JP4342023B2 - Hygroscopic film and organic EL display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hygroscopic film and an organic EL display device, and more particularly to a hygroscopic film made of alkaline earth monoxide and an organic EL display device including the hygroscopic film.
[0002]
[Prior art]
As display devices for display, cathode ray tubes, liquid crystals, plasmas, light emitting diodes, and EL (Electro Luminescence) are conventionally known. Computer displays, liquid crystals Widely used in display back panels.
[0003]
Among these, EL is a self-luminous type and can be a thin film, and thus is expected as a thin display element. As a thin film type direct current EL, an organic thin film EL that can be driven at a low voltage has recently attracted attention.
An organic EL element 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. Has been. Then, by energizing 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 a light emission phenomenon occurs due to the energy at this time. This light emission phenomenon is injection light emission similar to a light emitting diode, and is characterized by a low light emission voltage of 10 V or less.
[0004]
As an organic EL display device using such an organic EL element, a device in which the organic EL element structure is used as a unit pixel and the unit pixel is two-dimensionally arranged on a transparent substrate in a matrix drive is known. This consists of a striped transparent electrode group on a transparent substrate, an organic EL light emitting layer on the transparent electrode group, and a striped metal electrode group orthogonal to the transparent electrode group on the organic EL light emitting layer sequentially. It is formed, and the intersection between the transparent electrode group and the metal electrode group is two-dimensionally arranged in a plane as an organic EL element structure which is a unit pixel. In this type of display device, the intersection of two striped electrodes to which a voltage is applied becomes a light emitting portion, so that an image can be displayed by sequentially shifting the stripes to emit light by applying a voltage. The light emitted from the organic EL light emitting layer is reflected directly or by a 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.
[0005]
However, the organic light emitting material used for the organic EL element has a drawback that its water resistance is low and its life is shortened by moisture. Moreover, metal electrode layers, such as Mg alloy used for an organic EL element, also have the fault that the tolerance with respect to water or oxygen is low.
Japanese Patent Laid-Open No. 9-148066 discloses an organic EL display device in which an organic EL element is sealed in a sealing member and a hygroscopic agent is disposed on the inner surface of the sealing member.
[0006]
As shown in FIG. 6, this organic EL display device includes a transparent glass substrate 80, a transparent electrode layer 81a formed on the glass substrate 80, an organic EL light emitting layer 81b formed on the transparent electrode layer 81a, and an organic And an organic EL element 81 made of a metal electrode layer 81c formed on the EL light emitting layer 81b, and a sealing agent 82 is applied to the glass substrate 80 so as to cover the organic EL element 81 while enclosing an inert gas therein. The sealing member 83 is joined via. A hygroscopic agent 84 is fixed to the inner side surface of the sealing member 83 with an adhesive.
[0007]
In this organic EL display device, the sealing member 83 is bonded to the peripheral edge of the glass substrate 80 so as to cover the organic EL element 81 while enclosing an inert gas therein. Can be blocked. Further, 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 sealant 82. Therefore, the drying property in the enclosed space can be improved and the device life can be extended.
[0008]
[Problems to be solved by the invention]
Here, as one of the above-mentioned hygroscopic agents, monoxides of alkaline earth metals such as Ca, Ba and Mg are exemplified. Then, using this alkaline earth metal monoxide as a starting material, a PVD method (physical vapor deposition method) such as a vacuum evaporation method or a sputtering method is performed, and an alkaline earth metal monoxide is formed on the inner surface of the sealing substrate 83. It is also possible to form a hygroscopic film.
[0009]
However, when a hygroscopic film made of alkaline earth metal monoxide is formed on the inner surface of the sealing member 83 by the PVD method using alkaline earth metal monoxide as a starting material, the following problems occur: There is a point.
