TW202013787A - Organic el element and method of producing same - Google Patents

Abstract

The present invention discloses an organic electroluminescence (EL) element which includes: an element substrate; a light-emitting portion; a sealing substrate having a main surface facing the element substrate; a composite layer including a desiccant layer and a water repellent layer provided on the main surface; and a sealant. An airtight space is formed and surrounded by the element substrate, the sealing substrate, and the sealant, and the light-emitting portion and the composite layer are arranged in the airtight space.

Description

Organic electroluminescence element and its manufacturing method

The invention relates to an organic electroluminescence element and a manufacturing method thereof.

In order to prevent the luminescence part of the organic electroluminescence element (organic EL element) from decreasing the luminescence life due to moisture, the light emitting part already provided on the substrate is sometimes sealed by a sealing substrate, and a water-absorbing material is provided on the sealing substrate ( For example, Japanese Patent Laid-Open No. 2006-331766).

[Problems to be solved by the invention] In the manufacture of an organic electroluminescent element having a desiccant layer provided on a sealing substrate, in order to avoid the incorporation of moisture, it is necessary to form a desiccant layer on the sealing substrate under a dry atmosphere such as an inert gas. However, from the viewpoint of simplification of steps and equipment, it is desirable to be able to form a desiccant layer in an atmospheric atmosphere without a drying atmosphere. By using a desiccant with a high water absorption capacity, it is expected that even if the desiccant layer is formed in an atmospheric atmosphere, the desiccant layer can maintain sufficient water absorption capacity. However, it is clear that even if a desiccant with a high water absorption capacity is used, if a desiccant layer is formed on the sealing substrate in an atmospheric atmosphere, the light emitting area ratio of the organic electroluminescence element tends to become insufficient from the early stage immediately after production.

[Technical means to solve the problem] Therefore, an object of one aspect of the present invention is to provide an organic electroluminescence element capable of maintaining a sufficient initial light-emitting area ratio even when manufactured by a method including a step of forming a desiccant layer in an atmospheric atmosphere.

An aspect of the present invention relates to an organic electroluminescence device including: an element substrate; a light-emitting portion provided on the element substrate; a sealing substrate having a main surface opposed to the element substrate; and a composite layer including the arrangement A desiccant layer and a water-repellent layer on the aforementioned main surface; and, a sealant interposed between the element substrate and the sealing substrate, thereby bonding the element substrate and the sealing substrate. The light-emitting part has a pair of electrodes arranged oppositely and an organic layer provided between these. An airtight space surrounded by the element substrate, the sealing substrate and the sealant is formed. The light emitting section and the composite layer are arranged in the airtight space.

Another aspect of the present invention relates to a method of manufacturing an organic electroluminescent element. The method includes: a step of forming a composite layer including 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, in a direction where the main surface and the element substrate face each other, The step of bonding the sealing substrate to the aforementioned element substrate. The sealing substrate is adhered to the element substrate by the sealant interposed between the element substrate and the sealing substrate. An airtight space surrounded by the element substrate, the sealing substrate and the sealant is formed. The light emitting section and the composite layer are arranged in the airtight space.

[Effect of invention] By providing a desiccant layer and a water-repellent layer on the main surface of the sealing substrate, even when the desiccant layer is formed in the atmosphere, the organic electroluminescent element can easily maintain a sufficient initial light-emitting area ratio. The water-repellent layer suppresses the adsorption of moisture in the atmospheric atmosphere onto the sealing substrate. In addition, it is considered that the water repellent layer also suppresses the moisture absorbed on the sealing substrate from affecting the light-emitting portion.

Hereinafter, several 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 electroluminescence device. The organic electroluminescence 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 including a desiccant layer 10 and a water-repellent layer 11, and Sealant 5.

