JP2002033189A - Method for manufacturing organic electroluminescence element and organic electroluminescence element using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an organic electroluminescence element without using a transparent substrate, and a thin and hardly breakable organic electroluminescence element manufactured by use of it. SOLUTION: This method for manufacturing an organic electroluminescence element comprises formation and coating of an electrode without using a substrate on the display surface side. This electroluminescence element is manufactured by this method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a method for efficiently manufacturing an organic electroluminescence device.

[0002]

2. Description of the Related Art Organic electroluminescent elements (hereinafter abbreviated as "organic EL elements") are thin, lightweight and self-luminous, which are different from liquid crystal display elements (hereinafter abbreviated as "LCD"). It is expected to be used for equipment displays. In recent years, practical use has begun since it has become possible to improve the luminance and lifetime of organic materials such as a light emitting layer and to select a light emitting color. At present, an organic EL element is formed by forming ITO, which is a transparent electrode, on a glass substrate serving as a display surface by sputtering or the like, and stacking organic layers such as a hole transport layer and a light emitting layer thereon by vapor deposition,
Furthermore, after laminating a metal electrode thereon, the back surface is sealed with a metal cap or the like to manufacture the device.

On the other hand, in the LCD, an LCD using a substrate made of a polymer film sheet instead of a conventional glass substrate is used.
Has been rapidly used in electronic desktop calculators and mobile phones because of its advantages that it is lighter and harder to break than glass, and a plastic substrate is proposed for an organic EL device. However, since the substrates used in these LCDs need to be colorless and transparent, the heat resistance and solvent resistance required during good processing steps are limited,
Peripheral materials also require special specifications different from those for glass substrates. For this reason, there is a problem that the material cost becomes high, and it is necessary to develop an organic material such as a light emitting layer which does not adversely affect the plastic.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a method for efficiently manufacturing an organic electroluminescence device.

[0005]

According to the present invention, there is provided a method for manufacturing an organic electroluminescent element, wherein (1) an electrode is formed and coated on a display surface side without using a substrate;
(2) An organic electroluminescent device manufactured by the method described in (1), (3) An electrode is formed and coated on the display surface side without using a substrate, and a substrate other than glass is used for a back substrate. Organic electroluminescence element, (4)
The organic electroluminescence device according to item (3), wherein a polymer film sheet is used for the back substrate.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of manufacturing an organic EL device according to the present invention is to manufacture a device by the following steps. First, a metal electrode serving as a negative electrode is formed on a substrate serving as a back surface. At this time, when the back substrate is conductive like a metal or a semiconductor, a metal electrode is formed after forming an insulating layer. Subsequently, each layer to be an organic EL is formed. These layers are different depending on the method, but are formed as two layers of an electron transport layer / light emitting layer and a hole transport layer or an electron transport layer, a light emitting layer, and a hole transport layer in this order. Subsequently, ITO, which is a transparent electrode on the display surface, which is a positive electrode, is formed. These film forming steps may be performed continuously by a dry process, or each process may be performed individually. Further, a coating layer is formed on the ITO. This layer can be formed of SiO ₂ by a dry process, but it is preferable that the outermost surface be coated with a transparent resin in liquid form from the viewpoint of durability. Both may be used in combination. According to the manufacturing method of the present invention, since the substrate to be used does not need to be transparent, various materials having excellent heat resistance and solvent resistance can be used. On the other hand, the liquid resin coated on the outermost layer also
Since there is no need for heat resistance, a material having good transparency can be used.

Examples of the back substrate used in the present invention include a glass plate, a metal plate such as aluminum, a silicon wafer, a ceramic plate such as alumina, and a polymer film sheet such as a polyimide film or an epoxy plate. . Of these, it is preferable to use a material other than glass because damage due to cracking of the element can be prevented. In particular, a polymer film sheet is more preferable because a lightweight element or a bendable element can be manufactured. Preferred examples of the polymer film sheet include polyimide, polyamide, polyamide imide, epoxy resin, acrylic resin, polyester, polyether sulfone, polycarbonate, polyarylate, cycloolefin-based polymer, and resin blended with these. Is not limited to these.

In the present invention, examples of the metal forming the negative electrode on the back surface include an aluminum alloy and silver. Examples of the electron transport layer formed thereon include organic compounds represented by Formula (1), Formula (2), and Formula (3). Further, the molecules of the formulas (1) and (2) can be used also as the light emitting layer.

[0009]

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The light-emitting layer formed on the electron transport layer includes:
Organic compounds such as formulas (4) and (5) can be given. When the molecules of the formulas (1) and (2) are used as the electron transport layer and the light emitting layer, the light emitting layer may not be formed. Further, examples of the hole transport layer formed on the light emitting layer include organic compounds represented by formulas (6) and (7).

