JP2016038998A - Organic el element and organic el lighting system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible organic EL element excellent in barrier properties of gas compositions such as moisture and oxygen and also high in mechanical strength, and an organic EL lighting system using the organic EL element.SOLUTION: There is provided an organic EL element including an organic EL layer directly formed on a glass plate with a thickness of 200 μm or less and a sealing portion covering the organic EL layer. In the organic EL element, at least a part of an end surface of the glass plate is covered with a resin material. There is also provided an organic EL lighting system using the organic EL element.SELECTED DRAWING: Figure 1

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 devices have attracted attention as next-generation lighting because of their 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 example, studies have been made to reinforce by pasting resin films on both sides (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 above-described substrate in which a resin film is laminated on ultrathin glass, the organic EL element formed on the resin film has a high glass barrier property, but the resin film has a relatively low barrier property. Impurity gases such as moisture and oxygen tend to enter the sealing region from the portion, and 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 an object of the present invention is to provide a flexible organic EL element that has excellent barrier properties against gas components such as moisture and oxygen and has high mechanical strength. An object is to provide an EL element and an organic EL lighting device using the EL element.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found an organic EL element having an organic EL layer directly formed on a glass plate having a thickness of 200 μm or less and a sealing portion covering the organic EL layer. By forming the glass plate so that at least a part of the end face is covered with a resin material, an organic EL element with high mechanical strength can be realized while maintaining barrier properties against gas components such as moisture and oxygen. We have found out that we can do it and have reached the present invention.
Accordingly, the gist of the present invention is as follows.

(1) An organic EL element having an organic EL layer directly formed on a glass plate having a thickness of 200 μm or less and a sealing portion covering the organic EL layer, wherein at least a part of the end of the glass plate is a resin An organic EL element characterized by being covered with a material.
(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 organic EL layer.
(3) The organic EL device according to (1) or (2), wherein the resin material contains one or more selected from the group consisting of polyimide, polyamideimide, and polyamide.
(4) The resin material includes a copolymer of one or more selected from the group consisting of polyimide, polyamideimide, and polyamide, and another resin (1) to (3) The organic EL device according to any one of the above.
(5) An organic EL lighting device using the organic EL element according to any one of (1) to (4).

  According to the present invention, an organic EL element and an organic EL lighting device with high mechanical strength can be realized while maintaining sufficient flexibility and good barrier properties against gas components such as moisture and oxygen. .

It is typical sectional drawing which shows an example of embodiment of the organic EL element 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.

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 at least the organic EL layer 3 and the sealing portion 4 that covers the organic EL layer 3 on one surface of the glass plate 1 having a thickness of 200 μm or less. have.
Furthermore, at least a part of the end surface 1A of the glass plate 1 is covered with a resin material. Here, the surface on which the glass plate 1 is formed has a side surface portion parallel to the thickness direction of the glass plate 1 and a plane portion perpendicular to the thickness direction (hereinafter referred to as the front surface (or back surface) or the plate surface of the glass plate 1). 1A, the end surface 1A of the glass plate 1 in the present invention refers to the entire side surface portion. The resin material that covers at least a part of the end face 1A is hereinafter referred to as a resin material portion 2a. In the present invention, at least a part of the end surface 1A of the glass plate 1 is covered with the resin material portion 2a, so that it is difficult to be damaged by an external impact. Further, it is preferable that the end face 1A of the glass plate 1 is completely covered with a resin material because the impact resistance is further improved. Here, in order to reliably cover the end surface 1A with the resin material portion 2a, the resin material portion 2a extends not only to the end surface 1A but also to a part of the plate surface (front surface 1B and back surface 1C) in the vicinity of the end surface 1A. Is preferred. The mechanism for increasing the impact resistance is estimated as follows.

  On the end face 1A 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 resin material portion 2a, the stress concentration is relaxed, and as a result, even if the external stress continues, the threshold value for the destruction can be prevented from being exceeded.

  Furthermore, in the present invention, the organic EL layer 3 is formed directly on the glass plate 1. That is, the resin material portion 2a needs not to extend to the region where the organic EL layer 3 is formed on the surface 1B of the glass plate 1. Moreover, it is preferable that the resin material part 2a does not extend into the sealing space formed by the sealing part 4 and the glass plate 1. By doing so, impurity gases such as moisture, oxygen, and low boiling point organic substances intervening the resin material are prevented from entering the sealed space, and these impurity gases adversely affect the organic EL layer 3. Can be eliminated.

