JP2000260562A - Moisture absorptive film and organic el display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture absorptive film high in purity, high in homogeneity, and high in moisture absorbing performance. SOLUTION: This organic EL display device is equipped with a glass substrate 1 as a transparent substrate, an organic EL element 2 made up of a transparent electrode layer 21 formed on the transparent substrate 1, an EL luminescent layer 22 formed on the transparent electrode layer 21, and a metallic electrode layer 23 formed on the EL luminescent layer 22. and a back glass substrate 3 as a sealing member, with its interior filled with an inert fluid, joined to the transparent substrate 1 so as to cover the organic EL element 2. The inside surface of the back glass substrate 3 is filmed with a moisture absorptive film 6 made of an alkaline earth monoxide (BaO), formed by a PVD method using an alkaline earth peroxide (BaO2) as a target material. By using an alkaline earth peroxide which is stable in the atmosphere as a target material, the moisture absorptive film 6 becomes high in purity, high in homogeneity, and high in moisture absorbing performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a moisture absorbing film and an organic EL.
More specifically, the present invention relates to a moisture absorbing film made of alkaline earth monoxide and an organic EL display device having the moisture absorbing film.

[0002]

2. Description of the Related Art Display devices for display include:
CRT (Cathode Ray Tube), LCD (Liquid Cryst)
al), plasma (Plasma), light emitting diode (Light Em)
Itting Diode) and EL (Electro Luminescence) are conventionally known and widely used for computer displays, back panels of liquid crystal displays, and the like.

[0003] Among them, EL is a self-luminous type and can be formed into a thin film, so that it is expected as a thin display element. In recent years, an organic thin film EL that can be driven at a low voltage has attracted attention as a thin film DC EL. Organic EL
The device generally includes a transparent electrode layer formed on a transparent substrate, an organic EL light emitting layer formed on the transparent electrode layer,
And a metal electrode layer formed on the organic EL light emitting layer. Then, by applying electricity to the transparent electrode layer and the metal electrode layer, holes and electrons injected from the respective electrodes are recombined in the organic EL light emitting layer, and the energy at this time causes a light emission phenomenon. This light emission phenomenon is injection light emission similar to a light emitting diode, and is characterized by a light emission voltage as low as 10 V or less.

As an organic EL display device using such an organic EL element, there is known an organic EL display apparatus in which the organic EL element structure is used as a unit pixel and the unit pixels are two-dimensionally arranged two-dimensionally on a transparent substrate and driven in a matrix. ing. That is, a transparent electrode group having a stripe shape is formed on a transparent substrate, an organic EL light emitting layer is formed on the transparent electrode group, and a metal electrode group having a stripe shape orthogonal to the transparent electrode group is sequentially formed on the organic EL light emitting layer. The transparent electrode group and the metal electrode group are formed and two-dimensionally arranged in a plane as an organic EL element structure as a unit pixel. In this type of display device, the intersection of two voltage-applied stripe-shaped electrodes serves as a light-emitting portion. Therefore, an image can be displayed by sequentially shifting stripes to emit light by applying a voltage. And
The light emitted from the organic EL light emitting layer is transmitted directly or reflected by the metal electrode, passes through the transparent electrode and the transparent substrate, is emitted from the display side surface of the transparent substrate, and is visually recognized.

However, the organic luminescent material used in the organic EL device has low water resistance and has a short life due to moisture. In addition, Mg used for organic EL elements
Metal electrode layers such as alloys also have the disadvantage of having low resistance to water and oxygen. Japanese Patent Application Laid-Open No. 9-148066 discloses an organic EL device in which an organic EL element is sealed in a sealing member and a moisture absorbent is provided on the inner surface of the sealing member.
A display device is disclosed.

