂ S ₄ , CaGa ₂ S ₄ , Ga ₂ O ₃ , Zn ₂ SiO ₄ , Zn ₂ GaO ₄ , ZnGa ₂ O ₄ , ZnGeO ₃ , ZnGeO ₄ , ZnAl ₂ O ₄ , CaGa ₂ O ₄ , CaGeO ₃ , Ca ₂ Ge ₂ O ₇ , CaO, Ga ₂ O ₃ , GeO ₂ , SrAl ₂ O ₄ , SrGa ₂ O ₄ , SrP ₂ O ₇ , MgGa ₂ O ₄ , Mg ₂ GeO ₄ , MgGeO ₃ , BaAl ₂ O ₄ , Ga ₂ Ge ₂ O ₇ , BeGa ₂ O ₄ , Y ₂ SiO ₅ , Y ₂ GeO ₅ , Y ₂ Ge ₂ O ₇ , Y ₄ GeO ₈ , Y ₂ O ₃ , Y ₂ O ₂ S, SnO ₂ and mixed crystals thereof can be preferably used.

  In addition, as an activator for the EL phosphor particles used in the present invention, at least one ion selected from copper, manganese, silver, gold and rare earth elements can be preferably used. As the coactivator, at least one ion selected from chlorine, bromine, iodine and aluminum can be preferably used.

  As the emission center, metal ions such as Mn and Cr and rare earths can be preferably used.

  By appropriately selecting the matrix material, activator and emission center of the above EL phosphor particles and using a plurality of phosphor particles, 0.3 <x on the chromaticity diagram without using dyes or fluorescent dyes. White light emission in the range of <0.4 and 0.3 <y <0.4 can be substantially obtained.

The light emitting layer 3 can be formed by dispersing the phosphor particles described above in a dispersant. Examples of the dispersant used for dispersing the phosphor particles in the light emitting layer 3 include a polymer having a relatively high dielectric constant such as a cyanoethyl cellulose resin, polyethylene, polypropylene, polystyrene resin, silicone resin, and epoxy resin. A resin such as vinylidene fluoride can be used. In addition, the dielectric constant can be adjusted by appropriately mixing fine particles having a high dielectric constant such as BaTiO ₃ or SrTiO ₃ with these resins. As a dispersing method of the dispersant, a homogenizer, a planetary kneader, a roll kneader, an ultrasonic disperser, or the like can be used. It is preferable that the weight ratio of the particle | grains and a dispersing agent in a light emitting layer is 5.0-20.

  The thickness of the light emitting layer 3 is preferably thin, preferably 1 to 25 μm, and more preferably 3 to 20 μm. The light emitting layer 3 has a surface with respect to the thickness d of the light emitting layer 3 when the variation in the distance between the back electrode 1 and the transparent electrode 4 described later is viewed as the centerline average roughness Ra. It preferably has a smoothness of (d × 1/8) or less.

Next, the dielectric layer 2 will be described. The dispersion type EL display panel according to the present invention can be formed by adjoining the light emitting layer 3 with the dielectric layer 2 containing an inorganic dielectric substance, if necessary. As the inorganic dielectric substance, any material can be used as long as it has a high dielectric constant and insulation and has a high dielectric breakdown voltage. As the inorganic dielectric material, various metal oxides and nitrides can be used. For example, SiO ₂ , TiO ₂ , BaTiO ₃ , SrTiO ₃ , PbTiO ₃ , KNbO ₃ , PbNbO ₃ , Ta ₂ O ₃ , BaTa _2. O ₆ , LiTaO ₃ , Y ₂ O ₃ , Al ₂ O ₃ , ZrO ₂ , AlON, ZnS, or the like can be used. These can be used alone or in combination. The dielectric layer 2 may be formed as a uniform film or a film having a particle structure. Furthermore, the dielectric layer 2 may be a single layer or a laminate of different insulating layers.

  The dielectric layer 2 may have any structure of a thin film crystal layer structure and a particle shape structure, and may also have a combination thereof. The dielectric layer 2 may be provided only on one side of the light emitting layer 3 as shown in FIG. 2, but is preferably provided on both sides of the light emitting layer 3 from the viewpoint of obtaining high luminance. When the dielectric layer 2 has a thin film crystal layer structure, the dielectric layer 2 may be a thin film formed by a vapor phase method such as sputtering or a sol-gel film using an alkoxide such as Ba or Sr. When the dielectric layer 2 has a particle shape structure, the size of the dielectric substance is preferably sufficiently small compared to the phosphor particle size. Specifically, the particles of the dielectric material are preferably 1/3 to 1/1000 the average particle size of the phosphor particles.

  The EL display panel of the present invention has a structure having a light emitting layer containing a phosphor material sandwiched between a pair of opposing electrodes, at least one of which is transparent. Therefore, the total thickness (hereinafter also referred to as “element thickness”) of the light emitting layer 3 and the dielectric layer 2 is equal to or larger than the average sphere equivalent diameter of the EL phosphor particles, but ensures the smoothness of the element. For this purpose, the element thickness is preferably 1.1 to 10 times, more preferably 2 to 10 times, and more preferably 3 to 5 times the average sphere equivalent diameter of the EL phosphor particles. Further preferred.

