JP2003142259A - Organic thin film light emitting display and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic thin film light emitting display which can surely separate an organic light emitting layer from a second electrode, with high resolution and reliability and improved yield of work, and to provide a manufacturing method of the same. SOLUTION: For the organic thin film light emitting display, terminal pads for a first electrode and a second electrode extended from the first electrode are formed around an image display arranging area, and an electric insulation film is formed on a part of the first electrode, a transparent base board, and part of the terminal pad for the second electrode. The second electrode is connected to the terminal pad for the second electrode at the opening of the electric insulation film formed on the terminal pad for the second electrode. Barrier ribs, composed of a plurality of electric insulation bodies arranged in parallel with the second electrode protruding on the electric insulation film, are formed, and adjacent barrier ribs are jointed to each other at the upper part of the electric insulation film formed on the terminal pad for the second electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting device used as a display, and more particularly to a passive matrix type organic light emitting device having high definition, high reliability, low manufacturing cost and high efficiency, and a manufacturing method thereof. .

[0002]

2. Description of the Related Art A passive matrix type (simple matrix type) display is one of the organic thin film light emitting display panels utilizing the electroluminescence of organic compound materials.

A passive matrix type display comprises a plurality of first electrodes on a transparent substrate, a plurality of second electrodes orthogonal to the first electrodes, and an organic light emitting layer sandwiched between these electrodes. One pixel is formed with the light emitting portion in the intersecting region of the first electrode and the second electrode as one unit. An image display portion is formed by arranging a plurality of these pixels. Via the connection part formed by extending the first electrode and the second electrode (that is, the anode and the cathode) from the image display part to the periphery of the substrate,
An image display device is configured by connecting the external drive circuit and the screen display unit.

In recent years, research has been conducted on a high-definition passive matrix type color display utilizing the light emitting response speed of an organic light emitting element, and a high-quality display at a low cost for information device applications such as full-color display and moving image display. Expectations for realization are increasing.

In order to manufacture a high-definition display, the stripe width of the first electrode and the second electrode is several hundreds μm or less,
It is necessary to set the gap between adjacent stripes to several tens of μm or less.

[0006]

Generally, an organic light emitting layer is disclosed in Japanese Patent Application Laid-Open No. Hei 5 (1999) -53138 as a fine patterning method for the second electrode.
-275172, JP-A-5-258859, JP-A-5-258860, and JP-A-8-
The technology disclosed in Japanese Patent No. 315981 is known.
These publications describe a method in which stripe-shaped partition walls are formed in parallel on a substrate and the partition walls are used to form an organic light emitting layer and a second electrode.

In recent years, full-color development of organic light-emitting devices has been carried out, and a method of precisely coating the materials of the organic light-emitting layer of the three primary colors and the second electrode has been adopted by using the technique disclosed in the above-mentioned publication. . In this method, it is necessary to precisely align the substrate and the film forming mask in the film forming apparatus, which may increase the cost of the apparatus and reduce the manufacturing yield.

On the other hand, as a method for performing full-color display, there is also known a technique in which a color filter or a color conversion layer is formed on a substrate and then a white or blue light emitting layer is collectively formed. This technique does not require separate coating of the organic light emitting layer, and is advantageous in terms of device cost and production yield.

According to this method, the vapor deposition mask for the organic light emitting layer and the vapor deposition mask for the second electrode are aligned with each other on the substrate, and it is not necessary to separately paint the organic light emitting layer. No alignment required. However, today, there is a demand for a narrower frame and an increase in the number of manufactured glass sheets from the mother glass, and there is a demand for a method that can more easily align the vapor deposition mask and improve the production yield.

Further, in the method described in the above-mentioned JP-A-8-315981, an electrically insulating partition having an overhang portion projecting in a direction parallel to the surface of the substrate at the top is exposed at a part of the first electrode. It is formed on the electrically insulating film formed as described above. However, this structure has low mechanical strength when dissimilar materials are laminated, and peeling of partition walls is observed in tests such as heat cycle tests where thermal expansion and thermal contraction are severely repeated. There is a need for ways to improve.

