JP2010205714A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL lighting device capable of restraining degradation of light-emitting characteristics due to heat generation of an organic EL light-emitting element, and efficiently lowering a temperature in the vicinity of the element. <P>SOLUTION: The lighting device includes a light-emitting element such as an organic electroluminescent light-emitting element, and a heat conductive film with a heat conductivity of 1.0 W/m×K or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illuminating device excellent in heat dissipation, and in particular, the present invention relates to an illuminating device that can efficiently dissipate heat generated from a light emitting element by a heat conductive portion such as a heat conductive film. The present invention particularly relates to an illuminating device including a heat conductive portion for radiating heat generated in an organic electroluminescence (hereinafter, “electroluminescence” is abbreviated as “EL”) light emitting element or LED.

  As lighting devices, those using light emitting elements such as incandescent bulbs, fluorescent lamps, and LEDs are known, and in recent years, use of organic EL light emitting elements for lighting applications is expected. Since all of these light emitting elements generate heat during light emission, it is desirable for the lighting device to have a structure that takes heat dissipation into consideration.

  In general, an organic EL light source has a structure in which a transparent base material such as glass or plastic, a transparent conductive layer of an anode made of a transparent electrode, an organic light emitting layer made of an organic thin film, and a cathode layer made of a metal electrode are laminated. It has features of being able to illuminate a wide area because of low power consumption, high brightness and thinness, and a wide viewing angle of 170 degrees or more. In addition, the organic EL lighting device is expected as a next-generation lighting device because it can emit light with an arbitrary color tone by selecting a light emitting substance.

  The organic EL lighting device includes an organic EL light source in which a plurality of organic EL light emitting elements are arranged. The organic EL element is a current driving element and emits light when a current flows. In such an organic EL lighting device, heat is generated when a current flows through the organic EL light emitting element itself, and the temperature in the vicinity of the element becomes high, resulting in a disadvantage that the luminance life and the light emitting characteristics are adversely affected. Sometimes. Further, in order to emit light uniformly, it is necessary to supply a uniform current to each element. For this reason, if an excessive voltage is applied, phenomena such as luminance unevenness may occur.

  As described above, in the conventional organic EL lighting device, the heat generated in the vicinity of the organic EL light emitting element may deteriorate the characteristics of the element, but there is a problem that the heat cannot be released in an efficient and simple manner. .

  Therefore, conventionally, a method of cooling the heat generated in the organic EL light emitting element by flowing an inert gas into the panel has been proposed (Patent Document 1). However, the method of Patent Document 1 requires a large-scale device. As another solution, a method has been proposed in which the sealed space around the periphery of the organic EL element is filled with a liquid that is a heat conductor or a fluid solid (Patent Document 2). However, in the method of Patent Document 2, there is a concern about leakage at the time of breakage, and further, there is a problem that the process becomes complicated because it is necessary to reduce the pressure when injecting a liquid or the like as a heat conductor.

JP 2001-196165 A JP 2006-179218 A

An object of the present invention is to reduce an adverse effect caused by heat generation of a light emitting element of a lighting device.
In particular, the present invention has been made to solve the above-described problems of the prior art, and can suppress deterioration of the light emission characteristics due to heat generation of the organic EL light emitting element, so that the temperature in the vicinity of the element is sufficiently high. It is an object of the present invention to provide an organic EL lighting device that can be made low.

  The illuminating device of the present invention is characterized by having a light emitting element and a heat conductive part having a thermal conductivity of 1.0 W / m · K or more.

  In the lighting device of the present invention, the light-emitting element is preferably an organic electroluminescence light-emitting element, and the organic electroluminescence light-emitting element is a plate-shaped or sheet-shaped light-emitting element formed by laminating at least an anode, an organic light-emitting layer, and a cathode. It is preferable that

  In the illuminating device of this invention, it is preferable that a heat conductive part is formed from a heat conductive composition.

  In the lighting device of the present invention, the thermally conductive portion contains one or more thermally conductive inorganic compounds selected from the group consisting of boron nitride, aluminum nitride, silicon nitride, alumina, magnesia, silicon carbide, boron carbide, and glass powder. It is preferable that the thermally conductive inorganic compound contains boron nitride.

  In the illuminating device of this invention, it is preferable that a heat conductive part contains a high molecular polymer.

  In the illuminating device of the present invention, the heat conductive part is composed of barium oxide, calcium oxide, strontium oxide, calcium chloride, diphosphorus pentoxide, sodium hydroxide, potassium hydroxide, metallic sodium, anhydrous copper sulfate, magnesium perchlorate. And at least one water-collecting component selected from the group consisting of organic aluminum compounds.

