JP2000068046A - Electroluminescence device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a sealed container structure and an electrode take-out part, having stability against moisture in the air. SOLUTION: A back panel 3 is overlapped with an electroluminescent panel 2 provided with an organic light-emitting diode 1, and the periphery of them is sealed with a sealant 4 to form a sealed container. The sealant 4 is composed of a hydrophobic polymer composition after sealing and curing, and the shape of the sealant 4 in the sealed part is formed so as to satisfy the formula (sealing depth L/sealing thickness D) >20. The end of a thin-film negative electrode exposed from the sealed container is connected to the end of a lead wire, and they coated with a corrosion-resistant adhesive. Thus, the electroluminescence device, having the sealed container structure and an electrode take-out part having large stability against moisture in the air, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electroluminescent device used for a light emitting display, a light emitting diode, a surface emitting light source, and the like.

[0002]

2. Description of the Related Art Conventionally, a display panel made of an electroluminescent device (EL) has high visibility, excellent display capability,
It has the feature that high-speed response is also possible.

In recent years, reports have been made on injection-type electroluminescent devices using organic compounds as constituent materials (for example, see the related article Applied Physics Letters, No. 51).
Vol. 913, 1987 (Applied Physics Letters, 51, 1)
987, P.913.)).

In this report, C.I. W. Tang et al. Disclose an injection type electroluminescent device having a structure in which an organic light emitting layer and a charge transport layer are stacked. Here, a tris (8-quinolinol) aluminum complex (hereinafter abbreviated as Alq) having both high luminous efficiency and electron transport is used as a luminescent material.
An excellent injection type electroluminescent device has been obtained.

Also, Journal of Applied Physics, Vol. 65, p. 3610, 1989 (Journal
f Applied Physics, 65, 1989, p. 3610) states that Alq forming an organic light emitting layer has a coumarin derivative or DCM1 (Eastm).
An element doped with a fluorescent dye, such as an anionic chemical, is reported to change the emission color by appropriate selection of the dye, and it is disclosed that the luminous efficiency is increased as compared with the undoped one.

[0006] Following this research, many research and development have been carried out, and as a new functional material, a fluorescent chelating metal complex, an electron transporting organic molecule and a hole transporting organic molecule have been developed and studied.

As an electron injection electrode (thin film cathode) of an injection type electroluminescent device, Mg—A having a small work function is used.
g, Ca, Ag, Li-Al, Li-Ag, and Al
Metal thin film electrodes are disclosed in, for example, JP-A-60-16577.
No. 1, JP-A-5-121172, etc., in which electrodes are formed by vapor deposition.

In the above-described electroluminescent device, the materials such as the thin-film cathode and the hole transport layer are degraded due to moisture absorption of the device and ion conduction is caused at the same time. The device is sealed in a container to extend the life of the device.

[0009]

However, the performance of the sealing structure is not sufficient, and there is a problem that a black spot (non-light emitting portion) grows and a driving voltage increases.

Accordingly, a first object of the present invention is to improve a sealant constituting a sealed container. A second object is to provide a simple and high-performance desiccant pack suitable for being enclosed in a sealed container of an electroluminescent device.

A third object of the present invention is to provide an electrode take-out structure which prevents deterioration of the thin-film cathode exposed from the sealing container due to moisture.

[0012]

In order to achieve the first object, the present invention provides a transparent anode on a transparent substrate and a pair of electrodes comprising a thin film cathode containing an alkali metal or an alkaline earth metal. An electroluminescent panel composed of an organic light-emitting diode having an electron-transporting organic molecule and a hole-transporting organic molecule is overlaid on a back panel with the light-emitting surface facing outward, and the periphery is sealed with a sealant. In the electroluminescent device formed by forming a sealing container, the sealing agent may
It comprises a hydrophobic polymer composition having a hydrogen bonding functional group of not more than 5% by weight, and the shape of the sealing agent at the sealing portion is (depth of sealing /
(Sealing thickness) ratio> 20. Thereby, a sealing portion having extremely low moisture permeability is obtained.

