KR20050090543A - Dehumidifying method for organic electro luminescent devices using film-type desiccant body - Google Patents

Abstract

The present invention relates to a method for removing water inside an organic luminescent device used as a display device or a light emitting device of various information industrial equipment. An object of the present invention is to provide a simple method of removing the moisture of the organic light emitting diode by mounting the inside of the organic light emitting diode.

The water removal method of the organic electroluminescent device of the present invention for achieving the above object comprises the steps of forming a film-type moisture remover by mixing a moisture removal component for removing water by a chemical reaction and a thermoplastic polymer having a double bond; Thermally bonding the film type moisture remover to the inside of the organic light emitting display device; and embedding and sealing the electronic device. For example, metal, metal hydride, metal oxide, organometallic compound, etc. are used as the water removal component, and thermoplastic polymer having a double bond is used a thermoplastic copolymer including polybutadiene, polyisoprene, and the like. Is by heat source or high frequency.

Description

Dehumidifying method for organic electro luminescent devices using film-type desiccant body}

       The present invention relates to a method for removing water inside an organic luminescent device used as a display device or a light emitting device of various information industrial equipment, and more particularly, an organic electric field using a film type moisture remover. It is a method of removing water from a light emitting device.

       In the organic EL device, an organic light emitting layer is disposed between a pair of electrodes facing each other so that one electrode supplies electrons to the organic light emitting material layer and the other electrode supplies holes to the organic light emitting material layer, The holes combine with each other in the organic light emitting material layer to emit light, and have high resolution and impact resistance, and can implement various colors. Therefore, they are widely used as display devices of various information industrial devices.

However, these organic light emitting diodes have a deterioration in light emission characteristics such as brightness and uniformity of light as time passes. One of the causes of the organic light emitting diodes is moisture or defects or defects adsorbed on components of the organic light emitting diode at the time of manufacture. Water penetrates through.

Thus, a moisture remover is used to remove moisture in the organic electroluminescent device. The dehumidifying materials included in the moisture remover include moisture removed by physical adsorption and chemical reaction such as silica gel.

As a dehumidifying agent for sealed electronic devices using a physical adsorbent, US Pat. No. 5,304,419 discloses a method of preparing a combination of a pressure sensitive adhesive and a porous desiccant, and US Pat. A method of preparing a compound is disclosed, and US Pat. No. 5,591,379 discloses a method of blending a porous desiccant, such as a molecular sieve, with a moisture-permeable binder. In addition, there is a disadvantage of a physical adsorbent that re-releases water and a moisture absorption rate is slow because water must pass through the molecular layer of the binder to be adsorbed to the adsorbent.

As a dehumidifying agent for sealed electronic devices using a dehumidifying substance by chemical reaction, Japanese Laid-Open Patent Publication No. H3-261091 discloses a dehumidifying agent for organic EL devices in which phosphorus pentoxide powder is placed in a breathable container and mounted inside. Because it is a powder, it is difficult to handle, and the phosphoric acid produced by the reaction of phosphorus pentoxide with water has a low melting point of 41 to 44 ° C., and thus has a disadvantage in that it can flow out of the container and contaminate the electronic device even at a normal use temperature.

U.S. Patent 5,882,761 discloses a method of dehumidifying a metal oxide, a metal sulfate, a metal halide and a metal perchlorate in powder form or by coating the inside of a sealed case by vacuum deposition, sputtering or spin coating. As disclosed in Japanese Patent Laid-Open No. 3-261091, there is a problem such as contamination of manufacturing equipment, and the method of coating the dehumidifying agent on the inside of the case by vacuum deposition, sputtering, or spin coating is disclosed. It is not only easy, but also has a disadvantage in that the powder falls off over time.

Recently, since the thickness of the organic light emitting display device is becoming thinner, a method of curing and applying a liquid to reduce the thickness of the moisture remover is attempted, but the manufacturing process is complicated.

U.S. Patent 5,188,405 discloses a method of coating a mixture of a physical adsorbent and a polymer on an organic light emitting layer, but no specific process is presented. It reacts with water, so it has a disadvantage of low water removal.

U. S. Patent No. 6,226, 890 discloses a polymer having a high moisture vapor transmission rate and a metal oxide, a metal sulfate, a metal halide, or a metal perchlorate in a liquid state with a polymer to be incorporated into an organic light emitting device. Although a method of coating and curing is illustrated, there is a disadvantage that the time required for the process is long. In addition, the patent discloses a method of applying a liquid dehumidifying agent on one side of the film and applying an adhesive on the other side to cure and attaching the inside of the organic light emitting device, which is thick due to the thickness of the adhesive layer added to the film. There are disadvantages.

U.S. Patent Application 2002 / 0183431A1 discloses a method in which calcium oxide (CaO) is mixed with a fibrous polymer to be pressed and then adhered to an adhesive film, and then attached to the inside of the organic light emitting device using an adhesive. The disadvantage is that the thickness of occupies a significant portion.

