Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2000-11-08
2003-09-16
Kim, Robert H. (Department: 2882)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S583000, C313S584000, C313S585000, C313S586000, C313S587000
Reexamination Certificate
active
06621215
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a front plate of a plasma display panel (PDP) and the method of fabricating the same. More particularly, the present invention relates to a method of fabricating a front plate of a plasma display panel that is capable of preventing oxidation of the electrodes in bonding area of the plasma display panel.
2. Description of the Related Art
Recently, a variety of flat panel displays, such as a liquid crystal display (LCD) and a plasma display. panel (PDP) have been intensively developed for replacing the cathode ray tubes (CRT) display. In PDP, an ultra violet light is emitted for exciting the RBG phosphors to produce visible lights. The advantages of the PDP include large display area, wide viewing angle, and intense brightness.
FIG. 1
shows an exploded view of a conventional plasma display panel (referred as PDP) comprising a front plate
10
and a back plate
12
. The front plate
10
includes a glass substrate
14
, a plurality of scanning electrodes
16
, a transparent dielectric layer
18
, and a magnesium oxide (MgO) layer
20
. Each of the scanning electrodes
16
includes a sustaining electrode
22
and an auxiliary electrode
24
. A visible light is emitted by plasma generated between two adjacent transparent electrodes
22
after a voltage is applied to these electrodes
22
. In order to allow visible light to pass through the glass substrate
14
, each of the sustaining electrodes
22
is a transparent electrode
22
consisted of indium tin oxide (ITO) or SnO
2
. However, the resistance of the sustaining electrode is too high to be suitable for electrical conduction. For this reason, an auxiliary electrode
24
consisting of metal is disposed on every sustaining electrode
22
to enhance conductivity.
The back plate
12
comprises another glass substrate
30
, a plurality of data electrodes
32
, a dielectric layer
33
, a plurality of ribs
34
, and a plurality of fluorescence layers
36
. The data electrodes
32
of the back plate are perpendicularly to the scanning electrodes
16
of the front plate
10
. The space formed by two adjacent ribs
34
and two adjacent scanning electrodes
16
is called a “pixel”. The data electrode
32
is used for controlling the generation of the plasma. The scanning electrodes
16
are used to maintain the plasma. In addition, the fluorescence layers
36
can produce primary visible lights after absorbing UV ray generated by the plasma. The primary visible lights includes red, green, and blue light. The ribs
34
prevent the UV ray from leaking to the neighboring pixel and thereby prevent the color mixing phenomenon.
Referring to FIGS.
2
A through
FIG. 2C
,
FIG. 2A
shows a top view of the front plate of the PDP shown in
FIG. 1
, and
FIGS. 2B and 2C
show cross-sectional views of the front plate
10
along the a—a and b—b lines shown in
FIG. 2A
, respectively. A pixel area and a bonding area are formed on the glass substrate
14
, the a—a line crosses the pixel area and the b—b line crosses the bonding area. The auxiliary electrode
24
is divided into a pixel auxiliary electrode and a bonding auxiliary electrode. The bonding auxiliary electrode is the portion of the auxiliary electrode
16
extending to the edge of the front plate
10
and used for connection to an external driving circuit (not shown). As shown in
FIG. 2B
, in the pixel area, the pixel auxiliary electrode is covered by the dielectric layer
18
and MgO layer
20
. On the contract, in the bonding area as shown in
FIG. 2C
, the bonding auxiliary electrode is not covered by the dielectric layer
18
or MgO layer
20
.
Conventionally, each of the scanning electrodes
16
is constituted of a sustaining electrode
22
and an auxiliary electrode
24
such that the auxiliary electrode
24
is stacked on top of the sustaining electrode
22
. The auxiliary electrode
24
has a three-layered structure constituted of Cr—Cu—Cr, wherein Cr and Cu denote chromium and copper, respectively. In particular, a heating process of about 500° C. to 600° C. is used to sinter the dielectric layer
18
. However, the top Cr metal surface of the auxiliary electrode
24
tends to be oxidized easily during the heating process. It may cause a short circuit between the bonding auxiliary electrode and the external driving circuit, and the performance of the PDP will be reduced.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a front plate of a plasma display panel (PDP) capable of preventing the bonding electrode from being oxidized during the sequential heating process.
To achieve the above-mentioned object, the present invention provides a front plate of a PDP, comprising a glass substrate, an auxiliary electrode, and a protecting electrode. The auxiliary electrode is located on the glass substrate having a pixel area and a bonding area. The auxiliary electrode includes a pixel auxiliary electrode positioned at the pixel area and a bonding auxiliary electrode positioned at the bonding area. The protecting electrode is disposed above the bonding auxiliary electrode so that the bonding auxiliary electrode is covered by the protecting electrode and is not oxidized during the sequential processes.
According to the first embodiment of the present invention, the glass substrate includes a trench and the auxiliary electrode is embedded in the trench of the glass substrate. The auxiliary electrode includes a main conducting layer, a first medium layer positioned between the main conducting layer and the glass substrate, and a second medium layer positioned between the main conducting layer and the protecting electrode. The first medium layer is used to eliminate the stress between the main conducting layer and the glass substrate, and the second medium layer is used to eliminate the stress between the main conducting layer and the protecting electrode.
According to the second embodiment of the present invention, the glass substrate includes a trench, and the auxiliary electrode is embedded in the trench of the glass substrate. The auxiliary electrode includes a main conducting layer positioned under the protecting electrode and a first medium layer positioned between the main conducting layer and the glass substrate. The first medium layer is used to eliminate the stress between the main conducting layer and the glass substrate.
According to the third embodiment of the present invention, the front plate further incldues a buffer layer located on the glass substrate. The buffer layer has a trench and the auxiliary electrode is embedded in the trench of the buffer layer. The auxiliary electrode includes a main conducting layer, a first medium layer positioned between the main conducting layer and the buffer layer, and a second medium layer positioned between the main conducting layer and the protecting electrode. The first medium layer is used to eliminate the stress between the main conducting layer and the buffer layer, and the second medium layer is used to eliminate the stress between the main conducting layer and the protecting electrode.
According to the fourth embodiment of the present invention, the front plate further includes a buffer layer located on the glass substrate, the buffer layer has a trench, and the auxiliary electrode is embedded in the trench of the buffer layer. The auxiliary electrode includes a main conducting layer positioned under the protecting electrode and a first medium layer positioned between the main conducting layer and the buffer layer. The first medium layer is used to eliminate the stress between the main conducting layer and the buffer layer.
According to the fifth embodiment of the present invention, the front plate further includes a sustaining electrode located between the glass substrate and the auxiliary electrode. The auxiliary electrode includes a main conducting layer, a first medium layer positioned between the main conducting layer and the sustaining electrode, and a second medium layer positioned between the main conducting
Lin Yih Jer
Su Yao Ching
AU Optronics Corp.
Kim Robert H.
Ladas & Parry
Yun Jurie
LandOfFree
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