WO2010032757A1

WO2010032757A1 - Organic electroluminescent element, display device and illuminating device

Info

Publication number: WO2010032757A1
Application number: PCT/JP2009/066177
Authority: WO
Inventors: 勘治朗迫; 邦夫近藤
Original assignee: 昭和電工株式会社
Priority date: 2008-09-16
Filing date: 2009-09-16
Publication date: 2010-03-25
Also published as: TW201018299A

Abstract

An organic electroluminescent element (10) comprising a positive electrode layer (12), a negative electrode layer (14), a dielectric layer (13) formed between the positive electrode layer (12) and the negative electrode layer (14), a recess (16) so formed as to penetrate at least the dielectric layer (13), a light-emitting part (17) formed in contact with the inner surface of the recess (16), and a heat dissipation layer (15) for dissipating the heat generated in the light-emitting part (17). The organic electroluminescent element (10) is characterized in that a plurality of light-emitting units, each of which is composed of a positive electrode layer (12), a negative electrode layer (14) and a dielectric layer (13), are provided therein in such a manner that the plurality of light-emitting units form a laminate. The organic electroluminescent element (10) is reduced in luminance unevenness caused by ununiform heat generation and has a high luminous efficiency.

Description

Organic electroluminescent element, display device and lighting device

The present invention relates to, for example, an organic electroluminescent element used for a display device or a lighting device.

In recent years, devices using electroluminescence have become increasingly important. As such a device, there is an organic electroluminescent element that emits light by forming a light emitting material made of an organic material in a layer and providing a pair of electrodes consisting of an anode and a cathode on the light emitting layer and applying a voltage. It attracts attention. An organic electroluminescent element is produced by injecting holes and electrons from the anode and the cathode, respectively, by applying a voltage between the anode and the cathode, and the injected electrons and holes are combined in the light emitting layer. Uses energy to emit light. That is, the device utilizes a phenomenon in which light is generated when the light-emitting material of the light-emitting layer is excited by the energy of the coupling and returns from the excited state to the ground state again.

When this organic electroluminescent element is used as a display device, since an organic substance is used as a light-emitting material, it is easy to generate light with high color purity by selecting an organic substance, and thus a wide color reproduction range can be obtained. There is the feature that it is. In addition, since it is self-luminous, it has the characteristics of high response speed and wide viewing angle. Further, because of its structure, it is easy to reduce the thickness, so that it has an advantage that a thin display device can be manufactured. Furthermore, since it is possible to emit white light and it is surface light emission, an application in which an organic electroluminescent element is incorporated in a lighting device has been proposed.

As a structure of such an organic electroluminescent element, for example, Patent Document 1 includes a dielectric layer inserted between a hole injection electrode layer and an electron injection electrode layer, and at least the dielectric layer and the electrode layer Cavity light emitting electroluminescent devices have been proposed that extend through one and apply an electroluminescent coating material to an internal cavity surface comprising a hole injection electrode region, an electron injection electrode region, and a dielectric region.
Further, Patent Document 2 discloses a metal nitride or metal carbide in an organic electroluminescence element in which a carrier transport layer and a light emitting layer using at least an organic material are laminated between a hole injection electrode and an electron injection electrode. There has been proposed an organic electroluminescence element characterized in that a heat dissipation layer is provided.

Special table 2003-522371 JP-A-8-185982

However, the cavity light-emitting electroluminescent device described in JP-T-2003-522371 has a sufficient countermeasure against the problem that the device is deteriorated due to heat generated during light emission and the durability is not necessarily guaranteed. Not a structure. In particular, when the device is used for illumination or the like, it is necessary to emit light with a large area and high luminance, so that the amount of heat generated per unit area becomes very large. Therefore, it is necessary to take further measures against heat generation.
In addition, in an organic electroluminescence element provided with a heat dissipation layer made of metal nitride or metal carbide, the metal nitride or metal carbide is an opaque material, and light transmission is blocked, resulting in a decrease in light emission efficiency.

In view of the above-described problems, an object of the present invention is to provide an organic electroluminescence device having high luminance efficiency with less luminance unevenness due to uneven heat generation.
Another object is to provide a display device having high contrast and resolution and high luminous efficiency.
Furthermore, another object is to provide an illuminating device with less luminance unevenness and high light emission efficiency.

The organic electroluminescent element of the present invention comprises a first electrode layer, a second electrode layer, a dielectric layer formed between the first electrode layer and the second electrode layer, and at least a dielectric layer. A first electrode layer, a second electrode, and a first electrode layer and a second electrode, each having a recess formed through, a light emitting portion formed in contact with an inner surface of the recess, and a heat dissipation layer that dissipates heat generated from the light emitting portion A plurality of light emitting units each including a layer and a dielectric layer are provided, and the plurality of light emitting units form a laminated structure.

Here, the heat dissipation layer is preferably disposed between the light emitting units, and it is preferable that a second dielectric layer is further provided in contact with the heat dissipation layer. Moreover, it is more preferable that the heat dissipation layer be formed in accordance with the shape of the recess.

Furthermore, it is preferable that the recess has a substantially cylindrical shape penetrating the first electrode layer, the second electrode layer, the dielectric layer, and the heat dissipation layer, and the recess includes the first electrode layer, the second electrode layer, It is preferable to form grooves that are substantially parallel to each other and penetrate the dielectric layer and the heat dissipation layer. Further, it is preferable that the recess further penetrates at least one of the first electrode layer and the second electrode layer.

Further, the light emitting part preferably includes a phosphorescent material, and the phosphorescent material preferably has a molecular weight of 1,000 to 2,000,000 in terms of weight average molecular weight, and the phosphorescent material emits phosphorescence. More preferably, a phosphorescent unit and a carrier transporting unit for transporting carriers are provided in one molecule.

Furthermore, it is preferable that the first electrode layer and the second electrode layer are formed of an opaque material.

The display device of the present invention includes the organic electroluminescent element described above.

The lighting device of the present invention is characterized by including the organic electroluminescent element described above.

According to the present invention, it is possible to provide an organic electroluminescent device having high luminance efficiency and less luminance unevenness due to uneven heat generation.

It is sectional drawing explaining the 1st example of the organic electroluminescent element to which this Embodiment is applied. It is a figure explaining the other form of the shape of the light emission part. It is sectional drawing explaining the 2nd example of the organic electroluminescent element to which this Embodiment is applied. It is sectional drawing explaining the 3rd example of the organic electroluminescent element to which this Embodiment is applied. It is sectional drawing explaining the 4th example of the organic electroluminescent element to which embodiment is applied, and is the figure explaining the case where a recessed part does not penetrate the upper cathode layer. It is sectional drawing explaining the 5th example of the organic electroluminescent element to which this Embodiment is applied. FIG. 7 is a perspective view illustrating the entire organic electroluminescent element shown in FIG. 6. It is a figure explaining the manufacturing method of the organic electroluminescent element to which this Embodiment is applied. It is a figure explaining an example of a display apparatus provided with the organic electroluminescent element in this Embodiment. It is a figure explaining an example of an illuminating device provided with the organic electroluminescent element in this Embodiment.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a partial cross-sectional view illustrating a first example of an organic electroluminescent element to which the present exemplary embodiment is applied.
An organic electroluminescent element 10 shown in FIG. 1 includes an anode layer 12 as a first electrode layer for injecting holes and a cathode layer as a second electrode layer for injecting electrons on a substrate 11. Two light-emitting units each including a dielectric layer 13 for insulating the anode layer 12, the anode layer 12, and the cathode layer 14 are provided, and these two light-emitting units have a laminated structure. A heat dissipation layer 15 is provided between the two light emitting units. Moreover, it has the recessed part 16 formed penetrating these two light emission units and the thermal radiation layer 15, and has the light emission part 17 which is formed in contact with the inner surface of the recessed part 16, and light-emits by applying a voltage. In the light emitting portion 17, a light emitting material is applied to the inner surface of the recessed portion 16 without filling the entire recessed portion 16, thereby forming a second recessed portion 18.

