JP2001210469A - Manufacturing method of organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to form a second electrode, formed on an organic material layer, into prescribed pattern when a simple matrix type display panel using the organic electroluminescent element as a pixel luminescence part, is manufactured. SOLUTION: In the manufacturing method of a display panel using the organic electroluminescent element as a pixel luminescence part, inversely tapered structure (barrier rib) is formed on the organic material layer by transcribing an orderly tapered structure formed on an another film in advance, after forming the first electrode and an organic material on a substrate. Subsequently, a subscribed pattern is obtained by forming the film of the second electrode. Additionally, dark spot on the pixel luminescence part of the display panel is restrained.

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 electroluminescence device used for a simple matrix type display panel or the like.

[0002]

2. Description of the Related Art Organic electroluminescent devices are
These are light-emitting elements that have features such as thinness, all-solid-state, planar self-emission, and high-speed response, and are expected to be applied to flat display panels and backlights as man-machine interfaces in the coming multimedia era. Therefore, research has been actively conducted in various fields in recent years. Previously, the device characteristics were remarkably inferior to those of inorganic electroluminescence devices using inorganic substances.
In 1987, Kodak's Tang et al. Announced a method of forming a layered structure of organic layers (CWTang and SAVanslyk
e: Appl. Lett., 51 (12), 21 September 1987, pp913-915)
It is developing rapidly. A product using an organic electroluminescence element for a display panel is also on sale.

An organic electroluminescence element has a structure in which at least a light emitting layer made of an organic compound is sandwiched between a pair of electrodes facing each other on a substrate. When a voltage is applied, electrons are injected into this light-emitting layer from one electrode and holes are injected from the other electrode, and the organic molecules excited by the recombination of these electrons and holes relax to the ground state. Light emission is obtained. Therefore, it is preferable that one of the electrodes is transparent, and in many cases, light emission is often extracted by using a transparent conductive film for the first electrode provided on the substrate. At this time, it is desirable that the substrate is transparent.

In many cases, ITO (indium tin oxide) is used for the transparent conductive film as the first electrode. In many cases, a metal thin film is often formed on the second electrode on the organic material layer by a vacuum evaporation method.

An excellent feature of the organic electroluminescence element is that it is thinner than other display elements. In the organic electroluminescence element, the first electrode, the organic material layer, and the second electrode layer are each formed into a thin film, and the thickness of the parts excluding the substrate is on the order of micrometers or less. Considering the thickness of the substrate, resin, glass, and the like used for the sealing treatment, the overall thickness is a light emitting element that is extremely thin, on the order of millimeters.

Further, since it is an all-solid-state element, it is more resistant to shocks than liquid crystal display panels which are currently widely used as thin display panels, and can be used as a display device even in an environment where there is a lot of vibration such as in a car. I can do it.

Further, the entire light emitting layer composed of the organic material layer between the first electrode and the second electrode emits planar light, and the light emitting area is not limited. Therefore, it can also be used for a backlight such as a liquid crystal display panel. Further, the luminescent color can be freely determined depending on an extremely large number of kinds of materials used for the luminescent layer or materials doped in the luminescent layer. Until now, red, blue and green emitting materials have been developed in various fields. Therefore, by appropriately selecting and combining these, light-emitting elements of various colors according to the purpose of use, including full-color display, can be obtained.

[0008] One of the outstanding features is that it has a high-speed response. In an organic electroluminescence element, unlike a liquid crystal, molecules do not move during driving. Like a light emitting diode (LED), light is emitted only by the action of electrons and holes, and the response speed is very fast, on the order of tens of nanoseconds. Therefore, sufficient driving is possible even by applying a pulse voltage, and duty driving with a simple matrix panel configuration is possible. The voltage to be applied may be a DC voltage or an AC voltage, but since the organic electroluminescent element has a rectifying property, when an AC voltage is applied, light emission can be obtained only when a voltage is applied in the forward direction. become.

When manufacturing a simple matrix type display panel using an organic electroluminescent element for a pixel light emitting portion, it is necessary to form a line pattern in which a first electrode and a second electrode are orthogonal to each other. First, it is easy to pattern the first electrode provided on the substrate into a predetermined shape. It is possible to use a known photolithography method. In particular, ITO has very good processing accuracy and is most widely used.