  Further, the contact point is increased by covering the part of the upper part of the particle, that is, by coating the part of the light emitting layer 3 so that the dielectric layer 2 is partly inserted, or the smoothness of the element surface is improved. It is preferable because an effect such as improvement appears.

  The dielectric material contained in the dielectric layer 2 and the phosphor particles contained in the light emitting layer 3 can be in direct contact with the dielectric material, but the dielectric material is a non-light emitting shell. It is preferred to contact the phosphor particles that are completely or partially covered with a layer. Further, the contact between the dielectric material and the phosphor material may be merely contact, but the upper part of the phosphor particles is completely or partially covered, that is, the dielectric layer 2 is entirely formed on the light emitting layer 3. Coating or contacting the light-emitting layer 3 with the dielectric layer 2 partially in contact with the light-emitting layer 3 increases the contact point and improves the smoothness of the element surface. It is preferable from the viewpoint that effects such as

  The dielectric layer 2 and the light emitting layer 3 are preferably formed by coating using a spin coating method, a dip coating method, a bar coating method, a spray coating method, or the like. In particular, it is preferable to use a method that does not select a printing surface, such as a screen printing method, or a method that allows continuous application, such as a slide coating method. For example, in the screen printing method, a dispersion liquid in which fine particles of phosphor or dielectric are dispersed in a polymer solution having a high dielectric constant is applied through a screen mesh. The film thickness can be controlled by appropriately selecting the thickness of the screen mesh, the aperture ratio, and the number of coatings. By adjusting the dispersion liquid, not only the dielectric layer 2 and the light emitting layer 3 but also the back electrode 1 can be formed, and further, the area can be easily increased by changing the size of the screen mesh. The method for preparing the dielectric layer 2 may be a gas phase method such as sputtering or vacuum deposition. In addition, by applying the dielectric layer 2 so as to partially enter the light emitting layer 3, the contact point between the phosphor particles and the dielectric substance can be increased, and the smoothness of the EL display panel is further improved. It is preferable because an effect such as that can be obtained.

  The transparent electrode 4 can be formed of any commonly used transparent electrode material. Examples of such transparent electrode materials include a multilayer structure in which an oxide such as tin-doped tin oxide, antimony-doped tin oxide, zinc-doped tin oxide, tin-doped indium (ITO), or a silver thin film is sandwiched between high refractive index layers. , Π-conjugated polymers such as polyaniline and polypyrrole. The transparent electrode can be formed by providing a transparent conductive film formed of the transparent electrode material on a base material made of a transparent sheet such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

  The resistance value of the transparent conductive sheet preferably used as the transparent electrode 4 is preferably 0.05 to 50Ω / □, and preferably 0.1 to 30Ω / □ from the viewpoint of uniformity of luminance on the light emitting surface. Is more preferable.

The method for preparing the transparent electrode 4 may be a sputtering method or a gas phase method such as vacuum deposition. However, it may not be possible to sufficiently reduce the resistance of these alone. In that case, for example, it is preferable to improve the conductivity by arranging a mesh-like metal and / or alloy fine wire such as a comb or grid. Copper, silver, and aluminum are preferably used as the metal or alloy fine wire, but a transparent conductive material may be used depending on the purpose. It is preferable that the material has high electrical conductivity and thermal conductivity. The thickness of the thin wire of the metal and / or alloy is arbitrary, but is preferably between about 0.1 μm and 100 μm. The fine wires are preferably arranged at a pitch of 50 μm to 1000 μm, and a pitch of 100 μm to 500 μm is particularly preferable. By arranging metal and / or alloy fine wires, the light transmittance is reduced, but it is important that the reduction is as small as possible. The distance between the fine wires is too narrow, and the width and height of the fine wires are increased. It is important to ensure a transmittance of 90% or more and less than 100% without being too much.
Preferred fine wire shapes include a square mesh shape, a rectangular mesh shape, or a rhombus mesh shape. The width of the fine lines may be determined according to the purpose, but typically, the fine line interval is preferably 1 / 10,000 or more and 1/10 or less.
The height of the fine line is the same, but a range of 1/100 or more and 10 times the width of the fine line is preferably used.
As a method for forming a transparent electrode having a fine wire structure portion of metal and / or alloy, the fine metal wire may be bonded to a transparent conductive sheet, or a transparent electrode material such as ITO on a mesh-like fine metal wire formed on the sheet May be applied and evaporated.

  On the other hand, the back electrode 1 on the side that does not take light can be produced using any conductive material. For example, gold, silver, copper, aluminum, beryllium, cobalt, chromium, iron, germanium, iridium, potassium, lithium, magnesium, molybdenum, sodium, nickel, platinum, silicon, tin, tantalum, tungsten, zinc, and other metals, and The EL display panel manufactured from graphite or the like can be appropriately selected according to the form of the EL display panel and the temperature of the manufacturing process. Among them, it is preferable that the thermal conductivity is high from the viewpoint of suppressing the temperature rise due to heat generation in the EL display panel, specifically, it is preferably 100 W / m · K or more, and 200 W / m · K or more. Is more preferably 280 W / m · K or more. From this viewpoint, gold, silver, copper, aluminum, beryllium, iridium, potassium, magnesium, molybdenum, sodium, silicon, tungsten, zinc, graphite and the like are preferable, and gold, silver, copper, aluminum, beryllium, graphite and the like are more preferable. Moreover, you may use transparent electrodes, such as ITO, if it has electroconductivity. The back electrode is preferably formed in a sheet shape.

