Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
2002-05-07
2004-02-24
Philogene, Haissa (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C445S024000, C445S025000, C445S058000
Reexamination Certificate
active
06696796
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel and method of adjusting pressure.
2. Background of the Related Art
FIG. 1
illustrates a related art AC surface discharge plasma display panel (PDP). As shown in
FIG. 1
, the related art AC surface discharge plasma display panel includes a back glass substrate
20
, address electrodes A″ formed on the back glass substrate
20
, and a dielectric layer
23
covering the address electrodes A″. It also includes a front glass substrate
10
placed opposite to the back glass substrate
20
, pairs of sustain electrodes X and Y arranged in parallel on the front glass substrate, a dielectric layer
12
covering the pairs of sustain electrodes, and an MgO protection layer
13
formed on the dielectric layer
12
.
Also, the panel includes barrier ribs
21
arranged between the front and back glass substrates
10
and
20
to define discharge spaces, and a phosphor layer
24
coated on the barrier ribs
21
. The sustain electrodes X and Y have transparent ITO (Indium Tin Oxide) electrodes Xa and Ya and bus electrodes Xb and Yb placed on one side of the ITO electrodes, respectively.
FIG. 2
illustrates the related art AC PDP, shown in
FIG. 1
, sealed with a sealant. A cut-off exhaust pipe
30
is shown on the backside of the PDP.
In general, the process of fabricating a plasma display panel includes forming a front substrate
10
, forming pairs of sustain electrodes X and Y on the front substrate, covering the pairs of sustain electrodes X and Y with a dielectric layer
12
and forming the MgO protection layer
13
on the dielectric layer
12
. Next, a back substrate
20
is formed with a plurality of address electrodes A″ formed thereon wherein the address electrodes A″ are covered with a dielectric layer
23
. Barrier ribs
21
are then formed on the dielectric layer
23
to define discharge spaces with a phosphor layer
24
formed between the barrier ribs
21
.
Finally, the PDP is completed by sealing up marginal portions of the front and back substrates using a sealant to attach the two substrates to each other and injecting gas to evacuate the inside of the plasma display panel assembly through a exhaust pipe
30
by injecting Ne gas containing some Xe into the inside of the assembly. The gas is injected until an internal pressure of approximately 400-600 Torr is reached. When the desired pressure of the discharge gas is achieved, the PDP is completely sealed to maintain a constant and fixed permanent internal amount of gas by cutting off the exhaust pipe
30
, wherein the amount of gas present can no longer be changed.
When discharge gas is injected into the inside of the plasma display panel and the exhaust pipe is cut off to seal up the panel, the plasma display panel maintains a fixed, uniform amount of gas, which cannot be changed without breaking the seal on the panel. Further, if the panel is used in the same ambient pressure, the pressure in the panel is maintained. However, one problem that arises is that use may occur anywhere in the world including areas with different external environments and different ambient pressures. For example, while ambient pressure is 760 Torr at sea level, it is about 500 Torr at 3000 m above sea level, such as in the high altitude alpine zones of Mexico or South America.
These variations in ambient pressure can lead to problems since the amount of gas present will always be the amount present when at sea level with the pressure of the gas injected into the inside of a panel is 400-600 Torr. However, as illustrated in
FIG. 3.
, when the external pressure is reduced, like in a high altitude alpine area, the pressure of gas injected into the inside of the panel can cause the gap between the front and back substrates of the panel to increase due to the change in external pressure. This gap can lead to free movement of charges and a variation in the distance between the front and back substrates possibly generating spaces between the tops of the barrier ribs and the front substrate which can lead to partial crosstalk or generating distortions in the panel which can lead to an image change or general panel distortion. Furthermore, when the external temperature varies, gas pressure inside the panel can also change, and thus may generate problems similar to those created when the altitude is varied.
As described above, in the related art plasma display panel, the pressure ratio between discharge gas pressure to atmospheric pressure varies according to a variation in external environments, whereby affecting initially set discharge conditions and, consequently, can deteriorate picture quality.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.
SUMMARY OF THE INVENTION
An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.
An object of the present invention is to provide a plasma display panel having a means for adjusting discharge gas pressure.
To accomplish the object of the present invention, there is provided a plasma display panel, including a pair of substrates arranged having a predetermined distance between them, a plurality of first electrodes formed on one of the substrates, a plurality of second electrodes formed at a predetermined interval on the other substrate, wherein the second electrodes intersect the first electrodes, a dielectric covering the first and second electrodes, wherein the dielectric is formed on each of the pair of substrates, a barrier rib formed between the pair of substrates, a phosphor layer coated on the barrier rib, wherein discharge cells are formed at the intersections of the first and second electrodes, a sealant coated on marginal portions of the panel that seals the panel, a discharge gas injected with a predetermined pressure into the inside of the panel, and a pressure adjusting means for adjusting the pressure of the injected discharge gas in a sealed plasma display panel.
Another object of the present invention is to provide a pressure adjusting means integrated with an exhaust pipe that evacuates the inside of the sealed panel and injects the gas into the panel.
Another object of the present invention is to provide a pressure adjusting means which includes a case attached to the panel with an opening which connects the case with the inside of the panel, and a volume varying means for varying the volume of the case.
Another object of the present invention is to provide a case with two branches, one of which is an exhaust pipe and the other one of which has the volume varying means inserted therein.
Another object of the present invention is to provide a plasma display panel, including a pair of substrates having a predetermined distance between them, a plurality of first electrodes on one of the substrates, a plurality of second electrodes on the other substrate, barrier ribs formed on one of the substrates forming discharge cells, discharge gas injected into the panel with a predetermined pressure, and a re-adjustable pressure adjustor connected to the panel, wherein the adjustor can fixedly adjust the discharge gas initially upon formation of the panel and can readjust the pressure within the panel at least one other time after completed formation.
Another object of the present invention is to provide a plasma display panel, including a pair of substrates having a predetermined distance between them, a plurality of first electrodes on one of the substrates, a plurality of second electrodes on the other substrate, barrier ribs formed on one of the substrates forming discharge cells, discharge gas injected into the panel with a predetermined pressure, and a pressure adjustor connected to the discharge gas, wherein the plasma display panel and the pressure adjustor are sealed together and the pressure of the discharge gas in the plasma display panel can be fix
Fleshner & Kim LLP
Philogene Haissa
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