  In the illuminating device of the present invention, the heat conductive part is preferably in the form of a film, and the thickness of the film-like heat conductive part (hereinafter also referred to as a heat conductive film) is in the range of 10 μm to 1 mm. Is more preferable.

  The lighting device of the present invention preferably has a laminated structure in which an optical film, an organic electroluminescence light emitting element, a film-like heat conductive portion and a base film are laminated in this order, and the optical film side is preferably a light emitting surface. More preferably, at least a part of the outer edge portion of the film-like thermally conductive portion is sealed with a sealing material. In such an illumination device of the present invention, the optical film is more preferably a lens film.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device which suppressed the influence by the heat_generation | fever from a light emitting element can be provided. ADVANTAGE OF THE INVENTION According to this invention, the illuminating device which suppressed the deterioration of the light emission characteristic by the heat_generation | fever of an organic EL element especially can be provided.

  More specifically, the heat dissipation efficiency of heat generated from the organic EL element can be increased by bringing the heat conductive portion (heat conductive film) into close contact with the cathode and the housing of the organic EL element. Therefore, since the applied voltage can be increased and the current supplied to the element can be made uniform, uneven luminance of light emission can be suppressed, and at the same time, the life of the element can be extended. Moreover, it becomes possible to efficiently dissipate heat simply by attaching a heat conductive film, and a high-quality organic EL lighting device can be provided by a simple method.

FIG. 1 is a schematic view of an embodiment of a lighting device according to the present invention.

  Hereinafter, the present invention will be specifically described.

  The illuminating device of this invention has a light emitting element and a heat conductive part at least.

<Light emitting element>
Examples of the light emitting element constituting the illumination device of the present invention include incandescent light bulbs, fluorescent lamps, LEDs, organic ELs, and the like, but organic EL is particularly preferable. An organic EL light-emitting element as a light-emitting element has a thin organic light-emitting layer, can emit a wide range of surface light, has high light emission efficiency, low power consumption, can be made into a flexible and free shape, This combination is suitable because a free light emission color such as a color tone close to natural light can be obtained, and since no harmful substances such as mercury are contained, there is less concern about environmental pollution.

  The organic EL light-emitting element suitably used as the light source of the illumination device of the present invention has at least an anode, an organic light-emitting layer, and a cathode, and usually includes an anode transparent conductive layer and a light-emitting layer made of a transparent electrode. It has a structure in which an organic light emitting layer and a cathode layer made of a metal electrode are laminated.

  Moreover, in the illuminating device of this invention, it is also preferable that a light emitting element is LED.

<Thermal conductive part>
In the lighting device of the present invention, the thermal conductivity of the thermally conductive portion is usually 1.0 W / m · K or more, preferably 1.0 to 10.0 W / m · K. Here, the thermal conductivity is a value measured by a hot wire method thermal conductivity measuring method (QTM-500) manufactured by Kyoto Electronics Industry Co., Ltd.

  The thermal conductive part is not particularly limited as long as it has the above-described thermal conductivity and dissipates heat generated from the light emitting element, but contains a material having excellent thermal conductivity. It is preferable to contain an inorganic compound having excellent thermal conductivity (hereinafter also referred to as a thermal conductive inorganic compound). The thermally conductive inorganic compound is preferably one selected from boron nitride, aluminum nitride, silicon nitride, alumina, magnesia, silicon carbide, boron carbide, glass powder, or a combination of two or more, and particularly high heat Boron nitride is particularly preferable in terms of obtaining conductivity. Such a thermally conductive inorganic compound is preferably in the form of particles.

  It is preferable that the heat conductive part of this invention contains a high molecular polymer. When the heat conductive part contains a polymer, it is preferable because the heat conductive part can be easily formed into a desired shape such as a film.

  Moreover, it is also preferable that the heat conductive part of this invention contains the water-absorbing component which acts as a hygroscopic agent. The water-collecting component includes barium oxide, calcium oxide, strontium oxide, calcium chloride, diphosphorus pentoxide, sodium hydroxide, potassium hydroxide, metallic sodium, anhydrous copper sulfate, magnesium perchlorate and organoaluminum compounds. The water-capturing component selected from 1 can be suitably used singly or in combination of two or more.

When the thermally conductive part according to the present invention contains a polymer, a polymer that can be molded into a desired shape such as a film in the state of containing the thermally conductive inorganic compound is preferably used. be able to. For example, acrylic resins, polyimides, polyesters, polysiloxanes, and the like can be suitably used as the polymer that constitutes the thermally conductive portion. In particular, when the thermally conductive portion is formed by filling, for example, when the thermally conductive portion is formed by filling a thermally conductive composition for filling and molding into a film shape, It is preferable that the high molecular polymer contained in the conductive portion is an acrylic resin.

