JP6855418B2 - Organic EL device and its manufacturing method - Google Patents

Description

The present invention relates to an organic EL device and a method for manufacturing the same.

In order to prevent the light emitting part of the organic EL element from shortening the light emitting life due to moisture, the light emitting part provided on the substrate may be sealed by the sealing substrate, and a water catching material may be further provided on the sealing substrate. There is (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-331766

In the manufacture of an organic EL element having a desiccant layer provided on a sealing substrate, it is necessary to form a desiccant layer on the sealing substrate in a dry atmosphere such as an inert gas in order to avoid mixing of moisture. there were. However, from the viewpoint of simplifying the process and equipment, it is desirable that the desiccant layer can be formed in an air atmosphere without requiring a dry atmosphere. By using a desiccant having a high water catching capacity, it is expected that the desiccant layer can maintain a sufficient water catching capacity even if the desiccant layer is formed in an atmospheric atmosphere. However, even if a desiccant with a high water catching capacity is used, it is clear that if the desiccant layer is formed on the sealing substrate in an atmospheric atmosphere, the light emitting area ratio of the organic EL element tends to be insufficient from the initial stage immediately after production. became.

Therefore, an object of one aspect of the present invention is to provide an organic EL device capable of maintaining a sufficient initial emission area ratio even when manufactured by a method including a step of forming a desiccant layer in an atmospheric atmosphere. To do.

One aspect of the present invention is an element substrate, a sealing substrate provided on the element substrate and having a light emitting portion and a main surface facing the element substrate, a desiccant layer provided on the main surface, and water repellency. The present invention relates to an organic EL device comprising a composite layer composed of layers and a sealing agent that is interposed between the element substrate and the sealing substrate and thereby adheres the element substrate and the sealing substrate. The light emitting unit has a pair of electrodes arranged to face each other and an organic layer provided between them. An airtight space is formed surrounded by the element substrate, the sealing substrate, and the sealant. A light emitting unit and a composite layer are arranged in this airtight space.

Another aspect of the present invention relates to a method of manufacturing an organic EL device. In the method, a step of forming a composite layer composed of a desiccant layer and a water-repellent layer on the main surface of the sealing substrate, a step of forming a light emitting portion on the element substrate, and a step of forming the sealing substrate on the main surface A step of adhering to the element substrate in a direction facing the element substrate is provided. The sealing substrate is adhered to the element substrate by a sealing agent interposed between the element substrate and the sealing substrate. An airtight space is formed surrounded by the element substrate, the sealing substrate, and the sealant. A light emitting unit and a composite layer are arranged in this airtight space.

By providing a water-repellent layer together with a desiccant layer on the main surface of the sealing substrate, the organic EL element maintains a sufficient initial light emission area ratio even when the desiccant layer is formed in an atmospheric atmosphere. Easy to do. The water-repellent layer suppresses the adsorption of moisture in the atmospheric atmosphere to the sealing substrate. It is also considered that the water-repellent layer suppresses the influence of the water adsorbed on the sealing substrate on the light emitting portion.

According to one aspect of the present invention, there is provided an organic EL device capable of maintaining a sufficient initial emission area ratio even when manufactured by a method including a step of forming a desiccant layer in an atmospheric atmosphere. ..

It is sectional drawing which shows one Embodiment of an organic EL element. It is a top view which shows one Embodiment of a sealing substrate and a composite layer. It is sectional drawing which follows the line II-II of FIG. It is sectional drawing which shows one Embodiment of a sealing substrate and a composite layer. It is sectional drawing which shows one Embodiment of a sealing substrate and a composite layer. It is a top view which shows one Embodiment of a sealing substrate and a composite layer.

Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

FIG. 1 is a cross-sectional view showing an embodiment of an organic EL device. The organic EL element 20 shown in FIG. 1 includes an element substrate 1, a light emitting portion 7 provided on the element substrate 1, a sealing substrate 3, a composite layer 15 composed of a desiccant layer 10 and a water repellent layer 11. A sealant 5 is provided.

The sealing substrate 3 has a top plate portion 3A having a rectangular or square flat main surface 3S facing the element substrate 1 and a side wall extending from the outer peripheral end portion of the top plate portion 3A in a direction perpendicular to the main surface 3S. It has a part 3B. The top plate portion 3A and the side wall portion 3B form a recess having a main surface 3S as a bottom surface. The composite layer 15 is formed on the main surface 3S of the sealing substrate 3.