[0011]

The organic thin film light emitting display of the present invention for achieving the above object comprises a plurality of first electrode rows and a plurality of second electrode rows formed on a transparent substrate. Has an image display array region composed of pixels composed of intersections of the above, at least an organic light emitting layer is formed between the electrodes, and a voltage is applied between both electrodes forming a desired pixel to inject a current. Information is displayed by taking out the electroluminescence obtained by the above, and the terminal pad for the first electrode and the terminal pad for the second electrode extended from the first electrode are provided around the image display array area described above. Is formed, a part of the first electrode, a transparent substrate, and an electric insulating film is formed on a part of the terminal pad for the second electrode,
The second electrode is connected to the terminal pad for the second electrode at the opening of the electric insulating film on the terminal pad for the second electrode, and is parallel to the second electrode protruding on the electric insulating film. A partition wall made of a plurality of electrical insulators is formed, and the partition wall is formed by connecting adjacent partition walls to each other on the electrical insulating film on the terminal pad for the second electrode.

The method of manufacturing an organic thin film light emitting display according to the present invention comprises a step of patterning a plurality of first electrodes on a substrate and a terminal pad for a second electrode around the first electrodes. And a step of forming an electric insulating film on a part of the first electrode, the substrate, and a part of the terminal pad for the second electrode, and a partition made of an electric insulator on the electric insulating film. And a step of forming an organic light emitting layer on the opening of the electric insulating film on the electric insulating film and on the first electrode, the organic light emitting layer, the electric insulating film, and a terminal pad for the second electrode. And a step of forming a thin film to be a second electrode in the opening of the electrical insulating film on the second electrode,
The terminal pad for the second electrode is electrically connected through the opening of the electric insulating film on the terminal pad for the second electrode, and the partition wall made of the electric insulator defines the formation region of the second electrode.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing an example of the constitution of an organic thin film light emitting display according to the present invention, and FIG. 2 is an example of the organic thin film display shown in FIG.
A sectional view taken along the line is shown.

In the organic thin film light emitting display of the present invention, as shown in FIGS. 1 and 2, an intersection of a plurality of first electrode rows 2 and a plurality of second electrode rows 3 formed on a substrate 1. Has an image display array region composed of pixels configured by
At least the organic light emitting layer 4 is formed between the electrodes,
Information is displayed by applying a voltage between both electrodes forming a desired pixel and injecting a current. Around the image display array region, a first electrode terminal pad 2a extending from the first electrode and a second electrode terminal pad 5 are formed. A part of the first electrode 2 and the transparent substrate 1 are formed. , And an electric insulating film 6 is formed on a part of the terminal pad 5 for the second electrode. The second electrode 3 is connected to the terminal pad 5 for the second electrode in the opening 7 of the electric insulating film on the terminal pad 5 for the second electrode, and is connected to the second electrode protruding on the electric insulating film. Partition walls 8 made of a plurality of parallel electrical insulators are formed, and the partition walls are connected to each other on the electrical insulating film on the terminal pad for the second electrode.

A method of manufacturing an organic thin film light emitting display having such a structure will be described with reference to FIGS. FIG. 3 is a plan view showing an example of the configuration of the organic thin film light emitting display according to the present invention shown in FIG. 1 before forming the organic light emitting layer and the second electrode. FIG. 4 shows an example of the partition pattern in the present invention.

As an example of the organic thin film light emitting display of the present invention, a color display panel in which the panel includes a fluorescent color conversion filter and an organic light emitting body will be described. That is, light in the near-ultraviolet to visible region emitted from the organic light-emitting body, preferably light in the blue to blue-green region is incident on the fluorescent color conversion filter, and output as visible light of different wavelengths formed by the fluorescent color conversion filter. It was made to let.

First, a fluorescent color conversion filter is formed on a substrate, and a protective layer and a gas barrier layer are formed thereon (not shown). At this time, a protective layer made of acrylic resin or the like having both a flattening function and a protective function for the color conversion layer is formed as a protective layer, and a gas barrier layer made of SiO _x or SiO _x N _y is formed. Further, the function of the protective layer can be subdivided, and the number of layers can be increased for each function.