The substrate 11 serves as a support for forming the anode layer 12, the dielectric layer 13, the cathode layer 14, the heat dissipation layer 15, and the light emitting portion 17. A material that satisfies the mechanical strength required for the organic electroluminescent element 10 is used for the substrate 11.
As a material of the substrate 11, when light is to be extracted from the substrate 11 side of the organic electroluminescent element 10, it is necessary to be transparent to visible light. Specifically, glass such as soda glass and non-alkali glass; transparent plastic such as acrylic resin, methacrylic resin, polycarbonate resin, polyester resin and nylon resin; silicon resin and the like.
When it is not necessary to extract light from the substrate 11 side of the organic electroluminescent element 10, the material of the substrate 11 is not limited to a material transparent to visible light, and an opaque material can be used. Specifically, in addition to the above materials, silicon (Si), copper (Cu), silver (Ag), gold (Au), platinum (Pt), tungsten (W), titanium (Ti), tantalum (Ta) Alternatively, niobium (Nb) alone, alloys thereof, or materials made of stainless steel can also be used.
The thickness of the substrate 11 is preferably 0.1 mm to 10 mm, more preferably 0.25 mm to 2 mm, although it depends on the required mechanical strength.

The anode layer 12 applies voltage between the cathode layer 14 and injects holes into the light emitting portion 17. The material used for the anode layer 12 is not particularly limited as long as it has electrical conductivity, but preferably has a sheet resistance of 1000Ω or less in a temperature range of −5 ° C. to 80 ° C. More preferably, it is 100Ω or less. In addition, it is preferable that the electrical resistance does not change significantly with respect to the alkaline aqueous solution. Metal oxides, metals, and alloys can be used as materials that satisfy such conditions. Here, examples of the metal oxide include ITO (indium tin oxide) and IZO (indium-zinc oxide). Examples of the metal include stainless steel, copper (Cu), silver (Ag), gold (Au), platinum (Pt), tungsten (W), titanium (Ti), tantalum (Ta), niobium (Nb), and the like. . An alloy containing these metals can also be used. The thickness of the anode layer 12 is preferably 2 nm to 300 nm because high light transmittance is required when light is to be extracted from the substrate 11 side of the organic electroluminescent element 10. Further, when it is not necessary to extract light from the substrate 11 side of the organic electroluminescent element 10, it can be formed with a thickness of 2 nm to 2 mm, for example.

The dielectric layer 13 is provided between the anode layer 12 and the cathode layer 14, and separates and insulates the anode layer 12 and the cathode layer 14 at a predetermined interval and applies a voltage to the light emitting unit 17. It is. For this reason, the dielectric layer 13 needs to be a high resistivity material, and the electrical resistivity is required to be 10 ⁸ Ωcm or more, preferably 10 ¹² Ωcm or more. Specific examples of the material include metal nitrides such as silicon nitride, boron nitride, and aluminum nitride; metal oxides such as silicon oxide and aluminum oxide, but other polymer compounds such as polyimide, polyvinylidene fluoride, and parylene. Can also be used. The thickness of the dielectric layer 13 is preferably not more than 1 μm in order to suppress the total thickness of the organic electroluminescent element 10. In addition, the narrower the gap between the anode layer 12 and the cathode layer 14, the lower the voltage required for light emission. From this point of view, the thinner the electric conductor layer 13 is more preferable. However, if the thickness is too thin, the dielectric strength may not be sufficient for the voltage for driving the organic electroluminescent element 10. Here, the dielectric strength is preferably such that the current density of the current flowing between the anode layer 12 and the cathode layer 14 is 0.1 mA / cm ² or less when the light emitting portion 17 is not formed, and 0.01 mA. / Cm ² or less is more preferable. In addition, since it is preferable to withstand a voltage exceeding 2 V with respect to the driving voltage of the organic electroluminescent element 10, for example, when the driving voltage is 5 V, the anode layer 12 and When a voltage of about 7 V is applied between the cathode layers 14, it is necessary to satisfy the above current density. The thickness of the dielectric layer 13 satisfying this is preferably 10 nm to 500 nm, more preferably 50 nm to 200 nm.

The cathode layer 14 applies a voltage between the anode layer 12 and injects electrons into the light emitting portion 17. The material used for the cathode layer 13 is not particularly limited as long as it has electrical conductivity like the anode layer 12, but a material having a low work function and being chemically stable is preferable. . The work function is preferably −2.9 eV or less in view of chemical stability. Specifically, materials such as Al, MgAg alloy, Al and alkali metal alloys such as AlLi and AlCa can be exemplified. The thickness of the cathode layer 14 is preferably 10 nm to 1 μm, more preferably 50 nm to 500 nm.

Also, a cathode buffer layer (not shown) may be provided adjacent to the cathode layer 14 for the purpose of lowering the electron injection barrier from the cathode layer 14 to the light emitting portion 17 and increasing the electron injection efficiency. The cathode buffer layer needs to have a lower work function than the cathode layer 14, and a metal material is preferably used. For example, alkali metals (Na, K, Rb, Cs), alkaline earth metals (Sr, Ba, Ca, Mg), rare earth metals (Pr, Sm, Eu, Yb), or fluorides or chlorides of these metals, A simple substance selected from oxides or a mixture of two or more can be used. The thickness of the cathode buffer layer is preferably from 0.05 nm to 50 nm, more preferably from 0.1 nm to 20 nm, and even more preferably from 0.5 nm to 10 nm.

The heat dissipation layer 15 is for absorbing heat generated by the light emitting portion 17 to emit light and dissipating heat. In the organic electroluminescent element 10 shown in FIG. 1, two light emitting units each including an anode layer 12, a dielectric layer 13, and a cathode layer 14 are provided so as to form a laminated structure. A heat dissipation layer 15 is formed on the surface. And from the viewpoint of efficiently absorbing heat, the heat dissipation layer 15 is preferably formed in contact with the light emitting portion 17. The heat absorbed by the heat dissipation layer 15 conducts heat in the heat dissipation layer 15 and also generates heat conduction on the substrate 11 side and the opposite side of the substrate 11, so that heat can be efficiently radiated. As a result, in the surface of the organic electroluminescent element 10, luminance unevenness due to non-uniform heat generation can be made difficult to occur.

The heat dissipation layer 15 preferably has a thermal conductivity at room temperature of 10 W / (m · K) or more, and more preferably 15 W / (m · K) or more. When the thermal conductivity at room temperature is less than 10 W / (m · K), it is difficult to perform efficient heat dissipation.
As a material that can be used for the heat dissipation layer 15, in the present embodiment, it is necessary to be insulative in order to prevent a short circuit between two light emitting units. Specifically, metal nitrides with high thermal conductivity such as aluminum nitride and tantalum nitride; metal oxides such as alumina, sapphire, beryllium oxide, magnesium oxide; diamond-like carbon (DLC); single crystal silicon; Examples thereof include polycrystalline silicon; amorphous silicon; silicon carbide. A mixture of these may also be used.
Although not shown, when the heat dissipation layer 15 is provided between the anode layer 12 and the dielectric layer 13 or between the dielectric layer 13 and the cathode layer 14, the dielectric layer 13 is formed. The above-described short circuit problem between the two light emitting units does not occur. Therefore, not only the insulating material but also a conductive material can be used. Specifically, a metal or metal alloy having excellent thermal conductivity can be used. For example, manganese (Mn), nickel (Ni), aluminum (Al), copper (Cu), zinc (Zn), indium (In), tantalum (Ta), niobium (Nb), tungsten (W), titanium (Ti ), Molybdenum (Mo), gold (Au), silver (Ag), iron (Fe), platinum (Pt), zirconium (Zr), germanium (Ge), magnesium (Mg), etc., or alloys thereof Is done.
Alternatively, materials that are excellent in thermal conductivity but cannot be formed into a film by themselves because they are in powder form should be used after being mixed or dispersed in a resin and then formed into a film. Can do. For example, a carbon tube, particulate alumina, powder diamond, etc. mixed and dispersed in a polymer resin (polystyrene, polyimide, polypropylene, polyethylene, polyethylene terephthalate, polymethacrylic acid, polycarbonate) can be used. Among these materials, many metal materials are particularly excellent in thermal conductivity. For example, aluminum (Al), copper (Cu), tantalum (Ta), gold (having a thermal conductivity of 150 W / (m · K) or more ( Au), silver (Ag), magnesium (Mg) and the like can be used particularly preferably.

