JPH09283279A - Manufacture of organic el element - Google Patents

Abstract

(57) An object of the present invention is to provide a method for manufacturing an organic EL device, in which a large number of striped negative electrode layers can be easily formed in parallel at a predetermined pitch and interval. SOLUTION: A striped positive electrode layer 1 is formed on a substrate 11.
3 are formed in parallel, and the positive electrode layer 13 is formed on the positive electrode layer 13.
After forming the organic EL layer 15 covering the organic EL layer, the sample is transferred to a vacuum vapor deposition apparatus prepared for a metal electrode,
A wire mask 19 is arranged on the layer 15. The wire mask 19 has a structure in which a large number of wires 19a made of gold (Au) having a diameter of 10 μm are arranged in parallel at a pitch P2 of 100 μm in a large number of grooves provided in an outer frame (not shown) of a predetermined size. The surface of each wire 19a is covered with a volatile component-containing silicone oil. After that, magnesium (Mg) is vapor-deposited on the organic EL layer 15 through the wire mask 19 by a vacuum vapor deposition method to form a large number of striped negative electrode layers 17 in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic EL device utilizing the electroluminescence (EL) phenomenon.

[0002]

2. Description of the Related Art A typical conventional organic EL device has a transparent positive electrode on a substrate 11 which is transparent to emitted light, as shown in a perspective view of a main portion of FIG. Electrode layer 1
3. The organic EL layer 15 and the negative electrode layer 17 each composed of a single layer or a plurality of layers are provided in this order. FIG. 4 shows an example in which the organic EL layer 15 is composed of an organic hole transport layer 15a and an organic electron transport light emitting layer 15b (details will be described later).

When such an organic EL device is applied to a display device such as a display, it is necessary to produce a dot matrix or the like in which a plurality of the structures shown in FIG. 4 are developed in a plane. For that purpose, first, a large number of stripe-shaped positive electrode layers are formed in parallel on the substrate, then an organic EL layer covering the positive electrode layers is formed on the positive electrode layer, and then the stripe-shaped negative electrode layers are formed on the organic EL layer. A large number of electrode layers are formed parallel to each other in a direction orthogonal to the positive electrode layer. The negative electrode layer is, for example, magnesium (M
A metal such as g) is formed by a vacuum evaporation method using a metal mask. When the dot matrix is produced as described above, the size of one dot is determined by the stripe width of the positive electrode layer and the stripe width of the negative electrode layer.

[0004]

When this dot matrix is used as an actual display element, for example, even when considering monochrome display like a calculator, it is 2 to 1 mm.
A dot size of 3 pitches (about 400 μm square) or less is required.

However, since the negative electrode layer of the organic EL element is formed by a vacuum deposition method using a metal mask, it is very difficult to form a striped negative electrode layer having a width of several hundreds μm or less. This is because in the case of commonly used stainless steel, the limit of the thinness that can be processed is about 100 μm, so even if this metal mask is cut out into a stripe shape with a pitch of several hundred μm, the mask thickness On the other hand, the cut-out width of the stripe becomes very narrow, and therefore, the deposition portion on the surface of the organic thin film layer is shaded with respect to the deposition source. Also,
It is difficult to bring such a mask into close contact with the surface of the organic EL layer, and at the time of vapor deposition of the negative electrode layer, the vapor deposition raw material components also wrap around the surface of the organic EL layer hidden by the metal mask, so that the negative electrode layer stripes are formed. Will lose electrical insulation.

The striped negative electrode layer may be processed and formed by a photolithography technique and an etching technique, but at the time of processing, the organic EL is already formed.
Since the negative electrode layer reacts with water or the organic EL layer dissolves in the organic solvent, it cannot be washed because the organic layer and the negative electrode layer have been formed. Since the layer is weak to heat, the resist cannot be baked.
There are many problems.

Therefore, the advent of a method for manufacturing an organic EL device in which it is easy to form a large number of stripe-shaped negative electrode layers in parallel at a predetermined pitch and interval has been desired.

