JP6592883B2 - ORGANIC EL ELEMENT AND ORGANIC EL LIGHTING DEVICE USING SAME - Google Patents

Description

  The present invention relates to an organic EL element and an organic EL lighting device using the same.

  Conventionally, incandescent bulbs and fluorescent lamps have been widely used as illumination devices. On the other hand, in recent years, surface-emitting lighting equipment has been attracting attention as a next-generation lighting because of its soft impression light and energy saving performance. Organic electroluminescence (Organic EL (Electro Luminescence), OEL: Organic) Electro Luminescence), inorganic electroluminescence, or a combination of a light emitting diode and a light guide plate has been developed. Of these, organic EL has attracted attention because it is very thin, can be reduced in size and weight, and generates little heat.

  Organic EL refers to a phenomenon in which energy is applied as light to a light-emitting material made of an organic substance when energy is applied to the light-emitting material and the excited light-emitting material returns to its original state. In an organic EL element using an organic EL technology, an organic layer containing a light emitting material made of an organic substance and two electrodes (a cathode and an anode) facing each other so as to sandwich the organic layer are sequentially stacked on a substrate. Structure is commonly used.

  Since the organic EL element can be bent by using a flexible substrate, the expectation as flexible illumination is increasing. As a substrate, a plastic substrate made of a resin or the like, an ultrathin glass having a thickness of 200 μm or less, and the like are being studied. For the purpose, studies such as laminating and reinforcing resin films on both sides have been made (for example, Patent Document 1).

JP 2007-010834 A

  The organic layer constituting the organic EL element has a low durability against gas components such as moisture and oxygen, and is required to be sealed with a sealing material having a high barrier property. However, in the substrate in which the resin film is laminated on the ultrathin glass described above, the organic EL element formed on the resin film has a high barrier property against gas components such as moisture and oxygen in the glass portion, but the barrier of the resin film. Therefore, the durability tends to be lower than that of an organic EL element formed on a single glass substrate.

  The present invention has been made in view of such problems, and the object of the present invention is to maintain barrier properties of gas components such as moisture and oxygen in a flexible organic EL element while maintaining mechanical strength. An object of the present invention is to provide an enhanced organic EL element and an organic EL lighting device using the same.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are organic EL elements in which at least a surface resin layer, an organic EL layer, and a sealing portion are arranged in this order on a glass plate having a thickness of 200 μm or less. The sealing portion is formed so as to cover all surfaces of the surface resin layer and the organic EL layer, so that a barrier against gas components such as moisture and oxygen is maintained while maintaining mechanical strength. The present inventors have found that an organic EL element with high performance can be realized and have reached the present invention.

  Accordingly, the gist of the present invention is as follows.

(1) An organic EL element in which a surface resin layer, an organic EL layer, and a sealing portion are arranged in this order on a glass plate having a thickness of 200 μm or less, and the sealing portion includes the surface resin layer and the organic An organic EL element, which is disposed so as to cover all of the exposed surface of an EL layer.
(2) The organic EL element according to (1), which has a back surface resin layer on the surface of the glass plate and opposite to the surface resin layer.
(3) The organic EL element according to (2), wherein the film thickness of the back surface resin layer is larger than the film thickness of the surface resin layer.
(4) The organic EL element according to any one of (1) to (3), further including an end surface resin layer that covers at least a part of the end surface of the glass plate.
(5) An organic EL lighting device using the organic EL element according to any one of (1) to (4).

  ADVANTAGE OF THE INVENTION According to this invention, while maintaining mechanical strength, the flexible organic electroluminescent element and organic electroluminescent illuminating device which improved the barrier property of gas components, such as a water | moisture content and oxygen, are realizable.

It is typical sectional drawing which shows the structure of the organic EL element which concerns on embodiment of this invention. It is typical sectional drawing which shows an example of the laminated structure of the organic EL layer of the organic EL element of this invention. It is typical sectional drawing which shows the structure of the organic EL element which concerns on other embodiment of this invention.

Hereinafter, embodiments of the organic EL element of the present invention will be described in detail with reference to the drawings based on examples or modifications.
In addition, this invention is not limited to the content demonstrated below, In the range which does not change the summary, it can change arbitrarily and can implement. In addition, the drawings used for explaining the examples or the modifications schematically show the organic EL elements or their constituent members according to the present invention, and are partially emphasized, enlarged, reduced, Or the omission etc. are performed, and it may not represent correctly the reduced scale, the shape, etc. of each structural member. Furthermore, all the various numerical values used in the embodiment or the modification are examples, and can be variously changed as necessary.

  First, the configuration of an organic EL element 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of an organic EL element 100 according to this example.

  As can be seen from FIG. 1, the organic EL element 100 according to this example includes a glass plate 1, a flexible substrate 10 having a resin layer 2 on both plate surfaces, an organic EL layer 3, and a sealing portion 4. is doing. Here, the resin layer 2 refers to both the front surface resin layer 2a provided on the surface 1A on the organic EL layer 3 side of the glass plate 1 and the back surface resin layer 2b provided on the back surface 1B. In the present invention, it is sufficient that at least the front surface resin layer 2a is provided. However, by further providing the back surface resin layer 2b, it can be made more resistant to impact. The mechanism for increasing the impact resistance is estimated as follows.