That is, alkaline earth metal monoxide is unstable in the atmosphere and easily changes to a hydrate or a carbonate. For example, barium monoxide (BaO) is CO₂And H₂BaCO reacts with O as follows:_Three・ N (H₂O) and Ba (OH)₂・ N (H₂O) Hydrate and BaCO_ThreeIt changes to the carbon dioxide.
[0010]
BaO + CO₂→ BaCO_Three
BaCO_Three+ NH₂O → BaCO_Three・ N (H₂O)
BaO + H₂O → Ba (OH)₂
Ba (OH)₂+ NH₂O → Ba (OH)₂・ N (H₂O)
For this reason, the alkaline earth metal monoxide is used as a starting material as a powder as it is, or the powder is sintered and the sintered body is used as a starting material, and a hygroscopic film is formed by the PVD method. In this case, since there are hydrate and carbonate impurities in the starting material, it is impossible to form a stable film, and the quality of the formed film is inhomogeneous and low purity, and is homogeneous and high in purity. It is difficult to form a hygroscopic film, that is, a hygroscopic film having high hygroscopic performance.
[0011]
Further, when a hygroscopic film is formed on the inner side surface of the sealing member 83, an enclosed space is interposed between the organic EL element 81 and the hygroscopic film, and there is a distance between the two, and therefore the organic EL of the organic EL element 81 It is difficult to effectively prevent moisture from entering the light emitting layer 81b and the like.
The present invention has been made in view of the above circumstances, and it is a first technical problem to be solved to provide a hygroscopic film with high purity, high homogeneity, and high hygroscopic performance, such as an organic EL light emitting layer of an organic EL element, etc. It is a second technical problem to be solved to provide an organic EL display device having a hygroscopic film that can effectively prevent moisture from entering the glass.
[0012]
[Means for Solving the Problems]
The hygroscopic film of the present invention that solves the first problem is characterized by comprising an alkaline earth monoxide formed by a PVD method using an alkaline earth peroxide as a starting material. .
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 An organic EL device comprising a metal electrode layer formed on a light emitting layer, and a sealing member bonded to the transparent substrate so as to cover the organic EL device while enclosing 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 is an alkali film formed by a PVD method using an alkaline earth peroxide as a starting material. A moisture-absorbing film made of earth monoxide is formed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The hygroscopic film of the present invention comprises an alkaline earth monoxide formed by PVD using an alkaline earth peroxide as a starting material. Unlike alkaline earth monoxide, alkaline earth peroxide can be stably stored in the atmosphere. Therefore, 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 hygroscopic film made of a single oxide is formed, the starting material, for example, impurities such as hydrates and carbonates are not present at the grain boundaries of the sintered body. Can be formed. Therefore, the hygroscopic film of the present invention formed using an alkaline earth peroxide as a starting material exhibits high hygroscopic performance.
[0014]
The alkaline earth peroxide is an alkaline earth metal dioxide, that is, an alkaline earth metal oxide.₂ ^2-It can be produced by heating an alkaline earth metal in air or oxygen. Alkaline earth metals include Ca, Sr, Ba, Ra, Be and Mg, and any of the alkaline earth metals can be used for the moisture-absorbing film of the present invention. However, cost and availability of high-purity materials are easily available. Ca, Sr, Ba and Mg can be preferably used in consideration of the practicality and practicality.
[0015]
In order to form a hygroscopic film made of alkaline earth monoxide from this alkaline earth metal peroxide by the PVD method, a powder of alkaline earth peroxide is used as a starting material, or this powder is sintered. PVD may be performed using a sintered body as a starting material.
The conditions for adjusting the alkaline earth peroxide powder are not particularly limited, and may be ordinary conditions. For example, BaO₂When obtaining a powder, Ba powder, BaO · n (H₂O) Powder or BaO · CO_ThreeBy heating the powder at about 500 ° C. in an oxygen atmosphere, BaO₂It can be a powder.