However, patterning the second electrode formed on the organic material layer into a predetermined shape remains a very difficult problem. The base of the second electrode is an organic layer including at least the light emitting layer. In general, organic substances are very weak to organic solvents, moisture, oxygen and the like. Also, the physical strength is weak. Therefore, even if an attempt is made to use the photolithography method for patterning the second electrode, the underlying organic layer is damaged. When the organic layer is damaged, it has a fatal effect on the characteristics of the organic electroluminescence device.

Many techniques have been proposed for patterning the second electrode into a predetermined shape without damaging the organic material layer. First, when a second electrode is formed by a vacuum evaporation method, a method using a shadow mask provided between an evaporation source and a substrate has been used. Close contact of the shadow mask and the substrate,
Alternatively, by installing the second electrode at a distance of about several millimeters, the second electrode can be formed only in the opening of the mask. However, in this method, when the pattern is fine like a display panel, it is difficult to process the mask with precision and alignment, and the mask itself is deflected due to insufficient strength of the mask. The problem that wraparound occurs. As a result, a predetermined pattern shape cannot be obtained.

Another method for patterning the second electrode without using a shadow mask is disclosed in Japanese Unexamined Patent Publication No.
No. 75172, Japanese Patent Application Laid-Open No. 5-25859, and Japanese Patent Application Laid-Open No. 5-258860,
After patterning the first electrode into a predetermined shape, a stripe-shaped partition wall is prepared so as to be arranged in parallel in a direction orthogonal to the first electrode, then an organic material layer is formed, and then, when forming the second electrode, There is a method in which a second electrode material is vapor-deposited from an oblique direction with respect to a substrate. At this time, the second electrode does not adhere to the region of the substrate that is shadowed by the partition wall from the evaporation source, and as a result, the second electrode is patterned. However, this method has a problem in that deposition must be performed in an oblique direction when the second electrode is formed, and a device for tilting the substrate is required, or the diameter of the chamber of the vacuum deposition machine must be increased. Further, the pattern shape of the partition walls is limited to stripes, and there is also a problem that when the substrate has a large area, a distribution occurs at an angle at which the second electrode is deposited from an oblique direction.

In order to solve the above-mentioned problem, Japanese Patent Laid-Open No. Hei 8-3159 discloses that the cross-sectional shape of the partition is made to be an inverse taper type.
No. 81 has a report. After forming a first electrode on a substrate, a reverse tapered structure is formed, an organic layer is formed, and then a second electrode is formed. If the partition wall has this shape, no matter from which direction the second electrode material is deposited, when the evaporant from the deposition source adheres to the substrate, a portion that is shadowed by a reverse taper always occurs, and separation can be reliably performed. . Further, there is no limitation on the pattern shape, and the pattern can be formed with high accuracy.

[0014]

However, Japanese Patent Application Laid-open No.
When the method disclosed in Japanese Patent No. 315981 is used, new problems such as the reliability of the organic electroluminescence element and the contamination of the pixel portion, which are not found in the method using the shadow mask, occur. The inverse tapered partition is formed by photolithography after patterning the first electrode into a predetermined shape. In most cases, a negative type photosensitive resist is used for the material of the reverse tapered partition, but in consideration of the manufacturing process, the photosensitive photoresist is applied to the entire surface of the substrate on which the first electrode is formed by spin coating. Will do.

Therefore, the area serving as the pixel light emitting portion of the display panel is once contaminated. Of course,
Although cleaning is performed in a later step, residue may be left. Further, after forming a predetermined partition pattern, heat treatment is required to increase the strength of the reverse tapered partition.
After the heat treatment, it is difficult to completely remove dirt even if ultrasonic cleaning using an organic solvent is performed. If the remaining resist adheres to the region that becomes the pixel light emitting portion of the display panel, it causes crosstalk after the display panel is completed.

Not only when forming the second electrode but also when the organic layer is formed by a vacuum deposition method, a region which is not adhered to the substrate occurs due to the shadow of the inversely tapered partition. Therefore, when the second electrode is further formed thereon, the first electrode and the second electrode may come into contact with each other in a region where the organic material layer has not adhered, resulting in a short circuit.