  Depending on the manufacturing process, micro cracks called “griffith flow” may exist on the plate surface (front surface 1A, back surface 1B) of the glass plate 1. Usually, such a microcrack has a depth of several nanometers to several hundred nanometers and a length of several tens of nanometers to several hundred micrometers. When a force is applied from the outside and the glass plate 1 is deformed, the glass plate 1 starts to break when the stress is concentrated on the microcracks and the threshold value for the breakage is exceeded. If the stress concentration continues, the destruction finally reaches the entire glass plate 1. By providing the front surface resin layer 2a and the back surface resin layer 2b for the purpose of filling the Griffith flow that causes the destruction with the resin material, the concentrated stress is relieved, and as a result, even if the external stress continues, the destruction is caused. It is possible not to exceed the threshold.

(Glass plate 1)
The glass plate 1 is an ultrathin glass having a thickness of 200 μm or less. By using such a thin glass plate, a flexible substrate having flexibility can be obtained. The thickness of the glass plate 1 is preferably 1 μm or more, more preferably 10 μm or more, and further preferably 30 μm or more. By setting it as such thickness, mechanical strength can be raised more. The thickness of the glass plate 1 is preferably 100 μm or less, more preferably 50 μm or less. By setting it as such thickness, flexibility can be improved more.

  Examples of the material of the glass plate 1 include borosilicate glass, non-alkali glass, low alkali glass, soda lime glass, sol-gel glass, or those obtained by subjecting these glasses to heat treatment or surface treatment. Particularly preferred is alkali-free glass from the viewpoint of avoiding coloring due to impurities in the glass material.

  The refractive index of the glass plate 1 is usually about 1.5, but is not particularly limited, and can be appropriately selected according to the composition and structure of the organic EL element 100. Other characteristics of the glass plate 1 and the manufacturing method of the glass plate 1 can also be selected as appropriate.

(Resin layer 2)
A conventionally known resin material is appropriately used for the resin layer 2. Specifically, polyesters such as polyethylene, polypropylene, polyisobutylene, polyisoprene, polyethylene terephthalate, polystyrene, polyethersulfone, polyarylate, polycarbonate, polyurethane, acrylic resin, polyacrylonitrile, polyvinyl acetal, polyamide, polyamideimide, polyimide, Examples include diacryl phthalate resin, cellulosic resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, epoxy resin, other thermoplastic resins, and copolymers of two or more monomers constituting these resins. It is done. Among them, preferred is polyimide, polyamideimide, or polyamide, which can easily improve the adhesion to the glass plate 1.

  The film thickness of the resin layer 2 is usually 0.1 μm or more, preferably 1 μm or more, more preferably 3 μm or more. By making the film thickness of the resin layer 2 equal to or more than the above lower limit, the mechanical strength of the flexible substrate 10 can be increased. Moreover, the film thickness of the resin layer 2 is 50 micrometers or less normally, Preferably it is 20 micrometers or less, More preferably, it is 10 micrometers or less. By setting the film thickness of the resin layer 2 to the upper limit or less, the impurity gas generated from the resin layer 2 can be reduced, and the warp of the flexible substrate 10 due to internal stress can be reduced. Further, the film thickness of the resin layer 2 may be appropriately adjusted according to the thickness of the glass plate 1. For example, the thickness of the glass plate 1 is adjusted to 1/100 to 1 / 0.1, for example, 1/10.

  The film thickness of the front surface resin layer 2a and the back surface resin layer 2b may be the same or different. In the case of being the same, the manufacturing process can be simplified by forming the front surface resin layer 2a and the back surface resin layer 2b simultaneously.

If the influence of the impurity gas generated from the front surface resin layer 2a cannot be ignored, the strength of the entire flexible substrate can be increased by reducing the thickness of the front surface resin layer 2a as much as possible and increasing the thickness of the back surface resin layer 2b accordingly. Is preferably maintained.
In this case, for example, the thickness of the back surface resin layer 2b is preferably about 1.1 to 10 times the thickness of the surface resin layer 2a where the influence of the impurity gas can be ignored.

  Moreover, since the organic EL layer 3 and the sealing part 4 are formed on the surface resin layer 2a side, the balance of internal stress may be deteriorated if the film thicknesses of the surface resin layer 2a and the back surface resin layer 2b are made equal. . Accordingly, when the flexible substrate 10 is warped, it is preferable to suppress the warpage by making the thickness of the back surface resin layer 2b smaller than the thickness of the surface resin layer 2a.

  The refractive index of the resin layer 2 is not necessarily required to match the refractive index of the glass plate 1, and the lower limit is usually 1.2 or more, more preferably 1.3 or more, still more preferably 1.4 or more, and the upper limit is usually It is 2.5 or less, preferably 2.2 or less, and more preferably 1.9 or less.

Although the resin which comprises the surface resin layer 2a and the back surface resin layer 2b may use the resin which has a similar refractive index, both refractive indexes may differ.
When the refractive indexes of the resins constituting the front surface resin layer 2a and the back surface resin layer 2b are the same or similar, the manufacturing process can be simplified and the member cost can be reduced.
In the case where the refractive indexes of the resins constituting the front surface resin layer 2a and the back surface resin layer 2b are different from each other, an appropriate refraction is made in consideration of the refractive index of the glass plate 1 and the refractive index of the material constituting the organic EL element 100. By selecting the rate difference, the light extraction efficiency of the organic EL element 100 can be increased.

The birefringence of the resin constituting the resin layer 2 (the absolute value of the difference between the refractive index no for ordinary light and the refractive index ne for extraordinary light) is preferably as small as possible, but usually the birefringence at 550 nm is 0.2 or less. , Preferably 0.02 or less, more preferably 0.002 or less.
Instead of birefringence, retardation (phase difference: birefringence × layer thickness) may be used. In this case as well, the smaller the same, the better, but usually the retardation when the thickness of the surface resin layer 2a and / or the back resin layer 2b is 1.0 μm is 200 nm or less, preferably 20 nm or less, more preferably 2 nm or less. is there.

