Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2002-02-27
2003-02-18
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S584000, C313S582000
Reexamination Certificate
active
06522075
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a surface discharge type AC-driven plasma display panel, particularly to the discharge cell structure of such plasma display panel.
Recently, there has been appeared in the market a new type of display device which is large in size and small in thickness, with one example being a surface discharge type AC-driven plasma display panel.
FIG. 47
is a plane view schematically indicating a surface discharge type AC-driven plasma display panel made according to a prior art.
FIG. 48
is a sectional view taken along line V—V in
FIG. 47
,
FIG. 49
is a sectional view taken along line W—W in FIG.
47
.
As shown in
FIGS. 47-49
, the conventional plasma display panel has a front glass substrate
1
(serving as a displaying surface), a plurality of row electrode pairs (X′, Y′), a dielectric layer
2
covering the row electrode pairs (X′, Y′), a protection layer
3
consisting of MgO covering the dielectric layer
2
.
Referring to
FIG. 47
, each row electrode pair (X′, Y′) includes a pair of transparent electrodes (Xa′, Ya′) consisting of ITO transparent electrically conductive film and having a relatively large width, and a pair of bus electrodes (Xb′, Yb′) consisting of a metal film having a relatively small width. The bus electrodes (Xb′, Yb′) are provided to compensate for the electric conductivity of the transparent electrodes (Xa′, Ya′).
Further, two row electrodes forming each row electrode pair (X′, Y′) are arranged in parallel with each other, forming a discharge gap g′ therebetween, thereby forming one displaying line L for the plasma display panel (matrix display)
Referring to
FIGS. 48 and 49
, the conventional plasma display panel has a rear glass substrate
4
arranged space-apart from the front glass substrate
1
, thereby forming an electric discharge space S′ therebetween. Further, the display panel includes a plurality of column electrodes D′ arranged orthogonal to the row electrodes (X′, Y′), a plurality of belt-like partition walls
5
provided between and in parallel with the column electrodes D′, a fluorescent layer
6
including three kinds of original color portions
6
(R),
6
(G),
6
(B). In detail, the fluorescent layer
6
is so provided that it covers the side surfaces of the partition walls
5
and the column electrodes D′.
In this way, the row electrode pairs (X′, Y′) are intersected with the column electrodes D′, while the discharge space S′ is divided by the partition walls
5
into a plurality of smaller sections, thereby forming a plurality of electric discharge cells C′ serving as a plurality of light emission units, as shown in FIG.
47
.
A displaying process of the surface discharge type AC-driven plasma display panel having the structure shown in
FIGS. 47-48
will be described in the following.
At first, an addressing operation is conducted so that an electric discharge is effected selectively among the discharge cells C′ between the row electrode pairs (X′, Y′) and the column electrodes D. As a result, a plurality of lit-up cells (discharge cells C′ where wall charges have been formed in the dielectric layer
2
) and a plurality of extinguished cells (discharge cells C′ where wall charges are not formed in the dielectric layer
2
) are distributed on the panel corresponding to a picture to be displayed.
Subsequently, discharge sustaining pulses are simultaneously applied to all the displaying lines L in a manner such that the row electrode pairs (X′, Y′) will alternatively receive the discharge sustaining pulses. In this manner, surface discharge phenomenon will occur in lit-up cells once the discharge sustaining pulses are applied thereto.
At this moment, since ultraviolet light will be generated due to the surface discharge in the lit-up cells, the fluorescent layer
6
(R, G, B) will be excited to effect light emission, thereby displaying a picture on the plasma display panel.
In the above-described surface discharge type AC-driven plasma display panel, since a fluorescent layer
6
has been provided to cover not only the column electrodes D′ but also the side faces of the belt-like partition walls
5
, a light emission area within each discharge cell C′ has been increased, thus increasing the brightness of a picture being displayed on the panel.
However, with the above-described surface discharge type AC-driven plasma display panel, if it is desired to improve the fineness of a displayed picture by reducing the size of each discharge cell C′, a total surface area of the fluorescent layer
6
will also be undesirably reduced, resulting in a deterioration in the brightness of the displayed picture.
To cope with the above problem, it is allowed to consider making narrow the pitch between each row electrode pair (X′,Y′). This, however, would cause a problem called discharge interference between every two adjacent discharge cells C′, hence resulting in some misdischarges.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide an improved plasma display panel capable of ensuring an improved fineness for a picture being displayed on the panel, without causing the above-mentioned problems such as a decrease in a displaying brightness and some misdischarges in discharge cells.
It is a second object of the present invention to provide an improved plasma display panel capable of preventing a reflection of an external light incident on the panel, thereby improving the contrast of a picture being displayed on the panel.
It is a third object of the present invention to provide an improved plasma display panel capable having an improved resolution.
It is a fourth object of the present invention to provide an improved plasma display panel capable of preventing a warpage in partition walls (which are provided to divide a discharge space into a plurality of discharge cells), thereby preventing a possible deformation in the predetermined shape of the discharge cells.
It is a fifth object of the present invention to provide an improved plasma display panel capable of preventing the formation of unwanted slots between a front glass substrate and a rear glass substrate, thereby avoiding any possible defect caused by such slots in the display panel.
According to the present invention, there is provided a plasma display panel comprising: a front substrate; a plurality of row electrode pairs provided on the inner surface of the front substrate, said row electrode pairs being arranged in parallel with one another and extending in the row direction of the panel, with each row electrode pair forming a displaying line; a dielectric layer provided on the inner surface of the front substrate for coverring the row electrode pairs; a rear substrate arranged in parallel with and space-apart from the front substrate, forming a discharge space therebetween; a plurality of column electrodes provided on the inner surface of the rear substrate, said column electrodes being arranged in parallel with one another and extending in the column direction of the panel, in a manner such that at each intersection of a row electrode pair with a column electrode there is for med a light emission unit; a partition wall assembly provided between the front substrate and the rear substrate, said partition wall assembly including a plurality of longitudinal partition walls and a plurality of lateral partition walls, thereby dividing the discharge space into a plurality of discharge cells. In particular, the dielectric layer has a plurality of projection portions located corresponding to and protruding toward the lateral partition walls of the partition wall assembly, in a manner such that there would be no slots formed between the dielectric layer and the lateral partition walls.
In one more aspect of the present invention, a slot is formed between the dielectric layer
Amemiya Kimio
Komaki Toshihiro
Koshio Chiharu
Masuda Kosuke
Sakai Tatsuro
Arent Fox Kintner Plotkin and Kahn
Patel Ashok
Pioneer Corporation
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