Next, the power supply unit 5 will be described. The power supply unit 5 is a conductive bus line that is electrically connected to the transparent electrode 4. For example, as shown in FIGS. 1 and 2, the power supply unit 5 is between the light emitting layer 3 and the transparent electrode 4 and emits light. It can be placed on at least one side of the layer 3. Moreover, the power supply part 5 can also be mounted on at least one side vicinity of the transparent electrode 4 (illustration omitted). The power supply unit 5 can be formed of a printed layer of a conductive paste such as silver paste or carbon paste, for example. Also, metals such as gold, silver, copper, aluminum, beryllium, cobalt, chromium, iron, germanium, iridium, potassium, lithium, magnesium, molybdenum, sodium, nickel, platinum, silicon, tin, tantalum, tungsten, zinc, graphite, etc. It can also be formed by a sheet of these alloys and inorganic materials. In this case, lead pieces 12a and 12b, which will be described later, can be manufactured integrally with the power supply unit 5.
On the other hand, a power supply unit may be placed on the back electrode 1, and can be placed on at least one side of the back electrode 1 between the back electrode 1 and the dielectric layer 2.

  In the present specification, “installing in the vicinity of a side” means, of course, a case in which the panel is placed so as to be completely coincident with each side of the panel, and is about 1/100 to 1/10 of the panel side length. The case where it is placed at a position on the center side of the panel is also included.

  The length of the power supply unit 5 in the longitudinal direction and the width direction can be appropriately determined according to the size of the EL display panel to be designed. For example, in the case of the EL display panel shown in FIG. 1, the length of the power supply unit 5 in the longitudinal direction can be approximately the same as the length of the panel side in the longitudinal direction of the power supply unit 5.

  The light emitting unit 7 or the light emitting unit 7 and the power supply unit 5 can be covered with a moisture-proof film 6 so as to eliminate the influence of humidity from the external environment. When the light emitting unit 7 itself has a sufficient shielding property against humidity, a shielding sheet is overlaid on the formed light emitting unit 7 or the light emitting unit 7 and the power supply unit 5, and a curable material such as epoxy is used around the periphery. Use to seal. Such a shielding sheet is selected from metal, plastic film, etc. according to the purpose.

  The moisture-proof film 6 is preferably made of a lightweight and highly flexible material such as a resin film, for example, from the viewpoint of lightness, flexibility, and freedom of installation location. The moisture-proof film 6 can be a transparent film having a low water-humidity transmittance such as a polychlorotrifluoroethylene film. The moisture-proof film 6 includes the light emitting unit 7 or the light emitting unit 7 by sandwiching the light emitting unit 7 or the entire light emitting unit 7 and the power supply unit 5 between two sheets, and applying heat and roll pressure to seal the protruding part of the sheet. 7 and the power supply unit 5 can be sealed.

  When sealing the light-emitting part 7 or the light-emitting part 7 and the power supply part 5 with the moisture-proof film 6, in order to prevent moisture absorption of the light-emitting part 7 over time, the transparent electrode 4 and the moisture-proof film 6 are integrated with them. It is preferable to provide a moisture absorption layer (not shown). For the hygroscopic layer, a hygroscopic film such as a 6-nylon film can be used.

  The light emitting unit 7 is formed by laminating the dielectric layer 2 and the light emitting layer 3 in a desired shape on the back electrode 1 by using a spin coating method, a dip coating method, a bar coating method, a spray coating method, or the like. It can be produced by laminating the transparent electrode 4 on which 5 is mounted.

The EL display panel of the present invention is characterized in that a sheet or a linear body having good heat conductivity is disposed on the back side (for example, the outside of the moisture-proof film 6 on the back electrode 1 side in FIG. 1). To do.
Planar bodies and linear bodies do not impair the lightness, flexibility, and flexibility of installation location, and are excellent in heat dissipation, and are preferable for dissipating heat generated from the phosphor during voltage application. Shape. Particularly EL display panel of the present invention is excellent in high-luminance light emission with strong heating is suitable in the case of the luminance 100 cd / m ² or more, more suitable if the 200 cd / m ² or more. The material of the planar or linear body having good heat conductivity is not particularly limited as long as it has good thermal conductivity, but the thermal conductivity is preferably 50 W / m · K or more, and 100 W / M · K or more is more preferable, and 200 W / m · K or more is most preferable. Specific examples of preferable materials include gold, silver, copper, aluminum, beryllium, cobalt, chromium, iron, germanium, iridium, potassium, lithium, magnesium, molybdenum, sodium, nickel, platinum, silicon, tin, tantalum, tungsten, and zinc. , Metals such as graphite, and alloys thereof, inorganic materials, and the like. More preferable materials are gold, silver, copper, aluminum, beryllium, iridium, potassium, magnesium, molybdenum, sodium, silicon, tungsten, zinc, graphite And the like, and alloys thereof, and inorganic materials, and the most preferable materials include metals such as gold, silver, copper, aluminum, beryllium, graphite, and alloys thereof, and inorganic materials.