  As described above, in the organic EL element 100 shown in FIG. 1, the organic EL layer 3 is formed so as to be in contact with the surface 1 </ b> B of the glass plate 1, and the sealing portion 4 is a surface in contact with the glass plate 1 of the organic EL layer 3. The peripheral edge 4A of the sealing part 4 extends to the side of the organic EL layer 3 so as to be in contact with the surface 1B of the glass plate 1.

  In the present embodiment, the back surface resin layer 2b is further provided on the surface 1C of the glass plate 1 opposite to the organic EL layer forming surface 1B. Providing the back surface resin layer 2b is preferable because the mechanical strength of the glass plate 1 can be further improved. Because there may be a microcrack called “Griffith flow” depending on the manufacturing process on the plate surface of the glass plate 1 as well, as in the case of the resin material 2a described above, the back surface resin layer 2b. This is because stress concentration can be alleviated by providing.

  The resin material constituting the resin material portion 2a and the back surface resin layer 2b may be the same material or different materials, or may be formed integrally. By integrating the resin material portion 2a and the back surface resin layer 2b, the exposed portion of the glass plate 1 is reduced, which is more preferable in terms of mechanical strength.

(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. Other characteristics of the glass plate 1 and the manufacturing method of the glass plate 1 can also be selected as appropriate.

(Resin material portion 2a, back surface resin layer 2b)
Conventionally known resin materials are appropriately used for the resin material portion 2a and the back surface resin layer 2b. 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 these, it is preferable to include polyimide, polyamideimide, or polyamide that easily improves the adhesion to the glass plate 1.

  Further, it is also possible to use a copolymer of at least one of polyimide, polyamideimide, and polyamide and another resin, while maintaining the high heat resistance of polyimide, polyamideimide, or polyamide resin, and other resin. It is preferable to introduce a part of the chemical structure as a copolymer because it is possible to suppress high hygroscopicity (swelling / expansion due to moisture absorption, reduction in mechanical strength, etc.) which is a drawback of the resin group. .

The film thickness of the resin material portion 2a and the back surface resin layer 2b is usually 0.1 μm or more, preferably 1 μm or more, more preferably 3 μm or more, and usually 50 μm or less, preferably 20 μm or less, and more preferably 10 μm or less. Further, the film thicknesses of the resin material portion 2 a and the back surface resin layer 2 b 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.
Here, the film thickness of the resin material portion 2a refers to the film thickness when the end surface 1A of the glass plate 1 is used as a reference, and the film thickness when the surface 1B of the planar portion of the glass plate 1 is used as a reference. The entire resin material portion 2a need not have a uniform film thickness. When the film thickness of the resin material portion 2a is not uniform, the maximum film thickness is preferably in the above range.

  Furthermore, the film thickness of the resin material portion 2a and the back surface resin layer 2b may be the same or different. If they are the same, the manufacturing process can be simplified, and if they are different, it is possible to devise a design that further improves the breaking strength.

  As described above, the resin material portion 2a is preferably formed so as to cover not only the end surface 1A of the glass plate 1 but also the edge portions of the front surface 1B and the back surface 1C. The extension width (width w in FIG. 1) of the resin material portion 2a to the front surface 1B and the back surface 1C 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.

  The refractive index of the resin constituting the resin material portion 2a and the back surface resin layer 2b does not necessarily 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, Preferably, it is 1.4 or more, and the upper limit is usually 2.5 or less, preferably 2.2 or less, more preferably 1.9 or less.

In particular, as the resin of the resin material portion 2a, a resin having the same or similar refractive index as that of the back surface resin layer 2b may be used, but the refractive indexes of the two may be different.
When both refractive indexes are the same, a manufacturing process can be simplified and member cost can be reduced.
When the refractive indexes of the two are different, an effect is obtained such that light emitted from the organic EL layer 3 is guided and propagated to either the resin material portion 2a or the back surface resin layer 2b. The efficiency of the element 100 can be increased.

The birefringence (absolute value of the difference between the refractive index no for ordinary light and the refractive index ne for extraordinary light) of the resin constituting the resin material portion 2a and the back surface resin layer 2b is preferably as small as possible. The refraction 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 it is, the more preferable, but usually the retardation when the thickness of the resin material portion 2a or the back surface resin layer 2b is 1.0 μm is 200 nm or less, preferably 20 nm or less, more preferably 2 nm or less.