For the front resin layer 2a and the back resin layer 2b, resins having the same or similar birefringence may be used, but the birefringence of the two may be different.
When the birefringence of both is the same or comparable, a manufacturing process can be simplified and member cost can be reduced.
If the birefringence of the two is different, the surface resin layer 2a, by selecting an appropriate birefringence in consideration of the refractive index of the glass plate 1 and the refractive index of the material constituting the organic EL element 100, To obtain an effect that light emitted from the organic EL layer 3 is decomposed into ordinary light / abnormal light and propagates in a waveguide on one of the back surface resin layers 2b, or increases the efficiency of the organic EL element 100. Is possible.

The water permeability of the resin constituting the resin layer 2 is preferably as small as possible in terms of durability, but is usually 500 g / m ² / day or less, preferably 200 g / m ^{2 as} measured by an isobaric method at 40 ° C. / Day or less, more preferably 100 g / m ² / day or less.
Here, the isobaric method for measuring water permeability is a method defined by JIS-K7126-2, ASTM-D3985, ISO-14633-2, etc. as a coulometric method, according to JIS-K7126-2. For example, “Principle: The test piece is mounted in a state of hermetically sealing between the two chambers of the gas permeation cell (see Annex A FIG. 1 and Annex B FIG. 1). Then, the test gas is supplied to chamber A. The pressure in each chamber is equal (atmospheric pressure), but the test gas partial pressure is higher in chamber A, so Permeates and moves into the carrier gas in chamber B. The test gas permeated through the specimen is carried by the carrier gas to the sensor, the type of sensor used depends on the material being tested and Decide on the basis of gas to use. "That there is. For the evaluation of water permeability, usually, water vapor transmission rate (WVTR) is used, N ₂ , He, Ar, etc. are selected as the carrier gas, and the test gas is H ₂ O. Become. There are several types of sensors, and the most sensitive is an atmospheric pressure ionization mass spectrometer (API-MS). However, since the measurement dynamic range is not large, it is not suitable for measuring a test piece having a relatively high transmittance. In that case, a CRDS (Cavity Ring Down Spectroscopy), a MOCON method, or a differential pressure method (such as a DELTA PERM method) may be used.

In order for the sealing part 4 to be described later to be formed so as to cover all of the exposed surface of the organic EL layer 3 formed on the surface resin layer 2a and the surface resin layer 2a, the sealing part 4 of the glass plate 1 is used. In the peripheral portion of the surface 1B on the side, a region where the surface resin layer 2a is not formed is necessary so that the sealing portion 4 can be directly bonded to the glass plate 1.
That is, as shown in FIG. 1, the surface resin layer 2 a is formed at a portion other than the peripheral portion of the surface 1 B of the glass plate 1, and the peripheral portion 4 A of the sealing portion 4 is lateral to the organic EL layer 3 and the surface resin layer 2 a. Extending in contact with the surface 1A of the glass plate 1a.

  On the other hand, the back surface resin layer 2b may be formed on the entire surface of the back surface 1B opposite to the sealing portion 4 forming surface of the glass plate 1 or may be partially formed.

A method for forming the resin layer 2 may be selected as appropriate, and is exemplified below.
A rotating roll or the like is immersed in a liquid (resin solution) in which the resin material constituting the resin layer 2 is dissolved in an appropriate solvent, or in a liquid (melted resin) melted by raising the temperature of the resin material itself, The resin layer 2 can be formed by a method (so-called roll coating method) in which the plate surface of the glass plate 1 is pressed against the surface of the rotating roll or the like. The liquid may contain an appropriate auxiliary agent (for example, a surfactant for controlling the interfacial tension, an antioxidant, a reaction suppression stabilizer, etc.).
By applying the above method to both surfaces of the glass plate 1, the front surface resin layer 2a and the back surface resin layer 2b can be formed. At this time, the thickness of the resin layer 2 can be controlled by appropriately selecting the surface shape, material, hardness and the like of the roll, etc., and dripping and uneven thickness can be minimized.

  As other methods, spin coating, die coating, other printing methods (screen method, gravure method, offset method, gravure offset method, flexo method, etc.), spray coating method, ink jet method, coating by variations of any of the above methods The law etc. can be used. Furthermore, it is also possible to select a method such as transferring from a previously applied or laminated resin on another film or the like.

  If it is these methods, it is possible to provide the area | region in which the resin layer 2 is not formed in the peripheral part of the glass plate 1. FIG.

  Furthermore, it is possible to form the surface resin layer 2a by a method in which a resin is applied to the entire surface of the glass plate 1 and the resin other than the region where the desired surface resin layer 2a is formed is peeled off. In order to deposit the resin on the entire surface of the glass plate 1, the following method can be mentioned in addition to the above-described method.

  The glass plate 1 is dipped in the liquid (resin solution or molten resin), then pulled up from the liquid, and then dried or cured (hereinafter referred to as a dipping method) to cover the entire surface of the glass plate 1 with resin. Can be dressed. At this time, it is possible to control the thickness of the resin layer 2 by appropriately selecting the pulling speed, atmosphere, temperature, etc. that match the drying or curing speed of the resin, and to minimize dripping and uneven thickness.

  As a method for peeling the resin, a mechanical scraping method, a chemical etching method (liquid phase etching method, UV-Ozone method, etc.) and a physical etching method (sand blast method, ion milling method, reactive plasma etching). Law, etc.) can be adopted.

