Plasma display panel with first and second ribs structure

Details Plasma display panel with first and second ribs structure Plasma display panel with first and second ribs structure

1999-06-18

2001-05-22

Patel, Vip (Department: 2879)

Electric lamp and discharge devices

With gas or vapor

Three or more electrode discharge device

C313S582000

Reexamination Certificate

active

06236160

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel (also designated as a PDP hereinafter), and particularly to an AC driven PDP of surface discharge type which is driven with AC signals.
2. Description of Related Art
In recent years, the AC driven PDPs of surface discharge type have been expected as a large and thin color display apparatus.
FIG. 6
shows a cross-sectional view of one example of the structure of an AC driven PDP of surface discharge type.
Referring to
FIG. 6
, two pairs or more of row electrodes X and Y are laid on a glass substrate
21
to be a display screen side, the row electrodes extending in parallel to each other. The row electrodes X and Y are covered with a dielectric layer
24
. Each of the row electrodes X and Y is comprised of a transparent electrode
23
a
formed of a transparent conductive film, and a metal electrode
23
b
of a metal film formed on the electrode
23
a
in order to supplement the conductivity of the transparent conductive film with the metal film. The metal electrodes
23
b
are stacked on the ends portion of the transparent conductive films
23
a
opposite to a discharge gap
G
respectively.
The dielectric layer
24
is comprised of a first dielectric layer
24
a
which uniformly covers up the inner surface of the glass substrate
21
and the row electrodes X and Y, and a second dielectric layer
24
b
, i.e., a raising dielectric layer which formed on the first dielectric layer
24
a
at the corresponding portion to the metal electrode
23
b
. The second dielectric layer
24
b
causes the surface of the dielectric layer
24
to locally rise at the corresponding portion to the metal electrode
23
b
. Since the second dielectric layer
24
b
is formed with approximately the same width as that of the metal electrode
23
b
and in parallel to the metal film and locally forms a slightly elevated bank on the surface of the dielectric layer
24
, the layer
24
b
restricts spreading of discharge, thereby preventing adjoining discharge cells from erroneously discharging. A protection layer
25
of MgO is formed on this dielectric layer
24
.
On the other hand, a plurality of column electrodes
26
are formed on the inner surface of a glass substrate
22
to be a back side in parallel to one another at predetermined intervals therebetween, and a fluorescent layer
27
is formed on the column electrodes
26
and the inner surface of a glass substrate
22
.
The glass substrate
21
of the display screen side and the glass substrate
22
of the back side are secured apart from each other in such a manner that the row electrodes X and Y perpendicularly cross the column electrodes
26
in order to define a discharge space
28
between the inner surfaces of the substrates facing each other. The discharge space
28
is filled with a rare gas, and the assembled panel is sealed hermetically.
Ribs or partitions (not shown) having a predetermined height are formed between the column electrodes
26
on the back-side glass substrate
22
respectively to separate the column electrodes
26
and the plural pairs of row electrodes X and Y, thereby defining a unit of light-emitting regions having light-emitting surfaces with a predetermined area.
The dielectric layer
24
is formed by coating a low-melting point glass paste containing, for example, lead oxide (PbO) on the row electrodes X and Y and annealing it. Since the metal film needs to have a low electric resistance in order to supplement the conductivity of the transparent conductive film, Al (aluminum), Al alloy, Ag (silver), Ag alloy or the like is used for the metal film.
SUMMARY OF THE INVENTION
Since the raising dielectric layer mentioned above is formed by a screen printing, its precision in the height and positioning accuracy are insufficient. Such low precisions in manufacture result in giving an insufficient demonstration of the effect of the raising dielectric layer
24
b
to restrict a size of discharge spreading and prevent interference of discharge between adjoining cells.
Accordingly, the present invention is made to overcome the aforementioned problems and it is an object of the present invention to provide a plasma display panel which is capable of preventing the discharge interference and ensuring a stable function of displaying an image.
The aforementioned problems are overcome and advantages are provided by a plasma display panel according to the present invention which comprises:
a pair of first and second substrates facing each other spaced with a discharge space, which are on a display-screen side and on a back side respectively;
a plurality of pairs of row electrodes extending horizontally and arranged on an inner surface of the first substrate as corresponding to display-lines respectively, each of said paired row electrodes comprised of a main body portion extending horizontally and projecting portions each projecting from the main body portion toward the other row electrode in the pair in a manner that fellow front ends of the paired projecting portions face each other through a discharge gap;
a dielectric layer formed on said row electrodes;
a plurality of column electrodes extending vertically and arranged on an inner surface of said second substrate, each of said plurality of column electrodes associated with each of the row electrodes and defining a unit region of light-emission including the discharge gap and an intersection formed wherever one of said column electrodes crosses apart from one of said pair of row electrodes in said discharge space;
a plurality of first ribs extending vertically and disposed between said column electrodes to separate said discharge space for each of said unit regions of light-emission;
fluorescent layers covering up at least said column electrodes, and
a plurality of second ribs provided on said inner surface of said second substrate, each second ribs facing an opposite edge portion of said projecting portion to said discharge gap and a portion of the main body portion of the row electrode in vicinity of said opposite edge, and said second ribs being in contact with said dielectric layer.
According to this plasma display panel, the second ribs i.e., studs, each facing the opposite edge portion of the associated one of the projecting portions of the associated pair of row electrodes to the discharge gap and the body portion in the vicinity of the associated projecting portion, are provided on the inner surface of the back side substrate, and the studs are designed to be in contact with the dielectric layer. This structure therefore restricts discharge spreading toward adjoining unit regions of light-emission.
In a plasma display panel according to one embodiment in a first aspect of the present invention, the first and second ribs may be formed of a glass layer patterned by sandblasting, thereby improving the height and positional precisions.
In another plasma display panel according to one embodiment in a second aspect of the present invention, the fluorescent layer may be so provided as to cover the column electrodes, sides of the partitions of first ribs and sides of the studs of second rib, thereby increasing the area of the fluorescent layer in each unit region of light-emission.
In a further plasma display panel according to one embodiment in a third aspect of the present invention, a light-shielding layer may be provided on the inner surface of the first substrate and between adjoining pairs of row electrodes to improve the contrast for each unit region of light-emission.
In a still further plasma display panel according to one in a fourth aspect of the present invention, the occupying ratio of the fluorescent layer that contributes to light emission can be increased significantly by allowing at least one of the body portions of each pair of row electrodes to be shared by adjoining display-lines.


REFERENCES:
patent: 5889365 (1999-03-01), Tanabe

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