As for the thickness of the heat dissipation layer 15, when the heat dissipation layer 15 is provided outside the anode layer 12 and the cathode layer 14 as in the organic electroluminescent element 10 shown in FIG. Is preferably in the range of 0.2 μm to 1000 μm, and more preferably in the range of 0.5 μm to 500 μm. A thicker heat-dissipating layer 15 has higher heat conduction, which is preferable from the viewpoint of heat absorption and heat dissipation. However, when the heat-dissipating layer 15 is thicker than 1000 μm, the manufacturing accuracy of the recesses 16 described later tends to decrease.
In the case where the heat dissipation layer 15 is provided between the anode layer 12 and the cathode layer 14, the thickness is preferably 50 nm to 200 nm. If the heat dissipation layer 15 is 50 nm or less, the distance between the anode layer 12 and the cathode layer 14 becomes too narrow, and a short circuit is likely to occur between the anode layer 12 and the cathode layer 14. Therefore, it becomes difficult to drive stably. When the heat dissipation layer 15 is provided between the anode layer 12 and the dielectric layer 13 and the heat dissipation layer 15 is made of a conductive material such as a metal material, the work function of the heat dissipation layer 15 is as follows. It is preferable that the work function is higher. By doing so, it becomes easy to preferentially inject holes between the anode layer 12 and the light emitting portion 17, so that it is easy to prevent a short circuit from occurring. Further, in the embodiment in which the heat dissipation layer 15 is provided not between the anode layer 12 and the dielectric layer 13 but between the dielectric layer 13 and the cathode layer 14, the work function of the heat dissipation layer 15 is higher than the work function of the cathode layer 14. Preferably it is low. By doing so, it becomes easy to preferentially inject electrons between the cathode layer 14 and the light emitting portion 17, and thus it becomes easy to prevent a short circuit from occurring similarly. If the heat dissipation layer 15 is 200 nm or more, the drive voltage may be too high.

The concave portion 16 is for applying the light emitting portion 17 to the inner surface and taking out light from the light emitting portion 17. The concave portion 16 is an anode layer 12, a dielectric layer 13, and a second electrode layer which are first electrode layers. Are formed so as to penetrate the cathode layer 14 and the heat dissipation layer 15. The light emitted from the light emitting portion 17 by providing the concave portion 16 in this way propagates through the concave portion 16 and can be extracted in both directions on the substrate 11 side and the cathode layer 14 side. Here, since the recess 16 is formed so as to penetrate the anode layer 12, the dielectric layer 13, the cathode layer 14, and the heat dissipation layer 15, the anode layer 12 and the second electrode layer which are the first electrode layers. Light can be extracted even when a certain cathode layer 14 is formed of an opaque material.

Here, the shape of the concave portion 16 can be, for example, a substantially cylindrical shape, but is not limited thereto, and may be a shape that forms a groove shape that is substantially parallel to each other. When the recess 16 has a substantially cylindrical shape, the diameter is preferably 0.1 μm to 20 μm, and the distance between centers is preferably 0.2 μm to 40 μm. More preferably, the diameter is 0.1 μm to 10 μm, and the center-to-center distance is 0.2 μm to 20 μm. In the present embodiment, when the diameter of the recess 16 is 0.2 μm, the center-to-center spacing can be set to 0.3 μm to 1 μm, for example. When the recesses 16 are formed in a substantially parallel groove shape, the groove width is preferably 0.1 μm to 20 μm, and the interval between the groove centers is preferably 0.3 μm to 40 μm.
In the structure of the organic electroluminescent device 10 shown in FIG. 1, at least one of the anode layer 12 and the cathode layer 14 penetrates by forming the recess 16, so that light is emitted strongly at the edge portions of the anode layer 12 and the cathode layer 14. However, the light emission intensity at the center tends to be weak. Therefore, from this point of view, when the diameter and groove width of the recess 16 are 20 μm or more, the central portion of the recess 16 is likely to be in a non-lighting state, and as a result, the luminance per unit area of the organic electroluminescent element 10 is likely to decrease.

The light emitting portion 17 is a light emitting material that emits light when a voltage is applied. As described above, the light emitting portion 17 is applied to the inner surface of the recess 16 so as to form the second recess 18 by providing the light emitting material in contact with the recess 16. The In the light emitting unit 17, the holes injected from the anode layer 12 and the electrons injected from the cathode layer 14 are recombined to emit light.

As the material of the light emitting portion 17, either a low molecular compound or a high molecular compound can be used. For example, the luminescent low molecular weight compound and the luminescent high molecular weight compound described in Hiroshi Omori: Applied Physics, Vol. 70, No. 12, pp. 1419-1425 (2001) can be exemplified.

However, in this embodiment, a material excellent in applicability is preferable. That is, in the structure of the organic electroluminescent element 10 in the present embodiment, in order for the light emitting portion 17 to emit light stably in the recess 16, the light emitting portion 17 is in uniform contact with the inner surface of the recess 16 and the film thickness is uniformly formed. It is preferable that the coverage is improved. If the light emitting portion 17 is formed without using a material having excellent coating properties, the light emitting portion 17 is not in contact with the entire recess 16 or the film thickness of the inner surface of the recess 16 is not uniform. For this reason, variations in the brightness of light emitted from the recess 16 are likely to occur.
Moreover, in order to form the light emission part 17 uniformly in the recessed part 16, it is preferable to carry out by the apply | coating method. That is, in the coating method, it is easy to embed ink containing a light-emitting material in the concave portion 16, and thus it is possible to form a film with improved coverage even on a surface having irregularities. In the coating method, materials having a weight average molecular weight of 1,000 to 2,000,000 are preferably used mainly for the purpose of improving coating properties. Moreover, in order to improve applicability | paintability, coating property improvement additives, such as a leveling agent and a defoaming agent, can also be added, and binder resin with few charge trap ability can also be added.

Specifically, examples of the material having excellent coatability include, for example, an arylamine compound having a predetermined structure and a molecular weight of 1500 to 6000 as disclosed in JP-A-2007-86639, and JP-A 2000-034476. Examples thereof include the predetermined polymeric fluorescent substances.
Here, among materials having excellent coating properties, a light-emitting polymer compound is preferable in terms of simplifying the manufacturing process of the organic electroluminescent element 10, and a phosphorescent compound is preferable in terms of high light emission efficiency. Therefore, a phosphorescent polymer compound is particularly preferable. In addition, it is also possible to add a low molecular light emitting material (for example, molecular weight 1000 or less) in the range which does not impair the applicability | paintability by mixing several materials. In this case, the addition amount of the low molecular light emitting material is preferably 30 wt% or less.
The light-emitting polymer compound can be classified into a conjugated light-emitting polymer compound and a non-conjugated light-emitting polymer compound, and among them, the non-conjugated light-emitting polymer compound is preferable.
For the above reason, the light-emitting material used in this embodiment is particularly preferably a phosphorescent non-conjugated polymer compound (a light-emitting material that is both a phosphorescent polymer and a non-conjugated light-emitting polymer compound). .

The light emitting portion 17 in the organic electroluminescent device 10 of the present invention is preferably a phosphorescent polymer (in which a phosphorescent unit emitting phosphorescence and a carrier transporting unit transporting carriers are included in one molecule ( A phosphorescent material). The phosphorescent polymer can be obtained by copolymerizing a phosphorescent compound having a polymerizable substituent and a carrier transporting compound having a polymerizable substituent. The phosphorescent compound is a metal complex containing a metal element selected from iridium (Ir), platinum (Pt), and gold (Au), and among them, an iridium complex is preferable.