As shown in FIG. 6, this organic EL display device has a transparent glass substrate 80, a transparent electrode layer 81a formed on the glass substrate 80, and an organic EL light emitting layer formed on the transparent electrode layer 81a. Organic EL element 8 including a metal electrode layer 81c formed on the organic EL light emitting layer 81b and the organic EL light emitting layer 81b
1 and a sealing member 83 is joined to a glass substrate 80 via a sealing agent 82 so as to cover the organic EL element 81 while enclosing an inert gas therein. A hygroscopic agent 84 is fixed to the inner surface of the sealing member 83 with an adhesive.

In this organic EL display device, the sealing member 83 is joined to the periphery of the glass substrate 80 so as to cover the organic EL element 81 while sealing the inert gas therein. Can be isolated from the atmosphere.
In addition, the moisture absorbent 84 fixed to the inner surface of the sealing member 83 can absorb moisture that has entered the enclosed space via the sealing agent 82. Therefore, it is possible to enhance the drying property in the sealed space and extend the life of the element.

[0008]

Here, as one of the above-mentioned hygroscopic agents, monoxides of alkaline earth metals such as Ca, Ba and Mg are exemplified. Using the alkaline earth metal monoxide as a starting material, a PVD method (physical vapor deposition method) such as a vacuum evaporation method and a sputtering method is performed, and the alkaline earth metal monoxide is It is also possible to form a moisture-absorbing film made of the above.

However, when a moisture absorbing film made of an alkaline earth metal monoxide is formed on the inner surface of the sealing member 83 by a PVD method using an alkaline earth metal monoxide as a starting material, the following will be described. There is such a problem. That is, the alkaline earth metal monoxide is unstable in the air and easily changes to a hydrate or a carbonate. For example, barium monoxide (BaO) reacts with CO ₂ or H ₂ O as follows to form BaCO ₃ .n (H ₂ O) or Ba (OH) ₂ .n (H
₂ O) varies carbonates hydrates and BaCO ₃ in.

BaO + CO ₂ → BaCO ₃ BaCO ₃ + nH ₂ O → BaCO ₃ .n (H ₂ O) BaO + H ₂ O → Ba (OH) ₂ Ba (OH) ₂ + nH ₂ O → Ba (OH) ₂ .n (H _Two
O) For this reason, alkaline earth metal monoxide is used as a starting material as a powder as it is, or the powder is sintered,
When the sintered body is used as a starting material and a moisture-absorbing film is formed by the PVD method, a stable film cannot be formed due to the presence of hydrate or carbonate impurities in the starting material. In addition, the quality of the formed film becomes heterogeneous and low in purity, and it is difficult to form a uniform and high-purity moisture absorbing film, that is, a moisture absorbing film having high moisture absorbing performance.

When a moisture-absorbing film is formed on the inner surface of the sealing member 83, an enclosed space is interposed between the organic EL element 81 and the moisture-absorbing film, and there is a distance between the two.
It is difficult to effectively prevent moisture from entering the first organic EL light emitting layer 81b and the like. The present invention has been made in view of the above-described circumstances, and a first technical problem to be solved is to provide a moisture-absorbing film having high purity, high homogeneity, and high moisture-absorbing performance. The second problem to be solved is to provide an organic EL display device having a moisture absorbing film capable of effectively preventing moisture from entering the device.
Technical issues.

[0012]

Means for Solving the Problems The moisture absorbing film of the present invention for solving the above first problem is composed of an alkaline earth monoxide formed by a PVD method using an alkaline earth peroxide as a starting material. It is characterized by becoming. The organic EL display device of the present invention that solves the second problem includes a transparent substrate, a transparent electrode layer formed on the transparent substrate, an organic EL light emitting layer formed on the transparent electrode layer, and the organic EL device. An organic EL device comprising an organic EL device comprising a metal electrode layer formed on a light emitting layer, and a sealing member joined to the transparent substrate so as to cover the organic EL device while sealing an inert fluid therein. In the EL display device, at least one of the non-light-emitting portion on the organic EL element and the inner surface of the sealing member has a PV using alkaline earth peroxide as a starting material.
The method is characterized in that a moisture absorbing film made of an alkaline earth monoxide formed by the method D is formed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The moisture-absorbing film of the present invention comprises an alkaline earth monoxide formed by a PVD method using an alkaline earth peroxide as a starting material. Alkaline earth peroxides can be stably stored in the atmosphere, unlike alkaline earth monoxides. For this reason, alkaline earth peroxide powder is used as a starting material, or alkaline earth peroxide powder is sintered and this sintered body is used as a starting material. When a moisture-absorbing film composed of a monoxide is formed, a homogeneous and high-purity moisture-absorbing film is used because impurities such as hydrates and carbonates do not intervene in the starting material, for example, at grain boundaries of the sintered body. Can be formed. Therefore, the moisture-absorbing film of the present invention formed using alkaline earth peroxide as a starting material exhibits high moisture-absorbing performance.