  There is no particular limitation on the area and thickness of the sheet having good thermal conductivity, and unless the panel design is restricted, a larger area and a thicker layer are preferable because the thermal conductivity is better, but the area is too large. Alternatively, if the thickness is too thick, it is not preferable from the viewpoint of the lightness, flexibility, and freedom of installation location of the EL display panel. The area of the sheet having good heat conductivity is preferably (0.7 times) to (2 times) the area of the light emitting portion of the EL display panel, and (0.9 times) to (1.5 times). More preferably, The thickness of the planar body is preferably (0.1 mm) to (5 mm), and preferably (0.2 mm) to (3 mm). There are no particular limitations on the method of creating the planar body on the EL display panel. For example, vacuum deposition, sputtering, mounting with an adhesive, embedding in the EL display panel moisture-proof film 6, and solidifying the substrate with a resin can be used. Can be mentioned.

  The highly conductive linear body in the present invention may be configured in a mesh shape. The thickness of the linear body having good thermal conductivity is not particularly limited, but if it is too thin, the thermal conductivity of the linear body is impaired, and conversely if too thick, the thermal conductivity of the linear body is improved. However, the contact area with a panel will become small and the cooling effect of a panel will fall. The range of the thickness of the linear body having good heat conductivity is preferably (0.01 mm) to (5 mm), and more preferably (0.02 mm) to (2 mm). The cross-sectional shape of the linear body is not particularly limited, and may be a circle, an ellipse, a rectangle, or the like, but it is preferable to appropriately select one having a large contact area with the panel. As long as there is no restriction on the panel design, there is no particular limitation on the length of the linear body having good heat conductivity. Further, when the linear body having good heat conductivity is configured in a mesh shape, the mesh area (including the opening) is not particularly limited unless there is a restriction on the panel design. There are no particular restrictions on the method for producing the linear body on the EL display panel, and examples thereof include vacuum deposition, sputtering, mounting with an adhesive, embedding in an EL display panel moisture-proof film, and solidifying the substrate with a resin. be able to.

  It is more preferable that the good heat conductive planar body or linear body has a mechanism for cooling them for the purpose of enhancing the heat dissipation effect. Specific examples include a method of installing a cooling fin on the sheet or linear body having good heat conductivity, a method of installing an electronic cooling element such as a Peltier element, and the like.

  The material of the cooling fin is not particularly limited as long as it has good thermal conductivity, but the thermal conductivity is preferably 50 W / m · K or more, and more preferably 100 W / m · K or more. It is preferably 200 W / m · K or more. Specific examples of preferable materials include gold, silver, copper, aluminum, beryllium, cobalt, chromium, iron, germanium, iridium, potassium, lithium, magnesium, molybdenum, sodium, nickel, platinum, silicon, tin, tantalum, tungsten, and zinc. Metals such as graphite, and alloys thereof, inorganic substances, etc. can be mentioned, and more preferable materials are gold, silver, copper, aluminum, beryllium, iridium, potassium, magnesium, molybdenum, sodium, silicon, tungsten, zinc, graphite And the like, and alloys thereof, and inorganic materials, and the most preferable materials include metals such as gold, silver, copper, aluminum, beryllium, graphite, and alloys thereof, and inorganic materials.

  The size of the cooling fin is not particularly limited, and unless the design of the panel is restricted, it is preferable that the surface area of the fin is larger because the heat dissipation effect is higher. There are no particular restrictions on the method of attaching the heat conductive sheet or linear body, and examples thereof include mounting by screwing and mounting by an adhesive. A connection method having a high thermal contact with the planar body or the linear body is preferable. In this viewpoint, the cooling fin and the thermal conductive planar body or the linear body are formed by using a metal screw or crimping. It is preferable to attach by fixing so that it may be in direct contact and the contact area may be as large as possible.

  In addition, the method of attaching the Peltier element to the planar body or linear body is not particularly limited, and examples thereof include mounting by screwing and mounting by an adhesive. A connection method having a high thermal contact with the planar body or the linear body is preferable. From this viewpoint, it is preferable to use a metal screw or to make the contact area as large as possible by crimping.

  In the EL display panel of the present invention, lead wires 13 a and 13 b electrically connected to the back electrode 1 and the transparent electrode 4 are disposed for the purpose of applying an alternating electric field to the back electrode 1 and the transparent electrode 4. . The lead wires 13a and 13b are electrically connected to the back electrode 1 and the transparent electrode 4 via lead pieces 12a and 12b electrically connected to the back electrode 1 and the transparent electrode 4 or the power supply unit 5. Yes. From the viewpoint of high luminance emission of the EL display panel, it is preferable that the lead pieces 12a and 12b and the lead wires 13a and 13b have high electrical conductivity. The lead pieces 12a and 12b and the lead wires 13a and 13b, or the lead pieces 12a and 12b, the back electrode 1, the transparent electrode 4, or the power supply unit 5 may be produced integrally. Is more preferable.