As the substrate used in the present invention, a glass substrate, a film substrate such as a polymer film, a polyimide substrate, an acrylic substrate or the like can be used.

An organic luminescent material is formed on the gas barrier layer on the luminescent color conversion filter. The organic light-emitting body is sandwiched between a pair of electrodes, and has a structure in which a hole injection layer, a hole transport layer, or an electron injection layer is interposed between the electrodes as necessary. Specifically, one having the following layer structure is adopted. (1) Anode / organic light emitting layer / cathode (2) Anode / hole injection layer / organic light emitting layer / cathode (3) Anode / organic light emitting layer / electron injection layer / cathode (4) Anode / hole injection layer / organic Light emitting layer / electron injection layer / cathode (5) Anode / hole injection layer / hole transport layer / organic light emitting layer / electron injection layer / cathode

In the above layer structure, an anode (first electrode)
At least one of the cathode and the second electrode is preferably transparent in the wavelength range of light emitted by the organic light-emitting body, and emits light through the transparent electrode to emit light to the fluorescent color conversion film. Make it incident. In this technology,
It is known that it is easy to make the anode transparent, and it is desirable to make the anode transparent also in the present invention.

In order to form an organic light emitting body, first, a first electrode (anode) 2 and a terminal pad 2a for a first electrode extending from the first electrode 2a are formed on the gas barrier layer as shown in FIG.
To form a pattern. As the first electrode, indium tin oxide (ITO), indium zinc oxide, tin oxide, zinc oxide, aluminum tin oxide or the like which is a transparent conductive film material can be used.

Around the first electrode, as shown in FIG.
A terminal pad 5 for two electrodes is formed, and the area as shown in FIG. 3 is formed.
An electrically insulating film is formed in the surrounding area. Of the terminal pad for the second electrode
The material is, for example, the same material as the first electrode (such as ITO).
Etc.), metal materials such as Al, Cr, Mo, Cu, and W
Materials as well as alloys thereof. Electrical insulation
As the film material, for example, a positive type using novolac resin
Negative photoresist such as photoresist and acrylate
, Polyimide material, or SiO_x, SiO _xN_y,
SiN_x, And TiO_xUse an inorganic oxide film such as
You can This electrical insulation film is the terminal pad for the second electrode
5 and an opening 7 on a part of the first electrode 2
It has a feature. In addition, the electrically insulating film is formed on the edge of the first electrode.
You may form so that it may coat. Area where electrical insulation film is formed
Is not limited to that shown in FIG.
Form in a region that considers the amount of positional deviation between the plate and vapor deposition mask
This allows the first electrode (anode) 2 material and the second electrode (cathode)
Pole) to prevent short circuit between 3 materials and between terminal pads
it can. Also, the thickness of the insulating film is not applied when the panel is driven.
It is necessary to have the withstand voltage calculated from the applied voltage.

Next, the partition wall 8 is formed on the electric insulating film. A plurality of partition walls 8 are formed in the extending direction of the second electrode,
It extends to the terminal pad portion 5 for the second electrode formed around the first electrode. The adjacent partition walls may be vertically connected on the terminal pad for the second electrode as shown in FIG. 3 or may be connected by a curved line as shown in FIG. By connecting the partition walls, the strength of the partition walls is improved.
Examples of the electric insulator material forming the partition wall include:
Examples thereof include a negative photoresist and a positive photoresist using a novolac resin, and a negative photoresist such as acrylate.

At least the organic light emitting layer 4 is formed on the electric insulating film 6 between the partition walls 8 and on the opening 7 of the electric insulating film on the first electrode, as shown in FIG. At this time, if necessary, the hole injection layer, the electron injection layer, and / or the hole transport layer may be formed so as to have the above-mentioned layer structure.

Known materials are used as the materials for the respective layers. For example, in order to obtain blue to blue-green light emission as the organic light emitting layer, for example, a fluorescent whitening agent such as benzothiazole-based, benzimidazole-based, benzoxazole-based, metal chelated oxonium compound, styrylbenzene-based compound, aromatic Dimethylidene compounds are preferably used.