[0013] In order to achieve the second object, the present invention provides a method in which a transparent anode on a transparent substrate and a pair of electrodes comprising a thin film cathode containing an alkali metal or an alkaline earth metal are provided.
An electroluminescent panel composed of an organic light-emitting diode having an electron-transporting organic molecule and a hole-transporting organic molecule is overlaid on a back panel with the light-emitting surface facing outward, and the periphery is sealed with a sealant. An electric field emission device comprising a sealed container, and a desiccant pack in which a desiccant supported on a metal net is sealed in a hydrophobic polymer film bag in the sealed container. It is configured with a light emitting device. Thereby, a sealed container having an extremely low moisture content is obtained.

Further, in order to achieve the third object, the present invention provides a method comprising the steps of: providing a transparent anode on a transparent substrate and a pair of electrodes comprising a thin-film cathode containing an alkali metal or an alkaline earth metal;
An electroluminescent panel composed of an organic light-emitting diode having an electron-transporting organic molecule and a hole-transporting organic molecule is overlaid on a back panel with the light-emitting surface facing outward, and the periphery is sealed with a sealant. In the electroluminescent device formed by forming a sealed container, an end of the thin film cathode exposed from the sealing container is connected to a lead wire end, and the exposed end of the thin film cathode and the end of the lead wire are connected to each other. The connection portion is constituted by an electroluminescent device covered with a corrosion-resistant adhesive to prevent corrosion of the exposed electrode end. As a result, it is possible to obtain an electrode extraction portion that prevents deterioration of the thin film cathode exposed from the sealing container due to humidity.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention (Claim 1) provides an electron transporting organic molecule and a positive electrode between a pair of electrodes comprising a transparent anode on a transparent substrate and a thin film cathode containing an alkali metal or an alkaline earth metal. An electroluminescent panel composed of an organic light-emitting diode having a hole-transporting organic molecule is superimposed on a back panel with the light-emitting surface facing outward, and the periphery is sealed with a sealant to form a sealed container. In the electroluminescent device, the sealant comprises a hydrophobic polymer composition containing 1% by weight or less of a hydrogen bonding (adhesive) functional group after sealing and curing,
When the shape of the sealing agent in the sealing portion is (the sealing depth / the sealing thickness) ratio> 20
Due to the material and shape of the sealing agent, a sealing portion having extremely low moisture permeability while having strong adhesiveness due to hydrogen bonding can be obtained.

A hydrophobic polymer composition containing 1% by weight or less of a hydrogen bonding (adhesive) functional group refers to a hydrogen bond such as an amino group, an amide group, a hydroxyl group, a phenol group or a urethane group after sealing and curing. A hydrophobic polymer composition containing 1% by weight or less of a functional (adhesive) functional group, which may be a mixture of several polymers or a composition in which low molecules are dispersed in a polymer. . The concentration of the hydrogen bonding functional group is preferably as low as 1% by weight or less in order to give the composition an adhesive property while maintaining low moisture permeability.

Examples of the reactive functional group of the prepolymer before curing of the sealant include an epoxy group, an isocyanate group, a vinyl group, a hydroxyl group, an amino group, an amide group, and a carboxyl group. Specific compounds include epoxy-modified polyacrylate, urethane-modified polycyanoacrylate,
There are ultraviolet curable resins such as epoxy-modified polymethacrylate, ester-based epoxy resins, ether-based epoxy resins, and various urethanes. The epoxy resin generates a polymer and a hydroxyl group after ring-opening curing, and therefore has a high hydrogen bonding property and a high adhesive strength.

