JP2002299065A - Polymer el element and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an EL element that prevents peeling between a cathode and polymer luminescent layer, an emission from only a cathode end, and a short circuit at a cathode end, and ensures higher strength. SOLUTION: A polymer EL element has a lamination at least of luminescent layers 3 of a polymer between an anodic base A, where an anode of a transparent conductive material is formed and a cathodic base B, where the cathode of a conductive material is formed. At least either the anode or the cathode is patterned to form a pattern of a luminescent part, and a non-luminescent part is at least partly provided with a spacer layer 4 of insulation resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a polymer EL device utilizing the electroluminescence (hereinafter simply referred to as EL) phenomenon of an organic thin film and a method for producing the same.

[0002]

2. Description of the Related Art Polymer E using a polymer as a light emitting material
The L element is generally formed by laminating an anode, a polymer light emitting layer, and a cathode. Further, the polymer light emitting layer may have a multilayer structure in which a hole injection layer, a hole transport layer, a phosphor layer, an electron injection layer, an electron transport layer, and the like are stacked. By passing a current between the anode and the cathode, light emission occurs in the polymer light emitting layer,
By making one electrode transparent, light can be extracted to the outside.

Such a polymer EL device is a surface-emitting solid-state display device, and can be made thinner. Since a display using this is a self-luminous type, it has a feature of exhibiting a high viewing angle and a high luminance, and can be driven at a low voltage. Further, it has a feature that the response speed is fast.

In order to improve the productivity of such a polymer EL device, a first substrate including an anode substrate and a second substrate including a cathode substrate are separately manufactured, and both substrates are subjected to opposing pressure bonding. There is a proposal to manufacture an element by bonding together (see JP-A-2000-77192).
This proposal proposes that by using pressure bonding, it is possible to minimize uneven light emission caused by dust attached to the first substrate or the second substrate. was there.

In particular, since the peel strength between the cathode and the polymer light emitting layer is low, there has been a problem that the cathode is peeled off by a force applied at the time of pressure bonding, and further, the cathode itself is peeled off.

Further, when the cathode and anode substrates are pressed against each other due to the unevenness of the patterned cathode extraction electrode, cathode metal layer, and transparent electrode, the substrates themselves bend and force concentrates on the cathode end, and the cathode ends partially. Since the film thickness is small, there is a problem that light emission occurs only at the cathode end and an electrical short circuit occurs at the cathode end.

[0007]

SUMMARY OF THE INVENTION As described above, the present invention provides a polymer EL device, in particular, for preventing separation between the cathode and the polymer light emitting layer, light emission only at the cathode end, and short-circuiting at the cathode end. It is an object of the present invention to provide a stronger polymer EL device and a method for manufacturing the same.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. In the first aspect, the present invention comprises an anode substrate on which an anode made of a transparent conductive material is formed and a conductive material. In a polymer EL element in which at least a polymer light-emitting layer is laminated between a cathode substrate on which a cathode is formed, at least one of an anode and a cathode is patterned, and on at least one of the anode substrate and the cathode substrate A polymer EL device comprising a spacer layer made of an insulating resin. According to a second aspect of the present invention, in the polymer EL device according to the first aspect, the insulating resin is a photosensitive resist.
A third aspect of the present invention is the polymer EL device according to any one of the first to second aspects, wherein the insulating resin contains a pigment or a dye. The polymer EL device according to claim 4, wherein at least a polymer light emitting layer is laminated between an anode substrate on which an anode made of a transparent conductive material is formed and a cathode substrate on which a cathode made of a conductive material is formed. Manufacturing a first substrate having a first pressure-bonded surface by sequentially laminating a part of the polymer light-emitting layer on an anode substrate; and forming the polymer light-emitting layer on a cathode substrate A step of manufacturing a second substrate having a second pressure-bonded surface by sequentially laminating the remaining layers of, and providing a spacer layer made of an insulating resin on the first or second substrate, A method for manufacturing a polymer EL device, comprising a step of opposingly pressing a first pressure-bonded surface of one substrate and a second pressure-bonded surface of the second substrate.

DETAILED DESCRIPTION OF THE INVENTION

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The anode substrate used in the polymer EL device of the present invention is formed by forming an anode made of a transparent conductive material on a transparent substrate.