  In this invention, it is preferable that a heat conductive part is formed from the heat conductive composition which is a precursor. When the heat conductive composition which is a precursor of a heat conductive part is a composition for filling molding, it is preferable that this composition is a paste-form.

  Examples of the acrylic resin include a polyoxyalkylene-containing (meth) acrylic polymer (A) having a polyoxyalkylene moiety and a weight average molecular weight of 10,000 to 50,000, and / or a silicon-containing functional group (described later). A resin containing a silicon-containing (meth) acrylic polymer (B) having a structural unit having i) is preferred. As the acrylic resin, it is more preferable to include a polymer other than (A) and (B) together with the polymer (A) and / or the polymer (B).

  In the present invention, the “acrylic polymer” means a polymer containing a structural unit derived from a (meth) acrylate compound in an amount of 50 to 100% by weight in all the structural units.

  When the heat conductive composition contains the polymer (A) and / or the polymer (B), the polymer (A) and / or the film (A) and / or the film-like filler when the composition is used to form a green sheet or film-like filler. Alternatively, the polymer (B) functions as a plasticizer, so that it has excellent flexibility and transferability, and even when stress such as bending is applied, a minute crack (crack) is generated on the surface. In addition, even when wound and stored in a roll shape, the storage stability is good, and the surface hardness is less likely to cause dents and defects due to external stress.

  Therefore, the transfer film produced by applying the heat conductive composition onto the support film is also excellent in transferability, that is, heat adhesion to the substrate of the light emitting element.

  Furthermore, when the heat conductive film or the heat conductive composition contains the polymer (A) and / or the polymer (B), the dispersibility and the storage stability of the heat conductive composition are improved, and the resulting heat conduction is achieved. Since the surface smoothness of a conductive film improves, it is preferable.

The polyoxyalkylene-containing (meth) acrylic polymer (A) suitably contained in the acrylic resin has a weight average molecular weight (Mw) of 10,000 to 10,000 having a polyoxyalkylene moiety.
It is a 50,000 (meth) acrylic polymer.

  As the polymer (A), a homopolymer of a (meth) acrylate compound having a polyoxyalkylene moiety (hereinafter also referred to as “specific (meth) acrylate compound”), a specific (meth) acrylate compound, Examples thereof include a (meth) acrylate compound represented by the formula (1) (hereinafter also referred to as “(meth) acrylate compound (1)”) and / or a copolymer with another copolymerizable monomer.

(In formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a monovalent organic group.)
The molecular weight of the polymer (A) constituting the heat conductive composition such as the heat conductive film used in the present invention or the precursor of the heat conductive part is gel permeation chromatography ( The weight average molecular weight in terms of polystyrene by GPC (hereinafter also simply referred to as “weight average molecular weight” or “Mw”) is 10,000 to 50,000, preferably 20,000 to 40,000.

  Specific examples of such a polymer (A) include polyethylene glycol mono (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol ( Examples include meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, and nonylphenoxypolypropylene glycol (meth) acrylate.

  Examples of the (meth) acrylate compound (1) include alkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, phenoxyalkyl (meth) acrylate, alkoxyalkyl (meth) acrylate, cycloalkyl (meth) acrylate, benzyl ( And (meth) acrylate and tetrahydrofurfuryl (meth) acrylate.

  Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and t-butyl. (Meth) acrylate, pentyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, ethylhexyl (meth) ) Acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl Meth) acrylate, stearyl (meth) acrylate and isostearyl (meth) acrylate.

  Examples of the hydroxyalkyl (meth) acrylate include hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl. Examples include (meth) acrylate and 4-hydroxybutyl (meth) acrylate.

  Examples of the phenoxyalkyl (meth) acrylate include phenoxyethyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate.

  Examples of the alkoxyalkyl (meth) acrylate include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate and 2- And methoxybutyl (meth) acrylate.

  Examples of the cycloalkyl (meth) acrylate include cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentadienyl ( Examples include meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, and tricyclodecanyl (meth) acrylate.

  Among these, preferable examples of the (meth) acrylate compound (1) include butyl (meth) acrylate, ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isodecyl (meth) acrylate and 2-ethoxyethyl (meth). An acrylate etc. are mentioned.