[0008]

Therefore, according to the method of manufacturing an organic EL element of the present invention, a striped positive electrode layer is formed on a substrate, and an organic EL layer is formed on the positive electrode layer. By forming a number of stripe-shaped negative electrode layers in parallel on the organic EL layer at a predetermined pitch and at intervals so as to be orthogonal to the positive electrode layer, the organic EL layer is formed between the positive electrode layer and the negative electrode layer.
In manufacturing an organic EL element having a structure sandwiching layers, a wire having a diameter smaller than the distance between the negative electrode layers to be formed and having a surface coated with a substance containing a volatile component is formed on the negative electrode layer to be formed. It is characterized in that the negative electrode layer is formed by a thin film forming method using vacuum, using as a mask a wire mask having a plurality of parallel arrangements at the same pitch as the pitch.

As described above, when the negative electrode layer is formed by a thin film forming method using vacuum using the wire mask composed of the wire whose surface is coated with a substance containing a volatile component as a mask. First, the wire mask is arranged on the organic EL layer so that each wire forming the wire mask is orthogonal to the striped positive electrode layer formed on the substrate. Then, the negative electrode layer is formed by a thin film forming method using vacuum. In the vacuum state when forming the negative electrode layer, an atmosphere of volatile components is formed around each wire due to a component volatilized from the substance that coats the surface of each wire. Therefore, due to the influence of the atmosphere of volatile components, the negative electrode layer is not formed near the periphery of the wire, but the negative electrode layer is formed at a position apart from the wire to some extent. Therefore, it is considered that the negative electrode layers are formed at predetermined intervals due to the influence of the atmosphere of volatile components.
Further, even if the wire is slightly separated from the organic EL layer, the negative electrode layer is formed at the same interval as when the wire is in close contact with the organic EL layer due to the influence of the atmosphere of the volatile components formed around the wire. It is thought to be done.

In carrying out the present invention, a wire made of, for example, gold (Au) can be used as the wire, and a thin film forming method using vacuum is, for example, a resistance heating evaporation method or an electron beam evaporation method. The vacuum evaporation method or the sputtering method can be used.

The substrate used in the present invention can be any suitable one depending on the design of the organic EL element. Since the light is typically extracted to the substrate side, the substrate can be composed of a glass substrate or a film having a property of transmitting emitted light.

Also, the positive electrode layer may be any suitable one according to the design of the organic EL element. Since the light is typically extracted to the substrate side, the positive electrode layer can be made of a transparent conductive film such as ITO.

The layer structure of the organic EL layer is not particularly limited, and only the organic light emitting layer or a two-layer structure of an organic hole transporting layer and an organic electron transporting light emitting layer (described in the examples described later). Structure) or a two-layer structure of an organic hole transporting light emitting layer and an organic electron transporting layer, or a three layer structure in which an organic hole transporting layer, an organic light emitting layer and an organic electron transporting layer are laminated in this order. Can have a layered structure. The constituent material of the organic EL layer is not particularly limited, and various suitable organic compounds and combinations thereof are possible. For example, Document I
("Organic EL device development strategy" (Science Forum 1
The combination of compounds and laminations disclosed in (1992)) can be an example of application of the present invention.
In addition to the vacuum vapor deposition method, the organic EL layer may be formed by a wet method such as a dip coating method, a spin coating method, a Langmuir-Blodgett (LB) method, or a micelle electrolysis method. As such a method, it is possible to use an organic molecular beam deposition (OMBD) method, a plasma polymerization method, or the like.

As a constituent material of the negative electrode layer, for example, magnesium (Mg) is preferably used. Also,
An alloy in which a small amount of another metal is mixed may be used as the constituent material of the negative electrode layer in order to enhance the adhesion to these organic EL layers and stabilize them. For example, an alloy containing Mg as a main component, which is formed by mixing a small amount of silver (silver) or indium (In) with Mg, may be used.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention of the present application will be described below with reference to the drawings. In the drawings used in the following description, the respective constituent components are only schematically shown in size, shape and arrangement relationship to the extent that the present invention can be understood. Further, in each of the drawings used for the description, the same components are denoted by the same reference numerals, and the duplicate description thereof will be omitted. Further, the materials used and the numerical conditions such as the amount thereof, the processing time, the processing temperature, and the film thickness mentioned in the following description are only preferable examples within the scope of the present invention. Therefore, it should be understood that the invention according to this application is not limited to these conditions. Further, the "electron transport layer" used in the following description means that when an electron injection electrode having a small work function is used, a large amount of electrons can be injected and the injected electrons can move in the film, Holes are a thin film layer that is difficult to inject, or that can inject but does not easily move in the film. Further, the “hole transport layer” means that when a hole injection electrode having a large work function is used, a large amount of holes can be injected, and the injected holes can move in the film, while Is a thin film layer having a property that it is difficult to implant, or even if it can be implanted, it does not easily move in the film.