  In order to determine the peeling region, photolithography may be used in the etching method.

  Next, the organic EL layer 3 and the sealing portion 4 described later are formed on the flexible substrate 10 manufactured as described above. Here, in forming the organic EL layer 3 and the sealing portion 4, a carrier substrate may be bonded to the flexible substrate 10 in order to facilitate the conveyance of the flexible substrate 10. By providing the carrier substrate, a conventional organic EL device manufacturing apparatus using a thick glass plate can be used without modification, which is preferable in terms of cost. In this case, the carrier substrate may be peeled after the organic EL element is formed. The material of the carrier substrate is not particularly limited, but it is preferable to use the same type of glass as the glass plate 1 because the coefficients of thermal expansion coincide.

  The carrier substrate and the glass plate 1 may be the same size, but it is preferable from the problem of substrate handling that the glass plate 1 is slightly smaller than the carrier substrate. For example, when the carrier substrate has a thickness of 370 mm × 470 mm × 0.7 mm, the size of the glass plate 1 is preferably 360 mm × 460 mm. The problem with substrate handling is that the glass plate 1 may break when an impact is applied to the end of the substrate during transport, or when an impact is applied to the end of the substrate by using a butting method for positioning. It is.

About the method of bonding this carrier substrate, and the method of peeling, it can paste or peel according to a conventional method. In particular, as a peeling method, a laser peeling method, a water or solvent infiltration method, a mechanical peeling method, or the like can be adopted.
The bonding of the carrier substrate may be before or after the formation of the resin layer 2. Further, after the carrier substrate is peeled, the back surface resin layer 2b may be formed on the peeled surface.

(Organic EL layer 3)
The organic EL layer 3 according to the present embodiment is formed on the surface resin layer 2a of the flexible substrate 10 and includes at least a light emitting portion. Hereinafter, the organic EL layer 3 of this example will be described in detail with reference to FIG. 2 showing a cross-sectional view of the organic EL layer 3.

  The light emitting unit 11 is a part responsible for light emission of the organic EL element 100. In the organic EL element 100 shown in FIG. 2, the light emitting unit 11 includes a first electrode 20, an organic layer 30 having an organic light emitting layer 33 made of at least an organic light emitting material, and a second electrode 21 on the flexible substrate 10. Are stacked in this order.

  The light emitting unit 11 can change the emission color by arranging organic EL elements having red, green, and blue organic light emitting layers in parallel. In order to obtain white light emission, an organic EL element in which yellow and blue organic light-emitting layers or red, green and blue organic light-emitting layers are stacked can also be used. The yellow organic light emitting layer can also be obtained by mixing red and green materials.

  In the present embodiment, the light emitted from the light emitting unit 11 is configured to be emitted from the flexible substrate 10.

  Although not shown in FIG. 2, an insulating partition layer for holding a functional material solution applied when the organic layer 30 is produced by a wet process is formed on the first electrode 20. Later, the organic layer 30 and the second electrode 21 may be laminated.

<Organic layer>
The organic layer 30 may be a single layer of an organic light emitting layer or a multilayer structure of an organic light emitting layer and a charge transport layer. Specifically, the configurations as shown in the following (1) to (9) However, the configuration of the organic layer 30 according to the present invention is not limited to these.
(1) Organic light emitting layer (2) Hole transport layer / organic light emitting layer (3) Organic light emitting layer / electron transport layer (4) Hole transport layer / organic light emitting layer / electron transport layer (5) Hole injection layer / Hole transport layer / organic light emitting layer / electron transport layer (6) Hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer (7) Hole injection layer / hole transport layer / organic Light emitting layer / hole blocking layer / electron transport layer (8) Hole injection layer / hole transport layer / organic light emitting layer / hole blocking layer / electron transport layer / electron injection layer (9) Hole injection layer / hole Transport layer / electron prevention layer / organic light emitting layer / hole blocking layer / electron transport layer / electron injection layer

In addition, each of the organic light emitting layer, the hole injection layer, the hole transport layer, the hole blocking layer, the electron blocking layer, the electron transport layer, and the electron injection layer may have a single layer structure or a multilayer structure.
In FIG. 2, the configuration (8) is adopted, and the hole injection layer 31, the hole transport layer 32, the organic light emitting layer 33, and the hole blocking layer 34 are directed from the first electrode 20 to the second electrode 21. The electron transport layer 35 and the electron injection layer 36 are laminated in this order.

  The organic light emitting layer 33 may be composed of only an organic light emitting material exemplified below, or may be composed of a combination of a light emitting dopant material and a host material, and optionally a hole transport material, an electron transport material. , Additives (donors, acceptors, etc.) may be included, and these materials may be dispersed in a polymer material (binding resin) or an inorganic material. From the viewpoint of luminous efficiency and lifetime, a material in which a luminescent dopant material is dispersed in a host material is preferable.

  As the organic light emitting material, a known light emitting material for organic EL can be used. Such light-emitting materials are classified into low-molecular light-emitting materials, polymer light-emitting materials, and the like. Specific examples of these compounds are given below, but the present invention is not limited to these materials. Further, the light emitting material may be classified into a fluorescent material, a phosphorescent material and the like. From the viewpoint of reducing power consumption, it is preferable to use a phosphorescent material with high luminous efficiency, and from the viewpoint of device lifetime, it is preferable to use a fluorescent material with high durability, and a fluorescent material and a phosphorescent material are used in combination as appropriate. Also good.

  Here, specific compounds as light emitting materials for organic EL are exemplified below, but the present invention is not limited to these materials.