Examples of the polymerizable substituent in the phosphorescent compound include a urethane (meth) acrylate group such as a vinyl group, an acrylate group, a methacrylate group, and a methacryloyloxyethyl carbamate group, a styryl group and a derivative thereof, a vinylamide group and a derivative thereof, and the like. Among them, vinyl group, methacrylate group, styryl group and derivatives thereof are preferable. These substituents may be bonded to the metal complex via an organic group having 1 to 20 carbon atoms which may have a hetero atom.
A carrier transporting compound having a polymerizable substituent is a compound in which one or more hydrogen atoms in an organic compound having one or both of a hole transporting property and an electron transporting property are substituted with a polymerizable substituent. Can be mentioned.

The polymerizable substituent in the carrier transporting compound is a vinyl group. The vinyl group is a urethane (meth) acrylate group such as an acrylate group, a methacrylate group, or a methacryloyloxyethyl carbamate group, a styryl group and its derivative, a vinylamide group and its derivative. A compound substituted with a polymerizable substituent such as may be used. These polymerizable substituents may be bonded via an organic group having 1 to 20 carbon atoms which may have a hetero atom.

The polymerization method of the phosphorescent compound having a polymerizable substituent and the carrier transporting compound having a polymerizable substituent may be any of radical polymerization, cationic polymerization, anionic polymerization, and addition polymerization, but radical polymerization is preferred. The molecular weight of the polymer is preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000 in terms of weight average molecular weight. The molecular weight here is a molecular weight in terms of polystyrene measured using a GPC (gel permeation chromatography) method.

The phosphorescent polymer may be a copolymer of one phosphorescent compound and one carrier transporting compound, one phosphorescent compound and two or more carrier transporting compounds, or two. The above phosphorescent compound may be copolymerized with a carrier transporting compound.

The arrangement of the monomer in the phosphorescent polymer may be any of random copolymer, block copolymer, and alternating copolymer, the number of repeating units of the phosphorescent compound structure is m, and the repeating unit of the carrier transporting compound structure When the number is n (m, n is an integer of 1 or more), the ratio of the number of repeating units of the phosphorescent compound structure to the total number of repeating units, that is, the value of m / (m + n) is 0.001 to 0.00. 5 is preferable, and 0.001 to 0.2 is more preferable.

More specific examples and synthesis methods of phosphorescent polymers are disclosed in, for example, JP-A Nos. 2003-342325, 2003-119179, 2003-113246, and 2003-206320. JP-A-2003-147021, JP-A-2003-171391, JP-A-2004-346212, JP-A-2005-97589, and JP-A-2007-305734.

The light emitting portion 17 of the organic electroluminescent element 10 in the present embodiment preferably includes the above-described phosphorescent compound, but a hole transporting compound or an electron transporting compound is used for the purpose of supplementing the carrier transporting property of the light emitting portion 17. It may be included. As the hole transporting compound used for these purposes, for example, TPD (N, N′-dimethyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′diamine) , Α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), m-MTDATA (4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) And low molecular triphenylamine derivatives such as triphenylamine). In addition, polyvinylcarbazole, a triphenylamine derivative obtained by introducing a polymerizable functional group into a polymer; a polymer compound having a triphenylamine skeleton disclosed in JP-A-8-157575; polyparaphenylene vinylene, And polydialkylfluorene. Examples of the electron transporting compound include low molecular weight materials such as quinolinol derivative metal complexes such as Alq3 (aluminum triskinolinolate), oxadiazole derivatives, triazole derivatives, imidazole derivatives, triazine derivatives, and triarylborane derivatives. Can be mentioned. Further, a polymer obtained by introducing a polymerizable functional group into the above low molecular electron transporting compound, for example, a known electron transporting compound such as poly PBD disclosed in JP-A-10-1665 is exemplified. .

Further, the light emitting portion 17 can be formed even when a light emitting low molecular weight compound is used as the light emitting material used for the light emitting portion 17 instead of the light emitting polymer compound described above. In addition, the above-described light-emitting polymer compound can be added as a light-emitting material, and a hole-transporting compound or an electron-transporting compound can also be added.
Specific examples of the hole transporting compound in this case include, for example, TPD, α-NPD, m-MTDATA, phthalocyanine complex, DTDPFL, spiro-TPD, TPAC, PDA described in JP-A-2006-76901. Etc.

Specific examples of the electron transport compound include BPhen, BCP, OXD-7, TAZ and the like described in JP-A-2006-76901.

Also, for example, a compound having a bipolar molecular structure having a hole transporting property and an electron transporting property in one molecule described in JP-A-2006-273792 can be used.

In the organic electroluminescent element 10 described in detail above, in the organic electroluminescent element 10 shown in FIG. 1, the light emitting portion 17 is in contact with the concave portion 16 to form the second concave portion 18 by providing the light emitting material, and Although the bottom part of the 2nd recessed part 18 is formed so that it may be located in the location near the bottom part of the recessed part 16, it is not restricted to this.

FIGS. 2A to 2D are diagrams for explaining other forms of the shape of the light-emitting portion 17.
In the organic electroluminescent element 10 a shown in FIG. 2A, the depth of the second recess 18 is shallow, and the bottom of the second recess 18 is formed so as to be located closer to the top than the bottom of the recess 16. ing. In the organic electroluminescent element 10b shown in FIG. 2B, the second concave portion 18 is not formed, and the concave portion 16 is completely filled with the light emitting portion 17, and the upper surface of the light emitting portion 17 is the upper surface of the cathode layer 14. Is consistent with Furthermore, in the organic electroluminescent element 10c shown in FIG. 2C, the second concave portion 18 is not formed, the concave portion 16 is completely filled with the light emitting portion 17, and the upper surface thereof has a convex shape. Further, in the organic electroluminescent element 10 d shown in FIG. 2D, the second recess 18 is formed, but the depth of the second recess 18 is shallow, and the bottom of the second recess 18 is the bottom of the recess 16. The light emitting part 17 is formed so as to be developed not only inside the concave part 16 but also on the upper surface of the cathode layer 14.
Also in the

organic electroluminescent elements

10a, 10b, 10c, and 10d shown in FIGS. 2A to 2D, the light emitted from the light emitting section 17 propagates inside the light emitting section 17, and the organic electroluminescent elements described above are used. 10, it can be taken out from both the substrate 11 side and the cathode layer 14 side.

The shape of the light emitting portion 17 described with reference to FIGS. 1 and 2A to 2D can be selected, for example, according to the cross-sectional structures of the anode layer 12 and the cathode layer 14.
For example, as in the organic electroluminescent element 10 described in FIG. 1, when the substrate 11 side is the lower side and the opposite side of the substrate 11 is the upper side, the upper cathode layer 14 is penetrated by the recess 16 and the upper portion is In the case of an open shape, it is preferable to form the second recess 18. Further, in a structure in which the light emitting portion 17 is covered with the upper cathode layer 14 as in an organic electroluminescent element 40 as shown in FIG. 5 described later, the upper cathode layer 14 is formed after the light emitting portion 17 is formed. . Therefore, it is preferable to form the second recess 18 small or not because the coverage is improved when the cathode layer 14 is formed.

Further, in the organic electroluminescent element 10, the heat dissipation layer 15 is provided between the two light emitting units and is formed in contact with the lower cathode layer 14 and the upper anode layer 12, but this is not limited thereto. However, there are no particular restrictions on the locations to be provided.