The above-mentioned alkaline earth peroxide is an alkaline earth metal dioxide, that is, an oxide of an alkaline earth metal having O ₂ ^2-, and the alkaline earth metal is dissolved in air or oxygen. For example, by heating. Alkaline earth metals include Ca, Sr, Ba, R
There are a, Be and Mg, and any of alkaline earth metals can be used for the moisture absorbing film of the present invention. However, considering the cost, the availability of high-purity materials and the practicality, Ca, S
r, Ba, and Mg can be suitably used.

From this alkaline earth metal peroxide, PVD
In order to form a moisture-absorbing film made of alkaline earth monoxide by the method, a powder of alkaline earth peroxide is used as a starting material, or a sintered body obtained by sintering this powder is used as a starting material. The PVD method may be performed. Conditions for adjusting the alkaline earth peroxide powder are not particularly limited, and ordinary conditions can be used. For example, when obtaining BaO ₂ powder, Ba
By heating the powder, BaO.n (H ₂ O) powder or BaO.CO ₃ powder in an oxygen atmosphere at about 500 ° C., BaO ₂ powder can be obtained.

The sintering conditions for the alkaline earth peroxide sintered body are not particularly limited, and ordinary sintering conditions can be used. For example, when obtaining a sintered body of BaO ₂ powder,
Since BaO _{2 has} a melting point of 450 ° C., it can be sintered in the atmosphere at a temperature slightly lower than this temperature (about 400 to 440 ° C.) for about 30 to 60 minutes. When sintering an alkaline earth monoxide, for example, BaO, 10
Since sintering is performed at about 00 ° C. or higher, sintering at a low temperature is possible when sintering alkaline earth peroxide, which is advantageous in terms of cost and the like.

The PVD method is not particularly limited, but a vacuum evaporation method such as an electron beam heating method or an ion plating method, a sputtering method, or the like can be suitably employed. The film forming conditions can be appropriately set according to the starting material, the thickness of the moisture absorbing film to be formed, and the like. For example, when the electron beam heating method is adopted, the film forming conditions are as follows: output: about 1 to 20 kV, about 0.05 to 0.3 A, degree of vacuum: 2 × 10 ⁻⁶ Pa or less, film forming rate: 0.1 to 1 0.0 nm / sec. The film forming conditions when the ion plating method is adopted are as follows: Output: about 1 to 20 kV, about 0.05 to 0.3 A Vacuum degree: 0.5 to 2 × 10 ^-4 Pa (Argon pressure) Film forming speed: about 0.05 to 0.3 nm / sec. When the sputtering method is adopted, the film forming conditions are: output: about 50 to 500 W, degree of vacuum: 1 ８8 × 10 ⁻⁴ Pa (argon pressure) Film formation rate: about 5 to 40 nm / sec.

Here, when the moisture absorbing film is formed on the organic EL element, it is preferable to employ a vacuum evaporation method such as an electron beam heating method from the viewpoint of suppressing damage to the element during film formation. The thickness of the moisture-absorbing film is not particularly limited, but the greater the thickness, the higher the moisture-absorbing performance. Therefore, the thickness can be appropriately set so that the desired moisture-absorbing performance can be exhibited. If the thickness of the moisture-absorbing film is too large, the film-forming cost may increase or the moisture-absorbing film may peel off. Therefore, when applied to an organic EL display device, the thickness of the moisture absorbing film is preferably 100 μm or less, more preferably about 0.1 to 30 μm.