Regarding the shape of the sealant in the sealing portion, the amount of permeated moisture decreases as the sealing depth increases, and the amount of permeated moisture decreases as the sealing thickness decreases. For example, when the sealing depth is 30 mm and the sealing thickness is 150 μm or less, the amount of permeated water decreases. That is, when the (sealing depth / sealing thickness) ratio is 20 or more, the moisture in the sealing container can be kept extremely small, and the growth of black spots and the decrease in luminance during long-term use of the electroluminescent device can be suppressed to a very low level. .

According to the present invention (claim 2), the hydrophobic polymer composition contains 1% by weight or less of a hydrogen bonding functional group of a polymer having a hydrogen bonding functional group and a hydrophobic polymer. In the case of this mixture, the compatibility is low, the phase separation occurs within the composition, and the hydrogen bonding functional group is segregated at the bonding interface and is high. It has adhesiveness and low moisture permeability, and enables excellent sealing.

The present invention (Claim 3) provides a temporary curing adhesive in which the sealing agent has a curing time of 30 minutes or less, and a hydrophobic material containing 1% by weight or less of a hydrogen bonding functional group having low moisture permeability. An adhesive formed after the polymer composition is bonded and cured, which is sealed with a double structure sealant, and a temporary structure adhesive and a hydrophobic adhesive with a double structure sealant. This is advantageous for sealing work. As one of the specific materials, an epoxy resin is suitable, but a material having a short curing time has a limitation that the moisture permeability is high. Can be.

The present invention (claim 4) provides an electron transporting organic molecule and a hole transporting organic molecule between a transparent anode on a transparent substrate and a pair of electrodes comprising a thin film cathode containing an alkali metal or an alkaline earth metal. An electroluminescent panel comprising an organic light-emitting diode comprising molecules and an electroluminescent panel formed by superimposing an electroluminescent panel on a rear panel with the light-emitting surface facing outward and sealing the periphery with a sealant to form a sealed container. In the device, in the sealing container, a desiccant pack in which a desiccant supported on a metal mesh is sealed in a hydrophobic polymer film bag is sealed, and the desiccant is supported on the metal mesh. Therefore, it can be dried at a temperature of 300 to 400 ° C. before encapsulation, and can be immediately enclosed in a hydrophobic polymer film bag after quenching, so that the inside of the sealed container is kept in an extremely dry atmosphere. be able to. In order to carry the desiccant on the metal net, a heat-resistant inorganic binder such as water glass is used.

In the present invention (claim 5), the desiccant is a zeolite powder. Zeolite is a porous inorganic powder containing sodium aluminate as a main component, and has a selectivity depending on the pore size. And has a characteristic action of exhibiting a strong water adsorption property in a low humidity region. In addition, materials used as vacuum getters can also be used.

The present invention (claim 6) provides an electron transporting organic molecule and a hole transporting organic molecule between a transparent anode on a transparent substrate and a pair of electrodes comprising a thin film cathode containing an alkali metal or an alkaline earth metal. An electroluminescent panel comprising an organic light-emitting diode comprising molecules and an electroluminescent panel formed by superimposing an electroluminescent panel on a rear panel with the light-emitting surface facing outward and sealing the periphery with a sealant to form a sealed container. In the device, an end of the thin-film cathode exposed from the sealing container is connected to a lead wire end, and the exposed end of the thin-film cathode and the connection of the lead wire are connected with a corrosion-resistant adhesive. The coated thin-film cathode prevents corrosion at the end of the exposed electrode, and functions to prevent corrosion of the exposed end of the thin-film cathode due to moisture in the air by coating with a corrosion-resistant adhesive. When a film lead is used, the surface material of the film is preferably a film having good adhesiveness with an adhesive, such as an epoxy-based or acrylic-based film.
For connection between the thin film cathode and the lead wire, metal foil, quick-drying conductive paint, anisotropic conductive rubber, or the like is used.

An embodiment of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 shows an example of a sealing structure of an electroluminescent device according to the present invention, in which an electroluminescent panel 2 on which an organic light emitting diode 1 is formed as shown in FIG. Then, the sealing container is formed by overlapping with the back panel 3 and sealing the periphery with the sealing agent 4.