Further, there is a case where an insulating film layer having a shape in which only the pixel light emitting portion is opened is provided because there is a concern that the edge portion of the first electrode affects the light emitting characteristics of the organic electroluminescence element. However, since the photolithography method is used even when the insulating film layer is formed, the pixels are contaminated.

That is, forming a reverse tapered partition or insulating film layer after forming the first electrode on the substrate will contaminate the clean first electrode. When the first electrode is contaminated, it affects the device characteristics of the organic electroluminescence device. Specifically, a non-light-emitting region called a dark spot is generated in the pixel light-emitting portion, and the appearance as a light-emitting element is extremely deteriorated. Further, if minute dust adheres to the contaminated portion, a leak current occurs, or in the worst case, a short circuit occurs between the first electrode and the second electrode, and the element is destroyed. Further, in a simple matrix type display panel, crosstalk occurs, which has a fatal effect on the display quality of the display.

Further, in order to improve the characteristics of the organic electroluminescence element, before forming the organic material layer,
A process for cleaning the surface of the first electrode is performed. For example, ultrasonic cleaning using an organic solvent such as isopropanol, UV ozone treatment, oxygen plasma treatment, and the like are also performed. In particular, it is an indispensable step when using ITO for the first electrode. However, in the case where an inversely tapered partition or an insulating film layer is formed on a substrate as described above, if these processes are performed, the inversely tapered partition or the insulating film itself will be damaged.

In other words, considering these facts, the fact that components other than the first electrode are present on the substrate before the organic layer including at least the light emitting layer is formed is considered to be the characteristic and reliability of the organic electroluminescent element. Sex will be affected. After forming the first electrode on the substrate, it is necessary to deposit at least an organic layer including a light emitting layer as soon as the substrate is cleaned.

According to the present invention, in a simple matrix type display panel using an organic electroluminescence element for a pixel light emitting portion, a second electrode on an organic material layer is reliably formed separately, and a first electrode of a pixel light emitting portion of the display panel is formed. The present invention relates to a method for manufacturing a display panel capable of obtaining good light emission without contaminating the surface.

[0022]

According to the present invention, there is provided a method of manufacturing an organic electroluminescence device, comprising the steps of forming a forward tapered structure on a transfer substrate, and sequentially forming a first electrode and an organic material layer on a transparent substrate. Forming, bonding the transfer substrate and the transparent substrate, and transferring a forward tapered structure on the transfer substrate onto the organic material layer, thereby forming a reverse taper type on the organic material layer. A step of forming a structure, a step of removing the transfer substrate, and a step of forming a second electrode on the inverted tapered structure and the organic material layer.

The step of forming a reverse tapered structure on the organic material layer by transferring the forward tapered structure on the transfer substrate onto the organic material layer may include transferring from the back surface of the transfer substrate. An energy source is supplied to the substrate for use to transfer the forward tapered structure to the transparent substrate. In this method, the energy source is a laser.

Further, the forward tapered structure is characterized in that a photosensitive resin is formed by lithography.

Further, the transfer substrate is made of a polymer film.

A step of removing the transfer substrate;
Between the step of forming a second electrode, the organic material layer further,
It is characterized by having a forming step.

Further, in the step of bonding the transfer substrate and the transparent substrate, a thermocompression roller and a vacuum laminator are used.

Further, in the step of forming the second electrode, the second electrode is formed by a vacuum deposition method.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments that embody the present invention. According to this embodiment, a green monochrome display panel is manufactured.

Example 1 FIG. 1 shows a process for producing a substrate for producing a display panel using the organic electroluminescence device produced by the present invention.

As the first electrode, the most common ITO (indium tin oxide) among the transparent conductive films was used. A transparent substrate (101) made of borosilicate glass having a thickness of 1.1 mm and having ITO (102) (manufactured by Sanyo Vacuum Co., Ltd.) was subjected to ultrasonic cleaning with isopropanol for 3 minutes, followed by steam drying and cleaning. Minutes. Note that I
The thickness of TO was 1600 ° when measured with a stylus-type thickness gauge.
And the sheet resistance was 20Ω / □.

Subsequently, ITO was formed into a stripe shape with a width of 150 μm and a pitch of 300 μm by a known photolithography method, and this was used as a first electrode of an organic electroluminescence device. In this case, the first electrode is the anode.