Japanese Laid-Open Patent Publication No. 2003-144830 discloses a method of forming a thin moisture removing film by dissolving the organic metal compound in a solvent and then gradually removing the solvent. The process time is very long and there is no flexibility of the water removing film. The disadvantage is that cracks are likely to occur.

       An object of the present invention is to provide a simple method of removing the moisture of the organic electroluminescent device by mounting a moisture removal component for removing moisture by a chemical reaction inside the organic electroluminescent device.

The water removal method of the organic electroluminescent device of the present invention for achieving the above object comprises the steps of forming a film-type moisture remover by mixing a moisture removal component for removing water by a chemical reaction and a thermoplastic polymer having a double bond; Thermally bonding the film type moisture remover to the inside of the organic light emitting display device; and embedding and sealing the electronic device.

The water removal component is characterized by using a material that removes water by a chemical reaction. The water removal component is composed of metals, metal hydrides, metal oxides, organo metal compounds, or mixtures thereof. use.

The metal uses a metal having a higher tendency to ionize than hydrogen or a mixture thereof, and water is removed by the following Scheme 1.

M + nH ₂ O → M (OH) _n + n / 2H ₂

The metal hydride uses an alkali metal hydride, an alkali metal hydride, an alkali metal hydride including aluminum, or a mixture thereof, and water is removed by the following scheme 2.

MH _n + nH ₂ O → M (OH) _n + nH ₂

The metal oxide may be an alkali metal oxide, an alkaline earth metal oxide or a mixture thereof, and water is removed by the following scheme 3.

MO _n + nH ₂ O → M (OH) _n

The organometallic compound uses a compound represented by the following [Formula 1] or a mixture thereof.

Me-R _m R ' _n

In the above formula, Me is one or two same or different metals selected from alkali metal, alkaline earth metal, aluminum, titanium, zirconium, silicon, etc.

R is a saturated or unsaturated alkyl group, a saturated or unsaturated aryl group, a saturated or unsaturated alkyloxy group, a saturated or unsaturated allyloxy group,

R 'is hydrogen, saturated or unsaturated alkyl group, saturated or unsaturated aryl group, saturated or unsaturated alkyloxy group, saturated or unsaturated allyloxy group,

m and n are integers of 0-4, respectively, and m + n is 1-4.

For example, reaction schemes in which water is removed by sodium pentoxide and sodium bis (2-methoxyethoxy) aluminum hydride among organometallic compounds are shown in the following Schemes 4 and 5.

CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ O-Na + H ₂ O → CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ OH + NaOH

[(CH ₃ OC ₂ H ₄ O) ₂ AlH ₂ ] Na + 4H ₂ O → 2CH ₃ OC ₂ H ₄ OH + Al (OH) ₃ + NaOH + 2H ₂

The thermoplastic polymer having a double bond is used as a binder, and can be attached by heating and pressing without any pressure-sensitive adhesive, and has a strong self-adhesive strength and good water permeability.

Such materials include thermoplastic copolymers comprising polybutadiene, polyisoprene, specifically, block copolymers of polybutadiene and polystyrene, block copolymers of polyisoprene and polystyrene, or mixtures thereof.

The dehumidifier film is a thermoplastic polymer having a double bond with the selected chemical moisture removing material is heated, melted or dissolved in a solvent and mixed, and then molded using a device such as a calender roll.

The molded film is dried to a constant size, and thermally bonded to the inside of the organic light emitting display device by using thermal energy or high frequency. At this time, the temperature of the film surface is determined according to the properties and mixing ratio of the polymer used, the temperature control of the surface of the dehumidification film is adjusted by the intensity of the radiant energy or hot air, or by the time exposed to the radiant energy or hot air. If necessary, pressure may be applied to the opposite side to the adhesive side.

       Finally, the organic light emitting diode is sealed. The adhesion position of the dehumidification film may vary depending on the construction method of the organic light emitting display device.

       A representative structure of the organic light emitting device manufactured by the method of the present invention is shown in FIG. Reference numeral 10 is a dehumidifying film composed of a thermoplastic polymer having a water-removing component and a double bond, 11 is a layer to protect the organic electroluminescent device, 14 is an organic electroluminescent layer composed of a plurality of organic material and electrode layers. In addition, 12 is an insulating layer positioned between the organic electroluminescent layer and the self-adhesive dehumidifying film, and is composed of an inorganic layer such as a polymer layer, ceramic, or a gas layer, or two or more layers thereof. 13 is a sealant which bonds the layer which protects 11 organic electroluminescent elements, and the layer which protects 15 organic electroluminescent elements. However, 11 and 15 can also be joined directly, in which case 13 can be omitted.

<Example 1-4, Comparative Example 1>

Ten samples were produced in each glove box where moisture was kept below 1 ppm.

(1) Sample preparation

After mixing the dehumidifying material and the thermoplastic polymer having a double bond as described in Table 1, after processing into a flexible film of 200 micrometers thick by extrusion and calendering, it was cut into 20mm in width, 20mm in length.

(2) Adhesion of Samples and Sealing of Organic EL Devices

One side of the dehumidification film was melted and adhered to the inside of the organic light emitting display device by exposing one side of the dehumidifying film specimen to a 80W tungsten heater for 2 seconds, and the organic light emitting display device was sealed with a sealant.

division Substances that react with moisture Polymers with double bonds Substance weight% Substance weight% Example 1 Sodium Na 20 Polybutadiene-Polystyrene-Copolymer 80 Example 2 Calcium HydrideCaH ₂ 20 Polystyrene-Polyisoprene-Polystyrene Block Copolymer 80 Example 3 Strontium Oxide SrO 30 Polybutadiene-Polystyrene-Copolymer 70 Example 4 Sodium bis (2-methoxyethoxy) aluminum hydride [(CH ₃ OC ₂ H ₄ O) ₂ AlH ₂ ] Na 30 Polystyrene-Polyisoprene-Polystyrene Block Copolymer 70 Comparative Example 1 Do not put 0 Do not put 0

(3) peeling test

The organic electroluminescent device manufactured through the above process was stored for 300 hours at a temperature of 50 ^° C. and a relative humidity of 90% for 300 hours to decompose, and the surface of the dehumidification film was lined with a knife at intervals of 2 mm horizontally and vertically to make 100 grids. Peeling test was performed by attaching a cello tape and then pulling it at high speed to count the number of remaining grids without falling off.

If this value is usually 30/100 or more, it is known that it is not peeled off by a normal impact.

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Test result 63 94 57 82 none

(4) invasion test

In addition, the organic EL device manufactured through the above process was stored for 300 hours at a temperature of 50 ^° C. and a relative humidity of 90%, and the results of measuring the moisture concentration inside the organic light emitting device were shown in Table 3 below. .

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Moisture concentration (ppm) below 10 below 10 below 10 below 10 15,700

Comparing the results of Example 1-4 with Comparative Example 1, the organic electroluminescent device manufactured according to the present invention was maintained without difference with the initial moisture concentration, whereas the inside of the organic electroluminescent device of Comparative Example was water concentration. It can be seen that is very high.

       According to the present invention, there is provided a method of removing moisture by mounting a film-type dehumidifying agent containing a moisture removal component that removes moisture by a chemical reaction inside the organic light emitting device by a simple operation. In addition, the dehumidifying agent mounted inside the organic light emitting device has no adhesive layer and thus thins the organic light emitting device since the thickness of the dehumidifying agent does not occupy almost any volume.

1 is a conceptual diagram of an organic light emitting display device to which the present invention is applied.

* Explanation of Signs of Major Parts of Drawings *

10: film 11, 15 containing a dehumidifying component: protective layer

12: insulating layer located between the organic electroluminescent layer and the dehumidification film

13: sealant 14: organic light emitting layer

Claims (9)

Forming a film type moisture remover by mixing a moisture removing component which removes water by a chemical reaction and a thermoplastic polymer having a double bond, and thermally bonding the film type moisture remover to the inside of the organic light emitting device; A method of removing water from an organic light emitting display device, the method comprising: embedding and sealing a device. The method of claim 1, wherein the moisture removing component is selected from a metal, a metal hydride, a metal oxide, an organometallic compound, or a mixture thereof. The method of claim 1, wherein the thermoplastic polymer having a double bond is selected from polybutadiene, thermoplastic copolymer including polyisoprene, or a mixture thereof. The method of claim 1, wherein the energy to be thermally bonded is thermal energy or high frequency. The method of claim 2, wherein the metal is selected from a metal having a higher ionization tendency than hydrogen or a mixture thereof. The method of claim 2, wherein the metal hydride is selected from an alkali metal hydride, an alkali metal hydride, an alkali metal hydride including aluminum, or a mixture thereof. The method of claim 2, wherein the metal oxide is selected from alkali metal oxides, alkaline earth metal oxides or mixtures thereof. The method of claim 2, wherein the organometallic compound is selected from a compound represented by the following [Formula 1] or a mixture thereof. [Formula 1] Me-R _m R ' _n In the above formula, Me is one or two same or different metals selected from alkali metal, alkaline earth metal, aluminum, titanium, zirconium, silicon, etc. R is a saturated or unsaturated alkyl group, a saturated or unsaturated aryl group, a saturated or unsaturated alkyloxy group, a saturated or unsaturated allyloxy group, R 'is hydrogen, saturated or unsaturated alkyl group, saturated or unsaturated aryl group, saturated or unsaturated alkyloxy group, saturated or unsaturated allyloxy group, m and n are integers of 0-4, respectively, and m + n is 1-4. The organic electroluminescent device according to claim 3, wherein the thermoplastic copolymer comprising polybutadiene and polyisoprene is selected from a block copolymer of polybutadiene and polystyrene, a block copolymer of polyisoprene and polystyrene, or a mixture thereof. How to get rid of moisture.