Further, the other copolymerizable monomer is not particularly limited as long as it is a compound copolymerizable with the specific (meth) acrylate compound or the (meth) acrylate compound (1).
Aromatic vinyl compounds such as styrene, α-methylstyrene, vinyl benzoic acid, vinyl phthalic acid and vinyl toluene;
Such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, benzyl (meth) acrylate and cyclohexyl (meth) acrylate. Saturated carboxylic acid alkyl esters;
Unsaturated alkylaminoalkyl esters such as aminoethyl acrylate;
Unsaturated carboxylic acid glycidyl esters such as glycidyl (meth) acrylate;
Carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate;
Vinyl cyanide compounds such as (meth) acrylonitrile and α-chloroacrylonitrile;
Aliphatic conjugated dienes such as 1,3-butadiene and isoprene;
Unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid;
Unsaturated dicarboxylic acids such as itaconic acid, maleic acid and fumaric acid;
Other unsaturated carboxylic acids;
Vinyl ethers such as vinyl benzyl methyl ether and vinyl glycidyl ether;
Examples thereof include macromonomers such as polystyrene having a (meth) acryloyl group at the terminal, polymethyl (meth) acrylate, polybutyl (meth) acrylate, and polysilicone. These may be used alone or in combination of two or more.

Preferred examples of the other copolymerizable monomers include (meth) acrylic acid, vinyl benzoic acid, maleic acid and vinyl phthalic acid;
Examples include vinyl benzyl methyl ether, vinyl glycidyl ether, styrene, α-methyl styrene, butadiene and isoprene.

Specific examples of the polymer (A) include polyoxyalkylene (meth) acrylate homopolymers such as polymethylene glycol poly (meth) acrylate, polyethylene glycol poly (meth) acrylate, polypropylene glycol poly (meth) acrylate, and poly Examples include copolymers containing oxyalkylene (meth) acrylate. Preferred specific examples of the (meth) acrylic polymer (A) include polymethylene glycol (meth) acrylate-polybutyl methacrylate copolymer, polyethylene glycol (meth) acrylate-polybutyl methacrylate copolymer, polypropylene glycol ( (Meth) acrylate-polybutyl methacrylate copolymer, polyethylene glycol poly (meth) acrylate-methyl methacrylate-butyl methacrylate copolymer, polyethylene glycol poly (meth) acrylate-methyl methacrylate-butyl (meth) acrylate-styrene copolymer, Polyethylene glycol poly (meth) acrylate- (meth) acrylic acid-styrene copolymer, polypropylene glycol poly (meth) acrylate-2-
Ethoxyethyl (meth) acrylate-styrene copolymer, polymethylene glycol (meth) acrylate-2-ethylhexyl acrylate-styrene copolymer polyethylene glycol (meth) acrylate-2-ethylhexyl acrylate-styrene copolymer and polyprolene glycol ( And (meth) acrylate-2-ethylhexyl acrylate-styrene copolymer.

  The polymer (A) can be obtained by polymerizing the specific (meth) acrylate compound and, if necessary, the (meth) acrylate compound (1) and other copolymerizable monomers by a known method. . The molecular weight of the polymer (A) can be adjusted by appropriately adjusting the amount of the polymerization initiator, the polymerization temperature and the polymerization time.

  The silicon-containing (meth) acrylic polymer (B) preferably contained in the acrylic resin has a group represented by the following formula (i) (hereinafter also referred to as “silicon-containing functional group (i)”). The structural unit is usually contained in an amount of 0.01 to 50% by weight, preferably 0.1 to 30% by weight, more preferably 1 to 10% by weight in all the structural units.

  In formula (i), n represents an integer of 0 to 3, preferably 1 to 3. X represents a hydroxyl group or a hydrolyzable group, and when two or more X exist, they may be the same or different. R represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 5 carbon atoms, and when two or more R atoms are present, they may be the same or different.

  Examples of the hydrolyzable group include halogen atoms such as fluorine, chlorine and bromine; alkoxy groups such as methoxy group and ethoxy group; alkenyloxy groups such as vinyloxy group and propenyloxy group; acyloxy groups such as acetoxy group and benzoyloxy group Ketoximate groups such as dimethyl ketoxymate group and cyclohexyl ketoximate group; amino groups; amide groups such as acetamide; aminooxy groups; mercapto groups and the like. Among the above X, an alkoxy group or the like is preferable from the viewpoint of affinity with inorganic particles.

  The weight average molecular weight (Mw) of the polymer (B) is usually 10,000 to 400,000, preferably 20,000 to 200,000, more preferably 30,000 to 160,000. When Mw is in the above range, a thermally conductive portion such as a film having excellent adhesion to the substrate of the light emitting element or the like can be formed.