As the transparent substrate, a glass substrate or a plastic film or sheet can be used.
If a plastic film is used, the polymer EL can be manufactured by winding, and an element can be provided at low cost. As plastic films, polyethylene terephthalate, polypropylene, cycloolefin polymer, polyamide, polyether sulfone,
Polymethyl methacrylate, polycarbonate, and the like can be used. Also, on the side where the conductive layer is not formed, another gas barrier film such as a ceramic vapor-deposited film or polyvinylidene chloride, polyvinyl chloride, saponified ethylene-vinyl acetate copolymer is laminated, or a color filter layer is provided by printing. May be.

As the transparent conductive material, a composite oxide of indium and tin (hereinafter referred to as ITO) can be used.
Film formation can be performed by using a paste-like ITO by a coating method such as printing. Also, after applying a precursor such as indium octylate or acetone indium on the substrate,
It can also be formed by a coating thermal decomposition method of forming an oxide by thermal decomposition. Alternatively, a material in which a metal such as aluminum, gold, or silver is translucently evaporated can be used.

Transparent or translucent transparent conductive material (anode)
May be subjected to patterning by etching as necessary, or activation of the surface by UV treatment, plasma treatment, or the like.

The element structure that can be used in the present invention is as follows:
It may be a single layer of a polymer light emitting layer or a multilayer structure including a hole transport layer, a polymer light emitting layer, and the like. When a hole transport layer is provided, copper phthalocyanine or a derivative thereof,
1-bis (4-di-p-tolylaminophenyl) cyclohexane, N, N′-diphenyl-N, N′-bis (3
-Methylphenyl) -1,1'-biphenyl-4,4 '
-Diamine, N, N'-di (1-naphthyl) -N, N '
Low molecular weight compounds such as aromatic amines such as -diphenyl-1,1'-biphenyl-4,4'-diamine can also be used, but polyaniline, polythiophene, polyvinylcarbazole, poly (3,4-ethylenedioxythiophene) ) And polystyrene sulfonic acid are more preferable because they can be formed by a wet method.

Materials for forming the polymer light emitting layer include coumarin, perylene, pyran, anthrone, porphyrene, quinacridone, N, N'-dialkyl-substituted quinacridone, naphthalimide, N, N ' It is possible to use a fluorescent dye such as a diaryl-substituted pyrrolopyrrole type dissolved in a polymer such as polystyrene, polymethyl methacrylate, or polyvinylcarbazole, or a polymeric fluorescent material such as a polyarylvinylene type or a polyfluorene type. it can.

Materials for forming these polymer light emitting layers are as follows:
Toluene, xylene, acetone, methyl ethyl ketone,
Dissolve the polymeric fluorescent material in a single or mixed solvent such as methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, and water, and spin coat, spray coat, flexo, gravure, microgravure, intaglio The film can be formed using a coating method such as offset printing and a printing method.

In the polymer EL device of the present invention, a polymer light emitting layer is coated on an anode substrate and a cathode substrate.
When the substrate is glass, spin coating, roll coating,
Methods such as spray coating, slot coating, flexo, offset, intaglio offset can be used.
When a wound film is used as the substrate, various coating methods such as gravure, gravure offset, microgravure, flexo, die coat, and roll coat can be used. In particular, a method in which patterning such as flexo, offset, intaglio offset, and gravure can be performed simultaneously with coating is preferable.

When the polymer light emitting layer is composed of two or more layers, the solubility of the material constituting each layer is taken into consideration, for example, by selecting a water-soluble or oil-soluble resin. The coating conditions may be selected so as to use the difference or shorten the time from coating to drying so that the lower layer is not substantially affected. The thickness of the coating depends on the structure of the device, but is preferably 0.01 to 10 μm, and more preferably 0.05 to 0.5 μm.

As the conductive material used for the cathode, metal materials such as aluminum, copper and nickel can be used.
Note that these conductive materials are preferably in the form of a foil from the viewpoint of workability. Further, if necessary, a luminous efficiency can be increased by providing a buffer layer of lithium fluoride, alumina, polymethyl methacrylate, sodium polystyrene sulfonate, or the like. For the buffer layer using a polymer such as polymethyl methacrylate or sodium polystyrene sulfonate, a wet printing method can be used. Further, the buffer layer using these polymers can be used for pressure bonding. In addition, a metal foil of aluminum or the like on which calcium, magnesium, silver, gold, or the like is evaporated, sputtered, or plated can also be used. When the thickness of the metal foil is 1 μm or less, it is difficult to handle the metal foil. The thickness is preferably 5 μm or more, and more preferably 15 μm or more in order to prevent pinholes in the foil. By preventing pinholes in the foil, moisture and oxygen can be prevented from entering the inside of the element, and the life of the element can be extended with a simple configuration. A film of polyethylene terephthalate, nylon, or the like may be pressed in advance on the back surface of the metal foil to facilitate handling during manufacture.

