JPH11329724A - Organic el display element and production of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide production of an organic EL display element comprising a simple procedure, yet capable of forming diaphragms uniformly wherewith isolation between negative electrodes can be secured. SOLUTION: A striped translucent electrodes 3 exist on an upper side of a translucent substrate 1. Insulating films 5 exist between positive electrodes 3, and insulating films 6 exist on the positive electrodes 3, orthogonal to the insulating films 5. Insulating ribs 7 exist on the insulating films 6, and organic thin film layers 8 and striped negative electrodes 9 exist between the insulating films 6. A negative-type photosensitive polyimide is spread on a glass substrate 2 having the positive electrodes on it. The negative-type photosensitive polyimide is exposed with underdose light using an exposure mask having a pattern corresponding to that of the insulating films 5. Next, the negative-type photoresist polyimide is exposed with overdose light using an exposure mask corresponding to that of the insulating film 6 and developed. The underdose part suffers significant decrease in its film thickness, whereas the overdosed part suffers no decrease in its film thickness. A structure consisting of two- staged insulating layers can be formed in a single process. Insulating ribs 7 are provided on this structure. Further, organic thin film layers 8 and negative electrodes 9 are deposited. Adjacent negative electrodes 9 are electrically isolated mutually and the negative electrodes are also isolated from the positive electrodes with the insulating film 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL display device in which an anode and a cathode which intersect each other form a matrix.

[0002]

2. Description of the Related Art FIG. 4 is an enlarged sectional view of an organic EL display device disclosed in Japanese Patent Application Laid-Open No. 8-315981. This organic EL display element is an organic EL display having XY matrix electrodes in the form of stripes, and has partitions of an insulating film in order to separate and pattern the cathode in the form of stripes. This insulating partition has an inverted tapered shape (an inverted trapezoidal cross section in FIG. 4), has an overhang portion projecting in a direction parallel to the substrate, and has a film thickness (height).
Is formed in a range of 1 μm or more and 10 μm or less.

The following method is used to form the insulating partition having the overhang portion. A plurality of strip-shaped first display electrodes 101 are provided on a substrate 100.
(Anodes) are formed at predetermined intervals. A non-photosensitive polyimide film 102 is formed on the first display electrode 101.
Form on top. A single layer of photoresist is subjected to chlorobenzene treatment to form a partition 103 having an upper overhang having an inversely tapered cross section.

An organic layer 105 and a second display electrode 106 (cathode) are both formed on the substrate 100 on which the partition walls 103 are formed by a method such as vapor deposition.

[0005]

The self-alignment patterning of the second display electrode 106 by the inversely tapered partition wall 102 can prevent insulation failure between the lines of the second display electrode even when a slight variation occurs in the partition wall shape. There was a problem of causing it.

In the method of obtaining insulation between the second display electrodes (cathodes) according to the cross-sectional shape of the partition wall, the larger the area of the substrate, the more the partition wall shape varies, which affects the state of insulation between the lines of the second display electrode. give. As a result, there is a problem that insulation failure between the second electrode lines occurs.

Further, the formation of the inverted tapered shape requires a long and complicated process. Further, even in the case of a single layer, the process of chlorobenzene treatment is not preferable because the treatment material is a harmful substance. In addition, a single-layer partition wall of photoresist is RIE resistant.
The characteristics are not always good, and plasma dry cleaning of the surface of the first electrode (such as ITO) cannot be performed.

The present invention provides an organic EL display element in which the steps are simple, no harmful substances are used, the partition walls can be formed uniformly, and the insulation between the second display electrodes (cathodes) is ensured, and a method of manufacturing the same. It is intended to be.

[0009]

An organic EL display device (1) according to claim 1 is formed on a substrate (2) having a light transmitting and insulating property at a predetermined interval on the upper surface of the substrate. A first transmissive strip-shaped first display electrode (3) and a first transmissive first display electrode provided on the substrate between the first display electrodes.
And a second insulating film formed at a predetermined interval on the first display electrode and the first insulating film along a direction orthogonal to the longitudinal direction of the first display electrode. Between a film (6), at least one band-like organic thin film (8) formed on the first display electrode between the adjacent second insulating films, and the adjacent second insulating film; And a band-shaped second display electrode (9) formed on the organic thin film.

