Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
1998-12-11
2001-09-04
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C445S024000
Reexamination Certificate
active
06285128
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a surface discharge type plasma display panel, particularly to a surface discharge type plasma display panel (hereinafter simply referred to as PDP) whose discharge cells are arranged in matrix manner.
FIG. 5
is a plane view illustrating a basic structure of a surface discharge type PDP made according to a prior art. As shown in
FIG. 5
, a conventional surface discharge type PDP comprises a pair of glass substrate plates
11
,
21
facing each other and forming a discharge space therebetween. Such discharge space has a thickness of 100-200 &mgr;m and is formed by sealing together entire edge portions of the two glass substrate plates
11
,
21
. With such surface discharge type PDP having discharge cells arranged in a matrix manner, a plurality of row electrodes are arranged orthogonal to a plurality of column electrodes so that a displaying area EH is formed.
However, referring to
FIG. 5
, since a peripheral sealing material
31
positioned along the above edge portions will undesirably produces a gas during an electric discharge, the electric discharge within the discharge space is not stable in the vicinity of these sealed edge portions. To cope with this problem in order to ensure a stable electric discharge, it has been suggested that a non-displaying area EN be provided surrounding the displaying area EH. Usually, such non-displaying area EN has a width of 20 mm regardless of a size of a picture plane.
In more detail, a surface discharge type PDP has a plurality of display electrodes X,Y defining main discharge cells (surface discharge cells), a plurality of address electrodes A which together with the display electrodes Y serve to form selective discharge cells, and a plurality of strap-like partition walls
29
for dividing the discharge space within the displaying area EH into a plurality of smaller sections in the direction of displaying lines.
In fact, the display electrodes X,Y are covered by a dielectric layer (not shown in
FIG. 5
, but is used for AC driving the PDP using wall electric charges) in the discharge space. In practice, each pair of the display electrodes X,Y serve as a discharge maintaining electrode pair on each displaying line.
In use of the above surface discharge type PDP, a write-in address method or an erase address method is utilized to selectively accumulate wall charges in main discharge cells (to be lighted), so as to alternatively apply a discharge maintaining voltage to the display electrodes X,Y, thereby periodically causing a desired surface discharge (in a direction along the surfaces of the substrate plates) A displaying brightness may be adjusted by selecting the number of discharge times within each unit time.
However, the above surface discharge type PDP has been found to have at least one problem which will be described in detail below.
Namely, when a scanning pulse is applied to the discharge maintaining electrodes and at the same time an address pulse is applied to the address electrodes in accordance with display data, selective discharge will happen within discharge cells (to be lighted) and wall charges are accumulated. At this moment, since an electric field intensity obtained by an address potential of the address electrodes on the outmost sides will become weak, it will be difficult for the desired selective discharge to occur, resulting in a decrease of an address margin.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved surface discharge type PDP capable of preventing a decrease of an address margin on the outmost side of a displaying area, so as to solve the above-mentioned problems peculiar to the above-mentioned prior art.
According to the present invention, there is provided a surface discharge type plasma display panel having a plurality of discharge maintaining electrodes extending in parallel with displaying lines, and a plurality of address electrodes extending perpendicular to the discharge maintaining electrodes, characterized in that at least one dummy electrode is provided on a non-displaying area outside an outmost electrode of the above address electrodes, in a manner such that the dummy electrode is adjacent to and in parallel with said outmost address electrode and is electrically connected to the outmost address electrode by means of connecting conductors.
In one aspect of the present invention, the at least one dummy electrode has the same width as each address electrode and has a sufficient length capable of intersecting with all the discharge maintaining electrodes.
In another aspect of the present invention, the at least one dummy electrode and the connecting conductors, are formed at the same time when forming the address electrodes, using a film formation process in which a silver paste is printed followed by calcination.
In further aspect of the present invention, on a displaying area the plurality of discharge maintaining electrodes are each formed by a large width transparent conductive film and a narrow width metal film, while on the non-displaying area the plurality of discharge maintaining electrodes are each formed only by metal film.
In a still further aspect of the present invention, a discharge gap between each discharge maintaining electrode pair on the non-displaying area has a larger width than 'that on the displaying area.
The above objects and features of the present invention will become better understood from the following description with reference to the accompanying drawings.
REFERENCES:
patent: 5684362 (1997-11-01), Togawa
patent: 5952782 (1999-09-01), Nanto et al.
Arent Fox Kintner & Plotkin & Kahn, PLLC
Gerike Matt
Patel Ashok
Pioneer Electronic Corporation
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