In particular, for the resin of the resin material portion 2a, a resin having the same or similar birefringence as that of the back surface resin layer 2b 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 light emitted from the organic EL layer 3 is decomposed into ordinary light or extraordinary light in either the resin material portion 2a or the back surface resin layer 2b and propagates in a guided wave. It is possible to obtain the above effect and to increase the efficiency of the organic EL element 100.

The water permeability of the resin constituting the resin material portion 2a and the back surface resin layer 2b is preferably as small as possible in terms of durability, but is a measured value by an isobaric method at 40 ° C., usually 500 g / m ² / day or less, Preferably, it is 200 g / m < ² > / day or less, More preferably, it is 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 evaluation of water permeability, water vapor transmission rate (WVTR: Water Vapor Transmission Rate) is usually used, and N ₂ , He, Ar, etc. are selected as the carrier gas, and the test gas is H ₂ O. is there. 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.

The method for forming the resin material portion 2a may be selected as appropriate, and is exemplified below.
By a dipping method in which a glass plate is immersed in a liquid (dissolved resin) in which a resin material constituting the resin material portion 2a is dissolved in an appropriate solvent, or a liquid (molten resin) melted by raising the temperature of the resin material itself, A resin material can be applied to the end of the glass plate. The liquid may contain an appropriate auxiliary agent (for example, a surfactant for controlling the interfacial tension, an antioxidant, a reaction suppression stabilizer, etc.).

If the glass plate 1 is rectangular, for example, one of the edges of the glass plate 1 is coated by the dipping method and dried or cured, and then the remaining three edges are successively subjected to the same process through the same process. 2a can be formed. Even if the glass plate 1 has a shape other than a rectangle, only the end of the glass plate 1 is rotated by a dipping method involving rotation around the normal direction of the plane of the glass plate 1 and vertical movement linked to the rotation. A resin material can be deposited.
At this time, it is possible to control the thickness of the resin material portion 2a by appropriately selecting a rotation speed, a rotation pattern, an atmosphere, a temperature, and the like corresponding to the drying or curing speed of the resin, and to minimize wraparound and dripping. .

  As another method, a method (so-called roll coating method) is adopted in which a rotating roll or the like is dipped in the molten resin or molten resin and the end of the glass plate 1 is pressed against the surface of the rotating roll or the like. It is also possible to do. At this time, by appropriately selecting the surface shape, material, hardness, etc. of the roll or the like, it is possible to control the thickness of the resin material portion 2a and to minimize the wraparound and dripping.

  Further, as another method, the glass plate 1 is coated by a coating method described later on both surfaces of the glass plate 1 or transferred from a resin previously coated or laminated on another film or the like. The resin material portion 2a can also be formed by a method in which a resin is applied to the entire surface including the end portion of the resin and the resin other than the portion that contacts the resin material portion 2a is peeled off. Here, when the resin material portion 2a and the back surface resin layer 2b are formed, the resin other than the portions corresponding to the resin material portion 2a and the back surface resin layer 2b may be peeled off.

  As a method of 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, etc.), a method of adding a photosensitizer to the resin, and forming a peeling region in photolithography, etc. can be employed. In order to determine the peeling region, photolithography may be used in the etching method.

  Further, as other methods, a pattern printing method, a method of adding a photosensitizer to the resin to form a resin-free region in photolithography, and a region where the resin is not transferred to the glass plate 1 in the transfer method are transferred before transfer. A region where no resin is present may be provided as a resin material portion 2a by a method in which the resin on the film is formed in advance.

In the process of determining the peeled area and the process replacing it, for example, there is an advantage that an alignment mark can be formed at the same time when alignment is required in a subsequent process.
Furthermore, after applying or laminating the resin on one side of the glass plate 1 over the area of the glass plate 1 as described above, the resin is folded only on the opposite side surface including the end portion. A similar structure can be obtained even if the resin is applied. In this case, the method of depositing the resin only on the peripheral portion including the end portion can be appropriately selected from the methods described above.

  The back surface resin layer 2b can be formed before or after the resin material portion 2a is formed. Or it can form simultaneously with the resin material part 2a. The formation method includes spin coating, die coating, and other printing methods (screen methods) using a liquid in which the resin material constituting the back surface resin layer 2b is dissolved in an appropriate solvent or the temperature of the resin material itself is increased. , A gravure method, an offset method, a gravure offset method, a flexo method, etc.), a spray coating method, an ink jet method, a coating method by a variation of any of the above methods, or the like 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.

