Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2000-05-22
2002-11-12
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C445S025000, C445S038000
Reexamination Certificate
active
06479933
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a full-color plasma display panel, and more particularly, to a full-color plasma display panel that uses different discharge gases to emit different colored light.
2. Description of the Prior Art
Full-color plasma display panels (PDP) that use discharge gases to emit multi-colored light are a well-known type of planar display in the field. The luminous performance of the PDP is similar to that of millions of flat-shaped, minute fluorescent lights of various colors. The known PDP comprises phosphor materials that coat tiny discharge cells. The dimensions of these cells can be on the order of a few hundreds of microns. The cells are filled with a discharge gas made from neon (Ne) and xenon (Xe), or helium (He) and xenon (Xe). When excited, the discharge gas emits ultraviolet radiation. This irradiates the phosphor materials, which then emit red light, green light or blue light.
Please refer to FIG.
1
.
FIG. 1
is a perspective view of a full-color PDP
10
according to the prior art. The prior art full-color PDP
10
comprises a first substrate
12
, a second substrate
14
parallel to the first substrate
12
, a discharge gas (not shown) that fills the space between the first substrate
12
and the second substrate
14
, a plurality of first electrodes
18
, a plurality of second electrodes
20
, and a plurality of third electrodes
22
. The first electrodes
18
and the second electrodes
20
are positioned on the first substrate
12
in parallel and at regular intervals. Each of the third electrodes
22
are positioned on the second substrate
14
and are orthogonal to the first electrodes
18
and the second electrodes
20
. Each of the first electrodes
18
and the second electrodes
20
comprises a maintaining electrode
181
,
201
, respectively, made of ITO materials, and an auxiliary electrode
182
,
202
, respectively, made of a Cr/Cu/Cr metal alloy. The maintaining electrode
181
,
201
has high resistance and poor conductivity, but is transparent to visible light. The auxiliary electrode
182
,
202
has a low resistance, and so increases the conductivity of its respective electrode
18
,
20
.
The full-color PDP
10
further comprises a dielectric layer
24
that covers the surfaces of the first substrate
12
, the first electrodes
18
and the second electrodes
20
. A protective layer
26
covers the dielectric layer
24
. A plurality of barrier ribs
28
are positioned in parallel on the second substrate
14
, and isolate adjacent third electrodes
22
to define a plurality of discharge spaces
30
. A phosphor layer
32
coats the third electrode
22
and the barrier rib
28
within each discharge space
30
. The phosphor layer
32
under radiation may emit either red light, green light or blue light. Each of the discharge spaces
30
is part of a plurality of unit display elements
34
, which are a specific region defined by one of the first electrodes
18
, one of the second electrodes
20
, and one of the third electrodes
22
. When an initiating voltage is induced between the first electrode
18
and the third electrode
22
, an electric field results in ionization of the discharge gas between the first electrode
18
and the third electrode
22
and charges form on the walls. The first electrode
18
and the second electrode
20
drive the plasma formed in the unit display element
34
in an alternating fashion, causing it to continuously emit ultraviolet radiation. Under this ultraviolet radiation, the phosphor layer
32
emits light of a predetermined color, and this light is passed on to a user through the transparent first substrate
12
.
The color of the light emitted from the phosphor layer
32
depends upon the phosphor materials used. When ((Y,Gd)BO
3
) is applied to the phosphor, and Eu is added as an activating agent, the phosphor layer
32
will emit red light. When Zn
2
SO
4
is applied to the phosphor, and Mn is added as an activating agent, the phosphor layer
32
will emit green light. When BaMgAl
14
O
23
is applied to the phosphor, and Eu is added as an activating agent, the phosphor layer
32
will emit blue light. However, the fabrication process of the phosphor materials is complicated, and the price of these materials is not cheap. Additionally, the red light emitted from the phosphor layer
32
lacks color purity. The green light emitted from the phosphor layer
32
is too persistent. The blue light emitted from the phosphor layer
32
suffers from color degradation over time. Finally, the phosphor layer
32
coated within the discharge space
30
is easily damaged by plasma bombardment, which shortens the usable life of the full-color PDP
10
.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a full-color PDP that uses different discharge gases to emit specifically colored light, and which doesn't use phosphor materials, so as to avoid the above-mentioned problems.
In accordance with the claimed invention, the present invention PDP comprises a back substrate, and a front substrate positioned on the back substrate. A space is formed between the facing surfaces of the back substrate and the front substrate. A plurality of barrier ribs is positioned within the space for defining a plurality of discharge space groups. Each group comprises a first discharge space, a second discharge space, and a third discharge space, wherein each discharge space comprises an upper opening on an upper side of the discharge space and a lower opening on a lower side of the discharge space. Furthermore, a plurality of air-locking ribs are positioned within the space to seal the lower opening of the first discharge space, the upper opening and lower opening of the second discharge space, and the upper opening of the third discharge space. A first wall is positioned on an upper side of the plurality of the discharge space groups, wherein the first wall and the adjacent air-locking ribs define a first channel which is accessible through each of the upper openings of the first discharge spaces. A second wall is positioned on a lower side of the plurality of the discharge space groups, wherein the second wall and the adjacent air-locking ribs define a second channel which is accessible through each of the lower openings of the third discharge spaces. In addition, a first gas, a second gas, and a third gas respectively fill the first discharge space, the second discharge space, and the third discharge space to emit different colored light.
It is an advantage of the present invention that the PDP, without phosphor materials, uses different discharge gases as light sources, so the problems associated with phosphor materials are avoided, and the useable lifetime of the PDP is increased.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment which is illustrated in the various figures and drawings.
REFERENCES:
patent: 5525862 (1996-06-01), Miyazaki
patent: 5742122 (1998-04-01), Ammiya et al.
patent: 5825128 (1998-10-01), Betsui et al.
Acer Display Technology Inc.
Hsu Winston
Patel Ashok
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