Examples of the low-molecular organic light-emitting material include aromatic dimethylidene compounds such as 4,4′-bis (2,2′-diphenylvinyl) -biphenyl (DPVBi); 5-methyl-2- [2- [4- ( Oxazole compounds such as 5-methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazole; 3- (4-biphenylyl) -4-phenyl-5-t-butylphenyl-1,2,4-triazole ( Triazole derivatives such as TAZ); styrylbenzene compounds such as 1,4-bis (2-methylstyryl) benzene; fluorescent organics such as thiopyrazine dioxide derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, diphenoquinone derivatives, fluorenone derivatives, etc. Materials; and azomethine zinc complex, tris (8-hydroxyquinolinato Fluorescence emitting organic metal complex such as aluminum complex (Alq ₃₎ and the like.

Examples of the polymer light emitting material include poly (2-decyloxy-1,4-phenylene) (DO-PPP), poly [2,5-bis- [2- (N, N, N-triethylammonium) ethoxy]. -1,4-phenyl-alt-1,4-phenylene] dibromide (PPP-NEt ³⁺ ), poly [2- (2′-ethylhexyloxy) -5-methoxy-1,4-phenylenevinylene] (MEH- PPV), poly [5-methoxy- (2-propanoxysulfonide) -1,4-phenylenevinylene] (MPS-PPV), poly [2,5-bis- (hexyloxy) -1,4-phenylene Polyphenylene vinylene derivatives such as-(1-cyanovinylene)] (CN-PPV); polyspiro derivatives such as poly (9,9-dioctylfluorene) (PDAF) It is.

As the light-emitting dopant material arbitrarily contained in the organic light-emitting layer 33, a known dopant material for organic EL can be used. Examples of such dopant materials include styryl derivatives, perylene derivatives, iridium complexes, coumarin derivatives, lumogen F red, dicyanomethylenepyran, phenoxazone, and porphyrin derivatives, and bis [(4,6-difluorophenyl). -Pyridinato-N, C2 ′] picolinate iridium (III) (FIrpic), tris (2-phenylpyridyl) iridium (III) (Ir (ppy) ₃ ), tris (1-phenylisoquinoline) iridium (III) (Ir And phosphorescent organic metal complexes such as (piq) ₃ ).

  Moreover, as a host material when using a dopant material, the well-known host material for organic EL can be used. Examples of such a host material include the above-described low molecular weight light emitting materials, polymer light emitting materials, 4,4′-bis (carbazole) biphenyl, 9,9-di (4-dicarbazole-benzyl) fluorene (CPF), and the like. And carbazole derivatives.

  In addition, the charge injection transport layer is a charge injection layer (hole injection layer 31, electron injection) for the purpose of more efficiently injecting charge (holes, electrons) from the electrode and transporting (injection) to the organic light emitting layer. Layer 36) and charge transport layer (hole transport layer 32, electron transport layer 35), and may be composed only of the charge injection transport material exemplified below. Further, an additive (donor, acceptor, etc.) may optionally be included, and a structure in which these materials are dispersed in a polymer material (binding resin) or an inorganic material may be employed.

  As the charge injecting and transporting material, known charge transporting materials for organic EL and organic photoconductors can be used. Such charge injecting and transporting materials are classified into hole injecting and transporting materials and electron injecting and transporting materials. Specific examples of these materials are given below, but the present invention is not limited to these materials.

Examples of the hole injection / hole transport material include oxides such as vanadium oxide (V ₂ O ₅ ) and molybdenum oxide (MoO ₂ ); inorganic p-type semiconductor materials, porphyrin compounds, N, N′-bis (3 -Methylphenyl) -N, N′-bis (phenyl) -benzidine (TPD), N, N′-di (naphthalen-1-yl) -N, N′-diphenyl-benzidine (NPD), etc. Tertiary amine compounds; low molecular weight materials such as hydrazone compounds, quinacridone compounds, styrylamine compounds; polyaniline (PANI), polyaniline-camphor sulfonic acid (PANI-CSA), 3,4-polyethylenedioxythiophene / polystyrene sulfonate ( PEDOT / PSS), poly (triphenylamine) derivative (Poly-TPD), polyvinylcarbazole (PVC) z), polymer materials such as poly (p-phenylene vinylene) (PPV), poly (p-naphthalene vinylene) (PNV), and the like.

  In addition, as a material used for the hole injection layer, the highest occupied molecular orbital (HOMO) is better than the hole injection and transport material used for the hole transport layer in terms of more efficient injection and transport of holes from the anode. It is preferable to use a material having a low energy level. As the hole transport layer, it is preferable to use a material having a higher hole mobility than the hole injection transport material used for the hole injection layer.

  In order to further improve the hole injection / transport property, the hole injection / transport material is preferably doped with an acceptor. As the acceptor, a known acceptor material for organic EL can be used. Although these specific compounds are illustrated below, this invention is not limited to these materials.

As acceptor materials, inorganic materials such as Au, Pt, W, Ir, POCl ₃ , AsF ₆ , Cl, Br, I, vanadium oxide (V ₂ O ₅ ), molybdenum oxide (MoO ₂ ); TCNQ (7, 7 , 8,8, -tetracyanoquinodimethane), TCNQF ₄ (tetrafluorotetracyanoquinodimethane), TCNE (tetracyanoethylene), HCNB (hexacyanobutadiene), DDQ (dicyclodicyanobenzoquinone) and the like. Compounds having nitro groups such as TNF (trinitrofluorenone) and DNF (dinitrofluorenone); organic materials such as fluoranyl, chloranil and bromanyl. Among these, compounds having a cyano group such as TCNQ, TCNQF ₄ , TCNE, HCNB, DDQ and the like are more preferable because they can increase the carrier concentration more effectively.

