Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
1999-09-01
2001-07-24
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S584000, C313S587000
Reexamination Certificate
active
06265826
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a plasma addressing display device having a flat panel structure in which a display cell and a plasma cell are stacked to each other, and particularly to an electrode structure in each of discharge channels formed in the plasma cell.
A plasma addressing display device configured to use a plasma cell for addressing a display cell has been disclosed, for example, in Japanese Patent Laid-open No. Hei 4-265931.
As shown in
FIG. 1
, the plasma addressing display device disclosed in the above document has a flat panel structure including a display cell
1
, a plasma cell
2
, and a common intermediate substrate
3
interposed therebetween.
The plasma cell
2
has a lower substrate
8
joined to the intermediate substrate
3
with a specific gap kept therebetween. An ionizable gas is enclosed in the gap therebetween.
Stripe-shaped discharge electrodes
9
A and
9
K are alternately formed on the inner surface of the lower substrate
8
. The discharge electrode
9
A having a wide width functions as an anode, and the discharge electrode
9
K having a narrow width functions as a cathode. These discharge electrodes
9
A and
9
K are formed of a metal thin film.
Barrier ribs
10
are each formed on the anode side discharge electrode
9
A, to thereby divide a space filled with the ionizable gas into discharge channels
12
.
Each cathode side discharge electrode
9
K is positioned between the adjacent ones of the barrier ribs
10
.
The barrier ribs
10
can be formed by overlappingly coating the discharge electrodes
9
A with typically glass paste by a screen printing process. The tops of the barrier ribs
10
are in contact with the underside of the intermediate substrate
3
.
One discharge channel
12
includes one discharge electrode
9
K functioning as the cathode and two discharge electrodes
9
A functioning as the anodes disposed on both sides of the discharge electrode
9
K. The discharge channel
12
generates a plasma discharge between the cathode side discharge electrode
9
K and the anode side discharge electrodes
9
A.
The intermediate substrate
3
is jointed to the lower substrate
8
by means of glass frit
11
or the like.
The display cell
1
has a transparent upper substrate
4
. The upper substrate
4
is stuck on the intermediate substrate
3
with a specific gap kept therebetween by means of a sealing material
6
or the like, and the gap is filled with an electro-optic material such as a liquid crystal
7
. Signal electrodes
5
are formed on the inner surface of the upper substrate
4
. The signal electrodes
5
cross the stripe-shaped discharge channels
12
at right angles. Pixels are defined in a matrix pattern at portions where the signal electrodes
5
cross the discharge channels
12
.
In the plasma addressing display device having the above-described configuration, the display drive is performed by scanning rows of the discharge channels
12
on the plasma cell
2
side in such a manner as to switch them in line-sequence and applying image signals to columns of the signal electrodes
5
on the display cell
1
side in synchronization with the scanning of the discharge channels
12
. When a plasma discharge is generated in each discharge channel
12
, the interior of the discharge channel
12
becomes a substantially uniformly anode potential, to effect the pixel selection for each row. That is to say, the discharge channel
12
functions as a sampling switch. When an image signal is applied to each pixel in the state in which the plasma sampling switch is made conductive, sampling for the pixel is performed, to thereby control the turn-on/off of the pixel. Even after the plasma sampling switch becomes non-conductive, the image signal remains held in the pixel.
FIG. 2
is a typical perspective view showing an electrode structure and a barrier rib structure on the lower substrate
8
shown in FIG.
1
. The anode side discharge electrodes
9
A and the cathode side discharge electrodes
9
K, patterned into the stripe-shapes, are alternately arranged. These discharge electrodes are formed by depositing a metal thin film of aluminum or the like by sputtering or vacuum vapor-deposition and selectively etching the metal thin film into stripe shapes. The barrier ribs
10
are formed on the anode side discharge electrodes
9
A. The width of the barrier rib
10
is typically 160 &mgr;m which is narrower than the width (typically, 470 &mgr;m) of the anode side discharge electrode
9
A. The barrier ribs
10
can be formed by overlappingly coating the discharge electrodes
9
A with dielectric paste such as glass paste and being baked. In addition, the width of the cathode side discharge electrode
9
K is typically about 80 &mgr;m, and the lower substrate
8
is formed of typically a glass plate.
In the related art structure shown in
FIG. 2
, the barrier ribs
10
composed of the baked body of glass paste are formed on the broad discharge electrodes
9
A formed of a metal thin film. However, the adhesion between a metal thin film and a baked body of glass paste is generally weak. Accordingly, the related art structure causes a problem that the barrier ribs
10
may be peeled or damaged during the manufacturing process. To solve the problem, it may be considered to change the material of the discharge electrodes
9
A from the metal thin film of aluminum or the like into a baked body of conductive paste for improving the adhesion with the barrier ribs
10
made from the baked body of insulating paste such as glass paste; however, such a method has the following inconvenience. At present, only nickel paste containing nickel particles can be practically used as the conductive paste; however, if the discharge electrodes are made from the nickel paste, vapor of mercury must be previously contained in a discharge gas for preventing wear of nickel due to plasma discharge, giving rise to a problem in terms of both safety of products and environmental protection.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a plasma addressing display device, which is capable of increasing an adhesive strength of barrier ribs against a substrate while using a metal thin film as a material of discharge electrodes.
To achieve the above object, according to the present invention, there is provided a plasma addressing display device which basically includes: a plasma cell including discharge channels sequentially arranged along the scanning direction; and a display cell joined to the plasma cell, the display cell including signal electrodes sequentially arranged in the direction perpendicular to the scanning direction and an electro-optic material layer being in contact with the signal electrodes; wherein the plasma cell has a substrate jointed to the display cell side with a specific gap kept therebetween; discharge electrodes formed on the substrate in such a manner as to extend along the discharge channels; and barrier ribs formed on the substrate in such a manner as to partition adjacent ones of the discharge channels from each other. The plasma addressing display device is characterized in that each of the discharge electrodes is composed of a pair of parallel longitudinal electrode portions disposed on both sides of one of the barrier ribs, and a plurality of crossarm electrode portions disposed on the underside of the barrier rib in such a manner as to connect the pair of longitudinal electrode portions to each other.
Preferably, the discharge electrodes are formed of a metal thin film, and the barrier ribs are formed of a baked body of a dielectric paste.
The discharge electrodes are preferably anode electrodes.
The plurality of crossarm electrode portions are preferably arranged in such a manner as to be spaced at specific intervals and to cross the pair of longitudinal electrode portions at right angles, so that the discharge electrode is formed into a ladder shape in a plan view as a whole.
The plurality of crossarm electrode portions may obliquely cross the pair of longitudinal electrode portions.
Accord
Patel Ashok
Sonnenschein Nath & Rosenthal
Sony Corporation
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