JP2003229252A - Manufacturing method of organic led element using transfer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic LED element with a highly precise pattern restrained from deterioration. <P>SOLUTION: For the manufacturing method of an organic LED element interposed between a pair of electrodes formed on a base plate by depositing an organic layer by using a transfer film, the pair of electrodes interposing the organic layers are laminated on the transfer film, and conductive adhesive is applied on the base plate, and the pair of electrodes and the organic layer are transferred from the transfer film to the base plate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of manufacturing an organic LED panel using a transfer method.

[0002]

2. Description of the Related Art An organic LED panel has a structure in which a light emitting layer made of an organic material is sandwiched between a pair of electrodes, at least one of which is translucent, together with a hole injecting and transporting layer, an electron injecting and transporting layer and the like as required. Since it can drive at low voltage and emit light with high brightness, its research is being actively conducted. As a method for forming a light emitting layer made of an organic material, that is, an organic LED layer,
A mask vapor deposition method, an inkjet method, and the like have been proposed.

However, the mask vapor deposition method has a problem that vapor deposition on a large substrate is difficult, and the ink jet method also has a problem that productivity is reduced because it takes time to use a large substrate.

Therefore, a transfer method has been proposed as a patterning method capable of using a large-sized substrate and greatly shortening the manufacturing time (for example, Japanese Patent Application Laid-Open No. 9-1.
67684, JP-A-10-208881,
JP-A-11-237504, JP-A-11-260
549, JP2000-12216A, JP2000-77182A, JP2001-1301A.
41, Japanese Patent Laid-Open No. 2001-195012). These methods are patterning methods that utilize heat locally applied by laser irradiation or the like.

[0005]

When an organic LED panel is prepared by using a thermal transfer method, a method of transferring only an organic layer and forming an electrode later, a method of transferring an electrode and the like are conceivable. When only the organic layer is transferred, since the melting point of the organic layer is relatively low, patterning by transfer can be performed neatly, but there is a problem that the number of steps is increased because an electrode is formed later. Further, since the electrodes are preliminarily patterned on the substrate, there is a problem that the characteristics are deteriorated due to the oxidation of the electrode surface during electrode etching.

In addition, when transferring including the electrodes, oxidation of the electrode surface can be avoided, but since the melting interface is relatively low at the adhesive interface between the transfer film and the substrate and there is no layer that can be melted by heating, it follows the pattern of heating. However, there is a problem that the transfer condition cannot be properly transferred and the range of transfer conditions for a clean transfer is not provided or is extremely narrowed.

[0007]

The present invention is a method for producing an organic LED element in which an organic layer sandwiched between a pair of electrodes is deposited on a substrate by using a transfer film. , A pair of electrodes sandwiching an organic layer, a conductive adhesive is applied on a substrate, and the pair of electrodes and the organic layer are transferred from the transfer film to the substrate.
A method for manufacturing an ED element is provided. According to the present invention, it is possible to transfer the transfer layer including the electrodes.

The conductive adhesive may be applied only to the pixel portion on the substrate. As a result, since the transfer can be performed only on the pixel portion, the pixel can be separated. The conductive adhesive is preferably applied by an inkjet method. This allows
High-definition patterns can be transferred accurately.

The conductive adhesive is preferably applied by a stamper method. This enables transfer using an adhesive having a high viscosity, which cannot be applied by the inkjet method. Further, the step of applying the conductive adhesive includes the step of applying the conductive adhesive to the entire screen on the substrate, and the step of transferring the electrodes and the organic layer cures the conductive adhesive only in the pixel portion. It may consist of a step of transferring. This allows
A highly viscous adhesive can be applied by a simple method, and pixel separation is also possible.

Further, it is preferable that the conductive adhesive is cured by a laser. This makes it possible to apply an adhesive having a high viscosity by a simple method and to perform highly precise patterning and pixel separation. Further, the substrate may be an active matrix substrate including a driving element and a switching element as a TFT circuit. This makes it possible to easily manufacture a high-performance and high-definition organic LED panel.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As the conductive adhesive used in the present invention, a thermosetting epoxy adhesive containing a silver filler, metal fine particles, a thermosetting adhesive containing metal-coated resin beads, etc. Can be mentioned. In the present invention, the transfer film is one in which a transfer layer to be transferred by a transfer method is formed on a base film,
A transfer auxiliary layer is provided between the base film and the transfer layer as needed.