Examples of electron injection / electron transport materials include inorganic materials that are n-type semiconductors, oxadiazole derivatives, triazole derivatives, thiopyrazine dioxide derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, diphenoquinone derivatives, fluorenone derivatives, benzodifuran derivatives. And low molecular weight materials such as poly (oxadiazole) (Poly-OXZ) and polystyrene derivatives (PSS). In particular, examples of the electron injection material include fluorides such as lithium fluoride (LiF) and barium fluoride (BaF ₂ ), and oxides such as lithium oxide (Li ₂ O).

  The material used as the electron injection layer 36 is more efficient in injecting and transporting electrons from the cathode. The energy level of the lowest unoccupied molecular orbital (LUMO) than the electron and injection transport material used for the electron transport layer 35 is used. Preferably, a material having a higher electron mobility than the electron / injection transport material used for the electron injection layer 36 is preferably used.

In order to further improve the electron injection / transport property, it is preferable to dope the electron injection / transport material with a donor. As the donor, a known donor material for organic EL can be used. Although these specific compounds are illustrated below, this invention is not limited to these materials.
Donor materials include inorganic materials such as alkali metals, alkaline earth metals, rare earth elements, Al, Ag, Cu, and In; anilines, phenylenediamines, benzidines (N, N, N ′, N′-tetraphenyl) Benzidine, N, N′-bis- (3-methylphenyl) -N, N′-bis- (phenyl) -benzidine, N, N′-di (naphthalen-1-yl) -N, N′-diphenyl- Benzidine, etc.), triphenylamines (triphenylamine, 4,4′4 ″ -tris (N, N-diphenyl-amino) -triphenylamine, 4,4′4 ″ -tris (N-3- Methylphenyl-N-phenyl-amino) -triphenylamine, 4,4′4 ″ -tris (N- (1-naphthyl) -N-phenyl-amino) -triphenylamine, etc.), triphenyldiamines ( N, N'- Compounds having an aromatic tertiary amine such as di- (4-methyl-phenyl) -N, N′-diphenyl-1,4-phenylenediamine), phenanthrene, pyrene, perylene, anthracene, tetracene, pentacene, etc. There are organic materials such as condensed polycyclic compounds (wherein the condensed polycyclic compounds may have a substituent), TTFs (tetrathiafulvalene), dibenzofuran, phenothiazine, and carbazole. Among these, a compound having an aromatic tertiary amine as a skeleton, a condensed polycyclic compound, and an alkali metal are more preferable because the carrier concentration can be increased more effectively.

  The physical properties required for the material constituting the hole blocking layer 34 include a high electron mobility, a low hole mobility, a large energy gap (difference between HOMO and LUMO), and an excited triplet energy level (T1). ) Is high. Examples of the material of the hole blocking layer 34 satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum, bis (2-methyl-8-quinolinolato) (triphenylsilanolato) aluminum. Mixed ligand complexes such as, metal complexes such as bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolinolato) aluminum binuclear metal complexes, distyrylbiphenyl derivatives, etc. Of styryl compounds (JP-A-11-242996), triazole derivatives such as 3- (4-biphenylyl) -4-phenyl-5 (4-tert-butylphenyl) -1,2,4-triazole 7-41759), phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297), etc. It is below. Further, a compound having at least one pyridine ring substituted at positions 2, 4, and 6 described in International Publication No. 2005/022962 is also preferable as a material for the hole blocking layer 34.

The organic layer 30 composed of the hole injection layer 31, the hole transport layer 32, the organic light emitting layer 33, the hole blocking layer 34, the electron transport layer 35, and the electron injection layer 36 is formed by resistance heating the above materials. It is formed using a known dry process such as a vapor deposition method, an electron beam (EB) vapor deposition method, a molecular beam epitaxy (MBE) method, a sputtering method, and an organic vapor deposition (OVPD) method.
In general, an evaporation method is often used for forming an organic layer.

The organic layer 30 is also formed by using a composition for forming an organic layer (coating liquid) in which the above materials are dissolved and dispersed in a solvent, a spin coating method, a dipping method, a doctor blade method, a discharge coating method, a spray coating method, etc. It may be formed by using a known wet process such as a coating method, an ink jet method, a relief printing method, an intaglio printing method, a screen printing method, a microgravure coating method, or the like.
When the organic layer 30 is formed by a wet process, additives for adjusting the physical properties of the composition such as a leveling agent and a viscosity modifier may be blended in the composition for forming each organic layer.

The organic layer 30 can also be formed by a transfer method such as a laser transfer method or a thermal transfer method.
The transfer member used for transfer includes a transfer layer that is sequentially formed on a substrate and is heated and melted by the action of the photothermal conversion layer, the intermediate layer, and the photothermal conversion layer, and transferred to the image receiving element in a pattern. ing. The transfer layer contains a material constituting the organic layer 30.

  The film thickness of the organic layer 30 is usually about 1 to 1000 nm, but preferably 10 to 500 nm. If the film thickness is less than the above lower limit, it is difficult to obtain physical properties (charge injection characteristics, transport characteristics, confinement characteristics) that are originally required. In addition, pixel defects due to foreign matters such as dust may occur. If the film thickness exceeds the above upper limit, the driving voltage increases due to the resistance component of the organic layer 30, leading to an increase in power consumption.