The sealing substrate 3 has: a top plate portion 3A having a rectangular or square flat main surface 3S opposed to the element substrate 1; and a side wall portion 3B extending from the outer peripheral end of the top plate portion 3A perpendicular to the main surface 3S Direction extends. The top plate portion 3A and the side wall portion 3B form a concave portion having the 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 is interposed between the side wall portion 3B of the sealing substrate 3 and the element substrate 1, and bonds the sealing substrate 3 and the element substrate 1. Thereby, an airtight space 30 surrounded by the element substrate 1, the sealing substrate 3, and the sealant 5 is formed. The light emitting section 7 and the composite layer 15 are arranged in the airtight space 30. The sealing substrate 3 may be a flat plate-shaped body having no side wall portion 3B. In this case, generally, the sealant 5 is interposed between the top plate portion 3A of the sealing substrate 3 and the element substrate 1. In any case, the "main surface opposed to the element substrate" refers to the surface opposed to the element substrate in the airtight space where the light-emitting portion is arranged. The water repellent layer 11 is provided in contact with the main surface 3S. A desiccant layer 10 is provided on the surface of the water repellent layer 11 on the side opposite to the main surface 3S.

2 is a plan view showing an embodiment of a sealing substrate and a composite layer. FIG. 3 is a cross-sectional view taken along line II-II of FIG. 2. The plan view of FIG. 2 shows the state 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 a direction perpendicular to the main surface 3S of the sealing substrate 3, the area ratio of the composite layer 15 may be 50% or more, 60% or more, 70% or more, or 75% or more with respect to the area of the main surface 3S. It is considered that if the area ratio of the composite layer 15 is increased, the moisture attached to the main surface 3S of the sealing substrate 3 in the atmospheric atmosphere is less likely to affect the light-emitting portion 7. In addition, 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 includes a plurality of linear portions extending in a certain direction. The linear portion may extend along either side of the rectangular or square main surface 3S. As shown in FIGS. 2 and 3, adjacent linear portions may be separated, or may be partially or wholly contacted. In general, since each linear portion has a surface that is gently inclined with respect to the main surface 3S, even if adjacent linear portions contact, the linear portions can be distinguished. 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. Here, the "width of the linear portion" is the width of the linear portion in the direction perpendicular to the longitudinal direction. 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 need to extend straight, and may include a curved portion. The linear portion can extend in a straight line or a curve without crossing. For example, the linear portion can be curved, and can also extend in a spiral shape.

Since the desiccant layer 10 having a linear portion has a large surface area, it can exhibit a large water absorption capacity compared to a single film. In addition, in particular, in the case where the area of the main surface 3S is large, the desiccant layer 10 having a linear portion is advantageous compared to the point where a single film can be easily formed.

The water repellent layer 11 is a single film covering the entire 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 includes a portion covering the portion of the main surface 3S that is not covered by the desiccant layer 10. 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 FIG. 3. The water-repellent layer 11 includes a portion covering the portion of the main surface 3S that is not covered by the desiccant layer 10 and a portion covering 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 modification 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.

The details of each part constituting the organic electroluminescence element of the embodiment described above will be described below.

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

The oxide particles in the desiccant layer 10 include oxides of alkaline earth metals that can impart water absorption properties to the oxide particles. Taking the mass of the oxide particles as a reference, the oxide particles usually contain 80% by mass or more or 90% by mass or more of oxides of alkaline earth metals. The oxide particles can contain one type or two or more types of alkaline earth metal oxides having different compositions.

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

Using the mass of the desiccant layer as a reference, the content of oxide particles in the desiccant layer 10 may be 40 to 80% by mass. If the content of oxide particles is large, the water absorption capacity increases, so that even when the desiccant layer 10 is formed in an atmospheric atmosphere, it is easy to maintain sufficient water absorption capacity. From the same viewpoint, based on the mass of the desiccant layer, 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 diameter of the oxide particles is not particularly limited, but it may be, for example, 0.01 to 30 μm. If the average particle diameter of the oxide particles falls within this range, it tends to obtain higher water absorption performance. From the same viewpoint, the average particle diameter 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 this specification, the average particle size of oxide particles refers to the central value of the volume distribution measured by a dynamic light scattering particle size distribution meter. The average particle diameter is a value measured using a dispersion liquid prepared by dispersing oxide particles in a predetermined dispersion medium.