  The acrylic resin, which is a polymer that is suitably contained in the thermally conductive part according to the present invention, is a polyoxyalkylene-containing (meth) acrylic polymer (A) and / or a silicon-containing (meth) acrylic polymer. When a polymer other than the polymer (B) is further contained, a polymer other than the polymers (A) and (B) is used without any particular limitation as the polymer (A) and (B). Can do. When the resin other than the polymers (A) and (B) is an acrylic polymer, the heat conductive component such as the inorganic compound contained in the heat conductive portion can be suitably combined. The heat conductive portion is preferable because it is excellent in adhesion or adhesion to the light emitting element substrate.

  As the acrylic polymer (C) suitably used as necessary as a resin other than the polymers (A) and (B), those having appropriate adhesiveness capable of binding inorganic compound powders are available. preferable.

  As such an acrylic polymer (C), a homopolymer of the above (meth) acrylate compound (1), a copolymer containing two or more of the above (meth) acrylate compounds (1), and the above (meth) A copolymer of the acrylate compound (1) and the other copolymerizable monomer is included. The copolymer component derived from the (meth) acrylate compound (1) represented by the general formula (1) in the acrylic polymer (C) is usually 70% by weight or more, preferably 90% by weight or more. Specific examples of the preferred acrylic polymer (C) include polymethyl methacrylate, polybutyl methacrylate, and methyl methacrylate-butyl methacrylate copolymer.

  The molecular weight of such an acrylic polymer (C) is a weight average molecular weight (Mw), and is usually 4,000 to 300,000, preferably 10,000 to 200,000.

  In the heat conductive composition serving as the heat conductive part or the precursor thereof such as the heat conductive film according to the present invention, the polymer (A) and / or (B) is the total amount of the inorganic compound powder. The amount is usually 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight with respect to 100 parts by weight. When the total amount of the polymers (A) and / or (B) is less than the above range, the heat conductive composition is handled at room temperature and the heat conductive film obtained from the heat conductive composition is adhesive. May be inferior. On the other hand, if the amount of the polymer (A) and / or (B) is more than the above range, the adhesiveness and transferability of the heat conductive film become excessive, and it becomes difficult to peel off the support film. When the green sheet having a layer may be unsatisfactory, the thermal conductivity of the thermal conductive film becomes insufficient, the desired heat dissipation cannot be achieved, and the temperature of the lighting device rises to cause a malfunction. There is.

  Moreover, when the high molecular polymer is an acrylic resin and includes the acrylic polymer (C) together with the polymers (A) and / or (B), the content of the acrylic polymer (C) It is desirable that it is 20 parts by weight or less, preferably 5 to 15 parts by weight with respect to 100 parts by weight as a total of (A) and (B).

  When the heat conductive part according to the present invention is formed from a heat conductive composition containing a heat conductive inorganic compound, a polymer, and a water-collecting component, the heat conductive part such as a heat conductive film or a precursor thereof. In the thermally conductive composition to be, the high molecular weight polymer is usually preferably 5 to 80 parts by weight, more preferably 5 to 50 parts by weight, and still more preferably 5 to 50 parts by weight with respect to 100 parts by weight of the inorganic compound powder. 30 parts by weight are used. If the amount of the high molecular polymer is too small, the inorganic compound powder may not be securely bound and retained. On the other hand, when the amount of the high molecular polymer is excessive, the thermally conductive portion may not exhibit sufficient thermal conductivity.

  In the lighting device of the present invention, the heat conductive portion may have any shape that has the above-described excellent heat conductivity and efficiently diffuses and dissipates heat generated by the light emitting element. For example, the heat conductive portion is filled with a paste-like composition. However, it is preferably a film-like shape, that is, a heat conductive film.

<Lighting device>
The lighting device of the present invention has a structure including the above-described light emitting element and a heat conductive portion. Preferably, the organic EL light-emitting element has a structure in which the organic EL light-emitting element is disposed inside the housing, and usually includes at least the housing and an anode transparent conductive layer and a light-emitting layer including a transparent electrode disposed on the inner side of the housing. Thermal conductivity such as a light source (light emitting element) having a structure in which an organic light emitting layer and a cathode layer made of a metal electrode are laminated, a substrate on which the light source is mounted, and a heat conductive film for radiating heat generated by the light source Department. It is preferable that the thermally conductive portion is disposed so as to fill a gap between the housing and the light source. In such a configuration, since the heat conductive portion dissipates heat generated by the organic EL light source, it is possible to suppress deterioration of light emission characteristics due to heat generation.

  In this invention, it is preferable that heat conductive parts, such as the said heat conductive film, have covered the periphery except the transparent conductive layer of the anode of an organic electroluminescent light emitting element. Since the transparent conductive layer region is often used as an effective light-emitting region, if the region that avoids the effective light-emitting region is covered with a heat conductive portion, the heat radiation layer can be obtained without reducing the amount of light emitted from the organic EL light-emitting element. Can be provided.