Subsequently, the substrate with the first electrode was subjected to UV ozone treatment for 15 minutes using an excimer lamp manufactured by Ushio Inc.

Next, FIG. 2 shows a step of forming an organic layer on the substrate. 1 are given the same reference numerals.

The substrate with ITO was replaced with ITO (102)
Is set on a resistance heating evaporation device manufactured by Japan Vacuum Engineering Co., Ltd. so that the organic material layer faces the lower surface, and the organic layer is vacuumed at 1 × 10 ⁻⁶ t.
Vacuum deposition was performed at a vacuum degree of about orr and a deposition rate of about 2 ° per second.

First, CuPc (copper phthalocyanine) is used as the hole injection layer (104) as the organic material layer (103).
150 °, TPD as hole transport layer (105)
(N, N′-diphenyl-N, N ′ (3-methylphenyl) -1,1′-diphenyl-4,4′-diamine) at 400 ° and Alq ₃ (tris (8- (Quinolinol) aluminum) was deposited in a vacuum at a film thickness of 700 °. At this time, no particularly fine shadow mask was provided between the evaporation source and the substrate, and the organic material layer was formed on the entire surface of the substrate except for the terminal take-out portion and the sealing region to be formed later.

The materials used for the hole injection layer and the hole transport layer are not particularly limited.
It is desirable that the hole transport ability is high. In addition, it is desirable that the electron injection can be blocked from the viewpoint of improving the luminous efficiency of the organic electroluminescence element. Specific examples include heterocyclic compounds such as triphenylamine, imidazole derivatives, pyrazoline derivatives, oxadiazole derivatives, and phthalocyanine derivatives. The material used for the light-emitting layer is not particularly limited as long as holes and electrons are injected at the time of applying a voltage and recombination of these causes emission of electroluminescence. Specifically, there are benzothiazole, benzoxazole, metal chelated oxinoid compounds, styrylbenzene, oxadiazole derivatives, metal complexes and the like.

According to the present embodiment, the light emission obtained from the completed display panel is a single color of green. However, a red, green, and blue color is separately applied by using a shadow mask to obtain a full-color display panel. It is also possible. When separately applying the light emitting layer, a shadow mask is used between the substrate and the evaporation source. However, the shadow mask has a smaller aperture ratio than the shadow mask used when forming the second electrode,
The strength of the mask can be maintained. In addition, if the luminescent colors are arranged in a delta arrangement, the openings of the mask are independent for each pixel, so that the mask intensity is further increased.

The method for forming the organic material layer is not particularly limited to the vacuum evaporation method in this embodiment, and various known methods such as a spin coating method and a rubbing method can be used. It is.

Regardless of the method used, when forming an organic layer including at least a light emitting layer on the first electrode on the substrate, only the extremely clean first electrode is present on the substrate, and the The probability that the surface of the first electrode serving as the pixel light emitting portion is contaminated is extremely low.

After the completion of the organic layer formation, the substrate was taken out of the evaporation chamber. At this time, the surrounding environment was set to a sufficiently dry nitrogen atmosphere having a dew point temperature of -70 ° C or less so that the organic layer was not damaged by moisture or oxygen.

FIG. 3 shows a process for producing a forward tapered partition to be transferred to a transfer substrate. As the transfer substrate, a PET (polyethylene terephthalate) film (trade name: Lumirror) manufactured by Toray Industries, Ltd. having a thickness of about 0.2 mm was used. On this transfer film (107), a light-heat conversion layer (108) for converting light energy of a YAG laser into heat energy was formed. As the light-to-heat conversion layer, graphite powder having a particle size of 0.1 micron or less is mixed with an epoxy resin (trade name: Araldite) manufactured by Novelltis Pharma Co., Ltd. so that the film has a thickness of about 30 microns. And cured.

In this embodiment, a PET film is used as a transfer substrate. However, the present invention is not limited to this, and a film of polymethyl methacrylate (PMMA), polyester, or polycarbonate may be used. However, in the next step, it is necessary to bond the substrate on which the organic layer has been formed and the transfer substrate having the forward tapered structure, so that the transfer substrate preferably has flexibility. Therefore, a substrate having low flexibility such as glass, quartz, or silicon which is generally known as a substrate is not very suitable as a substrate for transfer, and a material having high flexibility such as a polymer film is preferable.

