Electric lamp and discharge devices – With luminescent solid or liquid material – Solid-state type
Reexamination Certificate
2002-12-27
2004-06-01
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With luminescent solid or liquid material
Solid-state type
C313S506000, C313S512000
Reexamination Certificate
active
06744197
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flat panel display device and more particularly, to an organic electroluminescent display (ELD) device and method of fabricating the same.
2. Discussion of the Related Art
In general, organic electroluminescent display (ELD) devices have electron-input electrodes (cathodes) and hole-input electrodes (anodes). The electrons and the holes are input into light-emitting layers from the cathode and anode electrodes, respectively, thereby forming an exciton. The organic electroluminescent display (ELD) devices emit light when the exciton is reduced from an excited state level to a ground state level. Since the organic electroluminescent display (ELD) devices do not need additional light sources, as compared to thin film liquid crystal display (LCD) devices, volume and weight of the organic electroluminescent display (ELD) devices can be reduced. In addition, the organic electroluminescent display (ELD) devices are advantageous with respect to their lower power consumption, high luminance, fast response time, and low weight. Accordingly, the organic electroluminescent display (ELD) devices can be implemented in mobile telecommunication terminals, car navigation systems (CNGs), personal digital assistants (PDAs), camcorders, and palm computers. In addition, since manufacturing processes for the organic electroluminescent display (ELD) devices are simple, manufacturing costs can be reduced. The organic electroluminescent display (ELD) devices can be classified into passive matrix-type and active matrix-type devices. Although the passive matrix-type organic electroluminescent display (ELD) devices have simple structures and manufacturing processes are simplified, they require high power consumption and are not suitable for large-sized display devices. In addition, aperture ratios decrease as the number of conductive lines increase. On the other hand, the active matrix-type organic electroluminescent display (ELD) devices have high light-emitting efficiency and high image display quality.
FIG. 1
is cross sectional view of an organic electroluminescent display (ELD) device according to the related art. In
FIG. 1
, the organic electroluminescent display (ELD) device
10
has a transparent first substrate
12
, thin film transistor array part
14
, a first electrode
16
, an organic light-emitting layer
18
, and a second electrode
20
, wherein the thin film transistor array part
14
is formed on the transparent first substrate
12
. A first electrode
16
, an organic light-emitting layer
18
, and a second electrode
20
are formed over the thin film transistor array part
14
, and the light-emitting layer
18
displays red (R), green (G), and blue (B) colored light, and is commonly formed by patterning organic material separately for each pixel for R (red), G (green) and B (blue). A second substrate
28
has a moisture absorbent desiccant
22
. The organic electroluminescent display (ELD) device
10
is completed by bonding the first and second substrates
12
and
28
together by disposing a sealant
26
between the first and second substrates
12
and
28
. The moisture absorbent desiccant
22
removes moisture and oxygen that may infiltrate into an interior of the organic electroluminescent display (ELD) device
10
. The moisture absorbent desiccant
22
is formed by etching away a portion of the second substrate
28
, filling the etched portion of the second substrate
28
with moisture absorbent desiccant material, and fixing the moisture absorbent desiccant material by tape
25
.
FIG. 2
is a plan view of a thin film transistor array pixel part of an organic electroluminescent display (ELD) device according to the related art. In
FIG. 2
, the thin film transistor array part of the organic electroluminescent display (ELD) device has a switching element T
S
, a driving element T
D
, and a storage capacitor C
ST
at every pixel region “P” that is defined on a substrate
12
. The switching element T
S
and the driving element T
D
may be formed with combinations of more than two thin film transistors. The substrate
12
is formed of transparent material, such as glass and plastic. A gate line
32
is formed along a first direction, and a data line
34
is formed along a second direction perpendicular to the first direction. The data line
34
crosses the gate line perpendicularly with an insulating layer between the gate and data lines
32
and
34
, and a power line
35
is formed along the second direction to be spaced apart from the data line
34
. Thin film transistors are used for the switching element T
S
and the driving element T
D
, wherein the thin film transistor for the switching element T
S
has a gate electrode
36
, an active layer
40
, a source electrode
46
, and a drain electrode
50
, and the thin film transistor for the driving element T
D
has a gate electrode
38
, an active layer
42
, a source electrode
48
, and a drain electrode
52
. The gate electrode
36
of the switching element T
S
is electrically connected to the gate line
32
, and the source electrode
46
of the switching element T
S
is electrically connected to the data line
34
. The drain electrode
50
of the switching element T
S
is electrically connected to the gate electrode
38
of the driving element T
D
through a contact hole
54
, and the source electrode
48
of the driving element T
D
is electrically connected to the power line
35
through a contact hole
56
. The drain electrode
52
of the driving element T
D
is electrically connected to a first electrode
16
in the pixel regions “P,” and the power line
35
and a first capacitor electrode
15
formed of a polycrystalline silicon layer forms a storage capacitor C
ST
.
FIG. 3
is a cross sectional view along III—III of
FIG. 2
according to the related art. In
FIG. 3
, a buffer layer
14
is formed on a substrate
12
and a thin film transistor T
D
is formed on the buffer layer
14
. The thin film transistor T
D
has a gate electrode
38
, an active layer
42
, a source electrode
56
, and a drain electrode
52
. An active layer
42
is formed on the buffer layer
14
, and a second insulating layer
37
is formed on the active layer
42
. A gate electrode
38
is formed on the second insulating layer
37
, and third and fourth insulating layers
39
and
41
are sequentially formed over the gate electrode
38
. The source and drain electrodes
56
and
52
are formed on the fourth insulating layer
41
. A power line
35
is formed between the third and fourth insulating layers
39
and
41
to contact the source electrode
56
. A fifth insulating layer
57
is formed on an entire surface of the substrate
12
on which the source and drain electrodes
56
and
52
are formed. A first electrode
16
is formed on the fifth insulating layer
57
, and the first electrode
16
contacts the drain electrode
52
of the driving element. A light-emitting layer
18
that emits lights of specific wavelengths is formed on the first electrode
16
, and a second electrode
20
is formed on the light-emitting layer
18
. Before forming the light-emitting layer
18
, a sixth insulating layer
58
is formed on the first electrode
16
, and is patterned to expose a portion of the first electrode
16
. The light-emitting layer
18
is formed on the exposed portion of the first electrode
16
, and the second electrode
20
is formed over the entire substrate
12
. A storage capacitor C
ST
is formed in parallel with the driving element T
D
and uses a power line
35
as a first capacitor electrode and a polycrystalline silicon pattern
15
as a second capacitor electrode
20
.
The organic electroluminescent display (ELD) device is commonly manufactured by forming the thin film transistor array part and the light-emitting part on a same substrate, and then bonding the substrate to an encapsulation. If the thin film transistor array part and the light-emitting part are formed on the same substrate, a yield of a panel having the thin film transistor array pa
Lee Nam-Yang
Park Jae-Yong
LG.Philips LCD Co. , Ltd.
Morgan & Lewis & Bockius, LLP
Patel Vip
LandOfFree
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