The polymer EL device of the present invention has a spacer layer made of an insulating resin. When the counter pressure bonding is performed, unevenness in the pressure and unevenness of the substrate due to the unevenness of the first and second substrates are caused. It is possible to prevent light emission or electrical short circuit only at the cathode end due to the concentration of the generated force on the cathode end.
Also, the size and shape of the spacer layer can be changed depending on the case. By providing the spacer layer, not only the patterning portions of the electrodes and the cathode, but also the other portions are pressure-bonded widely, so that the bonding strength is greatly increased. Therefore, it is possible to prevent peeling at the time of pressure bonding between the weak cathode and the polymer light emitting layer.

The pattern of the spacer layer can be used for patterning instead of etching the transparent or translucent conductive layer or the cathode metal layer.

As the insulating resin, a photosensitive resist, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like can be used. In particular, a photosensitive resist is suitable for a case where fine patterning is to be performed on the spacer layer.

As the thermoplastic resin, styrene-based, olefin-based, urethane-based, ester-based, and PVC-based resins can be used. As the thermosetting resin, a phenol resin, a urea resin, a melamine resin, an unsaturated polyester resin, an epoxy resin, a silicone resin, or the like can be used.

For the thermoplastic resin and the thermosetting resin, various coating methods such as gravure, gravure offset, microgravure, flexo, die coat and roll coat can be used. In particular, a method in which patterning such as flexo, offset, intaglio offset, and gravure can be performed simultaneously with coating is more preferable.

Further, by mixing a pigment or a dye with the insulating resin, the reflected light at the cathode can be suppressed, and the bleeding can be prevented and the contrast can be improved.

A glass or film having a transparent electrode is used as the first substrate, and a part of the polymer light emitting layer up to the first press-bonded surface is laminated. Next, as the second substrate, the remaining layer of the polymer light emitting layer up to the second pressure-bonded surface including the cathode is laminated. From the viewpoint of adhesiveness, it is preferable that the first crimping surface and the second crimping surface are layers made of the same material.
Then, the pressure bonding surfaces of the first substrate and the second substrate are opposed to each other,
Crimping or thermocompression bonding between metal rolls or rubber rolls,
Configure the element.

The spacer layer can be provided at any position on both the first and second substrates. Further, the step of providing the spacer layer can be at any stage.
In the case of a photosensitive resist, there is a possibility that the polymer light emitting layer may be destroyed at the stage of exposure, so it is desirable to form the photosensitive resist layer before the polymer light emitting layer. In addition, it is desirable to use a solvent having low solubility of the material on the application surface when applying.

According to the polymer EL device of the present invention,
By providing a spacer layer made of an insulating resin, it is possible to reduce the problem of edge light emission and short-circuit due to the bending of the two substrates to be pressed during the pressing, and to increase the peel strength of the polymer EL device manufactured by the pressing. Can be improved.

[0028]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

(Embodiment 1) A description will be given below with reference to FIG.
As the anode substrate, a transparent substrate 1 made of glass with an anode 2 made of ITO is used. Then, poly [2-methoxy-5- (2′-) represented by the following chemical formula 1 is formed on the anode substrate.
Ethyl-hexyloxy) -1,4-phenylene vinylene (Poly @ 2-methyoxy-5- (2'-et)
(Hylhexyloxy) -1,4-phenylene
e vinylene3 or less MEH-PPV)
The first substrate A was manufactured by performing coating with a thickness of 0.05 μm by spin coating and providing the polymer light emitting layer 3. In addition, a photosensitive resist is applied by spin coating on a transparent substrate 1 made of glass with a cathode 5 made of patterned ITO having a thickness of 0.16 μm, exposed and developed by using a mask, and a spacer is formed. Layer 4 was formed. The ITO portion is exposed. At this time, the thickness of the spacer layer is 0.22 μm. Aluminum is vacuum-deposited on the ITO of this substrate as a cathode 5 by 0.10 μm, and lithium fluoride 6 of 0.001 μm is formed by vacuum deposition. Further, MEH-PPV is formed.
The second substrate B was manufactured by performing coating with a thickness of 0.05 μm by spin coating and providing the polymer light emitting layer 3. First substrate A and second substrate B
Is laminated at 130 ° C. to obtain a polymer EL comprising the present invention.
An element was manufactured. When a voltage of 10 V was applied to this polymer EL device, light emission of 50 cd / m2 was obtained.