[0010] The organic EL display element according to the second aspect is the organic EL display element according to the first aspect,
The first insulating film (5) and the second insulating film (6)
A common photosensitive resin layer provided on the substrate (2) on which the first display electrode (3) is formed is subjected to two exposures with different exposure times through two types of masks having different patterns. It is characterized by being formed by performing.

According to a third aspect of the present invention, there is provided the organic EL display element according to the first or second aspect, wherein an insulating rib (7) is provided on an upper surface of the second insulating film (6). ) Is formed.

According to a fourth aspect of the present invention, there is provided a method for manufacturing an organic EL display element, wherein a first transparent display electrode having a light-transmitting property is provided at a predetermined interval on an upper surface of a substrate having a light-transmitting and insulating property. Forming (3), forming a first insulating film (5) on the substrate between the adjacent first display electrodes, and along a direction orthogonal to a longitudinal direction of the first display electrodes. Forming a second insulating film (6) at a predetermined interval on the first display electrode, and forming at least one layer on the first display electrode between adjacent second insulating films. A step of forming a strip-shaped organic thin film (8); and a step of forming a strip-shaped second display electrode (9) on the organic thin film between the adjacent second insulating films.

According to a fifth aspect of the present invention, there is provided a method of manufacturing an organic EL display device according to the fourth aspect, wherein the first insulating film (5) and the second insulating film ( 6) forming a photosensitive resin layer on the substrate to cover the first display electrode;
Using a first exposure mask having an opening corresponding to the shape of the insulating film to perform exposure under relatively underdose conditions; and forming a second exposure mask having an opening corresponding to the shape of the second insulating film. And a step of developing the exposed photosensitive resin layer under relatively overdose conditions using the exposure mask described above.

According to a sixth aspect of the present invention, there is provided a method of manufacturing an organic EL display element according to the fourth or fifth aspect, wherein the first insulating film (5) and the second
After the step of forming the insulating film (6) is completed, a photosensitive resin layer is provided on the substrate so as to cover the second insulating film, and is exposed using an exposure mask having an opening of a predetermined shape. A step of developing the photosensitive resin layer to form an insulating rib (7) on the upper surface of the second insulating film.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an organic EL display element 1 according to the present embodiment will be described with reference to FIGS. A stripe-shaped ITO electrode 3 is provided as a first display electrode (anode) on the upper surface of a glass substrate 1 which is a translucent and insulating substrate. The ITO electrode 3 is translucent, and light emission is extracted from the outside. There are a plurality of ITO electrodes 3 which are provided at predetermined intervals in parallel with each other.

A polyimide insulating film 4 is provided so as to cover the stripe-shaped ITO electrode 3. The insulating film 4 has a plurality of stages. First, a first insulating film 5 is provided on the glass substrate 2 between the adjacent ITO electrodes 3 and 3. The first insulating film 5 has a thickness of about 1 μm which is substantially equal to or slightly larger than the thickness of the ITO electrode 3. That is, the first insulating film 5 fills the gaps between the ITO electrodes 3 and is smooth, and is formed on the ITO electrodes 3 without breaking a layer structure described later. Next, the insulating film 4 is formed by forming a second insulating film 6 formed at predetermined intervals on the ITO electrode 3 and the first insulating film 5 along a direction orthogonal to the longitudinal direction of the ITO electrode 3. Have. The second insulating film 6 has a thickness of about 5 μm. The insulating film 4 is formed so as to cover all edges of the striped ITO electrode 3.

An insulating rib 7 is formed on the upper surface of the second insulating film 6 formed in a direction orthogonal to the ITO electrode 3. The insulating rib 7 is made of polyimide. Insulating rib 7
This pattern may be larger, smaller, or the same as the stripe width of the second insulating film 6 serving as the base.

The total thickness of the insulating film 4 and the insulating rib 7 is 10 μm.
m, and preferably 50 μm or less.

