Coating processes – Electrical product produced – Fluorescent or phosphorescent base coating
Reexamination Certificate
1999-06-16
2001-09-04
Beck, Shrive P. (Department: 1762)
Coating processes
Electrical product produced
Fluorescent or phosphorescent base coating
C427S068000, C427S596000, C430S200000, C156S232000, C156S234000, C156S237000
Reexamination Certificate
active
06284307
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color organic EL display using electroluminescence of an organic compound material and to a fabrication method thereof.
2. Description of the Related Art
In a conventional organic electroluminescence display apparatus using a color organic EL display, it is important to selectively form color light emission organic materials as color light emission devices in a fine pattern on a transparent electrode.
In providing such color emission devices on a transparent electrode a shadow mask method has been used in which, when a light emission organic material is selectively evaporated and formed as layer, an opening portion of a shadow mask is formed in a metal sheet (see FIG.
1
). In
FIG. 1
, a transparent anode
102
is disposed below a transparent glass substrate
101
. An organic fluorescent film and an organic positive hole transporting layer
103
are disposed below the anode
102
. A metal cathode
106
that is selectively evaporated is disposed below the organic positive hole transporting layer
103
. A metal sheet
104
as a shadow mask is disposed below the cathode
106
through a small space. An evaporation film
106
A is disposed below the metal sheet
104
. In addition, an evaporation material
105
is upwardly evaporated. Thus, the metal cathode
106
that is selectively evaporated and the evaporation film
106
A that is layered on the metal sheet
104
as the shadow mask are represented as remaining portions. The anode
102
and the cathode
106
are selectively disposed in the shape of lines and columns. A scanning voltage for generating an image is applied to the anode
102
and the cathode
106
.
However, in such a method, it is difficult to finely form a metal sheet corresponding to a fine light emission device area and accurately form an evaporation film to a light emission device area because of bend and expansion of a metal sheet. In addition, when the metal sheet contacts the positive hole transporting layer, the element portion breaks and thereby the light emission device becomes large and deteriorates accuracy. Thus, the resolution of the resultant display deteriorates. Moreover, since some light emitting devices do not light, the visual recognition characteristic lowers. Furthermore, the fabrication yield decreases. Thus, the conventional method is not sufficient for the visual recognition characteristic and fabrication yield. In other words, it is not suitable to use the shadow mask method of which an opening portion is formed in a metal sheet.
To solve such a problem, Japanese Patent Laid-Open Publication No. 2-176707 discloses a fabrication method for a color filter array device having a heated emboss surface. In the fabrication method, a plurality of dopant materials composed of sublimation coloring matters with different colors and respective acceptor devices composed of supporting members having coloring matter acceptor layers are used. The dopant materials are successively contacted with the acceptor devices. The dopant materials are contacted with heated emboss surfaces so that the dopant materials are heated in a pattern shape. Thus, the coloring matters are transferred to the acceptor layers. Consequently, an array of repetitive mosaic patterned coloring agents held on supporting members is fabricated.
However, since a metal sheet has a high heat conductivity, the heating roller heats the entire surface of the emboss surface of the sheet, sublimation materials, sublimate and transfer to other than the emboss surface. Thus, the dopant materials contaminate the acceptor elements. Consequently, color purity deteriorates.
In addition, since heat transfers in the state that the heating roller contacts the emboss metal, the contact surfaces should be highly accurate. Thus, the fabrication yield deteriorates. Moreover, since the heating temperature of the sublimation materials should be precisely controlled, the heating method using a heating roller causes the materials to unevenly sublimate.
Thus, when the related art reference disclosed in Japanese Patent Laid-Open Publication No. 2-176707 is applied to a color organic EL display, the colors of light emission devices fluctuate and some devices do not light.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a fabrication method for a color organic EL display free of mutual contaminations of color light emission organic materials in electroluminescence light emission device areas that have been accurately selected.
Another object of the present invention is to provide a fabrication method for a color organic EL display using laser light for heating particular areas so as to constantly sublimate color light emission organic materials.
A first aspect of the present invention is a fabrication method for a color organic EL display having a pair of electrodes and an organic light emission material, at least one of the electrodes being transparent or semi-transparent., the electrodes being oppositely disposed, the method comprising the steps of (a) preparing a transfer substrate having a convex protrusion with high heat conductivity, the light emission organic material being evaporated as a layer on the convex protrusion, (b) clamping the transfer substrate to a positive hole transporting layer formed on a transparent conductive substrate or a transparent conductive film, and (c) heating the convex protrusion of the transfer substrate.
A second aspect of the present invention is a fabrication method for a color organic EL display having an organic light emission material as a layer, comprising the steps of (a) layering a first electrode as a positive hole transporting layer to a glass substrate so as to form a first substrate, (b) layering a metal sheet having a protrusion portion whose edge is flat and which is hollow and layering an organic light emission material thereto so as to form a second substrate, (c) clamping the positive hole transporting layer of the first substrate and the organic light emission material of the second substrate, and (d) radiating laser light from the glass plate of the second substrate so as to raise the temperature of the protrusion portion and transferring the organic light emission material to the first substrate.
In addition, according to the present invention, since a protrusion portion is heated with laser light, fine light emission device areas can be selectively heated. Thus, a color organic EL display with three colors of light emissions has high visual recognition characteristic and a high angle of view field.
Thus, a transfer substrate having a protrusion on which a light emission organic material is evaporated and that has high heat conductivity is disposed. The protrusion causes the light emission organic material to selectively sublimate and transfer to a light emission device area.
Thus, the color purity due to mutual contamination of three color light emission organic materials can be prevented from deteriorating.
While the front surface of a protrusion and the front surface of a positive hole transporting layer are being clamped, laser light as a heating source is radiated to the interior of the protrusion and thereby the light emission organic material on the front surface of the protrusion is heated. Thus, the light emission organic material sublimates and transfers to the front surface of the positive hole transporting layer.
Thus, since laser light is radiated to only the front surface of the protrusion, a temperature slope takes place between the radiated portion and the non-radiated portion. Thus, since the light emission organic material does not sublimate, it does not contaminate to other light emission devices. Consequently, the color purity improves.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.
REFERENCES:
patent: 5688551 (1997-11-01), Littman et al.
patent: 571
Fukuzawa Shinichi
Otsuki Shigeyoshi
Beck Shrive P.
Cleveland Michael
NEC Corporation
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