Further, when the moisture absorbing film of the present invention is applied to an organic EL display device, it is bonded to a transparent substrate so as to cover the organic EL element, and forms a sealed space between the transparent substrate and an inert fluid. This moisture absorbing film can be formed on the inner surface of the sealing member to be formed. However, from the viewpoint of more surely preventing the intrusion of moisture into the organic EL light emitting layer and the like, the moisture absorbing film should be formed on the organic EL element. Is preferred. In this case, the moisture absorbing film is
In order to prevent the light emitting portion of the organic EL element from being damaged by heat or the like when forming a film by the VD method, it is preferable to partially form the moisture absorbing film on the non-light emitting portion on the organic EL element. When the moisture absorbing film is partially formed in the non-light emitting portion on the organic EL element as described above, it is possible to prevent moisture or oxygen adsorbed on the moisture absorbing film from adversely affecting the metal electrode layer or the like of the light emitting portion. In addition to this, it is not necessary to cover the metal electrode layer with a stable protective film in order to prevent such adverse effects as described later, which is advantageous in terms of cost and production. Note that the mode in which the moisture absorbing film is partially formed in the non-light-emitting portion on the organic EL element is such that a large number of non-light-emitting portions exist on the organic EL element or a pattern is formed using a mask, as in a segment display such as a clock. This can be more suitably applied to a pattern that is as coarse as possible.

Here, the moisture absorbing film can be formed on the entire surface of the organic EL element. In this case, a protective film such as a SiO ₂ film or a resin film is further formed on the moisture absorbing film. The sealing member can be omitted. Also, organic EL
When a moisture absorbing film is formed on the light emitting portion on the device (including the case where the moisture absorbing film is formed on the entire surface of the organic EL device), moisture and oxygen adsorbed on the moisture absorbing film adversely affect the metal electrode layer and the like. In order to prevent the metal electrode layer, a stable protective film (SiO ₂
It is preferable to cover with a film or a MgF film, and form a moisture absorbing film thereon.

It is, of course, possible to form the moisture absorbing film on both the non-light emitting portion on the organic EL element and the inner surface of the sealing member. In this case, the moisture absorbing effect of both moisture absorbing films allows the organic EL element to be used. Can be further extended. Thus, on the organic EL element, the moisture-absorbing film made of the alkaline earth monoxide formed by the PVD method using the alkaline earth peroxide as a starting material is used to form the non-light emitting portion on the organic EL element and In the organic EL display device of the present invention formed on at least one of the inner side surfaces of the sealing member, the life of the organic EL element can be extended by the moisture absorbing effect of the moisture absorbing film having high moisture absorbing performance. Further, if the moisture absorbing film is formed in the non-light emitting portion on the organic EL element, the distance between the organic EL light emitting layer or the like of the organic EL element and the moisture absorbing film becomes extremely short. Can be reliably prevented by the moisture absorbing film, and the life of the organic EL element can be effectively extended.

In this organic EL display device, a transparent substrate, a transparent electrode layer formed on the transparent substrate, an organic EL light emitting layer formed on the transparent electrode layer, and a transparent electrode layer formed on the organic EL light emitting layer are formed. An organic EL device comprising a metal electrode layer and a sealing member joined to the transparent substrate so as to cover the organic EL device while enclosing an inert fluid therein can be provided.

As the transparent substrate, a glass substrate is usually used, but a synthetic resin substrate can also be used. Also,
It is also possible to use a flexible synthetic resin film as the transparent substrate. When a synthetic resin film is used, the distance between the synthetic resin film and the transparent electrode layer formed on the synthetic resin film is set so as to absorb moisture and the like penetrating from the outside through the synthetic resin film itself. Also, it is preferable to form an auxiliary moisture absorbing film.