  In the present invention, as described above, the thermal conductive film has a thermal conductivity of 1.0 W / m · K or more, preferably 1.0 to 10.0 W / m · K. . The thickness of the heat conductive film may be appropriately selected according to the thickness and width of the light source, but is generally preferably 10 μm to 1 mm. Moreover, this heat conductive film may consist of another resin composition and multilayer structure according to the intended purpose.

  In the present invention, the heat conductive part preferably contains an inorganic compound having excellent heat conductivity, and a heat conductive composition in which a high molecular polymer is blended with an inorganic compound having excellent heat conductivity is formed into a film. A heat conductive film obtained by molding is more preferable. The heat conductive film may be previously formed into a film shape, or may be filled into a light emitting element in a housing and formed into a film shape.

  The heat conductive film used in the present invention may be a film obtained by simply forming the heat conductive composition into a film, or may be an inorganic film formed by baking a resin.

  The lighting device of the present invention is not particularly limited as long as it includes a light emitting element such as an organic EL light emitting element and a heat conductive portion such as a heat conductive film that dissipates heat from the light emitting element. However, for example, an organic EL light emitting device that is a laminate in which an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode are sequentially formed on a substrate is used. An example is a structure in which the periphery (that is, the portion other than the anode surface of the organic EL light-emitting element) is covered with a heat conductive film and then sealed with a stainless steel can and an epoxy resin.

  When plastic is used as the substrate of the organic EL light emitting device, the lighting device of the present invention has, for example, a gas barrier layer and a hard coat layer sequentially formed on one or both sides of the plastic substrate, and an insulating layer, An anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode are sequentially formed. After covering the cathode and the periphery of the laminate with a heat conductive film, they are sealed with a stainless steel can and an epoxy resin. Become. In the case of using a plastic substrate, the gas barrier layer, the hard coat layer, and the insulating layer are not necessarily required.

As the substrate material, for example, glass or plastic having a light transmittance of 50% or more in the visible light region is used. As a material for the gas barrier layer, SiOx, Al ₂ O ₃ , SiNx or the like can be used, and the thickness thereof is appropriately determined so that the moisture permeability of the substrate is 2 g / m ² · day · atm or less. . As the insulating layer, SiOx, Al ₂ O ₃ or the like can be used. As the anode, a conductive material capable of efficiently injecting holes into the hole transport layer is used. When light emission from the light emitting layer is extracted from the substrate direction, the light transmittance in the visible light region of the conductive material is 50. % Or more, and it is preferable to use a transparent conductive material such as ITO (Indium Tin Oxide). Further, the electrical resistance value of the anode is desirably low resistance in order to reduce power consumption and heat generation of the element.

In the organic EL light-emitting device suitably used in the present invention, the hole transport layer is laminated on the anode, has the ability to efficiently inject holes from the anode, and transport holes, and is superior to the light-emitting layer. It is made of a material that has a hole injection effect and can easily form a thin film. The light emitting layer is formed in the shape of the hole transport layer, and is made of a light emitting material and, if necessary, a doping material added thereto. The light-emitting material is made of a material that can form a thin film easily because electrons and holes injected from the electrode, the hole transport layer, or the electron transport layer are recombined in the light-emitting layer, and light can be emitted efficiently. The doping material is a material that is added to the light emitting layer when the light emission efficiency from the light emitting layer is improved or the emission color is changed. The electron transport layer is a material that is formed on the light emitting layer, has the ability to efficiently inject electrons from the cathode and transport electrons, has an excellent electron injection effect on the light emitting layer, and can be easily formed into a thin film It becomes more. This electron transport layer may be formed of the same material as the light emitting material. The cathode is formed on the electron transport layer, and is made of a material capable of efficiently injecting electrons into the electron transport layer, and can have a mixture of these materials or a laminated structure. Specific examples include a magnesium-aluminum alloy, a silver-magnesium alloy, and an aluminum-alumina alloy, but are not limited thereto.

  As a material for the thermally conductive part covering the cathode and the periphery of the laminate, a thermally conductive film having a thermal conductivity of 1.0 W / m · K or more is preferable. The thermally conductive film contains an inorganic compound having high thermal conductivity such as boron nitride, aluminum nitride, alumina, zirconia, magnesia, silicon nitride. In the present invention, the heat conductive film can be easily attached to a light emitting element as a light source by, for example, bending and laminating while expelling bubbles.