The sealant 5 adheres the sealing substrate 3 and the element substrate 1 while interposing between the side wall portion 3B of the sealing substrate 3 and the element substrate 1. As a result, an airtight space 30 surrounded by the element substrate 1, the sealing substrate 3, and the sealing agent 5 is formed. The light emitting unit 7 and the composite layer 15 are arranged in the airtight space 30. The sealing substrate 3 may be a flat plate-like body having no side wall portion 3B, and in that case, usually, the sealing agent 5 is formed between the top plate portion 3A of the sealing substrate 3 and the element substrate 1. Intervenes. In any case, the "main surface facing the element substrate" means a surface facing the element substrate in the airtight space in which the light emitting portion is arranged. The water repellent layer 11 is provided in contact with the main surface 3S. The desiccant layer 10 is provided on the surface of the water-repellent layer 11 opposite to the main surface 3S.

FIG. 2 is a plan view showing an embodiment of the sealing substrate and the composite layer. FIG. 3 is a cross-sectional view taken along the line II-II of FIG. The plan view of FIG. 2 shows a form in which the sealing substrate 3 and the composite layer 15 are viewed from a direction perpendicular to the main surface 3S of the sealing substrate 3. In the case of the embodiment of FIGS. 2 and 3, the composite layer 15 covers the entire main surface 3S. However, the composite layer 15 may cover a part of the main surface 3S. For example, when viewed from the direction perpendicular to the main surface 3S of the sealing substrate 3, the area ratio of the composite layer 15 is 50% or more, 60% or more, 70% or more, or 75 with respect to the area of the main surface 3S. It may be% or more. It is considered that when the area ratio of the composite layer 15 becomes large, the moisture adhering to the main surface 3S of the sealing substrate 3 in the atmospheric atmosphere is less likely to affect the light emitting portion 7. Further, from the viewpoint of ensuring stable adhesion between the sealing substrate and the element substrate, the area ratio of the composite layer 15 may be less than 90%.

The desiccant layer 10 is composed of a plurality of linear portions extending along a certain direction. The linear portion may extend along either side of the rectangular or square main surface 3S. Adjacent linear portions may be separated as shown in FIGS. 2 and 3, or may be partially or wholly in contact with each other. Normally, since each linear portion has a surface that is gently inclined with respect to the main surface 3S, each linear portion can be distinguished even if adjacent linear portions are in contact with each other. The width of each linear portion may be, for example, 0.5 mm or more and 50 mm or less, or 1 mm or more and 10 mm or less. The "width of the linear portion" here is the width in the direction perpendicular to the longitudinal direction of the linear portion. The thickness of the linear portion may be 50 μm or more and 200 μm or less. The linear portion of the desiccant layer 10 does not necessarily have to extend linearly, and may include a curved portion. The linear portions may extend linearly or curvedly without intersecting. For example, the linear portion may meander or may extend in a spiral shape.

Since the desiccant layer 10 having the linear portion has a large surface area, it can exhibit a larger water catching ability than a single membrane. Further, the desiccant layer 10 having a linear portion is also advantageous in that it can be formed more easily than a single film, particularly when the area of the main surface 3S is large.

The water repellent layer 11 is a single film that covers the entire surface of the main surface 3S. The thickness of the water-repellent layer 11 is not particularly limited, but may be smaller than the thickness of the desiccant layer 10. The thickness of the water-repellent layer 11 may be, for example, 0.1 μm or more and 10 μm or less.

FIG. 4 is also a cross-sectional view showing an embodiment of the sealing substrate and the composite layer. In the case of the embodiment of FIG. 4, the desiccant layer 10 includes a linear portion provided in contact with the main surface, and the water repellent layer 11 is a portion of the main surface 3S that is not covered by the desiccant layer 10. Including the covering part. A part of the surface of the desiccant layer 10 is exposed without being covered by the water repellent layer 11.

FIG. 5 is also a cross-sectional view showing an embodiment of the sealing substrate and the composite layer. In the case of the embodiment of FIG. 4, the desiccant layer 10 has the same structure as that of FIG. The water-repellent layer 11 includes a portion of the main surface 3S that is not covered by the desiccant layer 10 and a portion that covers the desiccant layer 10. In other words, the water repellent layer 11 covers the main surface 3S and the desiccant layer 10.

The form of the composite layer is not limited to those exemplified above. For example, as in the modified example shown in FIG. 6, the desiccant layer 10 may be a single film. In the embodiment of FIG. 6, the desiccant layer 10 covers the central portion of the surface of the water-repellent layer 11 provided in contact with the main surface of the sealing substrate 3.