The sealant 4 is made of a hydrophobic polymer composition containing 1% by weight or less of a hydrogen bonding functional group after the sealing and curing. (Depth L / sealing thickness D) ratio> 20.

As described above, according to the present embodiment, a sealing portion having extremely low moisture permeability can be obtained from the material and shape of the sealing agent.

(Embodiment 2) FIG. 2 shows a second embodiment of a sealing structure for an electroluminescent device according to the present invention.
The electroluminescent panel 2 on which the organic light emitting diodes 1 are formed as shown in FIG. 2 is overlapped with the back panel 3 with the light emitting surface facing outward, and the periphery is sealed with a sealing agent to form a sealed container.

This electroluminescent device comprises a temporary curing adhesive 5 having a curing time of 30 minutes or less, and a hydrophobic polymer composition containing 1% by weight or less of a hydrogen-bonding functional group having low moisture permeability after adhesion and curing. It is sealed with a double structure sealant with an adhesive 6 forming an object.

According to the present embodiment, since the sealing agent has a double structure of the temporary fixing adhesive and the hydrophobic adhesive, it is advantageous in the sealing operation.

(Embodiment 3) FIG. 3 shows an example of an electrode extraction structure of an electroluminescent device according to the present invention. An electroluminescent panel 2 on which an organic light emitting diode 1 is formed as shown in FIG. The sealing container is formed by overlapping with the back panel 3 toward the outside and sealing the periphery with the sealing agent 4.

The end 7 of the thin film cathode 7 exposed from the sealed container
A is connected to the lead wire end 8, and the exposed end 7A of the thin-film cathode 7 and the connection portion of the lead wire are covered with a corrosion-resistant adhesive 9 to form an alkali metal or alkaline earth metal. Including metal, it is possible to prevent corrosion of the exposed electrode end caused by moisture in the atmosphere.

[0032]

Next, specific examples of the present invention will be described.

(Example) A 10 cm × 5 cm glass substrate having a hole injection transparent electrode formed thereon was subjected to a hydrophobic treatment and mounted in a vacuum evaporation apparatus. On this, N, N'-bis (2-methylphenyl) -N, N'-
diphenyl- (1,1'-biphenyl) -4,4'-diamine (TPD),
An Al—Li alloy thin film containing Alq as an electron transporting organic molecule and 1% by weight of Li as an electron injecting cathode was formed to produce an electroluminescent panel including the organic light emitting diodes 1.

As shown in FIG. 2, the electroluminescent panel 2 is superposed on the back panel 3 with the light-emitting surface facing outward, and is 6 cm ×
Zeolite supported by water glass on a 3 cm stainless steel net is dehydrated by heating at 400 ° C. for 1 hour, and then sealed in two pieces of polyester adhesive tape, 7 cm × 4 cm × 400 μm thick
Was sealed in a container, and the periphery thereof was sealed with a sealant to form a sealed container.

As shown in FIG. 2, the sealing portion was double-sealed with a quick-setting temporary fixing adhesive 5 having a curing time of 10 minutes and an epoxy-modified methacrylate-based adhesive 6 having low moisture permeability. The shape of the adhesive 6 in the sealing portion was sealed in a shape of sealing depth L = 5 mm, sealing thickness D = 0.1 mm, sealing depth / sealing thickness) = 50.

The end 7A of the thin film cathode 7 exposed from the sealing container is connected to the lead wire end 8 with an acrylic quick-drying silver paint as shown in FIG. And was configured.

When a DC voltage was applied to the thus obtained electroluminescent device and its light emission characteristics were measured, the voltage was 5 V
When applied, a current of 2.5 mA / cm ² flows and 105 cd / cm ²
Brightness with high uniformity of m ² was obtained.

