Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
1999-04-13
2002-04-23
Day, Michael H. (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S582000, C313S587000
Reexamination Certificate
active
06376987
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an AC-driving plasma display panel (PDP) of a surface-discharge type.
2. Description of the Related Art
There is growing anticipation of making fit for practical use an AC-driving PDP of a surface-discharge type as a large-scaled and thin color display unit.
FIG. 4
shows a structural example of such an AC-driving PDP of the surface-discharge type. As shown in
FIG. 4
, plural pairs of row electrodes
12
are formed on a front glass substrate
11
constituting a display surface side so that the pairs of row electrodes
12
are set in parallel to each other and the row electrodes
12
making the pair are coated with a dielectric layer
13
, which is coated with a protective layer
14
of MgO. The row electrode
12
includes a transparent electrode
12
a
formed of a transparent conductive film such as an ITO film or the like and a metal auxiliary electrode (a bus electrode)
12
b
formed of a metal film for supplementing the conductivity of the transparent electrode
12
a.
On the other hand, a plurality of column electrodes
16
are disposed in parallel to each other at given intervals on the inner surface side of a back glass substrate
15
as the back side and a phosphor layer
17
for coating each of the row electrodes
16
is also formed thereon. The front glass substrate
11
and the back glass substrate
15
are disposed separately to form closed discharge spaces
18
.
Moreover, there are formed partition walls (ribs)
19
having a predetermined height and used for forming the discharge space
18
between the column electrodes
16
in each unit luminous area
22
. A discharge cell is formed at each of the intersections between the pair of row electrodes
12
and the column electrode
16
. Rare gas is enclosed in the discharge spaces
18
.
The dielectric layer
13
is formed by applying low-melting glass paste containing, for example, lead oxide (Pbo) onto the plurality of pairs of row electrodes
12
and calcining the row electrodes
12
. Furthermore, Al (aluminum), Al alloy, Ag (silver), Ag alloy or the like is used to form the metal film because the metal film is required to have low resistance in order to supplement the conductivity of the transparent conductive film.
FIG. 5
is a partial enlarged view of the pair of row electrodes as seen from the display surface side of PDP. As aforementioned, the pair of row electrodes
12
made up of the pair of transparent electrodes
12
a
and the pair of bus electrodes
12
b
which are stacked on and connected to the respective pair of the transparent electrodes
12
a
. The pair of transparent electrodes
12
a
in each unit luminous area (discharge cell)
22
have a plurality of opposing projecting portions
20
via a discharge gap
21
.
The use of the transparent electrodes provided with the projecting portions as stated above allows decreasing the area of the electrode and suppressing a discharge current value. However, the front glass substrate must be precisely registered with the back glass substrate when the PDP is made in order that the discharge characteristic of each discharge cell is uniformized because the discharge characteristic of the discharge cell is adversely affected by the distance between the leading end portions of the projecting portions near the discharge gap and the partition walls. Since the registration needs accuracy in proportion as the discharge cell is reduced in size, moreover, it has been difficult to employ a transparent electrode having such a projecting portion for an extremely small discharge cell.
SUMMARY OF THE INVENTION
An object of the present invention intended to solve the foregoing problems is to provide a plasma display panel capable of demonstrating improved reliability and fine alignment.
To achieve the above object, according to a first aspect of the invention, there is provided a plasma display panel comprising:
first and second substrates disposed opposite to each other via a discharge space, said first substrate being disposed at a display side;
plural pairs of row electrodes formed on an inner surface of said first substrate and extending in parallel in a first direction with each discharge gap held therebetween;
a dielectric layer coated on said row electrodes and partially defining said discharge space;
plural pairs of column electrodes formed on an inner surface of said second substrate and extending in a second direction perpendicularly crossing the first direction and forming unit luminous areas in intersecting portions with respect to the respective pairs of first row electrodes; and
belt-like partition walls for partitioning said discharge space into said unit luminous areas in said first direction;
wherein each of said row electrodes comprises: a transparent conductive film having a body portion extending in said first direction in the proximity of said discharge gap and a projecting portion projecting in each unit luminous area from said body portion in a direction away from said discharge gap, and a metal film connected to a leading end portion of the projecting portion of said transparent conductive film and extending in said first direction.
A second aspect of the invention has been achieved by the provision of the plasma display panel according to the first aspect of the invention, wherein the surface of the dielectric layer in a portion existing on the metal film and facing the partition walls is projected toward a portion in the proximity of the discharge gap.
A third aspect of the invention is achieved by the provision of the plasma display panel according to the second aspect of the invention, wherein the surface of the dielectric layer between the adjoining metal films of the adjoining metal film of the adjoining unit luminous areas in the second direction is projected toward a portion in the proximity of the discharge gap.
In the plasma display panel according to the present invention, as the row electrode includes the transparent conductive film having the body portion extending in the first direction in the proximity of the discharge gap and the projecting portion projecting in each unit luminous area from the body portion in a direction away from the discharge gap, and the metal film connected to the leading end portion of the projecting portion of the transparent conductive film and extending in the first direction, the influence of the discharge characteristic resulting from the shifting of the relative position of the transparent conductive film to the partition wall is made reducible, whereby the registration accuracy of the front glass substrate with respect to the back glass substrate can be lessened.
In the plasma display panel according to the present invention, moreover, as the surface of the dielectric layer between the adjoining metal films adjacent to the unit luminous area in the second direction of the metal film is projected toward the portion in the proximity of the discharge gap, whereby an error discharge between the adjoining discharge cells is suppressed.
REFERENCES:
patent: 5548186 (1996-08-01), Ota
patent: 5661500 (1997-08-01), Shinoda et al.
patent: 5952782 (1999-09-01), Nanto et al.
patent: 6236160 (2001-05-01), Komaki et al.
Amemiya Kimio
Nozu Mitsunori
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