Cu phthalocyanine, triphenylamine derivative, etc. are used as the hole injection layer, triphenylamine derivatives such as TPD and α-NPD are used as the hole transport layer, and electron injection layer is used. Metal complexes such as aluminum chelate complexes can be used, but the invention is not limited thereto.

Next, on the organic light emitting layer (electron injection layer if necessary) 4, on the electric insulating film 5, and on the opening 7 of the electric insulating film on the terminal pad for the second electrode, the second electrode ( Anode) 3 is formed. As a material for the second electrode, a metal having a low work function such as aluminum, magnesium, indium, silver, or an alloy thereof can be used.

According to the above-described embodiment, the patterns of the first electrode (anode) and the second electrode (cathode) are parallel stripes and are formed so as to intersect each other. In this case, the present invention allows the organic light emitting device to perform matrix driving, that is, a voltage is applied to a specific stripe of the first electrode (anode) and a specific stripe of the second electrode (cathode). Occasionally, in the organic light emitting layer, the portions where those stripes intersect emit light. Therefore, by applying a voltage to selected stripes of the first electrode (anode) and the second electrode (cathode),
Only the portion where the specific fluorescent color conversion film and / or the filter layer is located can emit light.

Further, the first electrode (anode) may be a uniform flat electrode having no stripe pattern, and the second electrode (cathode) may be patterned so as to correspond to each pixel. In that case, a so-called active matrix drive can be performed by providing a switching element corresponding to each pixel.

[0030]

[Embodiment] Here, the number of pixels (320 × RGB) × 24
An example in which the present invention is applied to an organic thin-film light emitting display panel having 0 dots and a pixel pitch of 110 × 330 μm and the number of sub-dots 230 and 400 will be described. The panel has a structure in which the data line formed by the first electrode is divided into two in the vertical direction of the panel.

First, a fluorescent color conversion filter is formed on the substrate.

[Preparation of blue filter] A blue filter material (manufactured by Fuji Hunt Electronics Technology: Color Mosaic CB-7001) was applied by spin coating.
Corning glass on a transparent substrate (50 x 50 x 1.1 m
m) and then patterned by photolithography to obtain a line pattern of a blue filter having a line width of 0.1 mm, a pitch of 0.33 mm and a film thickness of 10 μm.

[Preparation of Green Conversion Filter] Coumarin 6 (0.7 parts by weight) as a fluorescent dye was dissolved in 120 parts by weight of propylene glycol monoethyl acetate (PGMEA) as a solvent. Photopolymerizable resin "V259PA / P
5 "(trade name, Nippon Steel Chemical Co., Ltd.) was added and dissolved to obtain a coating solution. This coating solution
Corning glass (50 x 50 x 1.
1 mm) was applied by a spin coating method and patterned by a photolithography method to obtain a line pattern of a green conversion filter having a line width of 0.1 mm, a pitch of 0.33 mm and a film thickness of 10 μm.

[Preparation of Red Conversion Filter Layer] Coumarin 6 (0.6 parts by weight) as fluorescent dye, Rhodamine 6G
(0.3 parts by weight), basic violet 11 (0.
3 parts by weight) was dissolved in 120 parts by weight of a solvent propylene glycol monoethyl acetate (PGMEA). 100 parts by weight of a photopolymerizable resin "V259PA / P5" (trade name, Nippon Steel Chemical Co., Ltd.) was added and dissolved to obtain a coating solution. This coating solution was applied onto Corning glass (50 × 50 × 1.1 mm) as a transparent substrate by spin coating, and then by photolithography.
Patterning is performed, and the line width of the red conversion filter is 0.
A line pattern having a thickness of 1 mm, a pitch of 0.33 mm and a film thickness of 10 μm was obtained.

[Production of Protective Layer and Gas Barrier Layer] A UV curable resin (epoxy modified acrylate) was applied as a protective layer on this fluorescence conversion filter by a spin coating method and irradiated with a high pressure mercury lamp to give a film thickness. 5 μm was formed.
At this time, the pattern of the fluorescence conversion filter has no deformation,
Moreover, the upper surface of the protective layer was flattened and protected.