FIGS. 1 to 2 are process drawings showing step by step the manufacturing process of the organic EL element used in the description of this embodiment.

First, after cleaning the quartz glass substrate 11,
I is formed on the quartz glass substrate 11 by the sputtering method.
The TO film has a film thickness of 180 nm and a sheet resistance of 10 Ω /
□ Formed under the following conditions. Next, this ITO film is processed by a photolithography technique and an etching technique so that the pitch P1 of the positive electrode layers 13 becomes 100 μm and the distance D1 between adjacent stripes becomes 20 μm.
A large number of stripe-shaped positive electrode layers 13 were formed in parallel (FIG. 1A).

Next, the substrate 11 on which the positive electrode layer 13 has been formed is ultrasonically cleaned by sequentially using acetone and 2-propanol for 10 minutes each, and then dried, and further U
Washed with V / O ₃ . Then, the substrate 11 on which the positive electrode layer 13 has been formed is placed in a vacuum vapor deposition apparatus for forming an organic EL layer, and an organic EL layer 15 is formed as follows (FIG. 1).
(B)).

First, in order to form a hole transport layer, a triphenylamine derivative (N, N'-diphenyl-) is formed on the substrate 11 on which the positive electrode layer 13 has been formed by a vacuum deposition method.
N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine (hereinafter, also referred to as TPD) was vapor-deposited to a thickness of about 50 nm. In addition,
The vapor deposition rate at this time was 1.0 nm / s. Subsequently, in order to form an electron transporting light emitting layer, an aluminum quinolinol complex (tris (8-hydroxyquinolinol) aluminum (hereinafter, also referred to as Alq ₃ )) having a thickness of 50 nm is formed on the hole transporting layer by the same vapor deposition device. Vacuum deposition was performed so that the deposition rate was about 1.0 nm /
s. Therefore, the organic EL layer 15 has a structure in which a hole transporting layer and an electron transporting light emitting layer are laminated in this order, although not divided in FIG. 1B.

Next, this sample was transferred to another vacuum vapor deposition apparatus (vacuum vapor deposition apparatus prepared for a metal electrode), and this organic E
A wire mask 19 having the following structure was arranged on the L layer 15 as follows (FIG. 2A).

The wire mask 19 has a diameter of 10 μm in a large number of grooves provided in an outer frame (not shown) of a predetermined size.
The wire 19a made of gold (Au) is arranged in parallel at a pitch P2 of 100 μm, and the surface of each wire 19a is coated with a substance containing a volatile component. As a substance containing a volatile component, a substance containing silicon oil as a main component and containing a volatile component or a substance mixed therein (for example, KF96 manufactured by Shin-Etsu Chemical Co., Ltd.).
-50 (trade name) (hereinafter referred to as volatile component-containing silicone oil) and commercially available magic ink can be used. Then, this wire mask 19 was arranged on the organic EL layer 15 so that each wire 19 a was orthogonal to the striped positive electrode layer 13 formed on the substrate 11. At that time, many portions of each wire 19 a forming the wire mask 19 are in close contact with the organic EL layer 15. When the volatile component-containing silicone oil is used as the substance containing the volatile component, the surface of the wire 19a can be coated with the substance by applying the substance to the surface of the wire 19a. When a commercially available magic ink is used as the substance containing a volatile component, the surface of the wire 19a can be coated with the commercially available magic ink by applying the commercially available magic ink to the surface of the wire 19a.