  By sealing the above laminate with a material having a low moisture permeability such as glass or stainless steel, an organic EL lighting device having excellent heat dissipation efficiency of heat generated from the organic EL light emitting element can be obtained. A schematic diagram of a preferred example of the illumination device of the present invention is shown in FIG.

  In the lighting device of the present invention, as shown in FIG. 1, an optical film, an organic EL light emitting element, a heat conductive film, and a base film (substrate) are laminated in this order (in order from the bottom in FIG. 1). The structure in which the optical film side is the light emitting surface can be preferably employed. Here, the organic EL light-emitting element is a plate-shaped or sheet-shaped light-emitting element, the anode side is the light-emitting surface of the light-emitting element, and the thermally conductive film covers other than the anode surface that becomes the light-emitting surface of the light-emitting element. A structure is preferred. The anode surface of the organic EL light emitting element is preferably in contact with the optical film. Here, the optical film means a film having translucency, but this optical film is a lens film provided with a lens structure such as a prism shape or a lenticular shape according to desired illumination characteristics. May be. This optical film may be formed from one layer or may be formed from multiple layers. It is preferable that at least a part of the outer edge portion of the heat conductive film is sealed with a sealing material, and it is more preferable that the entire outer edge portion is sealed with the sealing material. That is, an illumination device having a structure in which an optical film, a sealing material, and a base film (substrate) serve as a casing, in which an organic EL that is a light-emitting element, and a heat conductive film are sealed. It can mention as one of the preferable aspects of the illuminating device of invention.

  Further, even when the light emitting element is an LED, a lighting device can be formed by applying the same thermal conductive film to a portion that needs to be radiated, as in the case of using the organic EL light emitting element.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

[Example 1]
An SiO _x layer having a thickness of 5 μm was formed as an insulating layer on a glass substrate by sputtering. Subsequently, an ITO film as an anode transparent electrode was deposited to 120 nm by sputtering, and an ITO film was formed into a 1 mm wide strip by wet etching.

  Further, α-naphthylphenyldiamine having a thickness of 50 nm was formed thereon as a hole transport layer, and then tris (8-quinolinol) aluminum was sequentially deposited under the same conditions as a light emitting layer with a thickness of 80 nm. Tris (8-quinolinol) aluminum used as the light emitting layer also serves as an electron transport layer. Next, magnesium-aluminum was deposited to form a cathode. The cathode was formed by using a metal mask at the time of vapor deposition to form a 1 mm wide strip pattern in a direction perpendicular to the ITO strip pattern.

  Next, the cathode and the periphery of the laminate were covered with a heat conductive film, and then sealed with stainless steel and an epoxy resin to obtain an organic EL lighting device 1. The thermally conductive film used here is an acrylic film obtained by copolymerizing 50 parts by weight of boron nitride, 50 parts by weight of alumina, 30 parts by weight of butyl methacrylate, 30 parts by weight of ethylhexyl methacrylate, and 20 parts by weight of 2-hydroxypropyl methacrylate. It consisted of 20 parts by weight of a copolymer (weight average molecular weight 8000), thermal conductivity was 2.8 W / m · K, and thickness was 100 μm.

  A voltage was applied to the obtained organic EL lighting device 1 to light it, and the temperature of the device surface was measured while maintaining the lighting state.

  As a result, in the organic EL lighting device 1, the temperature rose by 8 ° C. in 100 seconds from the start of voltage application, and thereafter changed at a substantially constant temperature.

[Comparative Example 1]
In Example 1, the organic EL lighting device 2 was manufactured by the same method as that for manufacturing the organic EL lighting device 1 except that a silicone oil was filled without using a heat conductive film between the cathode and the stainless steel. .

  A voltage was applied to the obtained organic EL lighting device 2 to light it, and the temperature of the device surface was measured while maintaining the lighting state.

  As a result, in the organic EL lighting device 2, an increase of 12 ° C. was observed in 100 seconds from the start of voltage application, and after the increase of 15 ° C. after 250 seconds had passed, the temperature changed at a substantially constant temperature. The surface temperature of the organic EL lighting device 1 in Example 1 was 7 ° C. lower.

[Comparative Example 2]
In Example 1, the organic EL lighting device 3 was manufactured by the same method as that for manufacturing the organic EL lighting device 1 except that a thermal conductive film was not used between the cathode and the stainless steel, and nitrogen was filled.

  A voltage was applied to the obtained organic EL lighting device 3 to light it, and the temperature of the device surface was measured while maintaining the lighting state.

  As a result, in the organic EL lighting device 3, an increase of 14 ° C. was observed in 100 seconds from the start of voltage application, and after the increase of 19 ° C. after 280 seconds elapsed, the temperature changed at a substantially constant temperature. The surface temperature of the organic EL lighting device 1 in Example 1 was 11 ° C. lower.