(First electrode and second electrode)
The first electrode 20 and the second electrode 21 shown in FIG. 2 function as a pair as an anode or a cathode of the organic EL element. That is, when the first electrode 20 is an anode, the second electrode 21 is a cathode, and when the first electrode 20 is a cathode, the second electrode 21 is an anode.

  Hereinafter, specific compounds that can be used as the first electrode 20 and the second electrode 21 and formation methods thereof will be exemplified, but the present invention is not limited to these materials and formation methods.

As an electrode material for forming the first electrode 20 and the second electrode 21, a known electrode material can be used.
As an electrode material for forming the anode, gold (Au), platinum (Pt) and nickel (work functions are 4.5 eV or more from the viewpoint of more efficiently injecting holes into the organic light emitting layer 33 in FIG. A metal such as Ni), an oxide (ITO) made of indium (In) and tin (Sn), an oxide of Sn (Sn) (SnO ₂ ), and an oxide made of indium (In) and zinc (Zn) ( Transparent conductive materials such as IZO).

  Further, as an electrode material for forming the cathode, lithium (Li), calcium (Ca), cerium having a work function of 4.5 eV or less from the viewpoint of more efficiently injecting electrons into the organic light emitting layer 33 in FIG. Examples thereof include metals such as (Ce), barium (Ba), and aluminum (Al), or alloys such as Mg: Ag alloy and Li: Al alloy containing these metals.

  The first electrode 20 and the second electrode 21 can be formed by a known method such as an EB vapor deposition method, a sputtering method, an ion plating method, or a resistance heating vapor deposition method using the above materials. It is not limited to the forming method. Further, if necessary, the formed electrode can be patterned by a photolithography method or a laser peeling method, and a patterned electrode can be directly formed by combining with a shadow mask.

  The film thickness of the electrode is preferably 50 nm or more. When the film thickness is less than 50 nm, the wiring resistance is increased, which may increase the drive voltage.

In order to extract light emitted from the organic light emitting layer 33 from the flexible substrate 10 side, the first electrode 20 is preferably a transparent electrode or a semitransparent electrode. As the transparent electrode material, ITO and IZO are particularly preferable.
The film thickness of the transparent electrode is preferably 50 to 500 nm, and more preferably 100 to 300 nm. When the film thickness is less than 50 nm, the wiring resistance is increased, which may increase the drive voltage. On the other hand, when the film thickness exceeds 500 nm, the light transmittance is lowered, and therefore the luminance may be lowered.

(Auxiliary electrode)
As a method of apparently lowering the resistance of the transparent electrode, the auxiliary electrode may be formed so as to be in contact with the transparent electrode. Usually, it is often formed on the anode (in rare cases, it may be below the anode), and usually an insulating film is formed so as to cover the auxiliary electrode in plan view (rarely an insulating film is formed) May not be.) The auxiliary electrode is effective in suppressing the voltage drop due to the resistance of the transparent electrode. However, since the charge is not injected or the emitted light is blocked, the auxiliary electrode is not a light emitting region but a “non-light emitting region”. . The ratio of the area of the light emitting region to the total area of the light emitting formation region is called the aperture ratio. When the aperture ratio is higher, the luminance is constant (= luminance x emission area) or the luminous flux (= radiance emission). (Integral value by angle) becomes high. Here, the light emission formation region is a region where an anode, an organic layer including a light emitting layer, and a cathode are formed to overlap each other in a plan view, and includes a region of an auxiliary electrode and an insulating film covering the auxiliary electrode. is there.

(Sealing part 4)
As shown in FIG. 1, the organic EL element 100 of the present invention is provided with a sealing portion 4 in order to protect the organic EL layer 3 from an impurity gas such as moisture and oxygen from the outside.

  Specifically, the sealing portion 4 is formed directly on the organic EL layer 3 or through an inorganic film or a resin film such as a metal oxide such as silicon or aluminum, a nitride, or an oxynitride. It is formed by providing a sealing portion made of a sealing substrate made of glass, resin, metal, or the like, or a sealing film.

  It is preferable that the sealing part 4 takes the structure which sticks the thermoplastic resin film which has an adhesion function on the organic EL layer 3, and covers the outer side with Al foil. With such a structure, it is possible to achieve both impact resistance and barrier properties against moisture and impurity gases. Furthermore, it is also preferable to arrange a desiccant between the thermoplastic resin film and the Al foil. Thereby, the water | moisture content which penetrate | invaded in the sealing structure can be prevented from reaching the organic EL layer 3, and the storage stability of the organic EL element 100 can be improved.

  The sealing substrate and the sealing film can be formed by a known sealing material and sealing method. In order to maintain the flexibility as the organic EL element, it is preferable that the sealing portion also has a certain degree of flexibility.

Specifically, it is preferable to form a sealing film by applying or bonding a resin on the second electrode 21 using a spin coat method, ODF, or a laminate method. After forming an inorganic film made of oxide, nitride, or oxynitride such as SiO, SiON, SiN, etc. on the second electrode 21 by plasma CVD, ion plating, ion beam, sputtering, etc. Furthermore, it is also preferable to form a sealing film by applying or bonding a resin using a spin coat method, ODF, or a laminate method.

  The sealing portion 4 can prevent the entry of oxygen and moisture from the outside into the organic EL layer 3, and the life of the organic EL element 100 is improved.

