Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
1999-12-01
2002-04-16
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S586000, C313S587000
Reexamination Certificate
active
06373191
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flat panel display apparatus, and in particular to a backplate of a PDP(Plasma Display Panel) has a high definition, a high aspect ratio, and a high luminance.
2. Description of the Background Art
Recently, a flat panel display apparatus such as a LCD(Liquid, Crystal Display), a FED(Field Emission Display) and a PDP(Plasma Display Panel) has been intensively studied. Among the above-described apparatuses, the PDP is easily fabricated because of its simple structure and has a high luminance and light emitting efficiency, a good memory function, and a wide view angle wider than 160°, so that the PDP is well applicable to a wide screen of more than 40 inches.
The construction of a surface discharge AC PDP of the conventional art will be explained with reference to FIG.
1
.
A front glass plate
10
and a back glass plate
20
are facing and distanced from each other, and a discharge region
30
which is defined by a corresponding barrier rib
23
is formed between the front glass plate
10
and the back glass plate
20
.
A plurality of address electrodes A are extended in a certain direction on the upper surface of the back glass plate
20
. A dielectric layer
22
is formed on the upper surfaces of the back glass plate
20
and the address electrodes A.
A plurality of barrier ribs
23
are formed on the upper surface of the dielectric layer between the address electrodes A. In addition, a fluorescent layer
24
is coated on both walls of each barrier rib
23
and on the upper surface of the dielectric layer
22
which covers the address electrodes A.
A sustain and display electrode Xn and a scan electrode Yn are spaced-apart in a parallel direction perpendicular to the direction of the address electrodes A on one surface of the front glass plate. The sustain and display electrode Xn is formed of a transparent ITO(lndium Tin Oxide), so that light passes through the same. Therefore, the sustain and display electrode is called as a transparent electrode. Bus electrodes
13
are formed at the end portions of the sustain and display electrode Xn and the scan electrode Yn for applying a stable driving voltage. The bus electrode
13
is formed of an aluminum or chrome/copper/chrome layers. In addition, a dielectric layer
14
which is formed of a PbO group material covers the sustain and display electrode Xn, the scan electrode Yn, the bus electrode
13
and the front glass plate
10
. MgO is coated on the surface of the dielectric layer
14
as a protection film
15
. The MgO protection film protects the PbO dielectric layer from a sputtering of ions and has a relatively higher secondary electron generating coefficient characteristic when an ion energy collides with the surfaces during a PDP plasma discharge and decreases a driving and sustaining voltage of the discharge plasma.
As shown in
FIG. 1
, He, Ne, Ar or a mixed gas of the same and a mixed gas of Xe
31
are filled in a discharge cell surrounded by the barrier rib of the PDP. The region between the barrier ribs becomes a discharge region
30
, namely, a discharge cell
30
for generating a discharge therein.
In the PDP, a plasma discharge is generated in the discharge region
30
by applying a certain voltage to the transparent electrodes. As an infrared ray generated by the plasma discharge excites the fluorescent layer formed on the backplate for thereby generating a visual ray. The thusly generated visual ray is made incident onto the front plate for thereby displaying a certain character or graphic. Therefore, the front plate is used as a plate for displaying graphics, and the backplate is used for generating visual light.
As described above, the PDP apparatus includes a plurality of discharge cells which are physically separated from each other by the barrier ribs. In order to fabricate a PDP apparatus having a lot amount of pixels using the same area panel, a plurality of discharge cells are required. However, when decreasing the size of the discharge region in order to increase the number of discharge cells, the discharge efficiency is decreased. Therefore, in a state that a certain size of the discharge region is maintained, in order to manufacture a large number of discharge cells, a higher and thicker barrier rib is required. A method for satisfying the above-described requirements has been intensively studied. The conventional barrier rib fabrication method will be explained with reference to
FIGS. 2 through 4
.
First, a fabrication method of a barrier rib based on a screen print method will be explained with reference to
FIGS. 2A through 2C
.
As shown in
FIG. 2A
, a dielectric film
201
is formed on an upper surface of a glass plate
200
. Next, a screen(not shown) having a pattern for fabricating a barrier rib is prepared on an upper surface of the glass plate
200
. An insulation paste is coated on the screen using a roller, etc. and is dried for thereby forming a first insulation paste pattern
202
as shown in
FIG. 2
a.
Thereafter, the screen is prepared thereon again, and an insulation paste is coated and then dried. The above-described operation is repeatedly performed, so that a second insulation paste pattern
203
is stacked on the first insulation paste pattern
202
as shown in
FIG. 2
b.
Next, the screen print method is repeatedly performed until the entire height of the stacked insulation paste pattern becomes 150~200 &mgr;m for thereby forming a barrier rib
204
as shown in FIG.
2
C.
The above-described barrier rib fabrication method based on the screen print method is simple, and the cost of the same is low. However, it is needed to adjust the position of the plate and the screen at every time when performing the screen print process. In addition, a certain small misalignment may occur when adjusting the positions of the screen and plate in the repeated screen print processes, it is difficult to fabricate an accurate barrier rib and high definition barrier rib. In addition, since the above-described print and dry processes are repeatedly performed, a fabrication time is too extended.
As another conventional barrier rib fabricating method, there is a sand blasting method. The above-described sand blasting method will be explained with reference to
FIGS. 3A through 3E
.
Next, as shown in
FIG. 3A
, an insulation paste
301
is formed on a glass plate
200
by a thickness of 150~200 &mgr;m.
Next, as shown in
FIG. 3B
, a photosensitive film
302
is formed on the insulation paste
301
. The photosensitive film
302
is formed in a tape shape by adding an organic material to a photosensitive slurry at a certain ratio and is stack-formed on the insulation paste.
The photosensitive film
302
is patterned by a photolithography method for thereby forming a photosensitive film pattern
302
a
as shown in FIG.
3
C.
As shown in
FIG. 3D
, the insulation paste
301
is etched by spraying an alumina or silica particle(polishing material) using the photosensitive film pattern
302
a
as a mask.
Thereafter, the photosensitive film pattern
302
a is removed for thereby forming a barrier rib
301
a
as shown in FIG.
3
E.
In the barrier rib fabrication method based on the sand blasting method, it is possible to form a barrier rib on a large area plate and to implement a high definition. However, since a lot amount of pastes which are removed by a polishing material is required, and the fabrication cost is high. In addition, since a physical impact is applied to the plate during the fabrication process, a crack may occur at the plate during the molding operation of the insulation paste.
As another conventional barrier rib manufacturing method, an additive method will be explained with reference to
FIGS. 4A through 4E
.
As shown in
FIG. 4
a
, a photosensitive film
401
is formed on a glass plate
400
. The above-described photosensitive film may be formed in a dry film shape and is attached on the glass plate. The photosensitive film may be formed is such as manner that a photosensitive resin is coated using a spi
Jang Woo-Sung
Kim Je-Seok
Fleshner & Kim LLP
LG Electronics Inc.
Patel Ashok
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