The binder resin may include polysiloxane resin, for example. The binder resin in the desiccant layer may contain a cross-linked polymer formed of a polymerizable compound. The polymerizable compound may be, for example, modified polysiloxane having (meth)acryloyloxy group. When the modified polysiloxane is polymerized, the desiccant composition hardens, and as a result, a desiccant layer containing a cross-linked polymer as polysiloxane resin is formed.

The modified polysiloxane with (meth)acryloyloxy group is represented by the following formula (I), for example. 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 modified polysiloxane 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 modified polysiloxane may be 80 to 100% by mass or 90 to 100% by mass relative to the total amount of modified polysiloxane and other polymerizable compounds.

Relative to the total mass of the desiccant composition, the total amount of modified polysiloxane and other polymerizable compounds having (meth)acryloyloxy groups in the desiccant composition may be 20 to 90% by mass. When the content of the polymerizable compound is within this range, there is a tendency that it is easier to ensure more excellent coatability and water absorption performance. From the same point of view, the total amount of modified polysiloxane and other polymerizable compounds having (meth)acryloyloxy groups can be 20% by mass or more or 50% by mass relative to the total mass of the desiccant composition % Or more, it may be 90% by mass or less or 70% by mass or less.

For photo hardening, the desiccant composition may further contain a photo radical polymerization initiator. Examples of the photo-radical polymerization initiator include 1-hydroxy-cyclohexyl-phenyl-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) -1-Butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1[4-(methylthio)phenyl]-2-? Porphyrin-1-one and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one. When the desiccant composition contains an optical radical polymerization initiator, the content of the polymerizable compound in the desiccant composition may be, for example, 0.01 to 10% by mass.

The desiccant layer and the desiccant composition used to form it may contain other components as needed. For example, the desiccant layer and the desiccant composition may contain a polysiloxane compound having no polymerizable group for the purpose of adjusting viscosity or improving the dispersibility of oxide particles.

The desiccant composition can be paste-like at 25°C. The viscosity of the desiccant composition at 25°C can be 5 to 500 Pa•s. If the viscosity of the desiccant composition at 25°C is within this range, the desiccant layer can be formed more easily by coating. The viscosity here is the value measured by a rotating viscometer such as a B-type viscometer and a rheometer.

The water-repellent layer 11 may be a layer containing various water-repellent materials. Examples of the water-repellent material include organic fluorine compounds such as fluororesins and polysiloxanes such as polydimethylsiloxane. The organic fluorine compound may be a compound having a perfluoroalkyl group. For example, a commercially available coating agent such as CYTOP (trade name, fluororesin) of AGC Inc., SFCOAT (trade name) manufactured by AGC SEIMI CHEMICAL CO., LTD can be used to form the water-repellent layer 11.

The element substrate 1 constituting the organic electroluminescence element 20 is not particularly limited, but it is typically a glass substrate having insulating and translucent properties and a rectangular main surface. The 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 by, for example, a method including: a step of forming an ITO film on the element substrate 1 by a PVD (Physical Vapor Deposition) method such as vacuum deposition method or sputtering method; and, by The step of forming the ITO film into a predetermined pattern shape by etching using photolithography. The electrode 51 can be drawn out to the outside of the airtight space 30, whereby the electrode 51 can be connected to the driving circuit.

The light-emitting section 7 includes: a pair of electrodes 51 and 52 disposed opposite to each other; and an organic layer 40 provided between the electrode 51 and the electrode 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 sequentially stacked from the electrode 51 side.