Next, magnesium (Mg) was vapor-deposited on the organic EL layer 15 by a vacuum vapor deposition method (for example, resistance heating vapor deposition method) through the wire mask 19 (FIG. 2).
(B)). In a vacuum state when vapor-depositing Mg, an atmosphere of a volatile component is formed around each wire 19a due to a component volatilized from the substance coating the surface of each wire 19a. Therefore, due to the influence of the atmosphere of volatile components, Mg is not deposited near the periphery of the wire 19a,
Mg is vapor-deposited at a position apart from the wire 19a to some extent. For example, when volatile component-containing silicon oil is used as the substance containing a volatile component, first, a Mg film having a film thickness of 20 nm is formed under the condition that the vapor deposition rate is 1.0 nm / s, and the vapor deposition rate is 0. By forming an Mg film having a film thickness of 180 nm under the condition of 0.2 nm / s, the pitch P
2 is 100 μm, and the distance D2 between adjacent stripes
A negative electrode layer 17 having a thickness of 200 μm and a thickness of 20 μm was formed. When a commercially available magic ink is used as the substance containing a volatile component, the pitch P2 is 100 μm and the distance D2 between adjacent stripes is 25 μm by depositing Mg by the same method.
The negative electrode layer 17 was formed. Therefore, the wire 19a having a diameter of 10 μm functions as a mask having a width of 20 μm by coating the surface with a volatile component-containing silicone oil, and functions as a mask having a width of 25 μm by coating the surface with a commercially available magic ink. You can think of The distance between the adjacent negative electrode layers is wider when using a commercially available magic ink, because the content of the volatile component in the commercially available magic ink is larger than the content of the volatile component in the volatile component-containing silicone oil. It is considered that this is because the amount is large and the volatile components of the commercially available magic ink are more volatile than the volatile components in the volatile component-containing silicone oil. Further, when the Mg film is formed in the two-stage structure as described above, the Mg film having good adhesion to the base (here, the organic EL layer 15 and the substrate 11) can be formed.

The cathode layer 17 will be described in more detail with reference to FIG.
The state of forming the will be described. Volatile components contained in the substance coating the surface of the wire 19a volatilize and diffuse,
It is assumed that an atmosphere having a high pressure is locally formed in the vicinity of the wire 19a. When the wire 19a coated with the substance containing the volatile component is arranged on the organic EL layer and Mg is vapor-deposited from the upper side of the organic EL layer, the Mg is substantially separated from the wire 19a by a certain distance. As a boundary, vapor deposition is performed from this boundary on the organic EL layer on the side opposite to the wire 19a. And Mg is not vapor-deposited inside this boundary on the wire 19a side. The cause is that the pressure of the volatile component is high near the wire 19a,
It is presumed that this is because it cannot reach the organic EL layer. Therefore, assuming that the diameter of the wire 19a is Y, and the distance from the wire where the pressure of the volatile component is high and Mg cannot reach the organic EL layer is X, Mg will not be deposited in the area within the distance range of Y + 2X. .

Therefore, the wire diameter Y is set so that the distance D2 between the adjacent negative electrode layers 17 is D2 = Y + 2X.
If theoretically defined, the negative electrode layer 1 is theoretically provided at an interval of Y + 2X.
7 can be formed in parallel. In this case, the distance of X depends on the substance that coats the surface of the wire 19a, and therefore it is necessary to examine beforehand the relationship between the substance that coats the surface of the wire 19a and X.

The organic EL device manufactured as described above has a quartz glass substrate 11 as a substrate, a plurality of stripe-shaped positive electrode layers 13 provided in parallel on the substrate 11 at a predetermined pitch and intervals, and a positive electrode layer 13. Positive electrode layer 13 on the electrode layer 13
An organic EL layer 15 composed of an organic hole transporting layer 15a and an organic electron transporting light emitting layer 15b provided so as to cover
And a striped negative electrode layer 17 provided in parallel on the organic EL layer 15 so as to be orthogonal to the positive electrode layer 13 at a predetermined pitch and at a predetermined interval. Therefore, this organic EL device has the organic EL element between the positive electrode layer 13 and the negative electrode layer 15.
It has a structure in which the L layer 15 is sandwiched. For example, when volatile component-containing silicon oil is used as the substance containing the volatile component, the width of the positive electrode layer 13 is 80 μm and the width of the negative electrode layer 17 is 80 μm. The size of one dot formed orthogonal to the electrode layer 17 is 80 × 80 μm ² . When a commercially available magic ink is used as the substance containing a volatile component, the width of the positive electrode layer 13 is 80 μm and the width of the negative electrode layer 17 is 75 μm. The size of one dot formed orthogonal to the layer 17 is 80 × 75
μm ² .