As in the conventional case, the organic EL element comprises a transparent electrode layer formed on a transparent substrate, an organic EL light emitting layer formed on the transparent electrode layer, and a metal formed on the organic EL light emitting layer. And an electrode layer. As a material of the transparent electrode layer, ITO (indium tin oxide), AZO (A
l-added ZnO), SnO _{2 and the} like. This transparent electrode layer can be formed by a method such as sputtering. The pattern of the transparent electrode layer is not particularly limited, and the transparent electrode layer can be formed in a pattern similar to a conventional one such as a stripe shape.

The organic EL light-emitting layer is composed of a hole transport layer, a light-emitting layer formed on the hole transport layer, and an electron-transport layer formed on the light-emitting layer in the same manner as in the prior art. Can be. This organic EL light emitting layer can be formed by using a vacuum evaporation method, a Langmuir-Blodgett evaporation method, a dip coating method, a spin coating method, a vacuum gas evaporation method, an organic molecular beam epitaxy method, or the like.

Examples of the material of the metal electrode layer include a conductive metal such as an Mg-Ag alloy and Al. Since this metal electrode layer is formed on the organic EL light emitting layer, it cannot be formed by a film formation method such as sputtering or the like in which a high-temperature or high-energy gas acts. Therefore, the material of the metal electrode layer is selected from materials that can be formed by an evaporation method or the like.

The shape of the sealing member is not particularly limited as long as the organic EL element can be hermetically sealed in the sealing member. For example, a box-shaped or plate-shaped sealing glass or resin having an opening on one side is used, and the peripheral edge of the sealing glass or the like is bonded to the peripheral edge of the transparent substrate with a sealing agent such as an adhesive, And the transparent substrate and the organic EL element can be disposed therein.

The distance between the sealing member and the metal electrode layer or the moisture absorbing film of the organic EL element is generally set to 10 to 150 μm.
If the distance is too small, the sealing member may come into contact with the organic EL element and damage the organic EL element. In addition, a spacer is interposed in a sealed space other than the organic EL element portion,
The organic EL element can be prevented from being damaged. The inert substance sealed in the sealing space may be any substance that is inert to the organic EL element, the sealing member and the sealing agent, and may be an inert gas such as a nitrogen gas, a helium gas, or an argon gas. Alternatively, a fluorine-based inert liquid can be used.

[0029]

The present invention will be described below in detail with reference to examples. (Embodiment 1) The organic EL display device of Embodiment 1 shown in FIG. 1 has the moisture absorbing film of the present invention provided on the inner surface of a sealing member.

This organic EL display device has a glass substrate 1 as a transparent substrate and an ITO formed on the glass substrate 1.
An organic EL element 2 including a transparent electrode layer 21 made of a film, an organic EL light emitting layer 22 formed on the transparent electrode layer 21 and a metal electrode layer 23 formed on the organic EL light emitting layer 22 and made of an Mg-Ag alloy; A back glass substrate 3 as a sealing member bonded to the glass substrate 1 so as to cover the organic EL element 2 while enclosing an inert fluid therein, and the peripheral edges of the glass substrate 1 and the back glass substrate 3 are bonded together. In addition, the back glass substrate 3 includes an adhesive 5 as a sealing agent that forms a sealing space 4 therebetween, and a moisture absorbing film 6 formed on the inner surface of the back glass substrate 3.

The glass substrate 1 and the rear glass substrate 3 are made of soda-lime glass, and each has a thickness of 1.1 mm. The transparent electrode layer 21 is formed in a stripe shape on the glass substrate 1 by sputtering, and has a thickness of 1000.
Å2000Å. The organic EL light emitting layer 22 includes a hole transport layer formed on almost the entire surface of the transparent electrode layer 21, a light emitting layer formed on the hole transport layer, and an electron transport layer formed on the light emitting layer. And each is formed from a known organic material by a vapor deposition method, and the total thickness is 100
0 to 1500 °.