Details of each part constituting the organic EL element according to the above-described embodiment will be described below.

The desiccant layer 10 contains, for example, oxide particles containing an oxide of an alkaline earth metal and a binder resin. The desiccant layer 10 can be formed, for example, by a method including applying a desiccant composition containing these to the main surface 3S of the sealing substrate or the previously formed water-repellent layer 11.

The oxide particles in the desiccant layer 10 contain an oxide of an alkaline earth metal that can impart water catching performance to the oxide particles. The oxide particles usually contain an oxide of 80% by mass or more, or 90% by mass or more, of an alkaline earth metal based on the mass of the oxide particles. The oxide particles can contain oxides of one kind or two or more kinds of alkaline earth metals having different components.

Examples of oxides of alkaline earth metals include magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO). The oxide of the alkaline earth metal may be magnesium oxide, calcium oxide or a combination thereof.

The content of the oxide particles in the desiccant layer 10 may be 40 to 80% by mass based on the mass of the desiccant layer. When the content of the oxide particles is large, the water catching capacity becomes large, so that a sufficient water catching capacity can be easily maintained even when the desiccant layer 10 is formed in the atmospheric atmosphere. From the same viewpoint, the content of the oxide particles may be 50% by mass or more, 55% by mass or more, or 60% by mass or more.

The average particle size of the oxide particles is not particularly limited, but may be, for example, 0.01 to 30 μm. When the average particle size of the oxide particles is in this range, higher water catching performance tends to be obtained. From the same viewpoint, the average particle size of the oxide particles may be 0.1 μm or more, 0.5 μm or more, or 1 μm or more, and may be 20 μm or less, 10 μm or less, or 5 μm or less. In the present specification, the average particle size of the oxide particles means the median value of the volume distribution measured by the dynamic light scattering type particle size distribution meter. This average particle size is a value measured using a dispersion prepared by dispersing oxide particles in a predetermined dispersion medium.

The binder resin may contain, for example, a silicone resin. The binder resin in the desiccant layer may contain a crosslinked polymer formed from a polymerizable compound. The polymerizable compound may be, for example, a modified silicone having a (meth) acryloyloxy group. When this modified silicone is polymerized, the desiccant composition is cured, and as a result, a desiccant layer containing a crosslinked polymer which is a silicone resin is formed.

The modified silicone having a (meth) acryloyloxy group is represented by, for example, the following formula (I). In formula (I), R ³ and R ⁴ each independently represent a divalent organic group, R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group, and x represents an integer of 1 or more. R ³ and R ⁴ may be an alkylene group.

The desiccant composition may further contain other polymerizable compounds that can be copolymerized with a modified silicone having a (meth) acryloyloxy group. The other polymerizable compound may be a (meth) acrylic compound having one or more (meth) acryloyl groups. From the viewpoint of the effect of improving the stability of viscosity, the content of the modified silicone may be 80 to 100% by mass, or 90 to 100% by mass, based on the total amount of the modified silicone and other polymerizable compounds. ..

The total amount of the modified silicone having a (meth) acryloyloxy group and other polymerizable compounds in the desiccant composition may be 20 to 90% by mass with respect to the total mass of the desiccant composition. When the content of the polymerizable compound is in this range, it tends to be easy to secure better coatability and water catching performance. From the same viewpoint, the total amount of the modified silicone having a (meth) acryloyloxy group and other polymerizable compounds may be 20% by mass or more or 50% by mass or more, and 90% by mass or less or 70% by mass or less. May be.

The desiccant composition may further contain a photoradical polymerization initiator for photocuring. Examples of the photoradical polymerization initiator include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, and 2,2-dimethoxy-1. , 2-Diphenylethane-1-one, 2-methyl-1 [4- (methylthio) phenyl] -2-moriphorinopropane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl]- 2-Hydroxy-2-methyl-1-propane-1-one can be mentioned. When the desiccant composition contains a photoradical polymerization initiator, the content thereof may be, for example, 0.01 to 10% by mass with respect to the mass of the polymerizable compound in the desiccant composition.

The desiccant layer and the desiccant composition for forming the desiccant layer may further contain other components if necessary. For example, the desiccant layer and the desiccant composition may contain a silicone compound having no polymerizable group for the purpose of adjusting the viscosity or improving the dispersibility of the oxide particles.