  In addition, in the EL display panel of the present invention, the thermal conductivity in the mounting portion is particularly suppressed for the purpose of suppressing deterioration in heat generation in the mounting portion of the lead pieces 12a and 12b to the back electrode 1 and the transparent electrode 4 or the power supply unit 5. Is increasing. Specifically, unless there is a restriction on the panel design, the larger the contact area between the back electrode 1 and the transparent electrode 4 or the power supply unit 5 and the lead pieces 12b and 12a, the higher the heat dissipation effect, which is preferable. More specifically, from the viewpoint of preventing remarkable heat generation at the contact surface between the power supply unit 5 and the lead pieces 12b and 12a, the contact between the back electrode 1 and the transparent electrode 4 or the power supply unit 5 and the lead pieces 12b and 12a. The area is preferably (1/500) or more of the area of the back electrode 1 or the transparent electrode 4, more preferably (1/200), and more preferably (1/100) or more. From the viewpoint of heat dissipation, it is preferable that the lead pieces 12a and 12b have high thermal conductivity. Specifically, the thermal conductivity is preferably 100 W / m · K or more, and more preferably 200 W / m · K or more. Examples of preferable materials include gold, silver, copper, aluminum, beryllium, iridium, potassium, magnesium, molybdenum, sodium, silicon, tungsten, zinc, graphite, and alloys thereof, and inorganic materials, and more preferable. Examples of the material include metals such as gold, silver, copper, aluminum, beryllium, and graphite, alloys thereof, and inorganic substances. The lead piece is preferably in the form of a sheet.

  In particular, from the viewpoint of increasing the thermal conductivity of the lead pieces 12a and 12b attached to the back electrode 1 and the transparent electrode 4 or the power supply unit 5, it is preferable to mount the power supply unit 5 on the transparent electrode 4.

  In particular, from the viewpoint of increasing the thermal conductivity of the lead pieces 12a and 12b attached to the back electrode 1 and the transparent electrode 4 or the power supply unit 5, the power supply unit 5 and the back electrode 1 mounted on the transparent electrode 4 are More preferably, the lead pieces 12a and 12b are integral with each other. More preferably, these and the lead wires 13a and 13b are integrated.

  The light emission color of the dispersion type EL panel used in the present invention is preferably white in consideration of the use as a light source. As a specific method for making the emission color white, for example, a method using phosphor particles that emit white light alone, such as a ZnS phosphor activated with manganese and gradually cooled after firing, or three primary colors Alternatively, it is preferable to use a method of mixing a plurality of phosphors that emit light of complementary colors (for example, a blue-green-red combination, a blue-green-orange combination, etc.). In addition, light is emitted at a short wavelength such as blue described in JP-A-7-166161, JP-A-9-245511, and JP-A-2002-62530, and light emission is performed using a fluorescent pigment or a fluorescent dye. It is also preferable to use a method of converting the wavelength of the part into green or red and then whitening it. Further, the CIE chromaticity coordinates (x, y) preferably have an x value in the range of 0.30 to 0.4 and a y value in the range of 0.30 to 0.40.

Usually, the dispersion type EL display panel is driven with an alternating current, and is typically driven with an alternating current power source of 100 V and 50 to 400 Hz. When the area of the distributed EL display panel is small, the luminance increases almost in proportion to the applied voltage and frequency. However, in the case of an EL display panel having a large area of 0.25 m ² or more, the capacitance component of the EL display panel increases, and a shift occurs between the EL display panel and the impedance matching of the power source, or storage in the EL display panel. The time constant required for the charge may increase. For this reason, in an EL display panel with a large area, power supply may be insufficient even when the voltage is increased, particularly the frequency is increased. In particular, in an EL display panel having a large area of 0.25 m ² or more, for AC driving of 500 Hz or more, the applied voltage often decreases with an increase in driving frequency, and a reduction in luminance often occurs.

On the other hand, an EL display panel having the following features (a) to (e) is driven at a high frequency, preferably at a frequency of 500 Hz to 5 KHz, more preferably at a frequency of 800 Hz to 4 KHz, even with a size of 0.25 m ² or more. Therefore, it can be preferably used as the EL display panel of the present invention.
(A) A back surface adjacent to an insulating dielectric layer in contact with the phosphor layer, including a transparent conductive sheet having a surface resistivity of 0.05 to 50 Ω / m ² and a phosphor layer having an average thickness of 1 to 25 μm. An EL display panel, wherein the electrode layer is formed of a metal sheet.
(B) The EL display panel of (a), wherein the back electrode in contact with the dielectric layer has a thermal conductivity of 280 W / m · deg or more.
(C) The EL display panel according to (a) or (b), wherein the average spherical equivalent diameter of the phosphor particles contained in the EL display panel is 0.1 to 15 μm.
(D) The EL display panel according to any one of (a) to (c), wherein a weight ratio of the phosphor layer particles to the dispersant is 5.0 to 20.
(E) When the phosphor particles are pulverized into fragments having a thickness of 0.2 μm or less, at least 50% of the fragments have a stacking fault structure of 10 layers or more at intervals of 5 nm or less. The EL display panel according to any one of (a) to (d).