The metal electrode layer 23 is formed to a thickness of 1500 to 2000 ° by a vapor deposition method via a mask, and has a stripe shape orthogonal to the transparent electrode layer 21. Therefore, in the organic EL element 2, the transparent electrode layer 21 and the metal electrode layer 2 driven by the dot matrix method are used.
Light is emitted by applying a DC voltage to the organic EL light emitting layer 22 through the light emitting layer 3, and the light is transmitted through the transparent electrode layer 21 and the glass substrate 1 and is visually recognized from the surface of the glass substrate 1.
If a predetermined point of the matrix formed by the transparent electrode layer 21 and the metal electrode layer 23 is selected and energized, the point becomes a pixel, so that an image can be displayed as a display.

The moisture-absorbing film 6 formed on the inner surface of the rear glass substrate 3 is made of P using an alkaline earth peroxide as a starting material.
It is composed of an alkaline earth monoxide formed by the VD method. The moisture absorbing film 6 is specifically made of barium dioxide (BaO ₂ ).
The target is a sintered body obtained by sintering the powder in air at 440 ° C. for 30 minutes. The target is a barium monoxide (BaO) film formed by an ion plating method. 1.0 μm thick on the inner surface of substrate 3
The thickness is formed as follows. Hereinafter, a method of forming the moisture absorbing film 6 will be described in detail.

First, the rear glass substrate 3 is washed with an alkali,
Pure water washing, spin drying with dry nitrogen, wet washing using ultrasonic waves, and dry washing with ultraviolet light were sequentially performed, and the surface was purified so that the contact angle with pure water was about 5 °. Then, using a device capable of vapor deposition and sputtering, RF reverse sputtering (Ar) was performed under a vacuum of 2.0 × 10 ⁻⁶ Pa.
(A method of cleaning by directly colliding gas particles with the substrate surface), and then heating the rear glass substrate 3 to 250 ° C. to further purify the surface. And the back glass substrate 3
Is heated to 250 ° C., DC ion plating is performed using the above-mentioned barium dioxide sintered body as a target, and barium monoxide (Ba) is formed on the surface of the back glass substrate 3.
O) was formed. The film forming conditions for ion plating are as follows. When the components of the obtained moisture absorbing film 6 were examined by X-ray diffraction and EPMA, the moisture absorbing film 6 was composed of only BaO.
No impurities were found in the sample. The density of the moisture absorbing film 6 was 5.72 g / cm ³ , which was almost the same as the bulk density.

Output: 10 kV, 0.15 A Degree of vacuum: 1.33 × 10 ⁻² Pa (Ar pressure) Film forming rate: 50 nm / sec Back glass substrate 3 on which the moisture absorbing film 6 was formed as described above.
Then, the glass substrate 1 on which the organic EL element 2 is formed is bonded to each other by an ultraviolet-curable adhesive 5 at the periphery thereof in a nitrogen gas atmosphere at 1 atm. The use of an ultraviolet-curable adhesive prevents a problem that the organic EL element 2 is deteriorated due to a high temperature at the time of bonding. The adhesive 5 is provided on the surface of the glass substrate 1 that is exposed without the transparent electrode layer 21, the organic EL light emitting layer 22, and the metal electrode layer 23. Thus, an airtight sealed space 4 is formed by the glass substrate 1, the rear glass substrate 3, and the adhesive 5, and a nitrogen gas is sealed in the sealed space 4. Note that the pressure of the nitrogen gas is set to be 1 atm at room temperature (25 ° C.). The nitrogen gas can be sealed in the sealing space 4 by bonding the glass substrate 1 on which the organic EL element 2 is formed in advance and the rear glass substrate 3 with an adhesive 6 in a nitrogen gas.