The desiccant composition can be in the form of a paste at 25 ° C. The viscosity of the desiccant composition at 25 ° C. may be 5 to 500 Pa · s. When the viscosity of the desiccant composition at 25 ° C. is in this range, the desiccant layer can be more easily formed by coating. The viscosity here is a value measured by a rotational viscometer such as a B-type viscometer or a rheometer.

The water repellent layer 11 can be a layer containing various water repellent materials. Examples of the water-repellent material include an organic fluorine compound such as a fluororesin and a silicone such as polydimethylsiloxane. The organic fluorine compound may be a compound having a perfluoroalkyl group. The water-repellent layer 11 may be formed by using a commercially available coating agent such as Saitop (trade name, fluororesin) manufactured by AGC Co., Ltd. or SF Coat (trade name) manufactured by AGC Seimi Chemical Co., Ltd.

The element substrate 1 constituting the organic EL element 20 is not particularly limited, but is typically a glass substrate having a rectangular main surface having insulating properties and translucent properties. An electrode 51 is formed on the element substrate 1 by a transparent conductive material (for example, ITO (Indium Tin Oxide)). The electrode 51 is formed into an ITO film on the element substrate 1 by, for example, a PVD (Physical Vapor Deposition) method such as a vacuum deposition method or a sputtering method, and the ITO film is patterned into a predetermined pattern shape by etching by a photoresist method. It is formed by a method that includes etching. The electrode 51 may be extended to the outside of the airtight space 30, whereby the electrode 51 may be connected to the drive circuit.

The light emitting unit 7 has a pair of electrodes 51 and 52 arranged to face each other, and an organic layer 40 provided between the electrodes 51 and 52. The electrode 51 may be an anode and the electrode 52 may be a cathode. The organic layer 40 has a hole injection layer 41, a hole transport layer 42, a light emitting layer 43, and an electron transport layer 44, and these are laminated in this order from the electrode 51 side.

The hole injection layer 41 is formed of, for example, copper phthalocyanine (CuPc) having a film thickness of several tens of nm. The hole transport layer 42 is formed of, for example, bis [N- (1-naphthyl) -N-phenyl] benzidine (α-NPD) having a film thickness of several tens of nm. The light emitting layer 43 is formed of, for example, tris (8-quinolinolato) aluminum (Alq ₃ ) having a film thickness of several tens of nm. The electron transport layer 44 is formed of, for example, lithium fluoride (LiF) having a film thickness of several nm.

The electrode 52 is laminated on the upper surface of the organic layer 40. The electrode 52 may be a metal thin film formed by a PVD method such as a vacuum vapor deposition method. Examples of the material of the metal thin film include simple metals having a small work function such as Al, Li, Mg and In, and alloys having a small work function such as Al-Li and Mg-Ag. The electrode 52 is formed with a film thickness of, for example, several tens of nm to several hundred nm, or 50 nm to 200 nm. The electrode 52 may be pulled out to the end of the element substrate 2, whereby the electrode 52 may be connected to the drive circuit.

The sealing substrate 3 may be a glass substrate. Moisture in the atmosphere is relatively easy to adhere to the surface of the glass substrate. Therefore, when the desiccant layer 10 is formed on the glass substrate as the sealing substrate 3 in the atmospheric atmosphere, it is very advantageous to provide the water repellent layer 11 together with the desiccant layer 10 as in the present embodiment.

The sealant 5 can be formed by using a material usually used for sealing an organic EL element. For example, the sealant 5 can be formed of an ultraviolet curable resin.

The organic EL element 20 includes, for example, a step of forming a composite layer 15 composed of a desiccant layer 10 and a water-repellent layer 11 on the main surface 3S of the sealing substrate 3, and a desiccant on the main surface 3S of the sealing substrate 3. The process includes a step of forming the layer 10, a step of forming a light emitting portion 7 on the element substrate 1, and a step of adhering the sealing substrate 3 to the element substrate 1 with the main surface 3S facing the element substrate 1. It can be manufactured by the method. The sealing substrate 3 is adhered to the element substrate 1 by the sealing agent 5 interposed between the element substrate 1 and the sealing substrate 3. An airtight space 30 surrounded by the element substrate 1, the sealing substrate 3, and the sealing agent 5 is formed. The light emitting unit 7 and the composite layer 15 are arranged in the airtight space 30.