The light absorber used in the light-to-heat conversion layer is not particularly limited to graphite powder, but may be iron oxide powder or an organic azo compound. Further, the material in which the light absorber is dispersed is not limited to the epoxy resin.

Next, a heat conductive layer (109) was formed on the light-to-heat conversion layer. The heat conduction layer is provided to transmit the heat energy converted by the light-to-heat conversion layer to the forward tapered structure formed thereon. Polypropylene was formed on the light-to-heat conversion layer to a thickness of about 1 micron.

In this embodiment, polypropylene is used as the heat conductive layer. However, the material is not particularly limited, and any material can be used as long as it can transmit the heat energy converted by the light-heat conversion layer.

Next, a forward tapered structure (110) to be transferred to a substrate was formed on the heat conductive layer. The forward tapered structure is manufactured by a known photolithography method. First, a photosensitive negative photoresist (isopropylene rubber-based resist, trade name: OMR) manufactured by Tokyo Ohka Kogyo Co., Ltd. as a material having a forward tapered structure was formed by a general spin coating method. At this time, the rotation speed of the spin coating was set to 1000 rpm. Subsequently, the solvent of the photosensitive resist was removed in a heating oven, and exposure was performed using a photomask having a width of 20 μm and a pitch of 300 μm,
Development (5 minutes) was performed to produce a forward tapered structure. The development was performed using an aromatic organic solvent, more specifically, xylene. The shape of the forward tapered structure depends on the development time, but by shortening it, a forward tapered shape was obtained. When the cross section was observed by SEM, the side in contact with the heat conductive layer was about 18 μm in width, and
It was confirmed that the micron had a forward tapered trapezoidal shape.

After the development, the substrate was washed with butyl acetate. Finally, heat treatment was performed at 150 ° C. for 30 minutes.

When a forward tapered structure is manufactured, the film, the light-to-heat conversion layer, and the heat conductive layer are exposed to a photolithography step, but have a very strong solvent resistance. But it was not damaged by it. It is effective to use a photosensitive resist as a material of a structure to be formed on the heat conductive layer also in a manufacturing process. Further, the influence on the film, the light-to-heat conversion layer, and the heat conduction layer was small. As described above, a forward tapered structure to be transferred was formed on the transfer substrate.

FIG. 4 shows a step of laminating the substrate after the formation of the organic material layer and the transfer substrate film having the forward tapered structure. The bonding step was also performed in a nitrogen atmosphere so that the organic layer on the substrate did not deteriorate.

The transparent substrate (101) is replaced with an organic layer (103).
The transfer substrate film (10
7) are bonded together so that the forward tapered structure (110) faces downward. At this time, the substrate is set so that the forward tapered structure and the ITO stripe pattern of the substrate are orthogonal to each other. The substrate and the transfer substrate film were brought into close contact with each other by a thermocompression bonding method using a heat roller. As the pressure bonding conditions, the roller temperature on the substrate side (lower side) was 110 ° C., and the roller temperature on the transfer substrate film (upper side) was 80 ° C. The operation was performed so that the moving speed of the roller was about 20 cm per minute.

However, the thermocompression bonding using a roller alone is not sufficient, and air bubbles may remain at the contact portion. Therefore, the substrate and the transfer substrate film are set on a vacuum laminator using an oil rotary pump and vacuum-laminated. Thereby, it was made to adhere completely and air bubbles were removed.

FIG. 5 shows a step of transferring the partition walls to the substrate. Remove from vacuum laminator and use YA for transfer
G laser was irradiated. The YAG laser irradiation device used was a YAG laser welding device manufactured by Toshiba Corporation. Irradiation was performed at a laser output of 15 W from the back surface of the film along the forward tapered structure (110).

The laser used is preferably a YAG laser. For example, when an excimer laser having a short oscillation wavelength is used, a portion irradiated with the laser is ablated and decomposed. As an energy source other than a laser, for example, an electron beam or the like can be used.

After the transfer, the film was slowly peeled off so as not to break the film, so that only the transferred partition walls remained on the substrate. At this time, the transfer causes the partition walls to adhere upside down, so that the forward tapered structure (110) on the film becomes an inverted tapered partition wall (111) when attached to the substrate.