[0016]
Moreover, the sintering conditions of the alkaline earth peroxide sintered body are not particularly limited, and may be normal sintering conditions. For example, BaO₂When obtaining a sintered body of powder, BaO₂Since the melting point is 450 ° C., it can be sintered in the air at a temperature slightly lower than this temperature (about 400 to 440 ° C.) for about 30 to 60 minutes. In addition, when sintering alkaline earth oxide such as BaO, for example, sintering is performed at about 1000 ° C. or higher. When compared with this, sintering of alkaline earth peroxide is performed at a low temperature. This is advantageous in terms of cost and the like.
[0017]
Although it does not specifically limit as said PVD method, Vacuum deposition methods, such as an electron beam heating method and an ion plating method, a sputtering method, etc. can be employ | adopted suitably. The film forming conditions can also be appropriately set according to the starting material, the film thickness of the moisture absorbing film to be formed, and the like. For example, the film forming conditions when the electron beam heating method is adopted are as follows:
Output: about 1-20kV, about 0.05-0.3A
Degree of vacuum: 2 × 10^-6Pa or less
Deposition rate: about 0.1 to 1.0 nm / sec
The film forming conditions when the ion plating method is adopted are as follows:
Output: about 1-20kV, about 0.05-0.3A
Degree of vacuum: 0.5-2 × 10^-FourAbout Pa (Argon pressure)
Deposition rate: about 0.05 to 0.3 nm / sec
The film formation conditions when the sputtering method is adopted are as follows:
Output: about 50-500W
Degree of vacuum: 1-8 × 10^-FourAbout Pa (Argon pressure)
Deposition rate: about 5 to 40 nm / sec
It can be.
[0018]
Here, when the hygroscopic 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 film thickness of the hygroscopic film is not particularly limited, but the higher the film thickness, the higher the hygroscopic performance. Therefore, the hygroscopic film can be appropriately set so as to exhibit the desired hygroscopic performance. Note that if the thickness of the hygroscopic film is too thick, the film formation cost may increase or the hygroscopic film may be peeled off. For this reason, when applied to an organic EL display device, the thickness of the hygroscopic film is preferably 100 μm or less, and more preferably about 0.1 to 30 μm.
[0019]
In addition, when the hygroscopic film of the present invention is applied to an organic EL display device, sealing is performed so as to cover an organic EL element and form a sealed space in which an inert fluid is sealed between the transparent substrate and the transparent substrate. Although this hygroscopic film can be formed on the inner side surface of the member, it is preferable to form this hygroscopic film on the organic EL element from the viewpoint of more reliably preventing moisture from entering the organic EL light emitting layer or the like. In this case, in order to prevent the light emitting portion of the organic EL element from being damaged by heat or the like when the hygroscopic film is formed by the PVD method, the moisture absorbing film may be partially formed on the non-light emitting portion on the organic EL element. preferable. Thus, when a hygroscopic film is partially formed on the non-light emitting portion on the organic EL element, it is possible to prevent moisture and oxygen adsorbed on the hygroscopic film from adversely affecting the metal electrode layer and the like of the light emitting portion. In addition, as described later, it is not necessary to cover the metal electrode layer with a stable protective film to prevent such adverse effects, which is advantageous in terms of cost and production. In addition, the mode of partially forming the hygroscopic film on the non-light emitting portion on the organic EL element is that there are many non-light emitting portions on the organic EL element or a pattern is formed with a mask as in the segment display of a watch or the like In the case of a pattern that is as rough as possible, it can be more suitably applied.
[0020]
Here, the hygroscopic film can be formed on the entire surface of the organic EL element. In this case, the hygroscopic film is further formed on the hygroscopic film.₂By forming a protective film such as a film or a resin film, the sealing member can be omitted. In addition, when a hygroscopic film is formed on the light emitting portion on the organic EL element (including the case where the hygroscopic film is formed on the entire surface of the organic EL element), moisture or oxygen adsorbed on the hygroscopic film is applied to the metal electrode layer, etc. In order to prevent adverse effects, the metal electrode layer is made of a stable protective film (SiO₂And a hygroscopic film is preferably formed thereon.