The hole injection layer 41 is formed of, for example, copper phthalocyanine (CuPc) with a film thickness of several 10 nm. The hole transport layer 42 is made of, for example, bis[N-(1-naphthyl)-N-phenyl]benzidine (bis[N-(1-naphthyl)-N-phenyl]benzidine) (α -NPD) formed. The light-emitting layer 43 is formed of, for example, tris(8-hydroxyquinoline) aluminum (Alq3) with a film thickness of several 10 nm. The electron transport layer 44 is formed of, for example, lithium fluoride (LiF) with a thickness of several nm.

An electrode 52 is stacked 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 vacuum evaporation. Examples of the material of the metal thin film include metal elements with small work functions such as Al, Li, Mg, and In, and alloys with small work functions of Al-Li and Mg-Ag. The electrode 52 is formed with a film thickness of, for example, several 10 nm to several 100 nm or 50 nm to 200 nm. The electrode 52 can be drawn out to the end of the element substrate 2, whereby the electrode 52 can be connected to the driving 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, in the case where the desiccant layer 10 is formed on the glass substrate as the sealing substrate 3 in the atmosphere, it is of great interest to provide the desiccant layer 10 and the water-repellent layer 11 as in the present embodiment.

The sealant 5 can be formed using materials commonly used for sealing organic electroluminescent elements. For example, the sealant 5 can be formed of ultraviolet curable resin.

The organic electroluminescent element 20 can be manufactured by, for example, a method including: a step of forming a composite layer 15 including a desiccant layer 10 and a water-repellent layer 11 on the main surface 3S of the sealing substrate 3; The step of forming the desiccant layer 10 on the main surface 3S of the step; the step of forming the light-emitting portion 7 on the element substrate 1; and, in the direction in which the main surface 3S faces the element substrate 1, the sealing substrate 3 is adhered to the element substrate 1 The steps above. The sealing substrate 3 is adhered to the element substrate 1 by the sealant 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 sealant 5 can be formed. The light emitting section 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 on the water repellent layer 11 in an atmospheric atmosphere. The "atmospheric atmosphere" mentioned in this specification can be an environment in which temperature and humidity are controlled by general air-conditioning equipment. For example, the atmospheric 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 on the main surface 3S of the sealing substrate 3 in an atmospheric atmosphere. Then, if necessary, the coating film of the desiccant composition is hardened in an air atmosphere. The desiccant composition can be applied using a dispenser, for example.

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

The composite layer 15 of the embodiment of FIGS. 2 and 3 can be formed by the steps including: forming a water-repellent layer 11 in contact with the main surface 3S; and, in the water-repellent layer 11 opposite to the main surface 3S The desiccant layer 10 is formed on one side. Part or all of these can be performed in an atmospheric atmosphere.

The composite layer 15 of the embodiment of FIG. 3 or FIG. 4 can be formed by the steps including: forming a desiccant layer 10 including a linear portion in contact with the main surface 3S; and, forming a layer covering the main surface 3S The part not covered by the desiccant layer 10 and the water-repellent layer 11 covering the desiccant layer 10 according to circumstances. Part or all of these can be performed in an atmospheric atmosphere.

The other steps can be performed according to a method generally used in the manufacture of organic electroluminescent elements. The step of adhering the sealing substrate to the element substrate is usually carried out under a dehumidified dry atmosphere.

According to an aspect of the present invention, it is possible to provide an organic electroluminescent device capable of maintaining a sufficient initial light-emitting area ratio even when it is manufactured by a method including a step of forming a desiccant layer in an atmospheric atmosphere.

1: component substrate 3: sealed substrate 3A: Seal the top part of the substrate 3B: Seal the side wall of the substrate 3S: Seal the main surface of the substrate 5: Sealant 7: Light emitting part 10: Desiccant layer 11: Water-repellent layer 15: Composite layer 20: Organic electroluminescence element 30: Airtight space 40: Organic layer 51, 52: electrode

FIG. 1 is a cross-sectional view showing an embodiment of an organic electroluminescence device. 2 is a plan view showing an embodiment of a sealing substrate and a composite layer. FIG. 3 is a cross-sectional view taken along line II-II of FIG. 2. 4 is a cross-sectional view showing an embodiment of a sealing substrate and a composite layer. 5 is a cross-sectional view showing an embodiment of a sealing substrate and a composite layer. 6 is a plan view showing an embodiment of a sealing substrate and a composite layer.