[0030]

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(Embodiment 2) A description will be given below with reference to FIG.
Poly (3,4-ethylenedioxythiophene) represented by the following chemical formula 2 and polystyrene sulfonic acid are used as a hole injection layer 8 on a transparent substrate 7 made of a polyethylene terephthalate film having an anode 9 made of patterned ITO. (Hereinafter referred to as PEDOT / PSS) was printed at 0.05 μm to prepare a first laminated film (substrate) A. In addition, a cathode 11 made of aluminum foil is preliminarily laminated on the base material 10, and in order to fill a step generated by the patterned anode 9, polyvinyl alcohol in which carbon black as a pigment is dispersed is patterned on the aluminum foil. Printing was performed with a thickness of 0.2 μm to form the spacer layer 12. Next, MEH
The polymer light emitting layer 13 made of PPV is printed at 0.1 μm, and the hole transport layer 14 made of PEDOT / PSS is further printed.
Is printed 0.05 μm, and the second laminated film (substrate) B
Was prepared. The first laminated film A and the second laminated film B were laminated at 80 ° C. to produce a polymer EL device according to the present invention. 5V is applied to this polymer EL element.
Applied, a uniform light emission of 100 cd / m 2 could be obtained. At this time, the peel strength is 1 kg.
/ 15 mm. The contrast ratio is 90: 1.
Met.

[0032]

Embedded image

Comparative Example 1 The polymer EL device of Example 2 was manufactured without using a spacer layer. This polymer EL
When a voltage of 12 V was applied to the device, only the end of the cathode emitted light. The peel strength at this time was 30 g / 1.
It was about 5 mm.

[0034]

According to the polymer EL device and the method of manufacturing the same according to the present invention, it is possible to eliminate uneven pressure at the time of pressure bonding and low peel strength, which are generated in the device manufacturing process.

[0035]

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a polymer EL device of the present invention.

FIG. 2 is an explanatory view showing another embodiment of the polymer EL device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transparent base material 2 ... Anode 3 ... Polymer light emitting layer 4 ... Surcer layer 5 ... Cathode 6 ... Lithium fluoride 7 ... Transparent base material 8 ...・ Polymer light-emitting layer 9 ・ ・ ・ Anode 10 ・ ・ ・ Base material 11 ・ ・ ・ Cathode 12 ・ ・ ・ Surcer layer 13 ・ ・ ・ Hole transport layer 14 ・ ・ ・ Polymer light-emitting layer

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Minato 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. F-term (reference) 3K007 AB15 AB17 AB18 BA06 CA01 CB01 DA01 DB03 EA00 EB00 FA01

Claims (4)

[Claims] 1. A polymer EL device in which at least a polymer light emitting layer is laminated between an anode substrate on which an anode made of a transparent conductive material is formed and a cathode substrate on which a cathode made of a conductive material is formed. And at least one of an anode and a cathode is patterned, and at least one of an anode substrate and a cathode substrate is provided with a spacer layer made of an insulating resin. 2. The polymer EL device according to claim 1, wherein said insulating resin is a photosensitive resist. 3. The polymer EL device according to claim 1, wherein the insulating resin contains a pigment or a dye. 4. A polymer EL device in which at least a polymer light emitting layer is laminated between an anode substrate on which an anode made of a transparent conductive material is formed and a cathode substrate on which a cathode made of a conductive material is formed. In the manufacturing method, a step of manufacturing a first substrate having a first pressure-bonded surface by sequentially laminating a part of the polymer light-emitting layer on the anode substrate, and forming the polymer light-emitting layer on the cathode substrate A step of manufacturing a second substrate having a second pressure-bonded surface by sequentially laminating the remaining layers, and a step of providing a spacer layer made of an insulating resin on the first or second substrate; A step of pressing the first pressure-bonded surface of the substrate and the second pressure-bonded surface of the second substrate in opposition to each other.