FIG. 3 is a cross-sectional view illustrating a second example of an organic electroluminescent element to which the exemplary embodiment is applied.
The organic electroluminescent device 20 shown in FIG. 3 is similar to the organic electroluminescent device 10 shown in FIG. 1 in that a heat dissipation layer 15 is provided between two light emitting units. Two second dielectric layers 19 are provided in contact with the heat dissipation layer 15 so as to sandwich 15. By providing the second dielectric layer 19 in this manner, the material used for the heat dissipation layer 15 is not limited to an insulating material, and a conductive material can be used. The second dielectric layer 19 is not particularly limited as long as it is a high resistivity material having an electrical resistivity of 10 ⁸ Ωcm or more, preferably 10 ¹² Ωcm or more, and is the same material as the dielectric layer 13. May be different materials. Specific examples of the material include metal nitrides such as silicon nitride, boron nitride, and aluminum nitride; metal oxides such as silicon oxide and aluminum oxide, as well as the dielectric layer 13, but other materials include polyimide, polyvinylidene fluoride, and the like. Also, polymer compounds such as parylene can be used.
Also in this embodiment, the heat generated from the light emitting unit 17 is absorbed by the heat dissipation layer 15, and the heat transferred through the heat dissipation layer 15 causes heat conduction on the substrate 11 side and the opposite side of the substrate 11, thereby efficiently radiating heat. It can be performed.

FIG. 4 is a cross-sectional view illustrating a third example of the organic electroluminescent element to which the exemplary embodiment is applied.
In the organic electroluminescent element 30 shown in FIG. 4, since the heat dissipation layer 15 is formed of a conductive material, the heat dissipation layer 15 itself also functions as an electrode (in this case, a cathode layer). Then, the anode layer 12, the dielectric layer 13, the heat dissipation layer 15, the dielectric layer 13, and the anode layer 12 are laminated in this order, so that one electrode of each of the upper light emitting unit and the lower light emitting unit is also used. By setting it as such a form, even when it has two light emission units, the thickness of the organic electroluminescent element 30 can be suppressed. In addition, since the number of layers in the stacked structure can be reduced and the number of electrodes can be reduced, the number of wirings can be reduced, so that the manufacturing cost can be suppressed. Also in this embodiment, the heat generated from the light emitting unit 17 is absorbed by the heat dissipation layer 15, and the heat transferred through the heat dissipation layer 15 causes heat conduction on the substrate 11 side and the opposite side of the substrate 11, thereby efficiently radiating heat. It can be performed.

Further, in the organic

electroluminescent elements

10, 10a, 10b, 10c, 10d, 20, and 30 described with reference to FIGS. 1 to 4, the recess 16 has the anode layer 12, the dielectric layer 13, the cathode layer 14, and the heat dissipation layer 15. However, the present invention is not limited to this. In order for the light emitting portion 17 to emit light, it is sufficient that at least the dielectric layer 13 penetrates through the recess 16. However, the recess 16 desirably has a structure that penetrates at least one of the anode layer 12 and the cathode layer 14.

FIG. 5 is a cross-sectional view illustrating a fourth example of an organic electroluminescent element to which the present exemplary embodiment is applied, and is a diagram illustrating a case where the concave portion 16 does not penetrate the upper cathode layer 14.
In the organic electroluminescent element 40 shown in FIG. 5, the concave portion 16 is filled with the light emitting portion 17 with respect to the organic electroluminescent element 10 shown in FIG. 1, and the second concave portion 18 is not formed. The upper cathode layer 14 is formed in a so-called solid film shape so as to be laminated on the upper dielectric layer 13. By forming the upper cathode layer 14 in this way, the recess 16 is covered. Even if the light emitting part 17 is not applied to the inner surface of the recessed part 16 so as to form the second recessed part 18, the light emitted by the light emitting part 17 propagates inside the light emitting part 17, and the above-described organic electroluminescent element 10, Similarly to 20 and 30, it is possible to take out from both the substrate 11 side and the upper cathode layer 14 side. However, in the case of this organic electroluminescent element 40, since the cathode layer 14 is a solid film and covers the light emitting portion 17, if the cathode layer 14 is not transparent to visible light, light is extracted from the cathode layer 14 side. It is not possible.

In addition, a plurality of light emitting units are not necessarily required in the entire region of the organic electroluminescent element, and a form in which a plurality of light emitting units are partially formed may be considered.
FIG. 6 is a cross-sectional view illustrating a fifth example of the organic electroluminescent element to which the exemplary embodiment is applied. The organic electroluminescent element 50 shown in FIG. 6 has two light emitting units, and the other part is one. That is, in the region indicated by “b”, two light emitting units including the anode layer 12, the cathode layer 14, and the dielectric layer 13 are provided on the substrate 11 in the same manner as the organic electroluminescent element 10 shown in FIG. The two light emitting units have a laminated structure, and a heat dissipation layer 15 is provided between the two light emitting units. On the other hand, in the region indicated by “a”, only one light emitting unit including the anode layer 12, the cathode layer 14, and the dielectric layer 13 is provided on the substrate 11, and the heat dissipation layer 15 is laminated. It is formed with. In the region “a”, the heat dissipation layer 15 is directly in contact with air and exposed.
FIG. 7 is a perspective view illustrating the entire organic electroluminescent element 50 shown in FIG.
As described with reference to FIG. 6, the organic electroluminescent element 50 is divided into a part having two light emitting units on the substrate 11 and a single part, but in FIG. 7, it is a part having two light emitting units. The region indicated by “b” is divided into a plurality of locations. And the circumference | surroundings become the area | region shown by "a" which is a location with only one light emission unit. The region indicated by “a” has a lattice shape. By adopting such a form, heat can be radiated directly from the heat radiating layer 15 into the air, so that heat can be radiated more efficiently.

As described above in detail, in the organic electroluminescence device of the present embodiment, the conventional sandwich composed of the anode layer, the light emitting portion, the cathode layer, etc., without providing the recesses 16 with respect to the position and number of the heat dissipation layers 15. The degree of freedom is higher than that of the organic electroluminescent device having the structure. That is, in the organic electroluminescence device having a sandwich structure, the entire surface is a light emitting area, and therefore a heat dissipation layer can be inserted only on the back surface of the back electrode, and even when inserted, only a small area can be inserted from the viewpoint of light emission efficiency. Moreover, even if only a small area is inserted, the luminous efficiency is reduced. On the other hand, in the organic electroluminescent element of the present embodiment, it is possible to provide a heat dissipation layer in any region other than the portion where the recess 16 is provided. That is, the heat dissipation layer can be formed in accordance with the shape of the recess, so that even when there are a plurality of light emitting units as in the present embodiment, the effect of heat dissipation is high, and non-uniform heat generation occurs in the organic electroluminescent element, It becomes easy to prevent uneven brightness from occurring. And it becomes easy to raise luminous efficiency. Further, since a part of the heat dissipation layer 15 is in direct contact with the light emitting portion 17, it is possible to effectively dissipate heat from the light emitting portion 17. Furthermore, there is no restriction | limiting in particular in the location in which the thermal radiation layer 15 is provided, Since it can provide in several places, it is easy to improve the thermal radiation effect.

In addition, it is possible to use a transparent material as a heat dissipation layer in order to prevent a decrease in luminous efficiency in a conventional organic electroluminescent device with a sandwich structure, but transparent and highly heat conductive materials such as sapphire and quartz It is an expensive material and is not practical for application. On the other hand, in the organic electroluminescent element of this embodiment, since an opaque material can be used, it is possible to use an inexpensive material with a high degree of freedom in material selection.

Furthermore, by using a plurality of light emitting units as in the present embodiment, there are a plurality of light emitting portions in the direction perpendicular to the substrate, so that the light emission intensity per unit area is large. Moreover, in such a form, the external extraction efficiency of light changes by the light interference effect. For this reason, it is possible to improve the effective heat radiation action and the light extraction efficiency by determining the optimum value of the thickness based on the wavelength and the distance between the light sources.

In the organic

electroluminescent elements

10, 10a, 10b, 10c, 10d, 20, 30, 40, and 50 described in detail above, when the substrate 11 side is the lower side, the anode layer 12 is lowered in one light emitting unit. However, the present invention is not limited to this, and the anode layer 12 and the cathode layer 14 are not limited to the above. An exchanged structure may be used. That is, when the substrate 11 side is the lower side, in one light emitting unit, the cathode layer 14 may be formed on the lower side, and the anode layer 12 may be formed on the upper side with the dielectric layer 13 interposed therebetween.