A flexible material is preferable as the base film in order to improve the adhesion to the substrate. Examples of such a material include polyethylene terephthalate (PE
Polymer materials such as T), polycarbonate (PC), polymethylmethacrylate (PMMA), polyester, polyepoxy, polyethylene and polystyrene can be used. Although not limited to these, polyethylene terephthalate and polycarbonate are preferable. The thickness of the film is preferably 10 to 600 μm and 50 to 20 μm.
0 μm is more preferable.

The transfer layer is a layer which is actually transferred in the transfer step, and the layer structure constituting the transfer layer used in the method of the present invention has, for example, an organic layer and an electrode layer used in a normal organic LED element. A combination of the above is sufficient, and the structure is the first electrode / organic layer / second electrode. Further, in order to take out light emitted from the organic layer to the outside, at least one of the first electrode and the second electrode needs to be transparent. The structure of the transfer layer may be in any order with respect to the base film.

The organic layer may have a single-layer structure or a multi-layer structure, and examples thereof include the following structures. (1) Organic light emitting layer (2) Hole transport layer / organic light emitting layer (3) Organic light emitting layer / electron transport layer (4) Hole transport layer / organic light emitting layer / electron transport layer (5) Hole injection layer / Hole transport layer / organic light emitting layer / electron transport layer

The organic light emitting layer may have a single-layer structure or a multi-layer structure. Further, it may be a layer in which a matrix material is doped with a dopant. The organic light emitting layer can be formed by a known method. For example, an organic light emitting material can be directly vacuum-deposited or EB.
It is possible to form a film by a dry process such as a method or an MBE method. Further, for example, using a coating liquid for forming an organic light emitting layer,
Spin coating method, doctor blade method, discharge coating method,
The film can be formed by a wet process such as a spray coating method, an inkjet method, a relief printing method, an intaglio printing method, a screen printing method, a microgravure coating method, and the like.

The organic luminescent layer-forming coating liquid is a solution containing at least a luminescent material, and may contain one kind or multiple kinds of luminescent materials. In addition, a leveling agent, a light emission assisting agent, an additive (donor, acceptor, etc.) charge transporting agent, a light emitting dopant, etc. may be contained.

As the light emitting material, known light emitting materials for organic LED elements can be used. Such light emitting materials are classified into low molecular weight light emitting materials, polymer light emitting materials, precursors of polymer light emitting materials, and the like. Examples of these specific compounds are shown below, but the present invention is not limited thereto.

As the low-molecular light emitting material, for example, 4,4
Aromatic dimethylideene compounds such as'-bis (2,2'-diphenylvinyl) -biphenyl (DPVBi), 5-
Oxadiazole compounds such as methyl-2- [2- [4- (5-methyl-2-benzoxazylyl) phenyl] vinyl] benzoxazole, 3- (4-biphenylyl)
-4-phenyl-5-t-butylphenyl-1,2,4
-Triazole compounds such as triazole (TZA),
Fluoryl organic materials such as styrylbenzene compounds such as 1,4-bis (2-methystyryl) benzene, thiovirazine dioxide derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, azomethine zinc complexes,
Examples include fluorescent organometallic compounds such as (8-hydroxynolinato) aluminum complex.

On the other hand, as the polymer light emitting material, for example,
Poly (2-decyloxy-1,4-phenylene) (DO
-PPP), poly [2,5-bis- [2- (N, N, N
-Triethylammonium) ethoxy] -1,4-phenyl-alto-1,4-phenylene] dibromide (PPP-NEt3 ⁺ ), poly [2- (2'-ethylhexyloxy) -5-methoxy-1, 4-phenylene vinylene] (MEH-PPV) and the like.