[0021]
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 the moisture absorbing films can further increase the length of the organic EL element. Life can be extended.
Thus, the moisture absorption film made of alkaline earth monoxide formed by the PVD method using an alkaline earth peroxide as a starting material on the organic EL element has a 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 surfaces of the sealing member, the lifetime of the organic EL element can be extended by the moisture absorption effect of the moisture absorption film having high moisture absorption performance. Further, if the moisture absorbing film is formed on the non-light emitting portion on the organic EL element, the distance between the organic EL emitting layer and the like of the organic EL element and the moisture absorbing film becomes extremely short. Can be reliably prevented by the moisture absorption film, and the life of the organic EL element can be effectively extended.
[0022]
The organic EL display device 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 a metal electrode layer formed on the organic EL light emitting layer. And an organic EL element, and a sealing member bonded to the transparent substrate so as to cover the organic EL element while enclosing an inert fluid therein.
[0023]
As the transparent substrate, a glass substrate is usually used, but a synthetic resin substrate can also be used. A flexible synthetic resin film can also be used as the transparent substrate. When a synthetic resin film is used, a gap between the synthetic resin film and the transparent electrode layer formed on the synthetic resin film is formed so as to absorb moisture or the like that has penetrated from the outside through the synthetic resin film itself. In addition, it is preferable to form an auxiliary hygroscopic film.
[0024]
The organic EL element 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, as in the past. Consists of.
As a material of the transparent electrode layer, ITO (indium tin oxide), AZO (Al-added ZnO), SnO are used as in the conventional case.₂Etc. are exemplified. This transparent electrode layer can be formed by a method such as sputtering. The pattern in particular of a transparent electrode layer is not restrict | limited, It can form in the same pattern as the past, such as stripe form.
[0025]
The organic EL light emitting layer can be configured in the same manner as the conventional one from a hole transport layer, a light emitter layer formed on the hole transport layer, and an electron transport layer formed on the light emitter layer. This organic EL light emitting layer can be formed by using a vacuum deposition method, a Langmuir Blodget deposition method, a dip coating method, a spin coating method, a vacuum gas deposition method, an organic molecular beam epitaxy method, or the like.
[0026]
Examples of the material for the metal electrode layer include conductive metals such as Mg—Ag alloy and Al. Since this metal electrode layer is formed on the organic EL light emitting layer, it cannot be formed using a film forming method in which high temperature or high energy gas acts such as sputtering. Therefore, the material of the metal electrode layer is selected from materials that can be formed by vapor deposition.
[0027]
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-like or plate-like sealing glass or resin having an opening on one surface is used, and the periphery of this sealing glass or the like is joined to the periphery of the transparent substrate by a sealing agent such as an adhesive, or a box-like The sealing space can be formed only by the sealing member, and the transparent substrate and the organic EL element can be disposed therein.
[0028]
The distance between the sealing member and the metal electrode layer or the hygroscopic film of the organic EL element is generally 10 to 150 μm. When this space | interval is too narrow, there exists a possibility that a sealing member and an organic EL element may contact and an organic EL element may be damaged. Moreover, the organic EL element can be prevented from being damaged by interposing a spacer in the enclosed space other than the organic EL element portion.
The inert substance enclosed in the enclosed space may be any substance that is inert with respect to the organic EL element, the sealing member, and the sealant, such as nitrogen gas, helium gas, and argon gas. Alternatively, a fluorine-based inert liquid can be used.
[0029]
【Example】
Hereinafter, the present invention will be described specifically by way of examples.
Example 1
The organic EL display device of Example 1 shown in FIG. 1 has the hygroscopic film of the present invention provided on the inner surface of a sealing member.