A desired organic thin film layer 8 is formed as a single layer or a multilayer on the exposed portion of the ITO electrode 3 between the adjacent second insulating films 6. For example, the organic thin film layer 8 may be a single layer of an organic light emitting layer, or may have a three-layer structure of an organic hole transport layer, an organic light emitting layer, and an organic electron transport layer. Alternatively, as shown, a two-layer structure of an organic hole transport layer 8a and an organic light emitting layer 8b also serving as an electron transport layer may be used. The pattern of the organic thin film layer 8 does not need to be particularly stripe-shaped.

A strip-shaped cathode 9 (second display electrode) is formed on the organic thin film layer 8 between the adjacent second insulating films 6 and 6. The cathode 9 is formed on the organic thin film layer 8 in a stripe shape so as to be orthogonal to the ITO electrode 3.

Electrical isolation between the first display electrode (ITO electrode 3) and the second display electrode (cathode 9) is achieved through the first and second insulating films 5, 6. Electrical insulation between the striped cathodes 9, 9 is achieved by insulating ribs 7.

Each pattern from the organic thin film layer 8 to the cathode 9 is uniquely defined by self-alignment.

A method for manufacturing the organic EL display element 1 of this embodiment will be described. Sputtering ITO film on glass substrate 2, EB
The film is formed by a method such as an evaporation method. The ITO film is patterned into a stripe shape as a first display electrode by a predetermined photolithography method to form an ITO electrode 3. For example, 0.
30 mm pitch, line width 0.25 mm, gap between lines 0.
A pattern having a geometrical dimension of 05 mm is used.

Next, an insulating film 4 is formed. The negative photosensitive polyimide is spread on the glass substrate 2 by spin coating so as to cover the ITO electrode 3, is formed to a coating thickness of 15 μm, and is subjected to a predetermined pre-bake treatment.

First, using a first exposure mask provided with an opening having a pattern corresponding to the shape of the first insulating film 5,
An exposure process is performed on the first insulating film 5 in a direction parallel to the O electrode 3. This exposure mask is manufactured so as to cover the edge of the ITO electrode 3. The exposure is performed under an underdose condition.

Next, using a second exposure mask provided with an opening having a pattern corresponding to the shape of the second insulating film 6,
An exposure process is performed on the second insulating film 6 in a direction orthogonal to the O electrode 3. The exposure at this time is performed under the condition of overdose.

After a two-stage photolithographic process performed on the same surface while changing the exposure time and the exposure pattern, a development process using a predetermined developing solution is performed. The underdose portion is severely reduced in film thickness, and the overdose portion is developed without any thinning. This makes it possible to automatically form a polyimide film pattern in two regions having different film thicknesses. That is, the first and second insulating films 5 each having a two-stage shape having different heights and shapes.
6 are formed. After the completion of the development processing, a predetermined post-bake is performed.

Next, on the insulating film 4, the same negative photosensitive polyimide as in the manufacturing process of the insulating film 4 is spin-coated to form a coating film thickness of 20 μm and prebaked. Thereafter, the photosensitive polyimide film is processed with an appropriate exposure using an exposure mask for insulating ribs. After the exposure, development and rinsing were performed under predetermined conditions to form a pattern of insulating ribs 7. At this time, the total thickness of the insulating ribs 7 was 33 μm, and the thickness of the other insulating film 4 was 3 μm.

Thereafter, a heat treatment (imidization) is performed at a peak of 400 ° C. in an N ₂ atmosphere for 30 minutes. By this heat treatment, the total thickness of the insulating ribs 7 finally becomes 16 μm
The thickness of the other insulating film 4 was 1.5 μm. A predetermined organic thin film layer 8 is formed on the glass substrate 2 on which the insulating film 4 and the insulating ribs 7 are formed by a vapor deposition method.
A thin film cathode 9 was formed by a vapor deposition method. The deposition of the organic thin film layer 8 and the cathode 9 is a normal forward deposition, and it is not particularly necessary to perform the deposition from an oblique direction.

The cathode 9 is completely electrically isolated by the insulating ribs 7 (height: 16 μm), and the insulation from the ITO electrode 3 is not problematic due to the insulating film 4.