Next, the manufacturing method of the EL display panel of the present invention will be described.
The EL display panel of the present invention includes a step of forming a light emitting unit 7 having a light emitting layer 3 between the transparent electrode 1 and the back electrode 4, a step of mounting a power supply unit 5 on the transparent electrode 4, and the back electrode 1. And the step of mounting the lead pieces 12a and 12b on the transparent electrode 4 or the power supply unit 5, the step of electrically connecting the lead wires 13a and 13b to the lead pieces 12a and 12b, the entire light emitting unit 7 or the light emitting unit 7 And by supplying at least a step of covering the entire power supply unit 5 with the moisture-proof film 6 and a step of disposing the sheet body 10 or the linear body 20 with good heat conductivity on the moisture-proof film on the back electrode 1 side. can do. Further, when the EL display panel of the present invention has the sheet 10 or the linear body 20 with good heat conductivity, the cooling fin 21 or the electronic cooling is provided on the sheet 10 or the linear body 20 with good heat conductivity. A step of disposing the element can be included.

  In the step of mounting the lead piece 12 a, the light emitting unit 7 or the power supply unit 5 and the light emitting unit 7 are attached in a state where the lead piece 12 a is electrically connected to the transparent electrode 4 or the power supply unit 5. In the step of mounting the lead wire 13a, the lead wire 13a is attached in a state where it is electrically connected. The lead piece 12a is preferably integrated with the power supply unit 5, and more preferably integrated with the lead wire 13a. The lead piece 12b can cover the light emitting unit 7 or the power supply unit 5 and the entire light emitting unit 7 with the moisture-proof film 6 in a state of being attached in a state of being electrically connected to the back electrode 1. In the step of placing the lead wire 13b, the lead wire 13b is attached in a state where it is electrically connected. The lead piece 12b is preferably integrated with the back electrode 1, and more preferably integrated with the lead wire 13b.

  In the step of disposing the good thermal conductive planar body 10 or the linear body 20, the good thermal conductive planar body 10 is formed on the moistureproof film 6 from the moistureproof film 6 on the back electrode 1 side of the EL display panel. Or it attaches in the state which contacted the linear body 20 so that heat transfer was possible.

  In the process of disposing cooling fins on the heat conductive planar member 10 or the linear member 20, cooling is performed on the end of the heat conductive conductive member 10 or the linear member 20, on the surface or on the line. The fins 21 are attached in contact with each other so as to allow heat transfer.

  In the step of disposing the Peltier element on the highly heat conductive planar body 10 or the linear body 20, the Peltier element is placed on the end of the highly heat conductive planar body 10 or the linear body 20, or on the surface or the line. Install the element in contact with the heat-transferable element.

  The EL display panel of the present invention can be used as, for example, a backlight of a film for a backlight display for ink jet recording on which an image is recorded by an ink jet recording method.

  In addition, the EL display panel of the present invention can be used as a backlight of a high-quality transmission print image having a maximum density of 1.5 or more, for example, and can realize a high-quality large-area advertisement or the like. .

Specific examples of the EL display panel and the EL display device of the present invention will be described below, but the present invention is not limited to these examples.
(Example 1)
An appropriate amount of NaCl, MgCl, and ammonium chloride (NH ₃ Cl) powders as fluxes are added to 25 g of zinc sulfide (ZnS) particle powder having an average particle size of 20 nm and a dry powder obtained by adding 0.07 mol% of copper sulfate to ZnS. The magnesium oxide powder was placed in a 20 wt% alumina crucible with respect to the phosphor powder, fired at 1200 ° C. for 3 hours, and then rapidly cooled. After that, the powder is taken out and pulverized and dispersed in a ball mill. Further, after adding 5 g of ZnCl ₂ and 0.10 mol% of copper sulfate to ZnS, 1 g of MgCl ₂ is added to prepare a dry powder, which is again put in an alumina crucible. Baked at 700 ° C. for 6 hours. At this time, firing was performed while flowing 10% hydrogen sulfide gas as an atmosphere.
After firing, the particles are pulverized again, dispersed and settled in 40 ° C. H ₂ O, washed with supernatant, washed with 10% hydrochloric acid, dispersed, settled and removed to remove unwanted salts. Removed and dried. Further, a 10% KCN solution was heated to 70 ° C. to remove Cu ions and the like on the surface.
Further, the surface layer corresponding to 10% by weight of the whole particles was etched with 6N hydrochloric acid.
The phosphor particles thus obtained have an average particle size of 9.6 μm, a coefficient of variation of 20%, and at least 80% or more of the debris particles have a stacking fault of 5 nm or less from the observation of the debris by an electron microscope. It had more than 10 layers.

