Active solid-state devices (e.g. – transistors – solid-state diode – Organic semiconductor material
Reexamination Certificate
2002-11-05
2004-12-28
Pham, Hoai (Department: 2813)
Active solid-state devices (e.g., transistors, solid-state diode
Organic semiconductor material
C257S072000, C438S099000, C438S151000
Reexamination Certificate
active
06835951
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an active matrix type organic light emitting device, and particularly, to an active matrix organic light emitting device and a method for fabricating the same that supplies an electric source to a power supply line for redundancy even if an opening is generated on the power supplying line.
2. Description of the Related Art
Currently, research for electrically conductive organic materials, such as conjugate polymers poly(p-phenylinevinyline) (PPV), for application to light emitting devices is ongoing. In addition, research is being conducted for application of the electrically conductive organic materials to thin film transistors (TFT), sensors, lasers, and photo-electric devices. Presently, light emitting devices made of inorganic phosphor materials are disadvantageous because an operating voltage of the devices should be higher than 200VAC. Accordingly, it is difficult to enlarge an overall size of the devices since they are fabricated using an evaporation process. Thus, achieving a blue light emission is difficult, and the cost for fabricating the devices is high. However, light emitting devices made of organic materials are advantageous because of their superior light emitting efficiency, simplicity in enlarging their overall size, simplified fabricating procedures, and improved blue light emission. In addition, light emitting devices made of organic materials have the ability to be curved. Thus, the light emitting devices made of organic materials are promoted as being the next generation of display devices.
FIG. 1
is a plan view of an active matrix organic light emitting device according to the related art. In
FIG. 1
, the active matrix organic light emitting device
10
includes a switching TFT
17
and a driving TFT
18
. In the active matrix organic light emitting device
10
, an N×M number of pixels are defined by a plurality of gate lines
11
and a plurality of data lines
13
arranged in a matrix form. Within each of the pixels, the switching TFT
17
is switched as a scanning signal is applied from the gate line
11
and a data signal of the data line
13
is inputted therein, the driving TFT
18
is enabled as the switching TFT
17
is turned ON, and an organic light emitting unit
19
for emitting light is turned ON. In addition, a power line
15
is arranged to be parallel with the data line
13
for applying an excitation signal to the organic light emitting unit
19
when the driving TFT
18
is enabled. A storage capacitor
20
is included to maintain the excited state of the organic light emitting unit
19
.
An outer driving circuit (not shown) is disposed along an outer side of the organic light emitting device
10
, and is electrically connected to the organic light emitting device
10
through bonding pads
21
and
22
formed on end parts of the gate line
11
and data line
13
. The power line
15
is also connected to the outer driving device (i.e., power supplying device). The gate lines
11
and the data lines
13
are directly connected to the outer driving circuit. However, the power line
15
is connected to the outer driving circuit through a power supplying line
23
. The power supplying line
23
is formed on a same layer upon which source/drain electrodes of the driving TFT
18
are formed, and is formed of the same metal as the source/drain electrodes. In addition, all of the power lines
15
are electrically connected to the power supply line
23
, thereby providing all of the power lines
15
with the exciting signal. When the driving TFT
18
is turned ON by application of a signal transmitted by the switching TFT
17
, electric power applied to the power supplying line
23
is applied to the organic light emitting unit
19
through the power line
15
, thereby emitting light from the organic light emitting unit
19
. Accordingly, an image data is displayed on a screen of the organic light emitting device
10
.
In
FIG. 1
, the power supplying line
23
is formed to extend from the first pixel to the last pixel along a transverse direction, or longitudinal direction of the panel
10
. Accordingly, the power supplying line
23
provides respective pixels with the exciting signal. The power supplying line
23
is formed by depositing and etching the same metal material as that of the source/drain electrodes of the driving TFT
18
when the source/drain electrodes are formed. Therefore, the power supplying line
23
may be damaged by inner processing conditions or by outer processing conditions during deposition and/or etching, or by exterior mechanical shock. As a result, an opening is generated in the power supplying line
23
, whereby the exciting signal is not transmitted to an adjacent pixel beyond the opening even if the driving TFT
18
is turned ON. Accordingly, the image data is not formed on the adjacent pixel of the organic light emitting device
10
, thereby rendering the organic light emitting device
10
operationally inferior.
In
FIG. 1
, the power supplying line
23
of the organic light emitting device
10
may be divided along a length direction, thereby creating plural power supplying lines. Accordingly, a total number of the power lines
15
connected to the power supplying line
23
is decreased. In addition, the effects of an opening in the power supplying line
23
is reduced. However, when the opening is generated in one power supplying line
23
, an entire row of pixels does not operate, thereby forming a strip shape on the screen. Moreover, when the opening is generated between the power supplying line
23
and the data line
13
, an entire column of pixels does not operate.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an active matrix organic light emitting device and a method of fabricating the same that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an active matrix organic light emitting device having a power supplying line for redundancy on a power supplying line to a supply power to a thin film transistor (TFT) for driving the organic light emitting layer.
Another object of the present invention is to provide a method for fabricating an active matrix organic light emitting device having a power supplying line for redundancy on a power supplying line to a supply power to a thin film transistor (TFT) for driving the organic light emitting layer.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, an active matrix organic light emitting device includes a plurality of gate lines and data lines respectively arranged along transverse and longitudinal directions for defining a plurality of pixel regions, a plurality of power lines arranged substantially parallel to the data lines, at least one switching thin film transistor disposed within one of the pixel regions, at least one driving thin film transistor disposed within the one of the pixel regions, an organic light emitting unit formed within the one of the pixel regions to emit light by application of a signal through one of the power lines as the driving thin film transistor is enabled, and a plurality of power supplying lines having at least two layers electrically interconnected to each other, the power supplying lines electrically connected with the plurality of the power lines to supply the signal to each of the power lines.
In another aspect, an active matrix organic light emitting device includes an array including a plurality
LG.Philips LCD Co. , Ltd.
Morgan & Lewis & Bockius, LLP
Smoot Stephen W.
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