[0031]

According to the present invention, the first display electrode and the second display electrode constituting the matrix are electrically insulated by the first and second insulating films. The first and second insulating films have different heights and shapes, but can be manufactured by performing the same photosensitive resin layer twice with different masks and exposure times. That is, an insulating film having excellent insulation properties and dimensions and shapes that do not hinder film formation in a later step can be formed by a simple operation.

In addition, if insulating ribs are formed on the insulating film, the height of the partition can be further increased. Since this height is much larger than before, even if the size of the substrate to be processed is increased, the electrically isolated X is not affected by the variation due to any process variation.
A -Y matrix electrode could be formed.

Further, since the insulating film and the insulating rib are made of a polyimide film having excellent heat resistance and RIE resistance, a plasma dry cleaning process can be performed before the deposition of the organic thin film layer, and the exposure of the ITO electrode can be prevented. It was also possible to easily remove local dust, foreign matter, and the like, and to completely eliminate dark spots or insulation failure between the first display electrode and the second display electrode.

[Brief description of the drawings]

FIG. 1 is a plan view of an organic EL display element as an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line BB of FIG. 1;

FIG. 4 is a sectional view of a conventional organic EL display element.

[Explanation of symbols]

 Reference Signs List 1 organic EL display element 2 glass substrate 3 ITO electrode as first display electrode 4 insulating film 5 first insulating film 6 second insulating film 7 insulating rib 8 organic thin film layer 8a organic hole transport layer as organic thin film layer 8b Organic light emitting layer as organic thin film layer 9 Cathode as second display electrode

Claims (6)

[Claims] 1. A substrate having a light-transmitting property and an insulating property; a first light-transmitting strip-shaped display electrode formed on a top surface of the substrate at a predetermined interval; A first insulating film provided on the substrate between the first display electrode and the first insulating film at a predetermined interval along a direction orthogonal to a longitudinal direction of the first display electrode. A second insulating film formed on the first display electrode between the adjacent second insulating films, at least one band-shaped organic thin film formed on the first display electrode, and the adjacent second insulating film And a band-shaped second display electrode formed on the organic thin film. 2. The method according to claim 1, wherein the first insulating film and the second insulating film are provided in two different patterns with respect to a common photosensitive resin layer provided on the substrate on which the first display electrode is formed. 2. The organic EL display element according to claim 1, wherein the organic EL display element is formed by performing two exposures with different exposure times through the mask. 3. The organic EL display device according to claim 1, wherein an insulating rib is formed on an upper surface of the second insulating film. 4. A step of forming a translucent band-shaped first display electrode at a predetermined interval on an upper surface of a substrate having translucency and insulation, and forming the first display electrode between the adjacent first display electrodes. Forming a first insulating film on a substrate and forming a second insulating film at a predetermined interval on the first display electrode along a direction orthogonal to a longitudinal direction of the first display electrode; Forming at least one band-like organic thin film on the first display electrode between the adjacent second insulating films; and forming an organic thin film on the organic thin film between the adjacent second insulating films. Forming a strip-shaped second display electrode in
A method for producing an organic EL display element having: 5. The step of forming the first insulating film and the second insulating film includes: providing a photosensitive resin layer on the substrate so as to cover the first display electrode; Using a first exposure mask having an opening corresponding to the shape of the insulating film to perform exposure under relatively underdose conditions, and a second step having an opening corresponding to the shape of the second insulating film. 5. The method for manufacturing an organic EL display element according to claim 4, comprising a step of exposing the photosensitive resin layer to a relatively overdose condition using an exposure mask, and a step of developing the exposed photosensitive resin layer. 6. After the step of forming the first insulating film and the second insulating film is completed, the second insulating film is formed on the substrate.
A photosensitive resin layer is provided to cover the insulating film, and is exposed using an exposure mask having an opening of a predetermined shape, and the photosensitive resin layer is developed to form an insulating rib on the upper surface of the second insulating film. 6. The method for manufacturing an organic EL display element according to claim 4, wherein a step of forming is performed.