Next, a method for manufacturing an organic electroluminescent element will be described by taking the case of the organic electroluminescent element 10 described in FIG. 1 as an example.
FIGS. 8A to 8F are diagrams illustrating a method for manufacturing the organic electroluminescent element 10 to which the present exemplary embodiment is applied.
First, the anode layer 12, the dielectric layer 13, the cathode layer 14, the heat dissipation layer 15, the anode layer 12, the dielectric layer 13, and the cathode layer 14 are formed on the substrate 11 in this order (FIG. 8A). . In order to form these layers, resistance heating vapor deposition, electron beam vapor deposition, sputtering, ion plating, or the like can be used. In addition, when a coating film forming method, that is, a method in which a target material is dissolved in a solvent and applied to a substrate and drying is possible, a spin coating method, a dip coating method, an ink jet method, a printing method, a spray method It is also possible to form a film using a method such as a dispenser method. The cathode buffer layer can also be formed by the same method.

Further, by performing surface treatment of the anode layer 12 after forming the anode layer 12, the performance of the overcoated layer (adhesion with the anode layer 12, surface smoothness, reduction of the hole injection barrier, etc.) can be improved. Can be improved. Surface treatment includes sputtering treatment, corona treatment, UV ozone irradiation treatment, oxygen plasma treatment, etc. as well as high-frequency plasma treatment.

Furthermore, the same effect as the surface treatment can be expected by forming an anode buffer layer (not shown) instead of performing the surface treatment of the anode layer 12. When the anode buffer layer is applied by a wet process, spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating The film can be formed using a coating method such as a spray method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, or an inkjet printing method.

The compound that can be used in the film formation by the wet process is not particularly limited as long as the compound has good adhesion to the light-emitting compound contained in the anode layer 12 and the light-emitting portion 17. Examples thereof include conductive polymers such as PEDOT, which is a mixture of poly (3,4) -ethylenedioxythiophene and polystyrene sulfonate, and PANI, which is a mixture of polyaniline and polystyrene sulfonate. Further, an organic solvent such as toluene or isopropyl alcohol may be added to these conductive polymers. Moreover, the conductive polymer containing 3rd components, such as surfactant, may be sufficient. The surfactant is, for example, selected from the group consisting of alkyl groups, alkylaryl groups, fluoroalkyl groups, alkylsiloxane groups, sulfates, sulfonates, carboxylates, amides, betaine structures, and quaternized ammonium groups. Surfactants containing one group are used, but fluoride-based nonionic surfactants can also be used.

Further, when the anode buffer layer is produced by a dry process, the anode buffer layer can be formed by using a plasma treatment or the like exemplified in Japanese Patent Application Laid-Open No. 2006-303412. In addition, a method of forming a film of a single metal, a metal oxide, a metal nitride, or the like can be given. Specific film forming methods include an electron beam evaporation method, a sputtering method, a chemical reaction method, a coating method, and a vacuum evaporation method. The method etc. can be used.

Next, the concave portion 16 is formed so as to penetrate each layer formed in the step of FIG. 8A. To form the concave portion 16, for example, a method using lithography can be used. In order to do this, first, a resist solution is applied on the cathode layer 14, and the excess resist solution is removed by spin coating or the like to form a resist layer 61 (FIG. 8B).

Then, when a mask (not shown) on which a predetermined pattern for forming the concave portion 16 is drawn is applied, and exposure is performed with ultraviolet rays (UV: Ultra Violet), electron beams (EB: Electron Beam), etc., the resist layer A predetermined pattern 62 corresponding to the concave portion 16 is exposed on 61 (FIG. 8C).

Next, when the exposed portion of the resist layer 61 is removed using a developer, the resist layer 61 in the portion of the pattern 62 is removed (FIG. 8D).

Next, the exposed portion of the cathode layer 14 is removed by etching, and a recess 16 is formed so as to penetrate each layer formed in the step of FIG. 8A (FIG. 8E). As the etching, either dry etching or wet etching can be used. At this time, the shape of the recess 16 can be controlled by combining isotropic etching and anisotropic etching. As dry etching, reactive ion etching (RIE) or inductively coupled plasma etching can be used. As wet etching, a method of immersing in dilute hydrochloric acid or dilute sulfuric acid can be used.

Next, the remaining resist layer 61 is removed using a resist removing solution or the like, and the light emitting portion 17 is formed, whereby the organic electroluminescent element 10 can be manufactured (FIG. 8F). The above-described coating method is used for forming the light emitting portion 17. First, an ink in which a light emitting material constituting the light emitting unit 17 is dispersed in a predetermined solvent such as an organic solvent or water is applied. When applying, various methods such as spin coating, spray coating, dip coating, ink jet, slit coating, dispenser, and printing can be used. After the application, the ink is dried by heating or evacuating, and the light emitting material adheres to the inner surface of the recess 16 to form the light emitting portion 17.

Further, after these series of steps, it is preferable to use the organic electroluminescent element 10 stably for a long period of time and to attach a protective layer or a protective cover (not shown) for protecting the organic electroluminescent element 10 from the outside. As the protective layer, polymer compounds, metal oxides, metal fluorides, metal borides, silicon compounds such as silicon nitride and silicon oxide, and the like can be used. And these laminated bodies can also be used. Further, as the protective cover, a glass plate, a plastic plate whose surface has been subjected to low water permeability treatment, a metal, or the like can be used. It is preferable that the protective cover is sealed with a thermosetting resin or a photo-curing resin and bonded to the element substrate. At this time, it is preferable to use a spacer because a predetermined space can be maintained and the organic electroluminescent element 10 can be prevented from being damaged. If an inert gas such as nitrogen or argon is sealed in this space, it becomes easy to prevent oxidation of the upper cathode layer 14. Further, by installing a desiccant such as barium oxide in this space, it becomes easy to suppress the moisture adsorbed in the series of manufacturing steps from damaging the organic electroluminescent element 10.

Next, a display apparatus provided with the organic electroluminescent element detailed above will be described.
FIG. 9 is a diagram illustrating an example of a display device using the organic electroluminescent element in this embodiment.
The display device 200 shown in FIG. 9 is a so-called passive matrix display device, and includes a display device substrate 202, an anode wiring 204, an anode auxiliary wiring 206, a cathode wiring 208, an insulating film 210, a cathode partition wall 212, and an organic electroluminescent element. 214, a counter substrate 216, and a sealing material 218.

As the display device substrate 202, for example, a transparent substrate such as a rectangular glass substrate can be used. The thickness of the display device substrate 202 is not particularly limited, but for example, a thickness of 0.1 to 1 mm can be used.

A plurality of anode wirings 204 are formed on the display device substrate 202. The anode wirings 204 are arranged in parallel at a constant interval. The anode wiring 204 is made of a transparent conductive film, and for example, ITO (Indium Tin Oxide) can be used. The thickness of the anode wiring 204 can be set to 100 nm to 150 nm, for example. An anode auxiliary wiring 206 is formed on the end of each anode wiring 204. The anode auxiliary wiring 206 is electrically connected to the anode wiring 204. With this configuration, the anode auxiliary wiring 206 functions as a terminal for connecting to the external wiring on the end side of the display device substrate 202, and the anode auxiliary wiring 206 is connected from a driving circuit (not shown) provided outside. A current can be supplied to the anode wiring 204 through the wiring. The anode auxiliary wiring 206 is made of a metal film having a thickness of 500 nm to 600 nm, for example.

Further, a plurality of cathode wirings 208 are provided on the display device substrate 202. The plurality of cathode wirings 208 are arranged so as to be parallel to each other and orthogonal to the anode wiring 204. As the cathode wiring 208, Al or an Al alloy can be used. The thickness of the cathode wiring 208 is, for example, 100 nm to 150 nm. Further, similarly to the anode auxiliary wiring 206 for the anode wiring 204, a cathode auxiliary wiring (not shown) is provided at the end of the cathode wiring 208 and is electrically connected to the cathode wiring 208. Therefore, current can flow between the cathode wiring 208 and the cathode auxiliary wiring.