Luminescence in the first embodiment shown in FIGS. 1 and 2 so that BaTiO ₃ fine particles having an average particle size of 0.02 μm are dispersed in a 30% by mass cyanoethyl cellulose solution and the dielectric layer thickness is 25 μm. According to the shape of the surface, it was applied on an aluminum sheet having a thickness of 75 μm (rear electrode 1: thermal conductivity 237 W / m · K) and dried at 120 ° C. for 1 hour using a hot air dryer.
Further, 100 parts by mass of the above phosphor particles and 1 part by mass of a red pigment (Sinleihi FA-001) having an average particle size of 4 μm were dispersed in a 30% by mass cyanoethyl cellulose solution. According to the shape of the light emitting surface in the first embodiment shown in FIGS. 1 and 2, the phosphor layer was applied so that the thickness of the phosphor layer was 20 μm. It dried for 1 hour at 120 degreeC using the warm air dryer.
On a sheet of ITO uniformly adhered to a thickness of 40 nm by sputtering on polyethylene terephthalate having a thickness of 100 μm, a square mesh of copper wires having a width of 5 μm and a height of 2.5 μm are spaced by 0.5 mm by vacuum deposition. According to the shape of the light emitting surface in the first embodiment shown in FIGS. 1 and 2, a silver paste was applied on the conductive surface of the transparent conductive sheet deposited in a shape to form a power supply unit. The surface resistivity of the conductive surface of the transparent conductive sheet was 5Ω / □. The power supply unit was placed near each side of the substrate of the transparent sheet, and the width was 10 mm. On this power supply section, a lead piece made of a copper aluminum sheet having a thickness of 80 μm was placed according to the first embodiment shown in FIGS. 1 and 2. The size of the contact portion between the lead piece and the power supply unit was 150 mm in the longitudinal direction of the power supply unit and 10 mm in the width direction of the power supply unit. The width of the lead piece lead-out portion was 5 mm. The coated surface of the aluminum sheet and the ITO surface of the transparent sheet were bonded together and thermocompression bonded.
According to the first embodiment shown in FIGS. 1 and 2, a lead piece made of a copper aluminum sheet having a thickness of 80 μm on the non-coated side of the aluminum sheet portion (back electrode) of the thermocompression bonded body. Was placed. The size of the contact portion between the lead piece and the aluminum sheet was 150 mm in the longitudinal direction of the power supply unit and 10 mm in the width direction of the power supply unit. The width of the lead piece lead-out portion was 10 mm. In accordance with the first embodiment shown in FIGS. 1 and 2, this was sandwiched between two water-absorbent sheets made of 6-nylon and thermocompression bonded. Further, according to the first embodiment shown in FIGS. 1 and 2, this is sandwiched between two moisture-proof films made of polychlorotrifluoroethylene having a thickness of 50 μm, and the protruding portion on the outer peripheral side of the moisture-proof film is subjected to thermocompression bonding. And sealed.

  The lead piece connected to the power supply unit and the lead piece connected to the aluminum sheet (rear electrode) are in a state of being drawn out of the moisture-proof film, and the core part is made of copper having a diameter of 2 mm. The lead wire is attached with solder.

  In accordance with the first embodiment shown in FIGS. 1 and 2, a copper plate (thermal conductivity 398 W) having a surface size of 500 mm × 520 mm and a thickness of 2 mm is formed on the back electrode side moisture-proof film using a silver paste. / M · K) was attached in close contact with the moisture-proof film. At least the entire back side of the light emitting portion of the EL panel was attached so as to contact the copper plate.

  In accordance with the first embodiment shown in FIGS. 1 and 2, a cooling fin made of a copper plate having a thickness of 0.5 mm was attached to the end of the copper plate with screws.

  Through the above steps, an EL display panel having the shape shown in FIGS. 1 and 2 was produced. The EL display panel was manufactured so that the size of the light emitting surface was 500 mm × 500 mm.

(Comparative Example 1)
FIGS. 3 and 4 are the same as in Example 1 except that the copper plate is not attached to the moisture-proof film from above the moisture-proof film on the back electrode side, and the cooling fin is not attached to the end of the copper plate. The EL display panel shown was produced.

When the EL display panels of Example 1 and Comparative Example 1 were driven in an environment with an air temperature of 20 ° C. and a humidity of 60% under driving conditions of a voltage of 200 V and a frequency of 1 KHz, the initial luminance was 600 cd / m ² . Furthermore, the luminance half-life (driving time required for the EL luminance to drop to half of the initial luminance) and the initial (10 minutes after the start of driving) of the element surface when these elements are continuously driven in the same environment. The average temperature is shown in Table 1.

The high heat generation of the element as described above is unlikely to occur in a conventional EL display panel with low emission luminance, and is remarkable in an EL display panel having an initial luminance of 200 cd / m ² or more.

  In Example 1, compared with Comparative Example 1, copper, which is a good heat conductive material, was attached to the moisture-proof film on the back electrode side of the EL display panel, and the heat dissipation was improved. Met.

(Example 2)
In Example 1, except that the 2 mm thick copper plate was replaced with a 2 mm thick aluminum plate (thermal conductivity 237 W / m · K), the same steps as in Example 1 were used. 1 and the EL display panel having the shape shown in FIG.

(Comparative Example 2)
Except for attaching the aluminum plate to the moisture-proof film from above the moisture-proof film on the back electrode side, and attaching the cooling fin to the end of the aluminum plate, the same process as in Example 2 was performed. A similar panel was produced. From above the moisture-proof film on the back electrode side of this panel, a heat pipe having an outer diameter of 10 mm was packed so as to be pressed by the transparent acrylic resin 31 according to the shape shown in FIGS. In accordance with the embodiment shown in FIGS. 5 and 6, a cooling fin 21 made of a copper plate having a thickness of 0.5 mm was attached to the end of the heat pipe with a screw to produce an EL display panel.