In the life test at 100 cd / m ² , the half-time of luminance was eight times as long as that of a conventional sealing element using a 24-hour curing epoxy resin (araldite). Also,
The growth rate of the sunspot was very slow, and no new sunspot with a diameter of 5 μm or more was observed at all until after two months.

[0039]

As described above, the present invention provides (1) a hydrophobic polymer composition in which the structure of the sealing portion contains 1% by weight or less of a hydrogen bonding (adhesive) functional group after sealing and curing. (2) The desiccant pack contains a desiccant carried on a metal net in a hydrophobic polymer film bag. According to the present invention, there is provided a sealed container structure which is extremely stabilized against atmospheric moisture according to the present invention. There is an advantageous effect that an electroluminescent device having an electrode extraction portion can be obtained.

As described above, the present invention is of great industrial value.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a sealing structure of an electroluminescent device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing another example of the sealing structure of the electroluminescent device according to the second embodiment of the present invention.

FIG. 3 is a diagram showing an example of an electrode extraction structure of an electroluminescent device according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Organic light-emitting diode 2 Electroluminescent panel 3 Back panel 4 Sealant 5 Quick-curing temporary fixing adhesive 6 Adhesive made of hydrophobic polymer composition 7 Thin film cathode 7A End of thin film cathode 8 Lead wire end 9 Endurance Corrosive adhesive 10 desiccant pack

Claims (6)

[Claims] An electron transporting organic molecule and a hole transporting organic molecule are provided between a transparent anode on a transparent substrate and a pair of electrodes comprising a thin film cathode containing an alkali metal or an alkaline earth metal. An electroluminescent device comprising an electroluminescent panel made of an organic light emitting diode, and a light emitting surface facing outward, superimposed on a rear panel, and a periphery sealed with a sealant to form a sealed container. Is composed of a hydrophobic polymer composition containing 1% by weight or less of a hydrogen bonding functional group after sealing and curing, and the shape of the sealing agent in the sealing portion is (the depth of sealing / the thickness of sealing)> 20. An electroluminescent device, characterized in that: 2. The electric field according to claim 1, wherein the hydrophobic polymer composition is a mixture of a polymer having a hydrogen bonding functional group and a hydrophobic polymer containing 1% by weight or less of a hydrogen bonding functional group. Light emitting device. 3. A bonding agent comprising a temporary curing adhesive having a curing time of 30 minutes or less and a hydrophobic polymer composition having a low moisture permeability and containing 1% by weight or less of a hydrogen bonding functional group. 2. The electroluminescent device according to claim 1, wherein the device is sealed with a double-layered sealant with an adhesive formed after curing. 4. An electron transporting organic molecule and a hole transporting organic molecule are provided between a transparent anode on a transparent substrate and a pair of electrodes comprising a thin film cathode containing an alkali metal or an alkaline earth metal. An electroluminescent device comprising an electroluminescent panel composed of an organic light-emitting diode, a superimposed organic EL device, a light-emitting surface facing outward, and a back panel, and sealing the periphery with a sealant to form a sealed container. An electroluminescent device, wherein a desiccant pack in which a desiccant carried on a metal net is enclosed in a hydrophobic polymer film bag is enclosed therein. 5. The desiccant is a zeolite powder.
An electroluminescent device according to claim 1. 6. An electron transporting organic molecule and a hole transporting organic molecule are provided between a transparent anode on a transparent substrate and a pair of electrodes comprising a thin film cathode containing an alkali metal or an alkaline earth metal. An electroluminescent device comprising an electroluminescent panel composed of an organic light-emitting diode, a superimposed organic EL device, a light-emitting surface facing outward, and a back panel, and sealing the periphery with a sealant to form a sealed container. The more exposed end of the thin-film cathode is connected to the end of the lead wire, and the exposed end of the thin-film cathode and the connection of the lead are covered with a corrosion-resistant adhesive, and the end of the exposed electrode is exposed. An electroluminescent device characterized by preventing corrosion.