[0030]
This organic EL display device includes a glass substrate 1 as a transparent substrate, a transparent electrode layer 21 made of an ITO film formed on the glass substrate 1, an organic EL light emitting layer 22 formed on the transparent electrode layer 21, and an organic EL. An organic EL element 2 formed on the light emitting layer 22 and made of a metal electrode layer 23 made of an Mg—Ag alloy and bonded to the glass substrate 1 so as to cover the organic EL element 2 while enclosing an inert fluid therein. A back glass substrate 3 as a sealing member, an adhesive 5 as a sealant that joins the peripheral edges of the glass substrate 1 and the back glass substrate 3 to form a sealing space 4 therebetween, and a back glass substrate 3 And a hygroscopic film 6 formed on the inner surface.
[0031]
The glass substrate 1 and the back glass substrate 3 are made of soda-lime glass, and the plate thickness is 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 to 2000 mm. 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 emitter layer formed on the hole transport layer, and an electron transport formed on the light emitter layer. Each layer is formed from a known organic material by a vapor deposition method, and the total thickness is 1000 to 1500 mm.
[0032]
The metal electrode layer 23 is formed in a thickness of 1500 to 2000 mm by a vapor deposition method through a mask, and has a stripe shape orthogonal to the transparent electrode layer 21. Therefore, in this organic EL element 2, light is emitted by applying a DC voltage to the organic EL light emitting layer 22 through the transparent electrode layer 21 and the metal electrode layer 23 driven by the dot matrix method, and the light emission is the transparent electrode layer 21. And visible through the surface of the glass substrate 1 through the glass substrate 1. Further, 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.
[0033]
The moisture absorption film 6 formed on the inner side surface of the back glass substrate 3 is made of alkaline earth monoxide formed by PVD using an alkaline earth peroxide as a starting material. The moisture absorption film 6 is specifically made of barium dioxide (BaO).₂) It consists of barium monoxide (BaO) formed by ion plating with a sintered body obtained by sintering powder in the atmosphere at 440 ° C. for 30 minutes as the target. The film is formed on the inner surface of the glass substrate 3 with a thickness of 1.0 μm. Hereinafter, the film forming method of the hygroscopic film 6 will be described in detail.
[0034]
First, the back glass substrate 3 is successively subjected to alkali cleaning, pure water cleaning, spin drying with dry nitrogen, wet cleaning using ultrasonic waves, and dry cleaning with ultraviolet rays so that the contact angle with pure water is about 5 °. Purified the surface. And using a device capable of vapor deposition and sputtering, the degree of vacuum is 2.0 × 10^-6RF reverse sputtering (a method in which gas particles such as Ar are directly collided with the substrate surface for cleaning) was performed under Pa, and then the rear glass substrate 3 was heated to 250 ° C. to further purify the surface. Then, in a state where the back glass substrate 3 is heated to 250 ° C., DC ion plating is performed using the sintered body of barium dioxide as a target, and a hygroscopic film made of barium monoxide (BaO) is formed on the surface of the back glass substrate 3. 6 was deposited. The ion plating film forming conditions are as follows. Further, when the components of the obtained hygroscopic film 6 were examined by X-ray diffraction and EPMA, the hygroscopic film 6 was composed only of BaO, and no presence of impurities was observed in the hygroscopic film 6. Further, the density of the hygroscopic film 6 is 5.72 g / cm.^ThreeIt was almost the same as the bulk density.
[0035]
Output: 10kV, 0.15A
Degree of vacuum: 1.33 × 10^-2Pa (Ar pressure)
Deposition rate: 50 nm / sec
The back glass substrate 3 on which the hygroscopic film 6 is formed as described above and the glass substrate 1 on which the organic EL element 2 is formed are UV-curing at the peripheral edges in a nitrogen gas atmosphere of 1 atm. Bonded with an adhesive 5. Note that the use of an ultraviolet curable adhesive prevents a problem that the organic EL element 2 deteriorates due to a high temperature during bonding. The adhesive 5 is provided on the surface of the glass substrate 1 exposed without the transparent electrode layer 21, the organic EL light emitting layer 22, and the metal electrode layer 23. Thus, an airtight enclosure space 4 is formed by the glass substrate 1, the back glass substrate 3 and the adhesive 5, and nitrogen gas is enclosed in the enclosure space 4. Note that the pressure of the nitrogen gas is set to 1 atm at room temperature (25 ° C.). Further, the nitrogen gas can be sealed in the sealing space 4 by bonding the glass substrate 1 on which the organic EL element 2 has been formed in advance and the rear glass substrate 3 with an adhesive 6 in nitrogen gas.