  Luminance half-life when the EL display panels of Example 2 and Comparative Example 2 are driven in an environment with an air temperature of 20 ° C. and a humidity of 60% under driving conditions of a voltage of 200 V and a frequency of 1 KHz (EL luminance is reduced to half of the initial luminance) Table 2 shows the drive time required for this.

  In Example 2, the contact area between aluminum, which is a good heat conductive material, and the moisture-proof film on the back electrode side of the EL display panel is larger than that in Comparative Example 2, and heat dissipation is improved. Long life. Further, the EL display panel of Comparative Example 2 is thicker by the amount of the heat pipe, and the lightness and flexibility of the panel by the amount of the heat pipe are impaired compared to Example 2, and the use of the EL display panel (For example, when installing a panel along the side of a columnar column in a station, the EL display panel of Example 2 can be obtained by bending the aluminum plate to the curved surface of the column. Although it is possible to install the panel as it is without performing the above process, in the EL display panel of Comparative Example 2, it is necessary to perform a process of digging a pillar by the thickness of the panel).

(Example 3)
The EL display panel having the shape shown in FIG. 1 and FIG. 2 was fabricated by the same process as in Example 1.

(Comparative Example 3)
An EL display panel having the shape shown in FIGS. 3 and 4 was produced through the same process as in Comparative Example 1.

  The measurement position on the display panel of Example 3 shown in FIG. 7 when the EL display panels of Example 3 and Comparative Example 3 are driven in an environment with an air temperature of 20 ° C. and a humidity of 60% under driving conditions of a voltage of 200 V and a frequency of 2 kHz. A, B, C, and relative values of initial panel surface temperature (after 10 minutes elapsed) and luminance after 100 hours elapsed at each of measurement positions D, E, F in the display panel of Comparative Example 3 shown in FIG. The values when the initial luminance at the position is 100) are shown in Table 3 (the cooling fin and the planar body are not shown in FIGS. 7 and 8).

  Compared to Comparative Example 3, in Example 3 in which copper, which is a good heat conductive material, was attached to the moisture-proof film on the back electrode side of the EL display panel, the unevenness of light emission in the panel surface after time was small.

  The EL display panel of the present invention can be used for a display device that emits light with high brightness for a long time. The EL display panel of the present invention is optimal as a surface light-emitting panel that is maintenance-free and does not require running costs because it does not cause a decrease in luminance even when light is emitted for a long time with high luminance, and uneven light emission is unlikely to occur.

1 is a schematic plan view of a distributed EL display panel constituting a distributed EL display device according to a first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view and an enlarged view of a dispersion type EL display panel constituting a dispersion type EL display device according to a first embodiment of the present invention. 11 is a schematic plan view of a dispersion type EL display panel constituting the dispersion type EL display device according to the aspect of Comparative Example 1. FIG. 11 is a schematic cross-sectional view of a dispersion type EL display panel that constitutes a dispersion type EL display device according to a mode of Comparative Example 1. 10 is a schematic plan view of a dispersion type EL display panel constituting a dispersion type EL display device of an aspect of Comparative Example 2. FIG. 11 is a schematic cross-sectional view of a dispersion type EL display panel constituting a dispersion type EL display device according to a mode of Comparative Example 2. FIG. 10 is a schematic plan view for explaining an EL luminance measurement position in a distributed EL display panel according to an embodiment of Example 3. FIG. 11 is a schematic plan view for explaining an EL luminance measurement position in a distributed EL display panel according to a mode of Comparative Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Back electrode 2 Dielectric layer 3 Light emitting layer 4 Transparent electrode 5 Power supply part 6 Moisture-proof film 7 Light emitting part 8a, 8b Lead 10 Good heat conductive planar body 12a, 12b Lead piece 13a, 13b Lead wire 20 Good heat conductive wire Shape 21 Cooling fin 30 Heat pipe 31 Acrylic resin

Claims (8)

  A dispersive electroluminescence display panel, wherein a sheet or linear body having good heat conductivity is disposed on the back side of a display panel having opposing back electrodes and transparent electrodes.   2. The dispersed electroluminescence according to claim 1, wherein the thermal conductivity of a sheet or linear body having good thermal conductivity disposed on the back side of the display panel is 50 W / m · K or more. Display panel.   The dispersive electroluminescence display panel according to claim 1 or 2, wherein the heat conductive planar or linear body disposed on the back side of the display panel is a metal.   The dispersion type electroluminescence display panel according to claim 1, wherein the back electrode has a thermal conductivity of 100 W / m · K or more.   5. The dispersive electroluminescence display panel according to claim 1, wherein the transparent electrode has a surface resistivity of 0.05Ω / □ to 50Ω / □.   The dispersive electroluminescence display panel according to claim 1, wherein the transparent electrode is made of a transparent conductive sheet and a transparent conductive sheet having a metal and / or alloy fine wire structure.   The dispersion type electroluminescence display panel according to claim 1, wherein a cooling fin is combined with the planar body or the linear body.   The dispersive electroluminescence display panel according to claim 1, wherein a planar body or a linear body is combined with an electronic cooling element.

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