FIG. 6 shows a step of forming the second electrode. Subsequently, the substrate (101) is set again on a resistance heating vapor deposition device manufactured by Japan Vacuum Engineering Co., Ltd. so that the organic layer faces the lower surface, and an aluminum: lithium alloy as the second electrode (112) is set at 10 ° / sec. Vacuum deposition was performed at a deposition rate of about 2,000 mm to a film thickness of about 2,000 mm. In this embodiment, the second electrode serves as a cathode. At this time, no special shadow mask was provided between the substrate and the vapor deposition source, and a simple mask was provided such that a terminal take-out portion of the display panel and a pasting area at the time of a sealing process were formed. . With respect to the pixel light emitting portion of the display panel, the inverse tapered partition (111) attached by transfer transfers
It will be patterned into a predetermined shape. In this embodiment, there is no problem in forming an aluminum: lithium alloy by a vacuum evaporation method, and a conventional vacuum evaporation method can be used.

Although the second electrode is a cathode in this embodiment, a metal is often used for the cathode. Although there is no particular limitation on the type of metal, a metal having a small work function value (specifically, magnesium, lithium, aluminum, silver, indium, etc.) is used to facilitate electron injection due to the characteristics of the organic electroluminescence device. Is desirable.

FIG. 7 shows a step of performing a sealing process. Subsequently, the vapor deposition machine chamber was leaked with sufficiently dried nitrogen, and a hollow seal was formed using an epoxy-based ultraviolet curable resin (113) (trade name: 30Y-296G) and excavated glass (114) manufactured by Three Bond Co., Ltd. Stop processing was performed. The sealing conditions are not particularly limited to the present embodiment, and a high-molecular resin is directly applied to the pixel light emitting portion without using a thermosetting resin as an adhesive or using dug glass. Sealing such as coating over the entire surface may be performed.

Thus, a green monochrome display panel is completed.

Although not used in this embodiment, in some cases, after forming a reverse tapered partition by a transfer method, an insulating film is formed so as to surround each pixel independently, and a first electrode and a second electrode are formed. May be reduced.

(Embodiment 2) Basically, it is manufactured in the same manner as in Embodiment 1. FIG. 8 shows a state in which partition walls are formed on the substrate manufactured in Example 2. After forming ITO (202) as a first electrode on a transparent substrate (201), PPV (poly p-phenylene vinylene) acting as a hole injection layer (204) among the organic layers of the organic electroluminescence element is spin-coated. The film was formed so as to have a thickness of 500 °.

Subsequently, in the same manner as in Example 1, a transfer substrate made of a PET film was provided with a forward tapered structure (21).
0) to form a forward tapered structure on a transparent substrate (20).
Transfer to 1). Thus, the transparent substrate (201)
On the hole injection layer (214) formed as above, a reverse tapered partition (211) was formed, and the transfer substrate film was peeled off.

Next, FIG. 9 shows a state in which an organic material layer (203) is formed by a vacuum evaporation method. However, in Example 1, CuPc as the hole injection layer (205) used was not formed, and TPD as the hole transport layer and the light emitting layer (20) were not used.
6) Alq ₃ was formed as a film of 400 ° each.

Subsequently, a film of an aluminum: lithium alloy as the second electrode (212) is formed, and an ultraviolet ray effect resin (2) is formed.
13) and the engraved glass (214) were sealed to produce a green monochrome display panel. FIG. 10 shows the organic electroluminescent device thus manufactured.

That is, in the first and second embodiments, whether the partition formed by the transfer method is formed on the organic material layer,
There is a difference between the organic layers formed. However, in each case, the organic layer closest to the substrate (that is,
In Example 1, CuPc was used, and in Example 2, PP was used.
When forming V), only the first electrode is formed on the substrate surface, and the organic layer can be formed in an extremely clean state.

Also in the second embodiment, if necessary, after forming a reverse tapered partition by a transfer method, an insulating film is formed so as to surround each pixel independently, and the edge of the first electrode or the second electrode is formed. The influence may be reduced.