On the protective layer, a SiO _x N _y film having a thickness of 300 nm was deposited as a gas barrier layer by a sputtering method. At this time, when the adhesion between the protective layer and the gas barrier layer was evaluated by the basic test according to JIS5400, a good adhesion of 8 points or more was shown.

In this way, the fluorescence conversion filter composed of the three primary colors was formed on the transparent substrate.

[Production of Organic Light-Emitting Element] An organic light-emitting element is formed on the obtained fluorescence conversion filter on the substrate.

First, the terminal pad portion 5 for the second electrode (cathode) is formed on the upper surface of the gas barrier layer which is the outermost layer of the filter portion.
And a resistivity of 1.5 × 10 ⁻⁵ as an auxiliary electrode portion of the anode
Mo of [Ω · cm] was formed with a film thickness of 300 nm and a width of 20 μm. A DC magnetron sputtering method is used for forming a film of Mo, a resist agent “OFRP-800” (trade name, manufactured by Tokyo Ohka Co., Ltd.) is applied on Mo, and then patterning is performed by a photolithography method to form a second electrode. Terminal pad 5
And the auxiliary electrode portion of the anode was formed. After that, a transparent electrode material (ITO) was formed on the entire surface by a sputtering method. ITO
After applying the resist agent "OFRP-800" (trade name, manufactured by Tokyo Ohka) on the top, patterning is performed by photolithography, and the light emitting portions (red, green,
And 94.), width 0.094 mm, spacing 0.
An anode 1 having a stripe pattern of 016 mm and a film thickness of 100 nm was obtained.

Next, a positive photoresist [WIX-2A] (trade name, manufactured by Zeon Corporation) was applied as an electric insulating film by a spin coating method, and patterning was performed by photolithography. The electric insulating film has a film thickness of 1 μm, has a plurality of openings of width 80 μm and length 290 μm (in the extending direction of the first electrode) on each first electrode 2, and on the terminal pad 5 for each second electrode. Has an opening with a width of 1 mm (the extending direction of the terminal pad) and a length of 290 μm. The angle of the end of the electric insulating film with respect to the substrate is an acute angle. In this way, as shown in FIG. 3, the insulating film was formed wider outside the display region than in the cathode formation region, and the openings 7 were provided on the anode and the cathode terminal pads.

The positive type photoresist used in this example was able to have a sufficient withstand voltage by being formed with a film thickness of approximately 800 nm or more.

Next, a negative photoresist [ZPN110
0] (trade name, manufactured by Zeon Corporation) was applied by a spin coating method, and partition walls 8 having a thickness of 4 μm were formed by photolithography as shown in FIG. The partition wall width in the cathode extension direction is 30
μm and the pitch is 330 μm. In addition, the ends of the barrier ribs are connected by the barrier ribs formed perpendicularly to the cathode extension direction.

By connecting the partition walls, the strength of the partition walls was improved, and the shape and adhesion stability of 400 cycles or more were confirmed in a heat shock test of -40 ° C to 95 ° C.

Next, the above-mentioned substrate was mounted in a resistance heating vapor deposition apparatus, and a hole injection layer, a hole transport layer, an organic light emitting layer, and an electron injection layer were sequentially formed without breaking the vacuum. During film formation, the internal pressure of the vacuum chamber was reduced to 1 × 10 ⁻⁴ Pa. The hole injection layer is copper phthalocyanine (CuPc)

[0045]

[Chemical 1]

100 nm was laminated. The hole transport layer is
4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD)

[0047]

[Chemical 2]

20 nm was laminated. The organic light emitting layer is 4,
4'-bis (2,2'-diphenylvinyl) biphenyl (DPVBi)

[0049]

[Chemical 3]

30 nm was laminated. The electron injection layer is a tris (8-hydroxyquinoline) aluminum complex (Al
q)

[0051]

[Chemical 4]

20 nm was laminated. The hole injecting layer, the hole transporting layer, the organic light emitting layer, and the electron injecting layer were formed using a vapor deposition mask having an opening of 107.6 × 81.2 mm.