Next, this organic EL device was operated as follows. The voltage applied between the positive electrode layer 13 and the negative electrode layer 17 is gradually changed. Regardless of whether volatile component-containing silicone oil is used as a substance containing a volatile component or a commercially available magic ink is used, when the applied voltage is 5V, dots only in the applied portion start to emit light, and the applied voltage is 15V. At that time, dots other than the application portion did not emit light. Moreover, a short circuit between the adjacent negative electrode layers did not occur in any case.

On the other hand, as a wire mask, the surface of each wire 19a is not coated with a substance containing a volatile component, that is, each wire 19a is not coated with a volatile component-containing silicone oil or a commercially available magic ink. In the organic EL element manufactured using the mask, a short circuit occurred between the adjacent negative electrode layers.

[0028]

As is apparent from the above description, according to the method of manufacturing an organic EL element of the present invention, the surface of the negative electrode layer to be formed has a diameter smaller than that of the negative electrode layer and the surface is covered with a substance containing a volatile component. The negative electrode layer is formed by a thin film forming method using vacuum using a wire mask having a configuration in which a large number of the formed wires are arranged in parallel at the same pitch as the negative electrode layer to be formed.

In the method of manufacturing such an organic EL device,
In the vacuum state at the time of forming the negative electrode layer, an atmosphere of volatile components is formed around each wire due to the components volatilized from the substance coating the surface of each wire. for that reason,
Due to the influence of the atmosphere of volatile components, the negative electrode layer is not formed near the periphery of the wire, but the negative electrode layer is formed at a position apart from the wire to some extent. Therefore, it is considered that the negative electrode layers are formed at predetermined intervals due to the influence of the atmosphere of volatile components, and it becomes easy to form a large number of stripe-shaped negative electrode layers in parallel at predetermined pitches and intervals.

[Brief description of drawings]

FIG. 1A and FIG. 1B are process drawings showing step by step a manufacturing process of an organic EL element used in the description of an embodiment.

2A and 2B are process diagrams showing stepwise a manufacturing process of an organic EL element, which is used for explaining the embodiment following FIG.

FIG. 3 is a schematic diagram for explaining a state of forming a negative electrode layer.

FIG. 4 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 11: Substrate 13: Positive Electrode Layer 15: Organic EL Layer 15a: Organic Hole Transport Layer 15b: Organic Electron Transport Light Emitting Layer 17: Cathode Electrode Layer 19: Wire Mask 19a: Wire

Claims (3)

[Claims] 1. A striped positive electrode layer is formed on a substrate, an organic EL layer is formed on the positive electrode layer, and a striped negative electrode layer is orthogonal to the positive electrode layer on the organic EL layer. As described above, a plurality of organic EL layers are formed in parallel at a predetermined pitch and a predetermined interval so that the organic E layer is formed between the positive electrode layer and the negative electrode layer.
In manufacturing an organic EL device having a structure in which an L layer is sandwiched, a wire having a diameter smaller than the space between the negative electrode layers to be formed and having a surface coated with a substance containing a volatile component is formed on the negative electrode layer to be formed. A method for manufacturing an organic EL element, characterized in that the negative electrode layer is formed by a thin film forming method using a vacuum, using as a mask a wire mask having a configuration in which a large number of wire masks are arranged in parallel at the same pitch. 2. The method for manufacturing an organic EL element according to claim 1, wherein the wire is a wire made of gold (Au). 3. The method for manufacturing an organic EL element according to claim 1, wherein the thin film forming method is a vacuum deposition method or a sputtering method.