Here, the peripheral portion 4 </ b> A of the sealing portion 4 completely covers the organic EL layer 3 so that the organic EL layer 3 is not exposed to the external atmosphere of the organic EL element 100, and a glass plate is formed around the organic EL layer 3. 1 is bonded. In the present invention, the sealing portion 4 also includes the surface resin layer 2a so that the surface or side surface of the surface resin layer 2a is not exposed to the external atmosphere of the organic EL element 100. And is adhered to the glass plate 1 at the periphery of the surface resin layer 2a.
By doing in this way, it can prevent effectively that impurity gas, such as a water | moisture content and oxygen in external atmosphere, penetrate | invade into the organic EL layer 3 through the surface resin layer 2a.

  Moreover, it is also preferable to use the flexible substrate 10 of this invention as a sealing substrate of the sealing part 4.

(Other configurations)
In this invention, it is also preferable to have the end surface resin layer which covers at least one part of the end surface of the glass plate 1. FIG.
FIG. 3 shows a schematic cross-sectional view of an organic EL element 100A using a flexible substrate according to an example in which the end face resin layer 5 is provided. The organic EL element 100A shown in FIG. 3 is different from the organic EL element 100 shown in FIG. 1 only in that the end face resin layer 5 is formed on the end face 1C of the glass plate 1, and the other configuration is the same. . In FIG. 3, members having the same functions as those shown in FIG.

  Here, the surface on which the plate-like glass plate 1 is formed is divided into a side surface portion parallel to the thickness direction of the glass plate 1 and a plane portion perpendicular to the thickness direction, that is, the plate surfaces of the glass plate 1 (front surface 1A and back surface 1B). When it divides | segments into, the end surface 1C of the glass plate 1 in this invention points out the whole side surface part. In the present invention, by covering at least a part of the end face 1C of the glass plate 1 with the end face resin layer 5, it becomes more difficult to be damaged by an external impact. Here, in order to reliably cover the end face 1C with the end face resin layer 5, it is preferable to extend the end face resin layer 5 not only to the end face 1C but also to a part near the end face 1C. Moreover, it is preferable that the end face 1C of the glass plate 1 is entirely covered with the end face resin layer 5 because the impact resistance is further improved. By forming such an end face resin layer 5, the mechanism of higher impact resistance is estimated as follows.

  On the end surface 1C of the glass plate 1 as it is cut, a large number of fine cracks called microcracks are usually generated. Usually, such a microcrack has a depth of several nanometers to several hundred nanometers and a length of several tens of nanometers to several tens of micrometers. When a force is applied from the outside and the glass plate 1 is deformed, the stress concentrates on the microcracks, so that the glass plate 1 starts to break by exceeding the threshold value for the breakage. If the stress concentration continues, the destruction finally reaches the entire glass plate 1. By filling the microcracks that cause the destruction with the end face resin layer 5, the stress concentration is relaxed, and as a result, even if external stress continues, the threshold value for the destruction can be prevented from being exceeded.

  The end face 1C of the glass plate 1A only needs to be at least partially covered with the end resin layer 5, but the fact that the entire end face 1C is covered with the end face resin layer 5 makes the impact resistance higher. preferable.

  The resin material and the forming method used for the end face resin layer 5 are the same as those of the resin layer 2 described above. Although the resin material of the resin layer 2 and the end surface resin layer 5 is preferably the same in terms of cost, they may be different. Moreover, it is preferable that the back surface resin layer 2b and the end surface resin layer 5 are integrally formed in that the impact resistance can be further improved and the manufacturing cost can be reduced.

  The end surface resin layer 5 is preferably formed so as to cover not only the end surface 1C of the glass plate 1 but also the edge portions of the front surface 1A and the back surface 1B. The extension width (width w in FIG. 3) of the end surface resin layer 5 to the front surface 1A and the back surface 1B of the glass plate 1 varies depending on the size and thickness of the glass plate 1, but is about 1.0 μm to 50 mm. It is preferable to do. More preferably, it is about 50 micrometers-20 mm, More preferably, it is about 200 micrometers-12 mm.

(Organic EL lighting device)
The organic EL lighting device of the present invention uses the above-described organic EL element of the present invention. There is no restriction | limiting in particular about the model and structure of the organic electroluminescent illuminating device of this invention, It can assemble in accordance with a conventional method using the organic EL element of this invention.

DESCRIPTION OF SYMBOLS 1 Glass plate 2 Resin layer 2a Front surface resin layer 2b Back surface resin layer 3 Organic EL layer 4 Sealing part 5 End surface resin layer 10 Flexible substrate 100,100A Organic EL element 11 Light emitting part 12 Sealing part 20 First electrode 21 Second electrode DESCRIPTION OF SYMBOLS 30 Organic layer 31 Hole injection layer 32 Hole transport layer 33 Organic light emitting layer 34 Hole blocking layer 35 Electron transport layer 36 Electron injection layer

Claims (5)

On a glass plate having a thickness of 200 μm or less,
An organic EL element in which a surface resin layer, an organic EL layer, and a sealing portion are arranged in this order,
The sealing portion is disposed so as to cover all of the exposed surface of the surface resin layer and the organic EL layer,
The peripheral part of this sealing part is provided so that it may extend to the side of this organic EL layer and this surface resin layer, and may be in contact with the surface of the said glass plate directly .   The organic EL element according to claim 1, wherein the organic EL element has a back surface resin layer on a surface of the glass plate opposite to the surface resin layer.   The organic EL element according to claim 2, wherein a film thickness of the back surface resin layer is larger than a film thickness of the front surface resin layer.   The organic EL element according to claim 1, further comprising an end surface resin layer that covers at least a part of an end surface of the glass plate.   The organic electroluminescent illuminating device using the organic electroluminescent element of any one of Claims 1 thru | or 4.

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