  Further, as described in the method of forming the resin material portion 2a, a region where no resin is present may be provided as a back surface resin layer 2b by a photolithography method, a pattern printing method, or the like. By doing so, there is an advantage that, for example, an alignment mark can be formed at the same time when alignment is required in a later process.

  As described above, the organic EL layer 3 and the sealing portion 4 described later are formed on the flexible substrate formed by forming the resin material portion 2a on the glass plate 1, preferably the resin material portion 2a and the back surface resin layer 2b. Is done. Here, when forming the organic EL layer 3 and the sealing part 4, in order to make conveyance of a flexible substrate easy, the carrier substrate may be bonded by the flexible substrate. 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 is 370 mm × 470 mm × 0.7 mm thick, the size of the glass plate 1 is 360 mm × 460 mm.
It is preferable that 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 with the glass plate 1, and the method of peeling the glass plate 1 from a carrier substrate, it can bond or peel according to a conventional method. In particular, as a peeling method, a laser peeling method, a water or solvent permeation method, a mechanical peeling method, or the like can be employed.
The bonding of the carrier substrate may be before or after the formation of the resin material portion 2a and the back surface resin layer 2b. 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 glass plate 1 and includes at least a light emitting unit.
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. In FIG. 2, reference numeral 10 denotes a flexible substrate in which a glass material 1 is formed with a resin material portion 2a, preferably a resin material portion 2a and a back resin layer 2b. When the flexible substrate 10 has the back surface resin layer 2b, the organic EL layer 3 is formed on the glass plate surface opposite to the back surface resin layer 2b.

  The light emitting unit 11 is a part responsible for light emission of the organic EL element 100 according to the present embodiment. The light emitting unit 11 has a configuration in which a first electrode 20, an organic layer 30 having an organic light emitting layer made of at least an organic light emitting material, and a second electrode 21 are laminated on the flexible substrate 10 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. Further, 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 laminated can also be used. The yellow organic light emitting layer can also be obtained by mixing red and green materials.

  In the present embodiment, since the light emitted from the light emitting portion 11 has a bottom emission structure configured to be emitted from the flexible substrate 10 side, the back surface resin layer 2b preferably has a certain degree of translucency. In the present invention, a top emission structure in which light is emitted from the sealing portion 4 side may be used. In this case, it is preferable that the sealing portion 4 has a certain degree of translucency. If it is a top emission structure, the back surface resin layer 2b may be opaque.

  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) Aluminum complex (Alq ₃₎ fluorescence emitting organic metal complex or the like, 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 of only 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 compounds 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 for 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 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 the formation method thereof will be exemplified, but the present invention is not limited to these materials and the formation method.

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 × light emitting area) or 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.

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

  It is preferable that the sealing part 3 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 into the organic EL layer 3 from the outside, and the life of the organic EL element 100 is improved.

  Here, the peripheral portion 4A of the sealing portion 4 may be partially in contact with the resin material portion 2a, but the organic EL layer 3 is in the sealed space formed by the sealing portion 4 and the glass plate 1 It is preferable that the peripheral edge portion 4A of the sealing portion 4 is formed so as to be in direct contact with the surface 1B of the glass plate 1. If the sealing part 4 is formed on the glass plate 1 with the resin material part 2a interposed, impurity gases such as moisture and oxygen may enter the sealing space through the resin material part 2a. is there.

(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 2a Resin material part 2b Back surface resin layer 3 Organic EL layer 4 Sealing part 100 Organic EL element 10 Flexible substrate 11 Light emission part 20 First electrode 21 Second electrode 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)

  An organic EL element having an organic EL layer directly formed on a glass plate having a thickness of 200 μm or less and a sealing portion covering the organic EL layer, wherein at least a part of an end surface of the glass plate is covered with a resin material. An organic EL element characterized by comprising:   The organic EL element according to claim 1, further comprising a back surface resin layer on the surface of the glass plate and opposite to the organic EL layer.   The organic EL device according to claim 1, wherein the resin material contains one or more selected from the group consisting of polyimide, polyamideimide, and polyamide.   The said resin material contains the copolymer of 1 type (s) or 2 or more types chosen from the group which consists of a polyimide, a polyamideimide, and polyamide, and another resin, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The organic EL device according to Item.   The organic electroluminescent illuminating device using the organic electroluminescent element of any one of Claims 1 thru | or 4.

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