Domestic storage information (please note in order of storage institution, date, number) no

Overseas hosting information (please note in order of hosting country, institution, date, number) no

1: component substrate

3: sealed substrate

3A: Seal the top part of the substrate

3B: Seal the side wall of the substrate

3S: Seal the main surface of the substrate

5: Sealant

7: Light emitting part

10: Desiccant layer

11: Water-repellent layer

15: Composite layer

20: Organic electroluminescence element

30: Airtight space

40: Organic layer

51, 52: electrode

Claims (11)

An organic electroluminescence element, which has: Component substrate A light-emitting portion, which is provided on the aforementioned element substrate, and has a pair of electrodes arranged oppositely and an organic layer provided between these; A sealing substrate having a main surface opposite to the aforementioned element substrate; A composite layer comprising a desiccant layer and a water repellent layer provided on the aforementioned main surface; and, A sealant interposed between the element substrate and the sealing substrate, thereby bonding the element substrate and the sealing substrate; Among them, an airtight space surrounded by the element substrate, the sealing substrate, and the sealant is formed, and the light emitting portion and the composite layer are arranged in the airtight space. The organic electroluminescence device according to claim 1, wherein the sealing substrate is a glass substrate. The organic electroluminescence element according to claim 1 or 2, wherein the water-repellent layer is provided in contact with the main surface, and the drying layer is provided on a surface of the water-repellent layer opposite to the main surface剂层。 Agent layer. The organic electroluminescent element according to claim 1 or 2, wherein the desiccant layer includes a linear portion provided in contact with the main surface, and the water repellent layer includes a non-desiccant covering the main surface. Part of the part covered by the layer. The organic electroluminescence device according to any one of claims 1 to 4, wherein the desiccant layer contains oxide particles containing an oxide of alkaline earth metal and a binder resin, Taking the mass of the desiccant layer as a reference, the content of the oxide particles is 40 to 80% by mass. A method for manufacturing an organic electroluminescent element, the method having: The step of forming a composite layer including a desiccant layer and a water-repellent layer on the main surface of the sealing substrate; A step of forming a light-emitting portion having a pair of electrodes arranged oppositely and an organic layer disposed between the element substrates; and, The step of adhering the sealing substrate to the element substrate with the sealant interposed between the element substrate and the sealing substrate in the direction in which the main surface faces the element substrate, in this step, forming An airtight space surrounded by the element substrate, the sealing substrate, and the sealant, and the light emitting portion and the composite layer are arranged in the airtight space. The method according to claim 6, wherein the desiccant layer is formed under an atmospheric atmosphere. The method according to claim 6 or 7, wherein the water repellent layer is formed under an atmospheric atmosphere. The method according to any one of claims 6 to 8, wherein the step of forming the composite layer on the main surface of the sealing substrate includes: Forming the water repellent layer in contact with the main surface; and, The desiccant layer is formed on the surface of the water-repellent layer opposite to the main surface. The method according to any one of claims 6 to 8, wherein the step of forming the composite layer on the main surface of the sealing substrate includes: Forming the desiccant layer including the linear portion in contact with the main surface; and, The aforementioned water repellent layer including a portion covering the portion of the aforementioned main surface that is not covered by the aforementioned desiccant layer is formed. The method according to any one of claims 6 to 10, wherein the desiccant layer contains oxide particles containing an oxide of alkaline earth metal and a binder resin, Taking the mass of the desiccant layer as a reference, the content of the oxide particles is 40 to 80% by mass.

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