In the organic EL display of this embodiment, the organic EL
Back glass substrate 3 as a sealing member for sealing L element 2
A moisture absorbing film 6 made of only alkaline earth monoxide (BaO) formed by an ion plating method using alkaline earth peroxide (BaO ₂ ) as a starting material.
Are formed. Since the moisture-absorbing film 6 is formed using the alkaline earth peroxide which is stable in the atmosphere as described above, the moisture-absorbing film 6 is uniform and has high purity.
Therefore, it exhibits high moisture absorption performance. Therefore, in the organic EL display device of the present embodiment, it is possible to effectively prevent moisture from entering the organic EL light emitting layer 22 and the like of the organic EL element 2, and to extend the life of the organic EL element 2. it can.

When the organic EL display device of the first embodiment is manufactured, a large glass substrate 1 and a rear glass substrate 3 are used, a plurality of organic EL elements 2 are formed on the glass substrate 1, and the rear glass is formed. After forming a plurality of moisture-absorbing films 6 on the entire surface of the substrate 3 or on a predetermined site using a mask, an adhesive 5 is applied to the predetermined site to join them together, and finally, the substrate is cut off. Can be manufactured with high productivity.

(Comparative Example 1) The same as in Example 1 except that BaO as an alkaline earth metal monoxide was used as a starting material instead of BaO ₂ as an alkaline earth metal peroxide. . (Comparative Example 2) Same as Example 1 except that the moisture absorbing film 6 was not formed.

(Evaluation) With respect to the organic EL display devices of Example 1 and Comparative Examples 1 and 2, the moisture absorbing performance of the moisture absorbing film 6 was evaluated. This is because the organic EL display device is left in a high-temperature and high-humidity atmosphere having a temperature of 85 ° C. and a relative humidity of 85%,
The observation was performed by observing the growth of a dark spot having a diameter of 8 to 15 μm observed in the initial state before standing. FIG. 2 shows the observation result, that is, the relationship between the standing time and the diameter of the dark spot. FIG. 2 shows a sample number of 30.
5 shows the average observation results for. Further, as the diameter of the dark spot increases, it indicates that moisture has penetrated into the organic EL element 2, that is, the moisture absorbing performance of the moisture absorbing film 6 is reduced.

As is apparent from FIG.
A film formed using BaO as a group monoxide as a starting material
The organic EL display device of Comparative Example 1 having a wet film and the moisture absorbing film
In comparison with the organic EL display device of Comparative Example 2 in which no electrode was formed,
The growth rate of dark spots with respect to
The device EL element 2 and the like have significantly deteriorated with time. This
On the other hand, BaO as an alkaline earth peroxide_TwoOut
Example 1 having the moisture absorbing film 6 formed as a raw material
In the EL display device, compared with those of Comparative Example 1 and Comparative Example 2,
The growth rate of dark spots is extremely small, and organic E
The degree of deterioration of the L element 2 and the like due to moisture is small. Accordingly
And BaO as alkaline earth peroxide _TwoStarting material
It can be seen that the moisture absorbing film 6 formed as
Call

(Second Embodiment) The organic EL display device of the second embodiment shown in FIGS. 3 and 4 uses the above-described moisture absorbing film 6 formed by using BaO ₂ as an alkaline earth peroxide as a starting material. It is formed partially on the EL element 2 at the non-light emitting portion. That is, in this organic EL display device, the organic EL element 2 driven by the dot matrix method is formed on the glass substrate 1 in the same manner as in the first embodiment, and then a masking process is performed. Only on the periphery where the metal electrode layer 23 is not formed,
The moisture absorbing film 6 was formed. In FIG. 4, an area A indicated by a hatched dotted line indicates a light emitting area where the metal electrode layer 23 is formed, and an area B indicated by an oblique line around this area is a non-light emitting area where the moisture absorbing film 6 is formed. Indicates the region that was performed.

