Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
2000-02-09
2003-02-11
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C313S582000, C313S584000
Reexamination Certificate
active
06517400
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plasma display panel(PDP), and more particularly to electrodes in the PDP and a fabrication method thereof that are capable of lowering their resistance components and fine-patterning them.
2. Description of the Related Art
Generally, a plasma display panel(PDP) radiates a fluorescent body by an ultraviolet with a wavelength of 147 nm generated during a discharge of He+Xe or Ne+Xe gas to thereby display a picture including characters and graphics. Such a PDP is easy to be made into a thin film and large-dimension type. Moreover, the PDP provides a very improved picture quality owing to a recent technical development. The PDP is largely classified into a direct current(DC) driving system and an alternating current(AC) driving system.
The PDP of AC driving system is expected to be highlighted into a future display device because it has advantages in the low voltage drive and a prolonged life in comparison to the PDP of DC driving system. Also, the PDP of AC driving system allows an alternating voltage signal to be applied between electrodes having a dielectric layer therebetween to generate a discharge every half-period of the signal, thereby displaying a picture. Since such an AC-type PDP uses a dielectric material, the surface of the dielectric material is charged with electricity. The AC-type PDP allows a memory effect to be produced by a wall charge accumulated to the dielectric material due to the discharge.
FIG. 1
is a sectional view showing the structure of a discharge cell in the conventional three-electrode AC-type PDP, in which a lower plate is illustrated in a state of rotating an angle of 90°. In
FIG. 1
, the discharge cell includes an upper plate
10
provided with a sustaining electrode pair
12
and
14
, and a lower substrate
20
provided with an address electrode
20
. The upper substrate
10
and the lower substrate
20
are spaced, in parallel, from each other with having a barrier rib
28
therebetween.
A mixture gas such as Ne—Xe or He—Xe, etc. is injected into a discharge space defined by the upper substrate
10
and the lower substrate
20
and the barrier rib
28
. The sustaining electrode pair
12
and
14
consists of transparent electrodes
12
A and
14
A and metal electrodes
12
B and
14
B. The transparent electrodes
12
A and
14
A are usually made from Indium-Tin-Oxide(ITO) and has an electrode width of about 300 &mgr;m. Usually, the metal electrodes
12
B and
14
B take a three-layer structure of Cr—Cu—Cr and have an electrode width of about 50 to 100 &mgr;m. These metal electrodes
12
A and
14
A play a role to decrease a resistance of the transparent electrodes
12
A and
14
A
6
with a high resistance value to thereby reduce a voltage drop. Any one
12
of the sustaining electrode pair
12
and
14
is used as a scanning/sustaining electrode that responds to a scanning pulse applied in an address interval to cause an opposite discharge along with the address electrode
22
while responding to a sustaining pulse applied in a sustaining interval to cause a surface discharge with the adjacent sustaining electrodes
14
. A sustaining electrode
14
adjacent to the sustaining electrode
12
used as the scanning/sustaining electrode is used as a common sustaining electrode to which a sustaining pulse is applied commonly. A distance between the sustaining electrode pair
12
and
14
is set to be approximately 100 &mgr;m. On the upper substrate
10
provided with the sustaining electrode pair
12
and
14
, an upper dielectric layer
16
and a protective layer
18
are disposed. The dielectric layer
16
is responsible for limiting a plasma discharge current as well as accumulating a wall charge during the discharge. The protective film
18
prevents a damage of the dielectric layer
16
caused by a sputtering generated during the plasma discharge and improves an emission efficiency of secondary electrons. This protective film
18
is usually made from MgO. The address electrode
22
is crossed with the sustaining electrode pair
12
and
14
and is supplied with a data signal for selecting cells to be displayed. On the lower substrate
20
formed with the address electrode
24
, a lower dielectric layer
24
is provided. Barrier ribs
28
for dividing the discharge space are extended perpendicularly on the lower dielectric layer
24
. On the surfaces of the lower dielectric layer
24
and the barrier ribs
28
is coated a fluorescent material
26
excited by a vacuum ultraviolet lay to generate a red, green, or blue visible light.
FIGS. 2A
to
2
E are sectional views for explaining a process of forming the sustaining electrode pair in
FIG. 2
step by step. In
FIG. 2A
, on the upper substrate
10
are sequentially disposed a transparent electrode material layer
12
A and a photosensitive resin pattern
28
. The transparent electrode material layer
12
A is formed on the surface of the upper substrate
10
using the sputtering technique or the vacuum vapor deposition technique. The photosensitive resin pattern
28
is provided by forming the photosensitive resin layer on the transparent electrode material layer
12
A and then patterning it.
Next, the transparent electrode
12
shown in
FIG. 2B
is provided by taking advantage of the photosensitive resin pattern
28
to make a patterning of the transparent electrode material layer
12
A under it. The photosensitive resin pattern
28
on the transparent electrode
12
is removed. After forming the transparent electrode
12
, the first chrome(Cr) thin film
30
, the copper(Cu) thin film
32
and the second Cr thin film
34
are sequentially disposed as shown in FIG.
2
C. The first Cr thin film
30
, the Cu thin film
32
and the second Cr thin film
34
are sequentially disposed on the upper substrate
10
provided with the transparent electrode
12
using the sputtering technique.
Next, as shown in
FIG. 2D
, the second photosensitive resin pattern
36
is provided by forming a photosensitive resin layer on the second Cr thin film
34
and thereafter patterning it. As shown in
FIG. 2E
, the first Cr pattern
30
A, the Cu pattern
32
A and the second Cr pattern
34
A are provided by taking advantage of the second photosensitive resin pattern
36
to make a sequential patterning of the second Cr thin film
34
, the Cu thin film
32
and the first Cr thin film
30
under it. The first Cr pattern
30
A, the Cu pattern
32
A and the second Cr pattern
34
A provide the bus electrode
14
shown in FIG.
1
. The second photosensitive resin pattern
36
on the second Cr pattern
34
A is removed.
In the conventional PDP bus electrode fabrication method as described above, the sputtering technique has been used for forming the first Cr thin film
30
, the Cu thin film
32
and the second Cr thin film
34
. However, the sputtering method is unsuitable for a mass production because expensive vacuum equipment must be used and a deposition time is long. In the PDP, the bus electrode
14
, particularly the Cr thin film, must be thickly provided so as to lower a resistance of the bus electrode
14
to increase the efficiency. To form the bus electrode
14
thickly using the conventional PDP bus electrode fabrication method has a problem in that an adhesive force is deteriorated by a stress, etc. to enlarge a resistance component and to lengthen a deposition time. For this reason, the prior art has widened a line width of the bus electrode
14
instead of adjusting a thickness thereof so as to lower the resistance component. If the line width of the bus electrode
14
is wide, however, then most visible lights generated by a radiation of the fluorescent material
26
are reflected by the bus electrode
14
to deteriorate the efficiency.
Otherwise, to form the bus electrode
14
using the screen printing technique like the address electrode
22
has an advantage in that its fabrication process is simple, while having a drawback in that an organization of the electrode fails to be dense to increase the resistance component
Cho Soo Je
Ryu Byung Gil
Fleshner & Kim LLP
LG Electronics Inc.
Ramsey Kenneth J.
LandOfFree
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