Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
1999-08-02
2002-07-09
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S582000, C313S584000, C313S586000
Reexamination Certificate
active
06417620
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a surface discharge type plasma display panel (PLASMA DISPLAY PANEL) having a matrix display system, and more particularly to a structure of a black stripe formed in parallel with a scanning electrode pair in each region between pixels in order to enhance a contrast of a screen.
BACKGROUND OF THE INVENTION
FIG. 10
is an exploded perspective view showing a sectional structure of a unit pixel of an AC surface discharge type plasma display panel (hereinafter referred to as a PDP) according to the prior art described in U.S. Pat. No. 5,661,500, for example.
A PDP shown in
FIG. 10
is of a surface discharge type having a three-electrode structure, and comprises a first glass substrate
1
provided on a screen side, a scanning electrode pair (X, Y) formed adjacently in parallel with each other in a transverse direction (a direction of A shown in
FIG. 10
) on a surface of the glass substrate
1
, a dielectric layer
4
for AC driving which has a discharging protective film
5
formed on a surface thereof, a second glass substrate
6
opposed to the first glass substrate
1
, a plurality of barrier ribs
7
formed in a direction orthogonal to the scanning electrode pair (X, Y) and defining a spacing dimension of a discharge space
10
by abutting on the discharging protective film
5
, phosphors
9
R,
9
G and
9
B having three primary colors of R (red), G (green) and B (blue) provided between the barrier ribs
7
, address electrodes (W) provided in the second glass substrate
6
each corresponding to each of the phosphors
9
R,
9
G and
9
B, and the like.
EU denotes unit luminescent areas each corresponding to each of the phosphors
9
R,
9
G and
9
B. A unit pixel region EG is formed by three unit luminescent areas EU.
A discharge region is partitioned by the barrier ribs
7
for each unit luminescent area EU. The discharge space
10
thus partitioned is filled with a neon-xenon mixed gas at a pressure of about 500 Torr as a discharge gas for radiating ultraviolet rays for exciting the phosphors
9
R,
9
G and
9
B.
Since the scanning electrode pair (X, Y) is to be provided on the screen side, it comprises band-shaped transparent conductor films (for example, a nesa film:tin oxide)
3
and metal films (for example, Ag:silver)
2
for compensating for conductive properties of the films
3
.
An upper layer portion of the barrier rib
7
, that is, a top
8
of the barrier rib is formed by a layer mixed with a black pigment in order to obtain the effect of enhancing contrast performance of a screen.
In such a surface discharge type PDP, a surface discharge occurs in each of intersecting portions of the scanning electrode pairs (X, Y) and the address electrodes (W) so that the unit luminescent areas EU are defined.
Accordingly, a portion corresponding to each unit luminescent area EU can be caused to selectively emit light. Thus, full color display can be obtained by the combination of R, G and B.
FIG. 11
is a plan view schematically showing a unit pixel portion of the PDP illustrated in FIG.
10
.
As shown in
FIG. 11
, the PDP has a structure in which each unit pixel region EG constituting the screen is formed by the three unit luminescent areas EU arranged in one direction and the phosphors
9
R,
9
G and
9
B having three colors for full color display are arranged in order corresponding to the unit luminescent areas EU.
In such a unit pixel region EG, the scanning electrode pair (X, Y) formed in the array direction of the unit luminescent area EU is arranged as electrodes for causing a surface discharge.
FIG. 12
is a plan view schematically showing another example according to the prior art in which black stripes
20
are provided between the unit pixel regions EG in parallel with the scanning electrode pairs (X, Y) in order to enhance the contrast of the screen in the conventional surface discharge type PDP described above, and
FIG. 13
is an exploded perspective view showing a sectional structure of FIG.
12
.
FIG. 14
is an exploded perspective view showing the first glass substrate
1
provided on the screen side in
FIG. 13
, which is seen from a non-screen side.
In
FIGS. 13 and 14
, regions enclosed by a heavy broken line indicate the black stripes
20
.
FIG. 15
is a sectional view showing a state in which the first glass substrate
1
having the dielectric layer
4
and the discharging protective film
5
formed on the scanning electrode pairs (X, Y) and the black stripes
20
and the second glass substrate
6
having the barrier ribs
7
formed thereon are stuck together, which is seen just horizontally (in the A direction of FIG.
10
).
In the drawings, for example, a thickness of the scanning electrode X or Y formed by the metal film
2
and the transparent conductor film
3
(that is, the sum of thicknesses of the metal film
2
and the transparent conductor film
3
) is about 0.5 &mgr;m, while a thickness of the black stripe
20
is about 10 &mgr;m. The dielectric layer
4
having a thickness of about 30 &mgr;m and the discharging protective film
5
having a thickness of about 0.7 &mgr;m are formed with almost uniform thicknesses over the scanning electrodes X and Y and the black stripes
20
.
For this reason, surface irregularities (concavities and convexities) are generated on the surfaces of the dielectric layer
4
and the discharging protective film
5
due to the thicknesses of the scanning electrodes X and Y and the black stripes
20
which are provided on the surface of the glass substrate
1
. In particular, convex portions are enlarged over the black stripes
20
.
By the way, the convex portions of the protective discharging film
5
provided above the black stripes
20
on the first substrate
1
side intersect with and abut on the tops
8
of the barrier ribs
7
provided on the second substrate
6
side. Consequently, the discharge spaces
10
are defined.
In such a conventional AC surface discharge type PDP, however, when the first substrate
1
side and the second substrate
6
side are stuck together to form the discharge spaces
10
, the protective discharging film
5
provided on the first substrate
1
side abuts on the tops
8
of the barrier ribs provided on the second substrate
6
side in the convex portions generated due to the thickness of the black stripe
20
as shown in FIG.
15
. Therefore, unnecessary clearances
30
are generated between the top
8
of the barrier rib and the protective discharging film
5
.
The clearance
30
has a thickness of about 3 &mgr;m in a central portion between the adjacent black stripes
20
so that an extra discharge space exists in a boundary portion between the adjacent unit luminescent areas EU.
Accordingly, also in a case where surface discharge should be caused in a specific unit luminescent area, for example, a unit luminescent area EU (R) and should not be caused in unit luminescent areas EU (G) and EU (B) adjacent to both sides of the unit luminescent area EU (R), there is a problem in that the surface discharge gets over the top
8
of the barrier rib
7
through the clearance
30
which is the extra discharge space, thereby causing erroneous discharge in the unit luminescent areas EU (G) and EU (B) on both sides or affecting the surface discharge in the unit luminescent areas EU (G) and EU (B) on both sides (for example, voltage margins are reduced in the unit luminescent areas EU (G) and EU (B) on both sides), and the like.
The present invention has been made in order to eliminate the above-described drawbacks of the prior art, and has an object to provide a high performance surface discharge type PDP capable of reducing extra discharge spaces (that is, the clearances
30
) generated between adjacent unit luminescent areas due to a thickness of a black stripe and of lessening defective writing caused by an erroneous discharge or the like.
DISCLOSURE OF THE INVENTION
The present invention provides a surface discharge plasma display comprising a first glass substrate having a plurality of scanning electrode pairs parallel with each other and bl
Haynes Mack
Mitsubishi Denki & Kabushiki Kaisha
Patel Vip
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