Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
1999-04-20
2001-07-03
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S587000
Reexamination Certificate
active
06255780
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a plasma display panel (PDP) of an AC driven surface discharge type.
Recently, there is expectation of realization of the AC driven surface discharge type PDP as a large and thin color display.
FIG. 4
shows a conventional PDP of the AC driven surface discharge type. The PDP comprises a pair of front and back glass substrates
11
and
12
disposed opposite to each other, interposing a discharge space
18
therebetween. The glass substrate
11
as a display side has a plurality of row electrodes X and Y which are alternately disposed in pairs to be parallel with each other at the inside portion thereof. Each of the row electrodes X and Y comprises a transparent conductive film
13
a
formed by an ITO having a large width and a metallic film
13
b
formed by a metallic film having a small width and layered on the transparent conductive film
13
a
for compensating the conductivity of the film
13
a
. The row electrodes X and Y are covered by a dielectric layer
14
.
A projected dielectric layer
14
a
is provided opposite to the metallic film
13
b
on the opposite side of the dielectric layer
14
. The projected dielectric layer
14
a
is provided for preventing error discharge in an adjacent discharge cell. A protection layer
15
made of MgO is coated on the dielectric layer
14
. On the glass substrate
12
, a plurality of data electrodes
16
are formed to intersect the row electrodes X and Y on the glass substrate
11
. A fluorescent layer
17
covers the data electrodes
16
. The discharge space
18
is filled with rare gas.
A plurality of partition ribs (not shown) are provided between the data electrodes
16
. Thus, a pixel cell is formed at the intersection of the row electrodes in pairs and the data electrode defined by a pair of ribs.
The dielectric layer
14
and
14
a
are formed by applying glass paste including a lead, for example lead oxide (PbO), and having a low melting point on the X, Y electrodes and by baking it. The metallic film
13
b
is formed by aluminum, aluminum alloy, silver or silver alloy, because the film is required to have a low resistance to compensate the conductivity of the transparent conductive film.
In the conventional PDP, the glass material used in the projected dielectric layer
14
a
or the baking condition of the projected dielectric layer is limited because of the disposition under the dielectric layer
14
.
More particularly, in order to increase the transmissibility of the dielectric layer, a glass having a low melting point is used and is baked at a sufficiently high temperature. However the fluidity of the projected dielectric layer
14
a
increases because of the disposition under the dielectric layer
14
. It is difficult to form the projected dielectric layer into a predetermined shape consequently. In addition, the glass material acts with the electrodes during the baking to generate bubbles in the dielectric layer. The bubbles decrease the pressure resistibility, which may cause dielectric brake down.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a plasma display panel in which the transmissibility of the dielectric layer is increased, thereby increasing the reliability of the display panel.
According to the present invention, there is provided a plasma display panel having a pair of substrates comprising a display side substrate and a back side substrate, a pair of opposed row electrodes disposed inside the display side substrate interposing a discharge gap, each of the row electrodes comprising a transparent conductive film and a metallic film formed on the transparent conductive film at a position opposite to the discharge gap, a dielectric layer covering the row electrodes, and a plurality of partitions formed on the back side substrate, intersecting with the row electrodes to form a plurality of pixel cells between the substrates.
The dielectric layer comprises a first dielectric layer including a first glass material and continuously formed on the inner surface of the display side substrate by baking the first glass material, a second dielectric layer including a second glass material, and formed on the first dielectric layer except the discharge gap and continuously formed along the partition by baking the second glass material, and a third dielectric layer including a third glass material formed on the first and second dielectric layers by baking the third glass material at a temperature sufficiently higher than a melting point of the third glass material.
The third glass material has a melting point lower than those of the first and second glass materials.
The present invention further provides a method for making a plasma display panel having a pair of substrates comprising a display side substrate and a back side substrate, a pair of opposed row electrodes disposed inside the display side substrate interposing a discharge gap, each of the row electrodes comprising a transparent conductive film and a metallic film formed on the transparent conductive film at a position opposite to the discharge gap, a dielectric layer covering the row electrodes, and a plurality of partitions formed on the back side substrate, intersecting with the row electrodes to form a plurality of pixel cells between the substrates.
The method comprises forming a first dielectric layer including a first glass material on the inner surface of the display side substrate by baking the first glass material, forming a second dielectric layer including a second glass material on the first dielectric layer except the discharge gap and continuously forming along the partition, and forming a third dielectric layer including a third glass material on the first and second dielectric layers by baking the third glass material at a temperature sufficiently higher than a melting point of the third glass material.
The third glass material has a low melting point than those of the first and second glass materials, and is formed by baking at a temperature sufficiently higher than the melting point thereof.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.
REFERENCES:
patent: 5742122 (1998-04-01), Amemiya et al.
patent: 5952782 (1999-09-01), Nanto et al.
patent: 5977708 (1999-11-01), Amatsu et al.
Komaki Toshihiro
Sakai Tatsuro
Taniguchi Hitoshi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Patel Ashok
Pioneer Electronic Corporation
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