[Example 2]
In Example 1, the organic EL lighting device 1 of Example 1 except that barium oxide containing 20% by weight of the total amount of the acrylic copolymer, boron nitride and aluminum oxide was used as the heat conductive film. The organic EL lighting device 4 was manufactured by the same method as that for manufacturing.

The obtained organic EL lighting device 4 is turned on by applying a voltage, and is left in an 85% RH environment at 85 ° C. while maintaining the lighting state, and a non-lighting portion (dark spot) on the light emitting surface of 2 mm □. Observed growth.

As a result, in the organic EL lighting device 4, no increase in the non-lighted portion was observed even after leaving for 1500 hours.
[Example 3]

  In Example 1, the organic EL lighting device 1 of Example 1 was used except that a strontium oxide containing 25% by weight of the total amount of the acrylic copolymer, boron nitride and aluminum oxide was used as the heat conductive film. The organic EL lighting device 5 was manufactured by the same method as that for manufacturing.

The obtained organic EL lighting device 4 is turned on by applying a voltage, and is left in an 85% RH environment at 85 ° C. while maintaining the lighting state, and a non-lighting portion (dark spot) on the light emitting surface of 2 mm □. Observed growth.

As a result, in the organic EL lighting device 4, no increase in the non-lighted portion was observed even after leaving for 1500 hours.
[Example 4]

  In Example 1, the organic EL lighting device 1 of Example 1 except that the heat conductive film further contains calcium oxide containing 20% by weight of the total amount of the acrylic copolymer, boron nitride and aluminum oxide. The organic EL lighting device 6 was manufactured by the same method as that for manufacturing.

The obtained organic EL lighting device 4 is turned on by applying a voltage, and is left in an 85% RH environment at 85 ° C. while maintaining the lighting state, and a non-lighting portion (dark spot) on the light emitting surface of 2 mm □. Observed growth.

  As a result, in the organic EL lighting device 4, no increase in the non-lighted portion was observed even after leaving for 1500 hours.

  From these results, in the illuminating device of the present invention provided with the thermally conductive film, heat can be radiated by the thermally conductive film, and thus an organic EL illuminating device excellent in heat dissipation can be provided. Furthermore, it turns out that an effect can be exhibited also in the improvement of the lifetime of a light emitting element by containing a water catching component.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device excellent in heat dissipation efficiency can be provided, and in detail, the high performance organic electroluminescent illuminating device excellent in heat dissipation efficiency and the cooling characteristic can be provided.

Claims (13)

  A lighting device comprising: a light-emitting element; and a heat conductive portion having a thermal conductivity of 1.0 W / m · K or more.   The lighting device according to claim 1, wherein the light emitting element is an organic electroluminescence light emitting element.   The lighting device according to claim 2, wherein the organic electroluminescence light-emitting element is a plate-shaped or sheet-shaped light-emitting element formed by laminating at least an anode, an organic light-emitting layer, and a cathode. The lighting device according to claim 1, wherein the heat conductive portion is formed of a heat conductive composition.   The thermally conductive part contains one or more thermally conductive inorganic compounds selected from the group consisting of boron nitride, aluminum nitride, silicon nitride, alumina, magnesia, silicon carbide, boron carbide, and glass powder. Item 5. The illumination device according to any one of Items 1 to 4.   The lighting device according to claim 5, wherein the thermally conductive inorganic compound contains boron nitride.   The lighting device according to any one of claims 1 to 6, wherein the heat conductive part contains a polymer.   The group in which the thermally conductive part is composed of barium oxide, calcium oxide, strontium oxide, calcium chloride, diphosphorus pentoxide, sodium hydroxide, potassium hydroxide, metallic sodium, anhydrous copper sulfate, magnesium perchlorate and an organoaluminum compound The lighting device according to claim 1, comprising at least one water-collecting component selected from the group consisting of:   The lighting device according to any one of claims 1 to 8, wherein the thermally conductive portion is in a film form.   The lighting device according to claim 9, wherein the thickness of the film-like thermally conductive portion is in a range of 10 μm to 1 mm.   11. An optical film, an organic electroluminescence light emitting element, a film-like thermally conductive portion, and a base film have a laminated structure in which they are laminated in this order, and the optical film side is a light emitting surface. The illuminating device in any one of.   The lighting device according to claim 11, wherein at least a part of an outer edge portion of the film-like thermally conductive portion is sealed with a sealing material.   The lighting device according to claim 11, wherein the optical film is a lens film.