As the precursor of the polymer light emitting material, for example, a poly (P-phenylene vinylene) precursor (Pre
-PPV), poly (P-naphthalene vinylene) precursor (Pre-PNV), and the like may be used as long as they can dissolve or disperse the above light-emitting material, and for example, pure water, methanol, ethanol, THF ( Tetrahydrofuran), chloroform, toluene, xylene, trimethylbenzene and the like.

The hole transport layer and the electron transport layer (collectively the charge transport layer) may each have a single layer structure or a multilayer structure. The charge transport layer can be formed by a known method similarly to the light emitting layer material. Known materials can be used as the charge transport material. The specific compounds are shown below, but the invention is not limited thereto.

Examples of the hole transport material include porphyrin compounds and N, N'-bis- (3-methylphenyl).
-N, N'-bis- (phenyl) -benzidine (TP
D), N, N'-di (naphthalen-1-yl) -N,
Aromatic tertiary amine compounds such as N'-diphenyl-benzidine (NPD), hydrazone compounds, quinacridone compounds, low molecular weight materials such as stilamine compounds, polyaniline, 3,4-polyethylenedioxythiophene / polystyrene sulfonate (PEDT) / PSS), poly (triphenylamine derivative), polyvinylcarbazole (PVCz) and other polymeric materials, poly (P-phenylenevinylene) precursor, poly (P-naphthalenevinylene) precursor and other polymeric material precursors Can be mentioned.

Examples of the electron transport material include low molecular weight materials such as oxadiazole derivatives, triazole derivatives, benzoquinone derivatives, naphthoquinone derivatives and fluorenone derivatives, and polymer materials such as poly [oxadiazole]. As the solvent, the solvent used for forming the light emitting material can be used.

A known electrode material can be used as the electrode material, and a metal having a high work function (A
u, Pt, Ni, W, etc.) or transparent electrode (ITO, I
DIXO, SnO _2, etc.) can be used, and the cathode contains at least a metal having a low work function (C
a, Ce, Cs, Rb, Ba, Al, Mg: Ag alloy,
(Al; Li alloy) or a lamination of a thin insulating layer and a metal electrode (LiF / Al etc.) can be used.

Embodiments The present invention will be described in detail below based on the embodiments shown in the drawings. This does not limit the invention. Example 1 An example will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, polyethylene terephthalate having a thickness of 150 μm is used as the base film 1,
The transfer layer 2 is formed thereon. In the transfer layer 2, indium oxide containing 10% zinc oxide as a transparent electrode I
The DIXO layer 2a is formed with a thickness of 150 nm.

The IDIXO layer 2a is formed by the DC magnetron sputtering method, and Ar gas containing 1% oxygen is used as the sputtering gas.

Further, in the transfer layer 2, an NPD layer 2b which is a hole transport material and an Alq ₃ layer 2c which is a light emitting layer are formed by vapor deposition with a thickness of 50 nm.

Further, as a cathode, a LiF / Al layer 2d,
2e is formed by resistance heating vapor deposition with a thickness of 1 nm and 150 nm, respectively.

The transfer film produced in this way is
The electrode pad 3 and the take-out wiring are previously formed of Al and bonded to the glass substrate 5 coated with the conductive adhesive 4,
The adhesive 4 is cured by heating. Then, as shown in FIG. 2, the film 1 is peeled off and sealed.

When a voltage is applied to the side of the IDIXO layer 2a + and to the side of the Al layer 2e-, Alq is passed through the IDIXO layer 2a.
Green light emission from the _three layers 2c was confirmed. With this method, the electrodes could be transferred at the same time, and it was possible to suppress the characteristic deterioration due to the oxidation of the cathode surface.

Second Embodiment A second embodiment will be described with reference to FIGS. 3 and 4. In this embodiment, the method for producing the transfer film and the method for forming the electrode pad and the take-out wiring of the substrate are the same as those in the first embodiment as shown in FIG.

The conductive adhesive 4 is applied by an ink jet method only on the upper portion of the electrode pad as shown in FIG.
The transfer film and the glass substrate 5 are bonded together, and the resin is cured by heating. After that, as shown in FIG.
Is peeled off and sealed.