After this, 200 nm thick Mg / Ag (1
A cathode (second electrode) 3 composed of a layer (0: 1 weight ratio),
Formed without breaking vacuum. Opening 11 for forming the cathode
A 1.6 × 81.2 mm vapor deposition mask was used. The accuracy of alignment between the vapor deposition mask and the substrate was ± 1 mm, and the cathode had a structure having a contact area of 1 mm with the cathode terminal pad 5.

By connecting the ends of the partition walls,
It was possible to completely define the formation region of each cathode and prevent the short circuit between the anodes and between the cathodes by forming the insulating film wider than the cathode region.

The organic light-emitting device thus obtained was sealed in a glove box under a dry nitrogen atmosphere (both oxygen and water concentrations were 10 ppm or less) using a sealing glass (not shown) and a UV curing adhesive. did.

The sealed substrate was taken out into the atmosphere and connected to the drive circuit terminals via the terminal pads using an anisotropic conductive adhesive (ACF).

By the above method, the number of pixels (320 × RG
B) An organic thin film light emitting display panel having 240 dots and a pixel pitch of 110 × 330 μm and having 230,400 sub-dots was produced.

[0058]

As described above, according to the present invention, the second electrode can be reliably separated in the production of a high-definition and highly reliable organic thin film light emitting display panel, and a vapor deposition mask can be easily formed. The manufacturing yield can be improved without cost.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a substrate structure of an organic thin film light emitting display according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a plan view showing an example of a substrate configuration of an organic thin film light emitting display according to the present invention.

FIG. 4 is a view showing an arrangement example of partition walls of the organic thin film light emitting display according to the present invention.

[Explanation of symbols]

1 substrate 2 First electrode (anode) 2a Terminal pad for first electrode 3 Second electrode (cathode) 4 Organic light emitting layer 5 Terminal pad for the second electrode 6 Electric insulation film 7 Opening of electrical insulation film 8 partitions

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 33/14 H05B 33/14 A 33/22 33/22 Z F term (reference) 3K007 AB04 AB18 BA06 BB06 CB01 CC05 DB03 EA00 FA01 FA02 5C094 AA08 AA42 AA43 AA44 AA48 BA27 CA19 CA24 DA13 DA15 DB02 DB04 EA05 EB02 ED02 FA01 FB01 FB15 FB20

Claims (2)

[Claims] 1. An image display array region having pixels formed by intersections of a plurality of first electrode rows and a plurality of second electrode rows formed on a transparent substrate, and between the electrodes. Is an organic thin-film light-emitting display that displays information by extracting electroluminescence obtained by applying a voltage and injecting a current between both electrodes that form a desired pixel. In the vicinity of the image display array region, a terminal pad for a first electrode and a terminal pad for a second electrode extended from a first electrode are formed, and a part of the first electrode, a transparent substrate,
And an electric insulating film is formed on a part of the terminal pad for the second electrode, and the second electrode is a terminal for the second electrode in the opening of the electric insulating film on the terminal pad for the second electrode. A partition wall formed of a plurality of electrical insulators connected to the pad and parallel to the second electrode protruding on the electrical insulation film is formed, and the partition wall is the electrical insulation film on the terminal pad for the second electrode. In the above, the organic thin film light emitting display is characterized in that adjacent barrier ribs are connected to each other. 2. A method of manufacturing an organic thin film light emitting display, the method comprising: patterning and forming a plurality of first electrodes on a substrate; and forming terminal pads for the second electrodes around the first electrodes. A step of forming, a step of forming an electric insulating film on a part of the first electrode, the substrate, and a part of the terminal pad for the second electrode, and a partition wall made of an electric insulator on the electric insulating film. A step of forming, an step of forming an organic light emitting layer in the opening of the electric insulating film on the electric insulating film and on the first electrode, on the organic light emitting layer, the electric insulating film, and the terminal pad for the second electrode And a step of forming a thin film to be a second electrode in the opening of the electric insulating film, the second electrode for the second electrode through the opening of the electric insulating film on the terminal pad for the second electrode. It is electrically connected to the terminal pad and is separated by an electrically insulating partition wall. The method for manufacturing an organic thin film light-emitting display, characterized in that, defining the formation area of the second electrode.