Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1999-03-02
2001-07-24
Saras, Steven (Department: 2675)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S067000, C313S492000
Reexamination Certificate
active
06266033
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display device, and more particularly, to a plasma display device with a reduced cell space by providing a crosstalk shielding electrode.
2. Description of the Related Art
In general, a plasma display device includes at least a pair of electrodes and generates discharge by a voltage applied to the electrodes. Due to excellent display characteristics such as display capacity, brightness, contrast and view angle, much attention has been paid to plasma display devices as flat display panels having almost the same performance as cathode ray tubes.
A plasma display panel is largely divided into a direct current (DC) plasma display panel and an alternating current (AC) plasma display panel according to its operational principles. In the DC plasma display panel, all electrodes are exposed to a discharge space, in which charges migrate directly from/to corresponding electrodes. On the other hand, the AC plasma display panel has a structure in which at least one electrode is surrounded by a dielectric material, wherein charges do not directly migrate from/to corresponding electrodes and discharging is performed by the electrical field of wall charges. The DC plasma display panel adopts both a DC driving method by which the polarity of a driving voltage does not change, and an AC driving method by which the polarity of a driving voltage changes. However, the AC plasma display panel adopts only the AC driving method.
Meanwhile, a plasma display panel is divided into a cross discharge type and a neighboring discharge type according to the discharge mechanism. The cross discharge type plasma display panel includes a scanning electrode opposite an address electrode, generates an addressing discharge therebetween and the addressing discharge is sustained by a sustaining discharge. The neighboring discharge type plasma display panel includes a scanning electrode and a common electrode which face an address electrode, and generates an addressing discharge between the address electrode and the common electrode and a sustaining discharge between the scanning electrode and the common electrode.
Referring to
FIGS. 1 and 2
, an example of a neighboring discharge type plasma display device will be described briefly. The plasma display device includes address electrodes
11
formed on a rear substrate
10
in a predetermined pattern, and a dielectric layer
12
covering the address electrodes
11
and the rear substrate
10
. A partition
13
formed on the dielectric layer
12
maintains a discharge distance, and a fluorescent layer
17
is formed between neighboring partitions
13
. A front substrate
16
is installed over the rear substrate
10
, and a scanning electrode
14
and a common electrode
15
, perpendicular to the address electrodes
11
, are alternately formed on the bottom of the front substrate
16
. A dielectric layer
18
is coated on the front substrate
16
and the scanning and common electrodes
14
and
15
. A protective film
20
is coated on the dielectric layer
18
. A predetermined discharge gas is injected to a discharge space S between the front substrate
16
and the rear substrate
10
.
Referring to
FIG. 2
, if a voltage is applied to the respective electrodes, ions of the discharge gas accumulate on the dielectric layer
12
. A trigger discharge is generated between the address electrode
11
and the common electrode
15
by the accumulated ions, and charged particles are formed on bottom surface of the dielectric layer
18
of the front substrate
16
. At this time, according to image signals, a sustaining discharge is generated in the discharge space S by a predetermined voltage V applied between the scanning electrode
14
and the common electrode
15
. Then, the fluorescent material is excited by the plasma formed in the discharge gas to then emit light.
Referring to
FIG. 3
, the electrodes
14
and
15
are repeatedly formed with a constant cell pitch CP on the front substrate
16
. The cell pitch CP is a constant value as a design factor determined in consideration of resolution in a given screen size. Thus, in order to improve discharge efficiency or the brightness under a given cell pitch CP, the electrode width EW must be increased. However, since the cell pitch CP is constant, increasing the electrode width EW requires a reduction in the cell space CS. Current having pulses of opposite polarities is applied to the electrodes
14
and
15
by a circuit equivalent to one as shown in FIG.
4
. In this case, if the cell space CS is small, a crosstalk discharge as well as a normal discharge is generated between the electrodes
14
and
15
positioned in the adjacent cells as shown in FIG.
5
. Thus, since the reduction in the cell space CS cannot exceed a certain limit, the electrode width EW must be unavoidably reduced, which results in the reduction in the light emission area in the discharge cell to thereby decrease brightness. Also, the plasma display requires a high voltage for normal discharge. Further, since the concentration of electrical fields is lowered during discharge, which degrades the overall discharge efficiency.
SUMMARY OF THE INVENTION
To solve the above problem, it is an objective of the present invention to provide a plasma display device having a shielding electrode, by which crosstalk discharge between cells is shielded, and thus the cell space can be reduced.
Accordingly, to achieve the above objective, there is provided a plasma display device including a plurality of discharge cells each having substrates, and at least two electrodes formed on the substrates, for generating a discharge therebetween, and a shielding electrode formed between the electrodes respectively positioned in the neighboring cells, for shielding crosstalk generated between the electrodes of the neighboring cells.
The shielding electrode is electrically floated.
Also, alternatively, the substrates include front and rear substrates facing each other, the electrodes include a first electrode formed on the upper surface of the rear substrate in a predetermined pattern, and a second electrode formed on the bottom surface of the front substrate to be perpendicular to the first electrode, wherein the shielding electrode is formed between the second electrodes positioned in the neighboring cells, respectively.
REFERENCES:
patent: 4638218 (1987-01-01), Shinoda et al.
patent: 4737687 (1988-04-01), Shinoda et al.
patent: 6034482 (2000-03-01), Kanazawa et al.
Lowe Hauptman & Gilman & Berner LLP
Mengisteab Tewolde
Samsung Display Device Co., Ltd.
Saras Steven
LandOfFree
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