Also in this embodiment, when a voltage is applied to the + side of the IDIXO layer 2a and − to the side of the Al layer 2e, IDIXO
Green light emission from the Alq ₃ layer 2c was confirmed through the layer 2a. In this method, since the adhesive 4 was applied only to the electrode pad 3, the separation between the pixels was also good.

When the adhesive 4 has a relatively high viscosity, it is difficult to apply the ink by the ink jet method. For example, the adhesive having been applied to the stamp having the convex portion corresponding to the electrode pad 3 is used. It is also possible to use a stamper method in which the adhesive 4 is pressed onto the electrode pad 3 and transferred onto the electrode pad 3.

Third Embodiment A third embodiment will be described with reference to FIGS. 5 and 6. In this example, the transfer film was produced in the same manner as in Example 1, as shown in FIG. On the other hand, the substrate 5 has organic LE on the glass.
A TFT circuit 7 including a D element driving transistor, a data writing transistor, and a data holding capacitor
A TFT substrate on which is formed is used.

After the TFT circuit 7 is formed, a flattening film 6 made of an epoxy resin is formed to flatten the surface, and an Al electrode pad 3 is formed. The conductive adhesive 4 is applied to the entire area of the display screen, bonded to the transfer film, and irradiated with laser light 8 from the glass substrate 5 side to heat and cure. After that, the film 1 is peeled off as shown in FIG.

For laser irradiation, the substrate 5 is placed on an XY stage and pulsed while moving, so that only the adhesive 4 in the pixel portion is cured. Since the beam diameter of the laser light can be narrowed down, it can be applied to high-definition electrode patterns.

When the adhesive is cured by heating by irradiation with light such as a laser, it is possible to irradiate light from the transfer film side. In this case, in order to prevent the organic layer from being deteriorated by light, it is preferable that the electrode on the light irradiation side is formed of a metal or the like to shield the light.

[0040]

According to the present invention, by simultaneously transferring the electrode layer and the organic layer by using the conductive adhesive, it is possible to manufacture an organic LED panel having a high-definition pattern without deterioration of element characteristics. .

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a first embodiment.

FIG. 2 is a cross-sectional view for explaining the first embodiment.

FIG. 3 is a cross-sectional view for explaining the second embodiment.

FIG. 4 is a sectional view for explaining the second embodiment.

FIG. 5 is a sectional view for explaining the third embodiment.

FIG. 6 is a cross-sectional view for explaining the third embodiment.

[Explanation of symbols] 1 ... Base film 2 ... Transfer layer 3 ... Electrode pad 4 ... Conductive adhesive 5 ... Glass substrate

Claims (7)

[Claims] 1. A method of manufacturing an organic LED element, which comprises depositing an organic layer sandwiched between a pair of electrodes on a substrate, by using a transfer film, wherein the pair of organic layers is sandwiched on the transfer film. 2. A method for manufacturing an organic LED element, which comprises laminating the electrodes of 1 above, applying a conductive adhesive on the substrate, and transferring the pair of electrodes and the organic layer from the transfer film to the substrate. 2. The organic LE according to claim 1, wherein the conductive adhesive is applied only to the pixel portion on the substrate.
Manufacturing method of D element. 3. The method of manufacturing an organic LED element according to claim 2, wherein the conductive adhesive is applied by an inkjet method. 4. The method of manufacturing an organic LED element according to claim 2, wherein the conductive adhesive is applied by a stamper method. 5. The step of applying the conductive adhesive comprises the step of applying the conductive adhesive to the entire screen on the substrate, and the step of transferring the electrode and the organic layer is the conductive adhesive only for the pixel portion. The method for manufacturing an organic LED element according to claim 1, comprising a step of curing and transferring the resin. 6. The method of manufacturing an organic LED element according to claim 5, wherein the conductive adhesive is cured by a laser. 7. The method of manufacturing an organic LED element according to claim 1, wherein the substrate is an active matrix substrate including a driving element and a switching element.