This moisture absorbing film 6 has the same structure as that of the first embodiment.
BaO as a alkaline earth peroxide _TwoAs starting material
Of BaO deposited by ion plating method
And the film thickness was 1 μm as in Example 1.
Have been. Other configurations are the same as in the first embodiment.
You. In this organic EL display device, the moisture absorbing film 6 is formed of an organic EL element.
On the element 2 and partially formed in the non-light emitting area B
Therefore, it absorbs with the organic EL light emitting layer 22 and the like of the organic EL element 2.
Since the distance from the wet film 6 is extremely short, the organic EL light emission
The moisture absorption film 6 ensures that moisture enters the layer 22 and the like.
Can effectively prevent the organic EL element 2 from having a longer life.
It becomes possible to plan.

Since the moisture absorbing film 6 is partially formed in the non-light emitting area B on the organic EL element 2, the light emitting area of the organic EL element 2 is heated by heat or the like when the moisture absorbing film 6 is formed. A
Can be prevented from being damaged. In addition, organic EL
Since the moisture-absorbing film 6 is partially formed in the non-light-emitting area B on the element 2, moisture and oxygen adsorbed on the moisture-absorbing film 6 adversely affect the metal electrode layer 23 and the like in the light-emitting area A. Can be blocked. Further, there is no need to cover the metal electrode layer 23 with a stable protective film in order to prevent such adverse effects, which is advantageous in terms of cost and production.

As shown in FIG. 5, when the organic EL element 2 is driven by the segment method, the moisture absorbing film 6 is provided on the organic EL element 2 and in the non-light emitting portion area B shown by oblique lines in FIG. Can be formed.

[0045]

As described in detail above, the moisture absorbing film of the present invention
Since it is composed of an alkaline earth monoxide formed by a PVD method using an alkaline earth peroxide that is stable in the atmosphere as a starting material, it has high purity and high homogeneity, and thus has high moisture absorption performance. Further, the organic EL display device of the present invention provided with such a moisture absorbing film having a high moisture absorbing performance can effectively prevent moisture from entering the organic EL light emitting layer and the like of the organic EL element. It is possible to extend the life of the element.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an organic EL display device according to one embodiment of the present invention.

FIG. 2 is a graph showing evaluation results of moisture absorption performance by a moisture absorption film and showing a relationship between a standing time and a dark spot diameter.

FIG. 3 is a cross-sectional view of an organic EL display device according to another embodiment of the present invention.

FIG. 4 is a plan view of an organic EL display device according to another embodiment, and is an explanatory diagram showing a region of a non-light emitting portion where a moisture absorbing film is formed.

FIG. 5 is a plan view of an organic EL display device according to still another embodiment of the present invention, and is an explanatory diagram showing a region of a non-light emitting portion where a moisture absorbing film is formed.

FIG. 6 is a sectional view of a conventional organic EL display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass substrate (transparent substrate) 2 ... Organic EL element 3 ... Back glass substrate (sealing member) 4 ... Enclosed space 5 ... Adhesive 6 ... Moisture absorbing film A ... Light emitting part area B ... Non-light emitting part area

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Yokoi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Koichi Koyama 1414 Shimonomoto, Oji, Higashimatsuyama City, Saitama F Terms (reference) 3K007 AB13 BA06 BB01 BB04 BB05 CA01 CB01 DA01 DB03 EB00 FA01 FA02 4K029 AA09 BA43 BC00 BD00

Claims (2)

[Claims] 1. A moisture absorbing film comprising an alkaline earth monoxide formed by a PVD method using an alkaline earth peroxide as a starting material. 2. A transparent substrate, comprising a transparent electrode layer formed on the transparent substrate, an organic EL light emitting layer formed on the transparent electrode layer, and a metal electrode layer formed on the organic EL light emitting layer. An organic EL display device comprising: an organic EL element; and a sealing member joined to the transparent substrate so as to cover the organic EL element while enclosing an inert fluid therein. At least one of the light-emitting portion and the inner surface of the sealing member is provided with a moisture-absorbing film made of an alkaline earth monoxide formed by a PVD method using an alkaline earth peroxide as a starting material. An organic EL display device comprising: