JP2002299041A - Film substrate and organic EL element used for organic EL device - Google Patents

Abstract

(57) [Summary] A sealing material required for commercializing an organic EL element as a display device requires a high gas barrier property. However, conventional gas barrier organic polymers and inorganic material vapor-deposited films have insufficient gas barrier properties and cannot be used as films for use in organic EL devices. A film-like base material obtained by reinforcing extremely thin glass having very good gas barrier performance with an organic resin and a film is used as a sealing material for passivation. [Effect] A transparent base material for passivation having excellent oxygen and water vapor barrier properties can be obtained. The film-like base material for passivation obtained by this is an organic EL
It can be used as a protective film for deterioration resistance of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film used for an organic EL device having a gas barrier property effective for deterioration resistance of the organic EL device, and an organic EL element using the film.

[0002]

2. Description of the Related Art An electroluminescent (EL) element is a light emitting device utilizing a phenomenon called electroluminescence or EL emission of a solid fluorescent substance, and an inorganic EL element using an inorganic material as a light emitter at present. It has been put to practical use, and is being applied to liquid crystal display backlights and flat displays. At present, researches for practical use of organic EL elements, which are expected to be able to be manufactured at a low cost with a simple process, are being actively conducted.

However, organic solids such as a light emitting layer and a hole transport layer used in an organic EL device are generally susceptible to moisture and oxygen.
Moisture and oxygen present in the device cause dark spots to grow and lower the luminance. Therefore, in order to guarantee the reliability of the organic EL element, the element must be sealed in order to prevent moisture and oxygen from entering the organic material and the electrode material.

[0004] A number of proposals have been made on a method of sealing an organic EL element. Methods that have already been put to practical use include a method of metal-sealing the organic EL element together with a moisture absorbing material, a method of providing a glass plate outside the back electrode, and sealing silicone oil between the back electrode and the glass plate. In addition, many methods for sealing an organic EL element with an organic film having excellent gas barrier properties or a film having an inorganic oxide vapor-deposited film have been proposed.

As a film for sealing the organic EL element, an organic thin film such as polychlorotrifluoroethylene (PCTFE) or a physical vapor deposition method (PVD method) such as a vacuum deposition method, a sputtering method, or an ion plating method. And
Using chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition,
A transparent gas barrier film in which an inorganic oxide film such as SiO ₂ , Al ₂ O ₃ , MgO or the like is formed on a plastic substrate has been proposed as a candidate.

The oxygen permeability of general-purpose organic polymers used for general food packaging is from several tens to several tens.
0 cc / m ² day, water vapor permeability from several tens to several hundreds g /
m ² day, polychlorotrifluoroethylene (P
An organic polymer having a molecular structure with enhanced barrier properties, such as CTFE), has an oxygen permeability of several cc / m ² days and a water vapor permeability of several g / m ² days.

On the other hand, a gas barrier film in which an inorganic oxide film such as SiO ₂ , Al ₂ O ₃ , MgO or the like is formed on a plastic substrate by using a PVD method or a CVD method is dense, for example, having a thickness of 30 μm PET. The oxygen permeability of a 5 μm thick SiOx film deposited on a substrate is 1 cc for a good film.
/ M ² day, and the water vapor permeability is about 1 g / m ² day. In JP-A-11-80934, a composite thin film of aluminum oxide and aluminum hydroxide is provided in a simple process by introducing a hydroxyl group after plasma-treating the surface of an Al ₂ O ₃ film deposited on the surface of a plastic substrate with oxygen gas. , Oxygen permeability 1.2 cc / m ² / day, water vapor permeability 2.0 g / m ² / d
ay. In Japanese Patent Application Laid-Open No. 11-332979, an oxygen permeability of 0.9 cc / m ² / day and a water vapor permeability of 0.8 g / day are obtained by forming a film of an inorganic oxide vapor deposition film after subjecting a PET substrate surface to a plasma treatment with oxygen gas. m ² / day
Has been realized.

[0008]

The sealing material required for commercializing an organic EL element as a display device is not only highly transparent but also much higher than that for conventional food packaging. Gas barrier properties are required. However, with respect to the above-mentioned gas barrier organic films and inorganic vapor-deposited films, no effective gas barrier properties for sealing organic EL have been realized in any of the reported examples. In order to realize a sufficient gas barrier property for encapsulating an organic EL device by increasing the thickness of a known gas barrier film, the film thickness needs to be about 10 cm. The gas permeability of the inorganic material-deposited film also decreases with an increase in the film thickness. However, when the film thickness exceeds 100 nm, the gas permeability becomes a constant value and does not decrease any more. Organic E
It is also difficult to achieve sufficient gas barrier properties for L element sealing. Therefore, a conventional gas barrier organic polymer or inorganic material vapor-deposited film cannot be used as a film used in an organic EL device by simply increasing the film thickness.

Although various proposals have been made for a method of sealing an organic EL device, no effective sealing method has yet been established for reducing the weight and thickness of the device.

An object of the present invention is to provide a film used in an organic EL device having a gas barrier property sufficient for protecting the organic EL device and an organic EL device structure using the film.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that extremely thin glass has a very high gas barrier performance, and that the glass is sandwiched by an organic resin or an organic film. Found that the glass reinforced material complements the brittleness of the glass, has flexibility, and has a very strong strength, and develops a film-like base material that has both gas barrier properties and strength. It has been reached.

The present invention can be realized as follows. That is, it is a film-like base material used for an organic EL device composed of an organic-inorganic hybrid material having an organic resin part and an inorganic glass part, and the film has a structure in which a glass base material is sandwiched between organic resin base materials. A film-shaped base material used for a characteristic organic EL device is produced. An organic EL device comprising an organic-inorganic hybrid material having an organic resin portion and an inorganic glass portion, wherein the film substrate has a thickness of 400 μm or less. This is a film-shaped substrate used for an EL device. Also,
A film-like base material used for an organic EL device comprising an organic-inorganic hybrid material having an organic resin part and an inorganic glass part, wherein the film has an organic resin sandwiching the glass base material having a thickness of 500 microns or less. A film-shaped substrate used for an organic EL device to be manufactured is produced. Also,
An organic EL device comprising an organic EL device comprising an organic-inorganic hybrid material having an organic resin portion and an inorganic glass portion, wherein the film is transparent and has a transmittance of 70% or more. This is a film-shaped substrate used for the apparatus. In addition, an organic EL device having a structure in which the film used for the organic EL device manufactured as described above is sealed from one surface or both surfaces by a heat laminating method or an adhesive is manufactured. In addition, an organic EL element having a structure without an opposing substrate was manufactured by using a film used for the manufactured organic EL device and sealing it from one side or both sides by a heat laminating method or an adhesive.

The film of the present invention has an extremely thin thickness of 40.
Use glass less than 0 microns. As is generally known, glass has a very good gas barrier performance because it has a stronger chemical bond and a smaller cohesive energy density and free volume fraction than organic polymers and the like. In addition, because of its extremely high transparency, it is optimal for optical applications. However, since it is an inorganic substance, it is the biggest disadvantage that it is very brittle. Increasing the thickness of the glass increases the strength, but increases the weight and the thickness of the base material, and is therefore avoided from being very light, thin and short. Although this gas barrier performance is good, it is possible to increase the strength while having flexibility by reinforcing a very fragile ultra-thin glass having a thickness of 400 μm or less with an organic resin or an organic film. Further, since the glass is interposed in the middle, the gas barrier performance is very good, and the permeability of water vapor and oxygen is 0.01 g / m ² / day or less. This value is below the detection limit of the MOCON device, which is a standard gas barrier property evaluation machine. Since this film-shaped substrate can be produced by a very simple method using a heat lamination method, a film-shaped substrate having good performance can be provided at low cost. In addition, the organic EL produced using this film-shaped substrate has a long life because there is no deterioration of the luminous body due to gas, and is extremely thin and lightweight because a can-sealing structure is not required unlike conventional ones. Is obtained. In addition, since this film-shaped base material is transparent, it is easy to realize a structure without an opposing substrate, contrary to the conventional light extraction direction, and a very good light extraction efficiency is obtained, and a high emission luminance is obtained. Is obtained.

By using the film used for the organic EL device according to the present invention and sealing the organic EL device from one side or both sides by a method such as an adhesive having a gas barrier property or a heat laminating method, a light and thin organic EL device is obtained. Get. Since the film used for the organic EL device of the present invention has high gas barrier properties and is transparent, the organic EL device can have a structure without an opposing substrate. With such a structure, a high-performance organic EL device having good light extraction efficiency and no reduction in luminance is provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples. <Example 1> A film used for an organic EL device according to the present invention was prepared by the following method.

An ultra-thin glass (borosilicate glass; B5 size) having a thickness of 50 μm is sandwiched between PET films (thickness: 30 μm; A4 size) with an adhesive as an organic film, and heated with a hot roll. And heat laminated. The adhesive used at this time was one that had optical compatibility with glass and organic films. As a result, a film-like base material having a very thin overall thickness of 110 μm but resistant to loads such as bending and twisting was obtained. This film has a very high transmittance of 80% in the visible light region. FIG. 1 shows the structure and production method of this film-shaped substrate. In the figure, 1:
Organic film (30 microns), 2: ultra-thin glass (50 microns), 3: adhesive layer, 4: hot roll. The gas barrier performance of this film-shaped substrate was measured by the following method.

(1) Measurement of oxygen permeability Using the gas-barrier film-like substrate prepared as described above, at a temperature of 30 ° C. and a humidity of 90% RH, an oxygen permeability manufactured by Mocon, USA Measuring device (Oxtran 2/2
0), and the oxygen permeability was measured under the condition of a pressure difference of 0.1 MPa. The measurement limit of the device is 0.01 cc / m ² / day.

(2) Measurement of Water Vapor Permeability Using a gas-barrier film-like substrate prepared as described above, at a temperature of 30 ° C. and a humidity of 90% RH, a moisture permeability measurement made by Mocon, USA Equipment (Permatran 2/2
Using 0), the water vapor permeability was measured under the condition of a pressure difference of 0.1 MPa. The measurement limit of the device is 0.01 g / m ² / day
It is.

Table 1 shows the measurement results.

The gas-barrier film-like substrate according to the present invention exhibited values below the measurement limit in both oxygen permeability and water vapor permeability, and it was revealed that the substrate had extremely good gas barrier performance. Table 1 shows the measurement results together with data of comparative samples.

Compared to the oxygen permeability and water vapor permeability of the PET substrate (No. 1) and the films (Nos. 2 and 3) in which the inorganic material vapor-deposited film (SiOx, ITO) is formed on the PET substrate.
It was shown that the film-shaped substrate (No. 4) of the present invention had extremely high gas barrier properties.

[0022]

[Table 1] Table 1

<Example 2> An organic EL device was produced using the high gas barrier film-like substrate produced in Example 1. As shown in FIG. 2, the organic EL device used in this experiment is a device in which a TFT array 10, a metal cathode 6, an organic EL layer (green) 7, and an ITO electrode layer 8 are laminated on a glass substrate 5. Organic EL device (15 mm x 20 mm) in a glove box in a nitrogen atmosphere at atmospheric pressure (0.1 MPa)
The organic EL element was sealed by bonding a passivation film-like base material 9 having a size of 40 mm × 50 mm onto the ITO electrode with an adhesive to obtain EL element A. Similarly, the organic EL element sealed with film 1 in Table 1 is referred to as EL element B, the organic EL element sealed with film 2 is referred to as EL element C, and the organic EL element sealed with film 3 is referred to as EL.
Element D was used as a comparative EL element.

These organic EL devices were placed in humid air at a temperature of 50 ° C. and a relative humidity of 90%,
Hz and connected to an AC power supply, and the brightness was measured after continuous lighting. FIG. 3 shows the results of measuring the change over time in luminance with the luminance immediately after the start of the experiment as 100%. It was confirmed that the EL element A sealed with the passivation film-shaped substrate of the present invention had a lower luminance reduction rate than other comparative EL elements. In other words, it was clarified that the organic EL device produced using the product of the present invention as a film material for sealing was a highly reliable and high performance device.

[0025]

According to the present invention, a transparent base material for passivation having excellent oxygen and water vapor barrier properties can be obtained. The film-like base material for passivation thus obtained can be used as a protection film for deterioration resistance of the organic EL device. In addition, high performance and high reliability organic EL
Products can be provided.

[Brief description of the drawings]

FIG. 1 is a structural example of a film-like base material for passivation and a manufacturing method thereof.

FIG. 2 is a structural example of an organic EL on which the film-form substrate for passivation shown in FIG. 1 is mounted.

FIG. 3 shows a change over time in luminance of an organic EL device sealed with a film according to the present invention.

[Explanation of symbols]

1: Organic film, 2: Ultra-thin glass, 3: Adhesive layer, 4:
Heat roll, 5: glass substrate, 6: metal cathode, 7: organic EL layer, 8: ITO electrode, 9: film-like base material for passivation, 10: TFT array.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kozo Sakamoto 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Takumi Ueno 7-1 Omikamachi, Hitachi City, Ibaraki Prefecture No. 1 Hitachi, Ltd., Hitachi Research Laboratory (72) Inventor, Kazukazu Araya 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term, Hitachi, Ltd. Hitachi Research Laboratory F-term (reference) 3K007 AB11 AB13 AB17 AB18 BA06 CA01 CB01 DA01 DB03 EA01 EB00 FA02

Claims (6)

[Claims] 1. A film-like base material used for an organic EL device comprising an organic-inorganic hybrid material having an organic resin part and an inorganic glass part, wherein the film has a structure in which a glass base material is sandwiched between organic resin base materials. Organic EL characterized by having
Film-shaped substrate used for equipment. 2. A film-like substrate for use in an organic EL device comprising an organic-inorganic hybrid material having an organic resin portion and an inorganic glass portion, wherein the film has a thickness of 40 mm.
A film-like base material used for an organic EL device, which has a size of 0 micron or less. 3. A film-like base material for use in an organic EL device comprising an organic-inorganic hybrid material having an organic resin part and an inorganic glass part, wherein the film has an organic resin sandwiching the glass base material having a thickness of 500 μm or less. A film-like substrate used in an organic EL device, which is characterized in that: 4. A film-like base material for use in an organic EL device comprising an organic-inorganic hybrid material having an organic resin part and an inorganic glass part, wherein the film is transparent and has a transmittance of 70% or more. Characteristic film-shaped substrate used for organic EL devices. 5. An organic EL device having a structure in which the film used for the organic EL device according to claim 1 is sealed from one side or both sides by a heat laminating method or an adhesive. 6. An organic EL device having a structure without an opposing substrate, wherein the film used for the organic EL device according to claim 1 is sealed by one side or both sides by a heat laminating method or an adhesive.