An insulating film 210 is formed on the display device substrate 202 so as to cover the anode wiring 204. The insulating film 210 is provided with a rectangular opening 220 so as to expose a part of the anode wiring 204. The plurality of openings 220 are arranged in a matrix on the anode wiring 204. In the opening 220, an organic electroluminescent element 214 is provided between the anode wiring 204 and the cathode wiring 208 as described later. That is, each opening 220 is a pixel. Accordingly, a display area is formed corresponding to the opening 220. Here, the film thickness of the insulating film 210 can be, for example, 200 nm to 300 nm, and the size of the opening 220 can be, for example, 300 μm × 300 μm.

An organic electroluminescent element 214 is formed at a location corresponding to the position of the opening 220 on the anode wiring 204. Here, in the organic electroluminescent element 214, since the anode wiring 204 replaces the substrate 11, the anode layer 12, the dielectric layer 13, the cathode layer 14, the heat dissipation layer 15, and the light emitting portion are directly formed on the anode wiring 204. 17 (see FIG. 1) is formed. The organic electroluminescent element 214 is sandwiched between the anode wiring 204 and the cathode wiring 208 in the opening 220. That is, the anode layer 12 of the organic electroluminescent element 214 is in contact with the anode wiring 204, and the cathode layer 14 is in contact with the cathode wiring 208. The thickness of the organic electroluminescent element 214 can be set to, for example, 150 nm to 200 nm.

A plurality of cathode partitions 212 are formed on the insulating film 210 along a direction perpendicular to the anode wiring 204. The cathode partition 212 plays a role in spatially separating the plurality of cathode wirings 208 so that the wirings of the cathode wirings 208 are not electrically connected to each other. Accordingly, the cathode wiring 208 is disposed between the adjacent cathode partition walls 212. As the size of the cathode partition wall 212, for example, a cathode partition with a height of 2 to 3 μm and a width of 10 μm can be used.

The display device substrate 202 is bonded to the counter substrate 216 via a sealing material 218. Thereby, the space in which the organic electroluminescent element 214 is provided can be sealed, and the organic electroluminescent element 214 can be prevented from being deteriorated by moisture in the air. As the counter substrate 216, for example, a glass substrate having a thickness of 0.7 mm to 1.1 mm can be used.

In the display device 200 having such a structure, a current is supplied to the organic electroluminescent element 214 via the anode auxiliary wiring 206 and the cathode auxiliary wiring (not shown) by a driving device (not shown), and the light emitting unit 17 is caused to emit light. Can emit light. An image can be displayed on the display device 200 by controlling light emission and non-light emission of the organic electroluminescence element 214 corresponding to the above-described pixel by the control device.

Next, a lighting device using the organic electroluminescent element 10 will be described.
FIG. 10 is a diagram illustrating an example of a lighting device including the organic electroluminescent element in the present embodiment.
10 is installed adjacent to the organic electroluminescent element 10 and the substrate 11 (see FIG. 1) of the organic electroluminescent element 10, and is connected to the anode layer 12 (see FIG. 1). A terminal 302, a terminal 303 installed adjacent to the substrate 11 (see FIG. 1) and connected to the cathode layer 14 (see FIG. 1) of the organic electroluminescent element 10, and an organic electric field connected to the

terminals

302 and 303. And a lighting circuit 301 for driving the light emitting element 10.

The lighting circuit 301 has a DC power source (not shown) and a control circuit (not shown) inside, and supplies a current between the anode layer 12 and the cathode layer 14 of the organic electroluminescent element 10 through the terminal 302 and the terminal 303. And the organic electroluminescent element 10 is driven, the light emission part 17 (refer FIG. 1) is light-emitted, light is radiate | emitted from the recessed part 16, and it uses as illumination light. The light emitting unit 17 may be made of a light emitting material that emits white light, and the organic electroluminescent element 10 using a light emitting material that emits green light (G), blue light (B), and red light (R). A plurality of them may be provided, and the combined light may be white. In the lighting device 300 of the present embodiment, when light is emitted with the diameter and interval of the recesses 16 (see FIG. 1) being reduced, it appears to the human eye to emit light.

Example 1
[Preparation of phosphorescent polymer compound]
A compound represented by the following formula E-2 (iridium complex having a polymerizable substituent), a compound represented by formula E-54 (hole transporting compound), and a compound represented by formula E-66 ( Electron transporting compound) is dissolved in dehydrated toluene at a ratio of E-2: E-54: E-66 = 1: 4: 5 (mass ratio), and V-601 (Wako Pure Chemical Industries, Ltd.) is used as a polymerization initiator. (Made by Corporation) was dissolved. And after performing freeze deaeration operation, it vacuum-sealed and stirred at 70 degreeC for 100 hours, and the polymerization reaction was performed. After the reaction, the reaction solution was dropped into acetone to cause precipitation, and the reprecipitation purification with dehydrated toluene-acetone was repeated three times to purify the phosphorescent polymer compound. Here, as dehydrated toluene and acetone, those obtained by further distilling a high-purity grade manufactured by Wako Pure Chemical Industries, Ltd. were used.
When the solvent after the third reprecipitation purification was analyzed by high performance liquid chromatography, it was confirmed that no substance having absorption at 400 nm or more was detected in the solvent. That is, this means that the solvent contains almost no impurities, which means that the phosphorescent polymer compound has been sufficiently purified. The purified phosphorescent polymer compound was vacuum dried at room temperature for 2 days. As a result, it was confirmed by high performance liquid chromatography (detection wavelength 254 nm) that the phosphorescent polymer compound (ELP) obtained had a purity exceeding 99.9%.

[Preparation of luminescent material solution]
3 parts by weight of the light-emitting polymer compound thus prepared (weight average molecular weight = 52000) was dissolved in 97 parts by weight of toluene to prepare a light-emitting material solution (hereinafter also referred to as “solution A”).

[Production of organic electroluminescence device]
As the organic electroluminescent element, the organic electroluminescent element 10 shown in FIG. 1 was produced by the following method.
Specifically, first, an ITO (Indium Tin Oxide) film having a thickness of 150 nm is formed on a glass substrate (25 mm square, 1 mm thickness) made of quartz glass using a sputtering apparatus (E-401s manufactured by Canon Anelva Co., Ltd.). Silicon (SiO ₂ ) layer is 100 nm, aluminum (Al) layer is 100 nm, alumina (Al ₂ O ₃ ) layer is 200 nm, ITO (Indium Tin Oxide) layer is 150 nm, silicon dioxide (SiO ₂ ) layer is 100 nm, aluminum ( A 100 nm thick Al) layer was sequentially formed. Here, the glass substrate corresponds to the substrate 11. The ITO film corresponds to the anode layer 12, the alumina (Al ₂ O ₃ ) layer corresponds to the heat dissipation layer 15, the silicon dioxide layer corresponds to the dielectric layer 13, and the aluminum layer corresponds to the cathode layer 14.

Next, a photoresist (AZ 1500 made by AZ Electronic Materials Co., Ltd.) was formed to a thickness of about 1 μm by spin coating. After exposure to _{ultraviolet, TMAH (Tetra methyl ammonium hydroxide:} (CH3) 4 NOH) developed with 1.2% solution, the patterned resist layer. Thereafter, heat was applied at 130 ° C. for 10 minutes (post-baking treatment).

Next, each layer was sequentially processed by dry etching using a reactive ion etching apparatus (RIE-200iP manufactured by Samco Corporation). At this time, the etching conditions of each layer are as follows.

As etching conditions for the aluminum layer and the ITO film, a mixed gas of Cl ₂ and SiCl ₄ was used as a reaction gas, and the reaction was performed at a pressure of 1 Pa and an output Bias / ICP = 200/100 (W) for 8 minutes.

