Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2000-11-08
2003-06-24
Kim, Robert H. (Department: 2882)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S582000, C313S583000
Reexamination Certificate
active
06583560
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a cell structure of a plasma display panel.
2. Description of the Related Art
Recent years, a plasma display panel (referred to “PDP” hereinafter) of a surface discharge scheme AC type as an oversized and slim display for color screen has been received attention, which is becoming widely available.
FIG. 8
is a schematically plane view of a conventional cell structure of such PDP.
FIG. 9
is a sectional view taken along the V—V line of FIG.
8
.
FIG. 10
is a sectional view taken along the W—W line of FIG.
8
.
In
FIG. 8
to
FIG. 10
, on the backside of a front glass substrate
1
to serve as a display screen of the PDP, there is sequentially provided with a plurality of row electrode pairs (X′, Y′); a dielectric layer
2
covering the row electrode pairs (X′, Y′); and a protective layer
3
made of MgO which covers a backside of the dielectric layer
2
.
The row electrodes X′ and Y′ respectively consist of wider transparent electrodes Xa′ and Ya′ each of which is formed of a transparent conductive film made of ITO (Indium Tin Oxide) or the like, and narrower bus electrodes Xb′ and Yb′ each of which is formed of a metal film, complementary to conductivity of the transparent electrode.
The row electrodes X′ and Y′ are arranged opposing each other with a discharge gap g′ in between, and alternate in the column direction to form a display line (row) L on a matrix display screen.
A back glass substrate
4
faces the front glass substrate
1
with a discharge space S, filled with a discharge gas, in between. The back glass substrate
4
is provided with a plurality of column electrodes D′ arranged to extend in a direction perpendicular to the row electrode pairs X′ and Y′; band-shaped partition walls
5
each extending between the adjacent column electrodes D′ in parallel; and a red phosphor layer
6
(R), green phosphor layer
6
(G) and blue phosphor layer
6
(B) which respectively overlay side faces of the partition walls
5
and the column electrodes D′.
In each display line L, discharge cells C are divided by the partition walls
5
in the column direction, and respectively formed at intersections of the column electrodes D′ and the row electrode pair (X′, Y′) in the discharge space S′.
In the above PDP, an image is displayed as follows:
First, through address operation, discharge (opposite discharge) is generated selectively between the row electrode pairs (X′, Y′) and the column electrodes D′ in the respective discharge cells C, to scatter lighted cells (the discharge cell C formed with wall charge on the dielectric layer
2
) and nonlighted cells (the discharge cell C not formed with wall charge on the dielectric layer
2
), over the panel in accordance with the image to be displayed.
After the address operation, in all the display lines L, the discharge sustain pulse is applied alternately to the row electrode pairs (X′, Y′) in unison, and thus discharge (surface discharge) is produced in the lighted cells on every application of the discharge sustain pulse.
In this manner, the surface discharge in each lighted cell generates ultraviolet light, and thus the red phosphor layer
6
(R) and/or the green phosphor layer
6
(G) and/or the blue phosphor layer
6
(B) each formed in the discharge cell C are excited to emit light, resulting in forming the display screen.
For the PDP as configured above, displaying images with definition needs to reduce a size of each discharge cell C to increase the number of pixels each made up of the phosphor layers
6
(R),
6
(G) and
6
(B) as a unit.
However, fulfilling such a demand for displaying images with high definition, if each discharge cell C is reduced in size,_it causes a reduced surface area in each of the phosphor layers
6
(R),
6
(G) and
6
(B) of the discharge cells C. This produces another problem of reduction in luminance.
In the PDP, the maximum length of extension of each of the transparent electrodes Xa′ and Ya′ of the respective row electrodes X′ and Y′ onto the discharge cell C, corresponds to approximately half the length of a longitudinal side of the discharge cell C. Therefore, when each size of the discharge cell C is reduced in order to achieve the high definition image as described above, the transparent electrodes Xa′ and Ya′ of the row electrodes X′ and Y′ are also reduced in length. This produces problems of reduction in efficiency of light emission and further reduction in luminance.
As described above, if each size of the discharge cells C is reduced to increase the number of pixels for the high definition image, this increases the number of partition walls
5
defining the discharge cells C and the row electrode pairs (X′, Y′), and in turn increases an area of portions reflecting ambient light incident from the panel surface of the PDP. As a result, a problem in that the reflected light promotes reduction in contrast of an image is produced.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problems associated with the conventional plasma display panel.
It is therefore a first object of the present invention to provide a plasma display panel which is capable of preventing reduction in luminance associated with increase in definition of images.
It is a second object of the present invention to provide a plasma display panel which is capable of preventing reduction in contrast of an image due to reflection of ambient light incident from the panel surface.
To attain the first object, a plasma display panel according to a first invention includes a plurality of row electrodes extending in the row direction on a backside of a front substrate and arranged in the column direction, and a plurality of column electrodes extending in the column direction on a surface of a back substrate facing the front substrate with a discharge space in between and arranged in the row direction. Such plasma display panel is characterized in that the row electrode has an electrode main body portions extending the row direction and a plurality of protrusion electrode portions extending in the column direction and arranged along the electrode main body portions to intersect and connect with the electrode main body portions. And also, an end of the protrusion electrode portion of the row electrode opposes to an end of the protrusion electrode portion of the row electrode adjacent thereto, with a required gap in between. And then, a unit light emitting area is formed in each discharge space between the back substrate and a section of the protrusion electrode portions which are paired by the two opposing ends of the protrusion electrode portions with the required gap in between.
In the plasma display panel according to the first invention, the row electrodes constituting the unit light emitting area together with the column electrode at an intersecting section of the row electrodes and column electrode, are respectively provided with a plurality of protrusion electrode portions each intersected with and connected to the electrode main body portion extending in the row direction, for each unit light emitting area. Each of the unit light emitting area is formed at a portion where the paired protrusion electrode portions of the adjacent two row electrodes are opposed, in the discharge space.
According to the first invention, hence, the protrusion electrode portion is intersected with and connected to the electrode main body, to extend from the electrode main body in the opposite direction of the mate of the paired protrusion electrode portions. For this reason, each unit light emitting area is formed not only between the two electrode main bodies connected to the pair of protrusion electrode portions but also on each opposite side of the pair of electrode main bodies. Therefore, increase in width of each unit light emi
Arent Fox Kintner Plotkin & Kahn
Pioneer Corporation
Yun Jurie
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