[0036]
In the organic EL display device of this example, an alkaline earth peroxide (BaO) is formed on the inner surface of the back glass substrate 3 as a sealing member for sealing the organic EL element 2.₂The hygroscopic film 6 made only of alkaline earth monoxide (BaO) is formed by an ion plating method using) as a starting material. As described above, the moisture absorbing film 6 is formed with the target being an alkaline earth peroxide that is stable in the atmosphere. Therefore, the moisture absorbing film 6 is homogeneous and has high purity, and thus exhibits high moisture absorbing 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 of the organic EL element 2, and to extend the life of the organic EL element 2. it can.
[0037]
When the organic EL display device of Example 1 is manufactured, a large glass substrate 1 and a back glass substrate 3 are used, and a plurality of organic EL elements 2 are formed on the glass substrate 1. After forming a plurality of hygroscopic films 6 on the entire surface or using a mask at a predetermined site, the adhesive 5 is applied to the predetermined site, the two are joined, and finally divided into a plurality of organic EL A display device can be manufactured with high productivity.
[0038]
(Comparative Example 1)
BaO as alkaline earth metal peroxide₂The same as Example 1 except that BaO as an alkaline earth metal monoxide is used as a starting material instead of.
(Comparative Example 2)
Except not forming the moisture absorption film | membrane 6, it is the same as that of the said Example 1. FIG.
[0039]
(Evaluation)
The organic EL display devices of Example 1 and Comparative Examples 1 and 2 were evaluated for moisture absorption performance by the moisture absorption film 6. This is because this organic EL display device is left in a high-temperature and high-humidity atmosphere at a temperature of 85 ° C. and a relative humidity of 85%, and a dark spot with a diameter of 8 to 15 μm observed in the initial state before being left is observed. It was done by doing. The observation result, that is, the relationship between the standing time and the diameter of the dark spot is shown in FIG. FIG. 2 shows an average observation result for 30 samples. Moreover, it shows that the water | moisture content penetrate | invades in the organic EL element 2, that is, the moisture absorption performance by the moisture absorption film | membrane 6 is falling, so that the diameter of a dark spot becomes large.
[0040]
As is apparent from FIG. 2, the organic EL display device of Comparative Example 1 provided with a hygroscopic film formed using BaO as an alkaline earth metal monoxide as a starting material, and Comparative Example 2 without a hygroscopic film formed In the organic EL display device, the growth rate of dark spots with respect to the standing time is large, and the organic EL element 2 and the like are greatly deteriorated with time. In contrast, BaO as an alkaline earth peroxide₂In the organic EL display device of Example 1 including the moisture absorbing film 6 formed using as a starting material, the growth rate of dark spots is extremely small as compared with those of Comparative Examples 1 and 2, and the organic EL element 2 and the like. Degradation due to moisture is small. Therefore, BaO as alkaline earth peroxide₂It can be seen that the hygroscopic film 6 formed using as a starting material exhibits high hygroscopic performance.
[0041]
(Second embodiment)
The organic EL display device of Example 2 shown in FIGS. 3 and 4 is made of BaO as an alkaline earth peroxide.₂The hygroscopic film 6 formed using as a starting material is partially formed on the organic EL element 2 in a non-light emitting portion.
