Electric lamp and discharge devices – With luminescent solid or liquid material – Solid-state type
Reexamination Certificate
2000-09-01
2004-02-03
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Solid-state type
C313S504000, C313S506000, C313S509000, C313S500000, C313S503000, C428S917000
Reexamination Certificate
active
06686693
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an organic electroluminescent (EL) device and a manufacturing method thereof; and, more particularly, to an organic EL device having a pair of electrodes at least one of which is transparent and a thin film made of an organic compound deposited between the electrodes, and a method for the manufacture thereof.
BACKGROUND OF THE INVENTION
There is shown in
FIG. 1
a schematic cross sectional view of a prior art organic electroluminescent (EL) device
31
.
As shown, the organic EL device
31
comprises a substrate
32
made of, e.g., glass, an anode layer
34
formed on the substrate
32
and a cathode layer having a plurality of cathodes
35
, and a thin-film organic layer
33
formed between the anode layer
34
and the cathode layer and incorporating therein a luminous layer made of an organic compound. The cathode layer includes a plurality of cathodes
35
. In such an organic EL device, when a predetermined voltage is applied between the anode layer
34
and the cathode layer, holes from the anode layer
34
and electrons from the cathodes
35
are injected into the organic layer
33
, wherein a hole is combined with an electron to generate light. By using the light radiated through the combination process of the holes and the electrons, i.e., one hole combining with one electron, it is possible to display desired images, e.g., alphanumeric characters and/or predetermined display patterns.
In such an organic EL device
31
, each of such characters and patterns includes one or more luminous segments. The luminous segments forming the characters and patterns are organized into several groups and the luminous segments in each group are electrically connected to each other by a single cathode.
Referring to
FIGS. 2A and 2B
, there are shown a schematic cross sectional view setting forth formation of the cathodes
35
and a top view of a deposition mask
41
for use in forming the cathodes
35
of the organic EL device
31
.
As shown in
FIG. 2B
, the deposition mask
41
is provided with a slit set
42
having three slits
42
a
,
42
b
,
42
c
corresponding to three groups of the luminous segments forming the characters and patterns. After depositing the anode layer
34
made of a transparent material, e.g., ITO (indium tin oxide) on the substrate
32
and then forming thereon the organic layer
33
made of an organic compound, the cathodes
35
are formed on the organic layer
33
by aligning the deposition mask
41
thereon and depositing, e.g., by evaporation, a conductive material therethrough, resulting in obtaining the cathodes
35
, each having shape identical to the shape of corresponding one of the slits
42
a
,
42
b
,
42
c
of the deposition mask
41
.
In such an organic EL device having the cathodes formed by using the mask, each of the cathodes is formed in an elongated slit shape. When forming the elongated slit-shaped cathodes by a mask deposition technique described above, there often occurs an electrical insulation failure due to bending or deformation of the mask.
To be more specific, when the widths of the slits of the mask are narrow, the thickness of the mask plate is required to be small. When the masking area is smaller than the depositing area (opening area of the mask, i.e., the area of the slits), the mask becomes less rigid or pliant. As a result, the mask can be readily deformed and it becomes difficult to handle the mask, thereby lowering the manufacturing efficiency and yield thereof. Further, the organic layer can be damaged by bending of the mask during the alignment of the mask with the substrate having thereon the anode layer and the organic layer deposited in sequence, thereby degrading the quality of display.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an organic electroluminescent device and a manufacturing method thereof, wherein an electrode layer made of patterned electrodes is formed by using a deposition mask without causing an electrical insulation failure between the electrodes and degradation of the display quality. The deposition mask of the invention eliminates or reduces the bending and deformation problems of the prior art deposition mask, to thereby improve the manufacturing efficiency and yield thereof.
In accordance with one aspect of the present invention, there is provided an organic electroluminescent device comprising:
an insulating substrate;
a first electrode layer, a second electrode layer, and a number of conductive wiring pads formed on the insulating substrate, wherein at least one of the electrode layers is transparent and the second electrode layer includes a plurality of disjointed electrodes, the disjointed electrodes being grouped into a plural number of groups and at least one of the groups having at least two disjointed electrodes; and
an organic layer interposed between the first and the second electrode layers,
wherein the electrodes of each of said at least one of the groups are electrically connected to each other via one or more selected wiring pads.
In accordance with another aspect of the present invention, there is provided a method for manufacturing an organic electroluminescent device comprising the steps of:
forming a first electrode layer on an insulting substrate;
forming wiring pads made of a first conductive material;
forming an organic layer on the first electrode layer; and
forming a second electrode layer on the organic layer by depositing a second conductive material through a mask, wherein the second electrode layer includes a plurality of disjointed electrodes and the disjointed electrodes are grouped into a plural number of groups, at least one of the groups having at least two disjointed electrodes,
wherein at least one of the electrodes is transparent and said electrodes of each of said at least one of the groups are electrically connected to each other via one or more selected wiring pads.
In accordance with a further aspect of the present invention, there is provided a method for manufacturing an organic electroluminescent device comprising the steps of:
simultaneously forming a first electrode layer and wiring pads made of a first conductive material on a transparent substrate;
forming an insulation layer on the structure obtained by the simultaneously forming step in such a way that a selected portion of the first electrode layer and at least a portion of each wiring pad are exposed;
forming an organic layer on the exposed first electrode layer; and
forming a second electrode layer on the organic layer and the exposed portions of the wiring pads by depositing a second conductive material through a mask, wherein the second electrode layer includes at least one group of separated electrodes and the separated electrodes included in each group are electrically connected to each other via exposed portions of selected one or more wiring pads.
REFERENCES:
patent: 5804917 (1998-09-01), Takahashi et al.
patent: 5998926 (1999-12-01), Tsuruoka et al.
patent: 6107736 (2000-08-01), Shi et al.
patent: 6191433 (2001-02-01), Roitman et al.
patent: 6373187 (2002-04-01), Nagayama et al.
patent: 11045781 (1999-02-01), None
Futaba Denshi Kogyo Kabushiki Kaisha
Katten Muchin Zavis & Rosenman
Patel Vip
Roy Sikha
LandOfFree
Organic electroluminescent device with disjointed electrodes... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Organic electroluminescent device with disjointed electrodes..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Organic electroluminescent device with disjointed electrodes... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3333052