Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
2001-07-24
2002-11-12
Nguyen, Hoang (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C315S169200, C313S582000
Reexamination Certificate
active
06479944
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel, apparatus for fabricating the same, and fabrication process thereof.
2. Background of the Related Art
This is the age of multimedia, which requires a display enabling to give expression to colors almost the same of the nature as well as fine and large image. For a wide display over 40 inches, it is difficult to introduce the, present CRT(cathode ray tube) and LCD(liquid crystal display) structures. Instead, a plasma display panel attracts public attention in a field of a next generation display.
Such a plasma display panel, as shown in
FIG. 1A
, is constructed with upper and lower plates
10
and
20
confronting and combined each other.
FIG. 1B
shows a cross-sectional structure of the plasma display panel in
FIG. 1A
, in which a face of the lower plate
20
is rotated by 90□ for the convenience of explanation.
The upper plate
10
is constructed with scan electrodes
16
and
16
′ and sustain electrodes
17
and
17
′ which are parallel each other, a dielectric layer
11
formed on the upper plate
10
including the scan electrodes
16
and
16
′ and sustain electrodes
17
and
17
′, and a passivation layer
12
on the dielectric layer
11
. And, the lower plate
20
is constructed with address electrodes
22
, a dielectric body layer
21
formed on an a front face of the plate including the address electrodes
22
, partition walls
23
formed on the dielectric body layer
21
between the address electrodes
22
, and a fluorescence material
24
formed on surfaces of the partition walls and dielectric body layers
21
in the respective discharge cells. And, mixed inert gas such as He, Xe and the like fills up a space between the upper and lower plates
10
and
20
so as to form a discharge area.
Operation of the above-constructed plasma display panel follows.
First, when a driving voltage is applied thereto, a confronting discharge occurs between the address and scan electrodes, whereby portions of electrons discharged from the inert gas in the discharge cells collide with a surface of the passivation layer. Subsequently, secondary electrons are discharged from the surface of the passivation layer by the collision of the electrons. Then, the discharged secondary electrons collide with plasma gas so as to spread the discharge. After the confronting discharge between the address and scan electrodes finishes, wall charges having opposite polarities are generated from the surface of the passivation layer on the address and scan electrodes.
When the driving voltage being applied to the address electrodes is cut off while the discharge voltage having opposite polarities is continuously applied to the scan and sustain electrodes, plane discharge occurs in the discharge area of the surfaces of the dielectric layer and passivation layer by a potential difference between the scan and sustain electrodes. Such confronting and plane discharges make the electrons in the discharge cell collide with the inert gas in the discharge cell. As a result of this, the inert gas in the discharge cell becomes excited and produces an ultraviolet ray having a wave of 147 nm in the discharge cell. Such an ultraviolet ray collides with the fluorescence material surrounding the address electrode, thereby realizing an image.
In order to make the plasma display panel exhibit its performance and elongate its durability, the layers inside the panel should be built solid and no impurity gas except the discharge gas should exist.
A process of fabricating such a plasma display panel may be divided into three parts such as a former process, a latter process, and a module process.
First, the former process is a process of forming various layers on the upper and lower plates
10
and
20
. The latter process includes combination of the upper and lower plates
10
and
20
, exhaust, discharge gas injection and tip-off, aging, and inspection. In this case, the tip-off is a process comprising the steps of completing the exhaust and discharge gas injection through an exhaust pipe and cutting and sealing the exhaust pipe. And, the aging is a process for removing impurities finally by driving electrodes for a predetermined time by applying a voltage thereto so as to attain a discharge voltage drop.
Finally, the module process is the last process of mounting circuits and assembling parts so as to complete a plasma display panel.
An apparatus for fabricating a plasma display panel and a method of fabricating a plasma display panel according to a related are explained as follows by referring to the attached drawings.
FIG. 2
illustrates a latter process for a plasma display panel and a process condition thereof according to a related art,
FIGS. 3A
to
FIGS. 3C
illustrate layouts for explaining a combining process in
FIG. 2
,
FIG. 4
illustrates a cross-sectional view of an exhaust pipe,
FIG. 5
illustrates a layout of a combination/exhaust separate type apparatus for a display panel according to a related art, and
FIG. 6
illustrates a cart structure in FIG.
5
.
The latter process for a plasma display panel(hereinafter abbreviated PDP) according to related art, as shown in
FIG. 2
, includes combination of the upper and lower plates
10
and
20
, exhaust, discharge gas injection and tip-off, aging, and inspection.
First, the upper and lower plates
10
and
20
are transferred to a combination apparatus. And, an edge of the upper plate
10
, as shown in
FIG. 3A
, is coated with a sealing material
31
, i.e. frit, to the uniform thickness using a dispenser. In this case, the frit consists of glass, SiO
2
, and an additive for improving adhesiveness.
And, they are dried at about 120° and thermally treated at a high temperature over 400° C. in order to remove impurities remaining in the frit.
Then, the thermally-treated upper and lower plates are transferred to a combination apparatus. In this case, the upper plate
10
is transferred to the combination apparatus by being exposed to the atmosphere.
AS shown in
FIG. 3B
, the upper and lower plates
10
and
20
are aligned to each other in the combination apparatus. And, the upper and lower plates
10
and
20
are fixed by combination clamps
32
. Then, the upper and lower plates
10
and
20
, as shown in
FIG. 3C
, are combined with each other by melting the frit.
When carrying out the combination process, an exhaust pipe
40
consisting of a long-straw type glass is attached to an exhaust hole
42
of the lower plate
20
using a frit ring.
Then, a panel of which combination is finished is transferred to an exhaust and gas injection apparatus.
The exhaust and gas injection apparatus carries out an exhaust process exhausting impurities sticking to a layer and impurity gas generated from the layer outside using the exhaust pipe
40
formed in the combination process.
Then, discharge gas is injected through the exhaust pipe
40
. And, a tip of the exhaust pipe
40
is tipped off by applying a heat thereto, thereby preventing the leakage of the injected discharge gas.
Subsequently, the process is completed by inspecting a state of the panel after the aging.
Thus, a separate type fabrication apparatus, which carries out the combination and the exhaust and gas injection separately in exhaust pipe type fabrication apparatuses, is divided into the combination apparatus and the exhaust and gas injection apparatus. The exhaust and gas injection apparatus, as shown in
FIG. 5
, includes a hot-wind heating furnace
51
to establish an exhaust and discharge gas injection condition and a cart
52
loading a panel and unloading the panel on which the exhaust and discharge gas injection has been carried out in the hot-wind heating furnace
51
.
The cart
52
, as shown in
FIG. 6
, is constructed complicatedly with a vacuum pump
61
to make vacuum inside the panel, a vacuum pipe system including an exhaust manifold
62
, valves and pipes, a bombe
65
for discharge gas injection, a ga
Im Jun Yong
Lee Mi Kyoung
Lee Won Jeong
Yang Nam Yeol
Fleshner & Kim LLP
LG Electronics Inc.
Nguyen Hoang
LandOfFree
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