The desiccant layer 10 may be formed on the main surface 3S or the water repellent layer 11 in an atmospheric atmosphere. The "atmosphere" referred to herein may be an environment in which temperature and humidity are controlled by ordinary air conditioning equipment. For example, the atmosphere may be an atmosphere of 15 to 30 ° C. and a relative humidity of 40 to 80%. In this case, the desiccant composition is applied to the main surface 3S of the sealing substrate 3 in an atmospheric atmosphere. Then, the coating film of the desiccant composition is cured in an air atmosphere, if necessary. The desiccant composition can be applied using, for example, a dispenser.

The water repellent layer 11 may be formed on the main surface 3S or on the main surface 3S and the desiccant layer 10 in an atmospheric atmosphere. In this case, a coating agent containing a water-repellent material is applied to the main surface 3S or the main surface 3S and the desiccant layer 10 of the sealing substrate 3 in an atmospheric atmosphere. Then, the coating film of the coating agent is dried or cured in an air atmosphere, if necessary. The coating agent can be applied using, for example, a dispenser.

The composite layer 15 according to the embodiment of FIGS. 2 and 3 forms a water-repellent layer 11 in contact with the main surface 3S, and the desiccant layer 10 is formed on a surface of the water-repellent layer 11 opposite to the main surface 3S. It can be formed by a step including forming the above. Some or all of these may be performed in an air atmosphere.

The composite layer 15 according to the embodiment of FIG. 3 or FIG. 4 forms a desiccant layer 10 including a linear portion in contact with the main surface 3S, and a portion of the main surface 3S that is not covered by the desiccant layer 10. And, in some cases, it can be formed by a step including forming a water-repellent layer 11 that covers the desiccant layer 10. Some or all of these may be performed in an air atmosphere.

The other steps can be performed according to the methods usually used in the manufacture of organic EL devices. The step of adhering the sealing substrate to the element substrate is usually performed in a dehumidified and dry atmosphere.

1 ... Element substrate, 3 ... Encapsulation substrate, 3A ... Top plate portion of encapsulation substrate, 3B ... Side wall portion of encapsulation substrate, 3S ... Main surface of encapsulation substrate, 5 ... Sealing agent, 7 ... Light emitting portion, 10 ... desiccant layer, 11 ... water repellent layer, 15 ... composite layer, 20 ... organic EL element, 30 ... airtight space, 40 ... organic layer, 51, 52 ... electrodes.

Claims (6)

With the element board
A light emitting unit having a pair of electrodes arranged to face each other and an organic layer provided between them, which are provided on the element substrate.
A sealing substrate having a main surface facing the element substrate and
A composite layer composed of a desiccant layer and a water-repellent layer provided on the main surface,
A sealant that is interposed between the element substrate and the sealing substrate and thereby adheres the element substrate and the sealing substrate.
With
The sealing substrate is a glass substrate, and the sealing substrate is a glass substrate.
The element substrate, the sealing substrate and the airtight space surrounded by the sealant is formed, the light emitting portion and said composite layer is disposed on the airtight space,
The water-repellent layer is provided in contact with the main surface, and the desiccant layer is provided on a surface of the water-repellent layer opposite to the main surface.
Organic EL element. The desiccant layer contains oxide particles containing an oxide of an alkaline earth metal and a binder resin.
The content of the oxide particles is 40 to 80% by mass with respect to the mass of the desiccant layer.
The organic EL element according to claim 1. A step of forming a composite layer composed of a desiccant layer and a water-repellent layer on the main surface of the sealing substrate, and
A step of forming a light emitting portion having a pair of electrodes arranged to face each other and an organic layer provided between them on the element substrate.
A step of adhering the sealing substrate to the element substrate with a sealing agent interposed between the element substrate and the sealing substrate with the main surface facing the element substrate. A step of forming an airtight space surrounded by the sealing substrate and the sealing agent, and arranging the light emitting portion and the composite layer in the airtight space.
Bei to give a,
The sealing substrate is a glass substrate, and the sealing substrate is a glass substrate.
The step of forming the composite layer on the main surface of the sealing substrate is
Forming the water-repellent layer in contact with the main surface and
To form the desiccant layer on the surface of the water-repellent layer opposite to the main surface,
including,
A method for manufacturing an organic EL element. The method according to claim 3 , wherein the desiccant layer is formed in an atmospheric atmosphere. The method according to claim 3 or 4 , wherein the water-repellent layer is formed in an atmospheric atmosphere. The desiccant layer contains oxide particles containing an oxide of an alkaline earth metal and a binder resin.
The content of the oxide particles is 40 to 80% by mass with respect to the mass of the desiccant layer.
The method according to any one of claims 3 to 5.

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