(Comparative Example 1) Basically, it is manufactured in the same manner as in Example 1, except that the partition has a forward tapered shape. FIG. 11 shows such an organic electroluminescence element. Reference numeral 301 denotes a transparent substrate, 302 denotes ITO,
303 is an organic layer, 304 is a hole injection layer, 305 is a hole transport layer, and 306 is a light emitting layer.

A reverse tapered structure was manufactured using a material in which the shape of the partition formed on the heat conductive layer formed on the transfer substrate was reverse tapered. A negative photoresist (specifically, BPR-500) manufactured by JSR Co., Ltd. was used as a material of the partition wall to be an inverse taper type. Subsequently, Example 1
A transparent substrate and a transfer substrate are bonded in the same manner as in
By transferring the reverse tapered structure to 06, a forward tapered partition wall (315) was formed, and then a sealing process was performed in the same manner as in Example 1 to produce a green monochrome display panel. This was designated as Comparative Example 1.

That is, Comparative Example 1 is different from Example 1 in that the shape of the partition wall formed on the organic material layer (303) is a forward taper type.

(Comparative Example 2) In the same manner as in Example 1 or Example 2, the first electrode ITO (4) was formed on the transparent substrate (401).
After patterning No. 02) into a predetermined shape, an inversely tapered partition wall (411) was formed on the first electrode. This is shown in FIG.

Subsequently, the organic layer (403) (the hole injection layer (404), the hole transport layer (405), and the light emitting layer (40)
6)), a second electrode (412) was formed, and a UV-curable resin (413) and a dug-in glass (414) were sealed in the same manner as in Examples 1 and 2. . Through the above steps, a green monochrome display panel was manufactured. FIG. 13 shows a cross-sectional view of the element manufactured in Comparative Example 2. This was designated as Comparative Example 2.

That is, in Comparative Example 2, when forming the organic material layer of the organic electroluminescence element, not only the first electrode but also a reverse-tapered partition wall formed by the transfer method exists on the substrate surface. This is a point different from the first and second embodiments.

The green monochrome display panels produced in Examples 1 and 2 and Comparative Examples 1 and 2 were driven at a pulse voltage of 60 Hz and 1/120 duty.

In Examples 1 and 2, light emission of display quality sufficiently satisfactory as a display panel could be obtained. Further, regarding the second electrode formed on the organic material layer, adjacent second electrodes are completely separated from each other, and the reverse tapered partition formed by the transfer method effectively acts on the electrode separation. I knew it was there. In addition, no short-circuit due to direct contact between the first electrode and the second electrode was observed, and the occurrence of crosstalk was suppressed.

When the pixel light emitting portion of the display panel was observed with a microscope, the number of dark spots was very small. This is because when the organic layer is formed, only the first electrode that maintains an extremely clean surface is formed on the substrate, and therefore the interface between the first electrode and the organic layer is not contaminated. .

From the above, it has been found that the present invention is effective for formation of the second electrode and prevention of contamination of the pixel light emitting portion, which are problems when producing a simple matrix type display panel.

On the other hand, in the display panel of Comparative Example 1, the number of dark spots was small in each pixel light emitting portion. However, with respect to the second electrode on the organic material layer, there were some spots where they were in contact with each other. And it could not be completely separated and formed. Even when the cross section was observed with an SEM, the aluminum: lithium alloy, which is the material of the second electrode, had adhered to the side surface of the partition. This is because the shape of the partition wall formed by the transfer method is a forward taper type,
This is because it did not effectively act on the separation of the second electrode.

Next, in the display panel of Comparative Example 2, with respect to the second electrode formed on the organic material layer,
The adjacent second electrodes were completely separated from each other, and it was found that the reverse tapered partition formed by the transfer method was effective for separating the electrodes. Observed in the above, there were more dark spots than in Example 1, Example 2, and Comparative Example 1. In addition, although the second electrodes were completely separated from each other, occurrence of crosstalk was observed, and furthermore, a portion where the pixel light emitting portion was destroyed due to a short circuit between the first electrode and the second electrode was also observed. . This is because not only the first electrode but also the partition wall formed by the transfer method exists on the substrate when the organic layer of the organic electroluminescence element is formed. When forming this reverse-tapered partition wall, at the time of thermocompression bonding or vacuum lamination with a roller, because the surface of the first electrode that has been cleaned up is contaminated, a dark spot source at the interface between the first electrode and the organic material layer This is because some dirt will adhere.