As etching conditions for the silicon dioxide (SiO ₂ ) and alumina (Al ₂ O ₃ ) layers, CHF ₃ was used as a reaction gas, pressure 0.3 Pa, output Bias / ICP = 50/100 (W), 18 minutes Reacted.

By the dry etching process described above, the concave portion 16 penetrating the cathode layer 14, the dielectric layer 13, the heat radiation layer 15, and the anode layer 12 was formed. Then, the resist residue was removed with a resist removing solution. And this recessed part 16 was cylindrical shape with a diameter of 2 micrometers, and the distance between the edges of the recessed part 16 became 2 micrometers.

Next, the glass substrate was washed by spraying pure water and dried using a spin dryer.

Next, the solution A was applied by a spin coating method (rotation speed: 3000 rpm), and then allowed to stand at 120 ° C. for 1 hour in a nitrogen atmosphere and dried to form the light emitting portion 17.

The organic electroluminescent element 10 was able to be manufactured by the above process.

(Example 2)
As the organic electroluminescent element, the organic electroluminescent element 20 shown in FIG. 3 was produced by the following method.
A second dielectric layer 19 was added to Example 1 and formed. As a material for forming the second dielectric layer 19, silicon nitride (Si ₂ N ₃ ) is used, and it is formed by using a sputtering apparatus (E-401s manufactured by Canon Anelva Co., Ltd.) in the same manner as the other layers. be able to. At this time, the film thickness was 200 nm. The etching of the second dielectric layer 19 performed when forming the recess 16 can be performed under the same conditions as for SiO ₂ .

(Example 3)
An organic electroluminescent device 20 was produced in the same manner as in Example 2 except that the material for forming the heat dissipation layer 15 in Example 2 was changed to an alumina (Al ₂ O ₃ ) layer and a silver (Ag) layer was used. . The film thickness of the silver layer was 200 nm, the same as in Example 2. Moreover, when forming the recessed part 16, the etching of a silver layer can be performed on the conditions similar to an aluminum layer.

Example 4
The organic electroluminescent element 30 shown in FIG. 4 was produced.
The organic electroluminescent element 30 can be produced by using the same method as in Example 1 except that the layer configuration is changed with respect to Example 1. The heat dissipation layer 15 was an aluminum (Al) layer, and the film thickness was 200 nm. The ITO film was 150 nm, the silicon dioxide layer was 100 nm, and the same as in Example 1.

(Example 5)
The organic electroluminescent element 40 shown in FIG. 5 was produced.
As a manufacturing method, first, in Example 1, a laminated body having no uppermost aluminum layer was manufactured, and the recess 16 was formed by dry etching treatment. Then, after forming the light emitting portion 17, it was put into a vacuum vapor deposition chamber, and an aluminum (Al) film having a thickness of 150 nm was formed as the cathode layer 14 on the light emitting portion 17 and the dielectric layer 13 with a vacuum vapor deposition apparatus.

(Comparative Example 1)
An organic electroluminescent device was produced in the same manner as in Example 1 except that the material for forming the heat dissipation layer 15 in Example 1 was replaced with an alumina (Al ₂ O ₃ ) layer to form a silicon dioxide (SiO ₂ ) layer. did. The film thickness of the silicon oxide layer was set to 200 nm as in Example 1. In this case, the silicon dioxide layer has a lower thermal conductivity than the alumina layer, and is insufficient as a function of the heat dissipation layer.

[Evaluation of organic electroluminescence device]
About each organic electroluminescent element produced by the Example and the comparative example, heat dissipation was evaluated with the following method.

(Evaluation of heat dissipation)
The organic electroluminescent element was allowed to emit light for a certain time with a constant voltage (9 V) applied, and the ratio of luminance reduction (deterioration ratio) at the center of the organic electroluminescent element before and after this was used as an index.
The luminance was quantified using a luminance meter (Topcon Co., Ltd., BM-9, viewing angle 0.2 degree) with a circular measurement area with a diameter of approximately 0.5 mm.
At this time, the luminance at the beginning of lighting of the organic electroluminescent element and the luminance after 24 hours from lighting were measured. The luminance at the beginning of lighting was measured within 5 seconds after the organic electroluminescence device was energized.
The ratio of the luminance at the beginning of lighting to the luminance distribution 24 hours after lighting was used as an index of heat dissipation. That is, if the heat emitted from the organic electroluminescent device is accumulated in the electroluminescent device as a result of the heat rise, the deterioration is accelerated. Therefore, it can be determined that the larger the value of this ratio is, the lower the luminance decrease (deterioration) is and the higher the heat dissipation.

The results of evaluation are shown in Table 1 below.

As can be seen from Table 1, as compared with the organic electroluminescent element of Comparative Example 1, all of the organic electroluminescent elements of Examples 1 to 5 have a lower luminance reduction. In other words, in the present embodiment, it can be seen that providing the heat dissipation layer 15 improves the heat dissipation and suppresses the heat increase of the organic electroluminescent element.
In addition, when Example 3 and Example 2 are compared, the direction of using a silver rather than an alumina as a material which forms the thermal radiation layer 15 has a small brightness | luminance fall. This can be considered that silver has a higher thermal conductivity than alumina and thus has improved heat dissipation.
Moreover, it turns out that what changed the layer structure like Example 4, 5 has the heat dissipation equivalent to or more than Example 1. FIG.

DESCRIPTION OF

SYMBOLS

10, 20, 30, 40, 50 ... Organic electroluminescent element, 11 ... Board | substrate, 12 ... Anode layer, 13 ... Dielectric layer, 14 ... Cathode layer, 15 ... Radiation layer, 16 ... Recessed part, 17 ... Light emitting part, 18 ... 2nd recessed part, 19 ... 2nd dielectric material layer, 200 ... Display apparatus, 300 ... Illumination device

Claims

A first electrode layer;
A second electrode layer;
A dielectric layer formed between the first electrode layer and the second electrode layer;
A recess formed through at least the dielectric layer;
A light emitting part formed in contact with the inner surface of the recess;
A heat dissipation layer that dissipates heat generated from the light emitting part,
An organic electroluminescence device comprising a plurality of light emitting units each including the first electrode layer, the second electrode layer, and the dielectric layer, wherein the plurality of light emitting units form a laminated structure.
The organic electroluminescence device according to claim 1, wherein the heat dissipation layer is disposed between the light emitting units.
The organic electroluminescent element according to claim 1, wherein a second dielectric layer is further provided in contact with the heat dissipation layer.
The organic electroluminescence device according to any one of claims 1 to 3, wherein the heat dissipation layer is formed in accordance with the shape of the recess.
5. The concave portion according to claim 1, wherein the concave portion has a substantially cylindrical shape penetrating the first electrode layer, the second electrode layer, the dielectric layer, and the heat dissipation layer. 6. The organic electroluminescent element as described.
5. The concave portion according to claim 1, wherein the concave portion has a groove shape that penetrates the first electrode layer, the second electrode layer, the dielectric layer, and the heat dissipation layer and is substantially parallel to each other. 2. The organic electroluminescent element according to item 1.
The organic electroluminescent element according to any one of claims 1 to 6, wherein the recess further penetrates at least one of the first electrode layer and the second electrode layer.
The organic electroluminescent element according to any one of claims 1 to 7, wherein the light emitting part includes a phosphorescent light emitting material.
The organic electroluminescence device according to claim 8, wherein the phosphorescent material has a molecular weight of 1,000 to 2,000,000 in terms of weight average molecular weight.
The organic electroluminescent element according to claim 8 or 9, wherein the phosphorescent material comprises a phosphorescent unit that emits phosphorescence and a carrier transport unit that transports carriers in one molecule.
The organic electroluminescent element according to any one of claims 1 to 10, wherein the first electrode layer and the second electrode layer are formed of an opaque material.
A display device comprising the organic electroluminescent element according to any one of claims 1 to 11.
A lighting device comprising the organic electroluminescent element according to any one of claims 1 to 11.