Electric lamp and discharge devices – With luminescent solid or liquid material – Solid-state type
Reexamination Certificate
2001-03-29
2002-08-06
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Solid-state type
C313S506000, C313S512000, C313S498000, C313S500000
Reexamination Certificate
active
06429584
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an organic electroluminescence display panel which has a plurality of organic electroluminescence elements formed on a substrate in a predetermined pattern in which each organic electroluminescence element comprises one or more thin films of an organic compound material including a light emitting layer which exhibits the electroluminescence which emits light in response to a current injected thereinto (hereinafter also referred to as “EL”), and more particularly, to a method of fabricating the organic electroluminescence display panel.
2. Description of the Related Art
Generally, an organic EL element includes a transparent electrode as an anode, at least one organic compound thin film and a metal electrode as a cathode, which are laminated on a transparent substrate in due order. The organic compound thin film(hereinafter referred to as the “organic functional layer”) may be a single light emitting layer, or a laminate which includes a three-layer structure composed of an organic hole transport layer, a light emitting layer and an organic electron transport layer, or a two-layer structure composed of an organic hole transport layer and a light emitting layer. The organic EL element may also include an electron or hole injection layer inserted between appropriate ones of these layers.
An organic EL display panel comprises a plurality of organic EL elements formed on a substrate in a predetermined pattern. For example, a matrix type display panel is disclosed in Japanese Unexamined Patent Publication No. Hei
8-102393.
The disclosed full color display includes a light emitting device which has an image display array comprised of a plurality of light emitting pixels of organic EL elements arranged at respective intersections of intersecting rows and columns. For example, a matrix display type one is composed of row electrodes including transparent electrode layers, organic functional layers, and column electrodes including metal electrode layers which intersect the row electrodes. These layers are laminated in sequence. The row electrodes are each formed in a strip shape, and arranged in parallel with each other with a predetermined spacing therebetween. The same is applied as well to the column electrodes. In this way, the display panel of matrix display type has an image display array comprised of light emitting pixels which are formed of a plurality of organic EL elements positioned at respective intersections of a plurality of row electrodes with a plurality of column electrodes.
This organic EL display panel, when exposed to the atmosphere, suffers from a significant deterioration in characteristics due to moisture, particularly on the interface between the cathode layer and the organic functional layer of the organic EL elements, and when exposed to moisture in the air, undergoes a chemical change which results in ablation between the organic functional layer and the cathode to produce light emission disabled regions, i.e., so-called dark spots. As methods for solving this problem associated with moisture, structures for sealing simple organic EL element units have been proposed as disclosed in Japanese Unexamined Patent Publications Nos. Hei 8-111286, Hei 9-148066 and Hei 10-144468.
However, in the organic EL display panel comprised of the above-mentioned organic EL elements which requires ramparts between adjacent cathode lines, the use of the conventional sealing structure for organic EL element units gives rise to another problem that light emission disabled regions are produced near the ramparts.
OBJECT AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an organic EL display panel which is less susceptible to the deterioration in the light emission characteristic due to moisture.
The present invention provides an organic electroluminescence display panel which comprises a plurality of organic electroluminescence elements each comprised of a first display electrode, one or more organic functional layers including a light emitting layer formed of an organic compound, and a second display electrode, laminated in order on a substrate; a plurality of ramparts disposed between the organic electroluminescence elements on the substrate and protruding from the substrate; a sealing film for covering the organic electroluminescence elements and at least both side surfaces of the ramparts; and an inorganic passivation film formed of an inorganic material for covering the sealing film, wherein the sealing film includes a top surface having an inclined surface which is inclined at an inclination smaller than a right angle in a region extending from a top edge of each rampart to a center peak of an adjacent one of the electroluminescence elements.
As to the organic electroluminescence display panel according to the invention, the panel further comprising an internal inorganic passivation film formed of an inorganic material disposed between said organic electroluminescence elements and said ramparts and said sealing film for covering said organic electroluminescence elements and said ramparts.
According to the invention, a method of manufacturing an organic electroluminescence display panel having a plurality of organic electroluminescence elements each having a first display electrode, one or more organic functional layers including a light emitting layer made of an organic compound, and a second display electrode, which are laminated in order on a substrate; a plurality of ramparts disposed between said organic electroluminescence elements on said substrate and protruding from said substrate, is characterized by comprising the steps of:
forming a sealing film for completely covering said organic electroluminescence elements and at least both side surfaces of said ramparts in such a manner that said sealing film includes a top surface having an inclined surface which is inclined at an inclination angle smaller than a right angle in a region extending from a top edge of each said rampart to a center peak of an adjacent one of said organic electroluminescence elements; and
forming an inorganic passivation film made of an inorganic material on the sealing film for completely covering said sealing film.
As to the method of manufacturing an organic electroluminescence display panel according to invention, the method further comprises, a step of forming an internal inorganic passivation film formed of an inorganic material disposed between said organic electroluminescence elements and said ramparts and said sealing film for covering said organic electroluminescence elements and said ramparts, before forming the sealing film.
REFERENCES:
patent: 5962970 (1999-10-01), Yokoi et al.
patent: 6099746 (2000-08-01), Kim
patent: 6137220 (2000-10-01), Nagayama et al.
patent: 09161969 (1997-06-01), None
Patel Nimeshkumar D.
Pioneer Corporation
Roy Sikha
Sughrue & Mion, PLLC
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