[0079]

According to the present invention, the reverse taper type partition wall can effectively act on the electrode separation, no short-circuit due to direct contact between the first electrode and the second electrode is observed, and the crosstalk is reduced. It was also possible to suppress the occurrence. Further, in the present invention, when forming the organic material layer, only the first electrode having an extremely clean surface is formed on the substrate, and thus the interface between the first electrode and the organic material layer is contaminated. As a result, the number of dark spots formed in the pixel light emitting portion of the display panel could be extremely reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a process in the course of manufacturing an organic electroluminescence device according to Example 1 of the present invention.

FIG. 2 is a view showing a process in the course of manufacturing the organic electroluminescence device according to Example 1 of the present invention.

FIG. 3 is a view showing a step in the process of manufacturing the organic electroluminescence element according to Example 1 of the present invention.

FIG. 4 is a view illustrating a process in the course of manufacturing the organic electroluminescence element according to the first embodiment of the present invention.

FIG. 5 is a view showing a step in the process of manufacturing the organic electroluminescence element according to Example 1 of the present invention.

FIG. 6 is a view showing a part of the manufacturing process of the organic electroluminescence element according to Example 1 of the present invention.

FIG. 7 is a diagram illustrating a process in the course of manufacturing the organic electroluminescence element according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a process in the course of manufacturing the organic electroluminescence element according to the second embodiment of the present invention.

FIG. 9 is a diagram showing a step in the process of manufacturing the organic electroluminescence element according to Example 2 of the present invention.

FIG. 10 is a diagram showing a step in the process of manufacturing the organic electroluminescence element according to Example 2 of the present invention.

FIG. 11 is a view showing a part of the manufacturing process of the organic electroluminescence element manufactured as Comparative Example 1.

FIG. 12 is a view showing a part of the manufacturing process of the organic electroluminescence element manufactured as Comparative Example 1.

FIG. 13 is a diagram illustrating a process in the course of manufacturing the organic electroluminescence element manufactured as Comparative Example 2.

[Explanation of symbols]

 101, 201, 301, 401 Transparent substrate 102, 202, 302, 402 ITO 103, 203, 303 Organic layer 104, 204, 304, 404 Hole injection layer 105, 205, 305, 405 Hole transport layer 106, 206, 306, 406 light emitting layer 107 transfer substrate 108 light-to-heat conversion layer 109 heat conductive layer 110 forward tapered structure 111, 211, 311, 411 reverse tapered structure 112, 212, 312, 412 second electrode 113, 313, 413 UV curing Resin 114, 214, 314, 414 Engraved glass 315 Forward tapered partition

Claims (8)

[Claims] A step of forming a forward tapered structure on a transfer substrate; a step of sequentially forming a first electrode and an organic material layer on a transparent substrate; and bonding the transfer substrate and the transparent substrate. Forming a reverse tapered structure on the organic material layer by transferring the forward tapered structure on the transfer substrate onto the organic material layer; and removing the transfer substrate. And a step of forming a second electrode on the reverse tapered structure and the organic material layer. A method for manufacturing an organic electroluminescence device, comprising: 2. The step of forming a reverse tapered structure on the organic material layer by transferring a forward tapered structure on the transfer substrate onto the organic material layer, wherein the step of transferring is performed from the back surface of the transfer substrate. Supply the energy source to the substrate for
The method according to claim 1, wherein the forward tapered structure is transferred to the transparent substrate. 3. The method according to claim 2, wherein the energy source is a laser. 4. The method for manufacturing an organic electroluminescence device according to claim 1, wherein said forward tapered structure is formed by forming a photosensitive resin by a lithography method. 5. The method for manufacturing an organic electroluminescence device according to claim 1, wherein the transfer substrate is made of a polymer film. 6. The method according to claim 1, further comprising a step of forming an organic material layer between the step of removing the transfer substrate and the step of forming the second electrode. A method for producing the organic electroluminescence device according to the above. 7. The method according to claim 1, wherein in the step of bonding the transfer substrate and the transparent substrate, a thermocompression roller and a vacuum laminator are used. Method. 8. The method according to claim 1, wherein in the step of forming the second electrode, the second electrode is formed by a vacuum deposition method.