[0011]

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[0012]

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[0013]

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An ITO which is a transparent electrode on the display surface which is a positive electrode
Can be formed by vapor deposition, sputtering, a sol-gel method, or the like. Coating layer formed on the upper layer of the ITO, the SiO ₂ deposition, sputtering, sol - or formed by a gel method, the transparent liquid resin i.e. liquid polymer precursor monomers or oligomers, by coating a polymer solution hardening Alternatively, it can be formed by drying. Examples of the liquid resin include, but are not limited to, an acrylic monomer composition, an epoxy resin composition, a polymethyl methacrylate solution, and the like.

[0015]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to the examples. Example 1 A 100 μm-thick polyimide film (“UPILEX S” manufactured by Ube Industries, Ltd.) was used as a substrate, and an Al / Li alloy was deposited to a thickness of 80 nm and patterned to form a negative electrode. The polyimide film was light brown, though transmitting light. Alq3, which is an organic compound having the structure of the above formula (1), was deposited thereon to a thickness of 100 nm as an electron transporting layer and a light emitting layer. Further, α-NPD, which is an organic compound having the structure of the above formula (7), was deposited thereon as a hole transport layer by a thickness of 100 nm, and then ITO was deposited to a thickness of 100 nm under a condition of introducing a small amount of oxygen. Further, after forming a film of SiO ₂ to a thickness of 20 nm by sputtering, a 10% solution of polycarbonate in methylene chloride was applied and dried to form a coating having a thickness of 10 μm, thereby producing an organic EL device. When the thickness of this organic EL element was measured, it was about 110 μm. The organic EL element was dropped on concrete from a height of 1 m, but no damage was observed in appearance. When a direct current was further applied to the electrode, favorable green light emission was obtained. Subsequently, this element was bent at a radius of curvature of 10 cm.
No defect was observed in both appearance and light emission.

Example 2 An aluminum sheet having a thickness of 300 μm was used as a substrate, and SiO ₂ was formed to a thickness of 100 nm.
After forming a film by sputtering, the Al / Li alloy is
A negative electrode was formed by vapor deposition to a thickness of nm and patterning. An organic compound having a structure of the above formula (3), TAZ, having a thickness of 60 nm is formed thereon as an electron transport layer, and an organic compound having a structure of the above formula (4), DP, is formed as a light emitting layer.
2Me-TPD which is an organic compound having a structure of the above formula (6) as a hole transport layer having a thickness of VBi of 60 nm
Is deposited to a thickness of 60 nm, and then ITO is deposited to a thickness of 100 nm.
Under a condition of introducing a small amount of oxygen. Further, after forming a film of SiO ₂ to a thickness of 20 nm by sputtering, a 10% solution of polycarbonate in methylene chloride was applied and dried to form a coating having a thickness of 10 μm, thereby producing an organic EL device. When the thickness of this organic EL element was measured, it was found to be about 31
It was 0 μm. The organic EL element was dropped on concrete from a height of 1 m, but no damage was observed in appearance. When a direct current was further applied to the electrode, favorable blue light emission was obtained.

Comparative Example Using a glass substrate having a thickness of 550 μm as a substrate, ITO was formed to a thickness of 100 nm by sputtering, followed by patterning to form a positive electrode. An organic compound having a structure of the above formula (7), α-NPD, having a thickness of 100 nm is deposited thereon as a hole transport layer, and then an organic compound having a structure of the above formula (1) as an electron transport layer and a light emitting layer. Was deposited to a thickness of 100 nm. An organic EL element was fabricated by covering a 0.7 mm deep sealing can formed of an aluminum plate having a thickness of 300 μm thereon and stopping the periphery with a UV curing resin. When the thickness of this organic EL element was measured, it was about 1.3 mm. When the organic EL element was dropped on concrete from a height of 1 m, the glass was broken.

[0018]

By using the method for producing an organic electroluminescence device of the present invention, an organic EL device can be produced without using a colorless and transparent substrate. In addition, by using a polymer film or a metal plate as a substrate other than glass, an element that is thin and hard to be damaged even when dropped can be manufactured. Further, when a substrate made of a polymer film sheet is used, it is possible to produce an element which is hardly damaged even when bent.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/14 H05B 33/14 A

Claims (4)

[Claims] 1. A method for manufacturing an organic electroluminescent device, comprising forming and coating an electrode on a display surface side without using a substrate. 2. An organic electroluminescent device produced by the method according to claim 1. 3. An organic electroluminescent device wherein an electrode is formed and coated on a display surface side without using a substrate, and a substrate other than glass is used for a back substrate. 4. The organic electroluminescence device according to claim 3, wherein a polymer film sheet is used for the back substrate.