That is, in this organic EL display device, the organic EL light emitting layer 22 is formed by performing the masking process after forming the organic EL element 2 driven by the dot matrix method on the glass substrate 1 as in the first embodiment. The hygroscopic film 6 was formed only on the peripheral edge on which the metal electrode layer 23 was not formed. In FIG. 4, a region A indicated by a dotted diagonal line indicates a light emitting portion region where the metal electrode layer 23 is formed, and a region B indicated by a diagonal line around this region is a non-light emitting portion region and the moisture absorbing film 6 is formed. Indicates the region that was created.
[0042]
This hygroscopic film 6 is similar to Example 1 in that BaO as an alkaline earth peroxide is used.₂As a starting material, the film thickness is 1 μm, as in Example 1.
Other configurations are the same as those of the first embodiment.
In this organic EL display device, the hygroscopic film 6 is partially formed on the organic EL element 2 and in the non-light emitting region B, so that the organic EL light emitting layer 22 of the organic EL element 2 and the hygroscopic film 6 are formed. Since the moisture absorption film 6 can surely prevent moisture from entering the organic EL light emitting layer 22 and the like, the life of the organic EL element 2 can be effectively extended. It becomes.
[0043]
Further, since the hygroscopic film 6 is partially formed in the non-light emitting region B on the organic EL element 2, the light emitting region A of the organic EL element 2 is damaged by heat or the like when the hygroscopic film 6 is formed. Can be prevented.
Furthermore, since the hygroscopic film 6 is partially formed in the non-light emitting area B on the organic EL element 2, moisture and oxygen adsorbed on the hygroscopic film 6 adversely affect the metal electrode layer 23 and the like in the light emitting area A. Can be prevented. Further, it is not necessary to cover the metal electrode layer 23 with a stable protective film to prevent such adverse effects, which is advantageous in terms of cost and production.
[0044]
As shown in FIG. 5, when the organic EL element 2 is driven by the segment method, the hygroscopic film 6 is formed on the organic EL element 2 and in the non-light emitting portion region B indicated by hatching in FIG. be able to.
[0045]
【The invention's effect】
As described in detail above, the hygroscopic film of the present invention is composed of alkaline earth monoxide formed by the PVD method using an alkaline earth peroxide that is stable in the atmosphere as a starting material. It is highly homogeneous and therefore has high moisture absorption performance.
In addition, the organic EL display device of the present invention having the moisture absorption film having high moisture absorption performance can effectively prevent moisture from entering the organic EL light emitting layer or 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 an embodiment of the present invention.
FIG. 2 is a graph showing the results of evaluation of moisture absorption performance by a moisture absorption film and showing the relationship between the standing time and the 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 described above, and is an explanatory view showing a region of a non-light-emitting portion where a hygroscopic 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 view showing a region of a non-light emitting portion on which a hygroscopic film is formed.
FIG. 6 is a cross-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 ... Hygroscopic film
A: Light emitting area B: Non-light emitting area

Claims (3)

  A hygroscopic film comprising an alkaline earth monoxide formed by a PVD method using an alkaline earth peroxide as a starting material. An organic EL element comprising 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 metal electrode layer formed on the organic EL light emitting layer; In an organic EL display device comprising a sealing member bonded to the transparent substrate so as to cover the organic EL element while enclosing an inert fluid therein,
The non-light emitting portion on at least the organic EL element of the inner surface of the non-light emitting portion and the sealing member on the organic EL element is formed by a PVD method using an alkaline earth peroxide as a starting material An organic EL display device, wherein a moisture absorption film made of the alkaline earth monoxide is formed. An organic EL element comprising 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 metal electrode layer formed on the organic EL light emitting layer; In an organic EL display device comprising a sealing member bonded to the transparent substrate so as to cover the organic EL element while enclosing an inert fluid therein,
At least the inner surface of the non-light emitting portion on the organic EL element and the inner surface of the sealing member is formed by PVD using an alkaline earth peroxide as a starting material. An organic EL display device comprising a hygroscopic film made of alkaline earth monoxide.

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