Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2002-12-30
2004-06-08
Patel, Vip (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S583000, C313S586000, C313S292000
Reexamination Certificate
active
06747409
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a plasma display panel (PDP), and, more particularly, to a PDP improved with rightness.
DESCRIPTION OF RELATED ARTS
Plasma display panel (hereinafter referred as to PDP) is a flat board display device using the effect of vacuum ultraviolet rays that excites red (R), green (G) and blue (B) fluorescent substances and subsequently generates visible rays. The vacuum ultraviolet rays are emitted from plasma generated during the discharge out as, such as Ne or Xe, filled in a space between the front plate and the rear plate.
PDP is divided into a direct current (DC) type and an alternating current (AC) type. In a DC-type PDP, an electrode used to supply voltage from outside to form plasma is exposed directly to the plasma and the conduction current flows directly through the electrode. It has an advantage that the structure is very simple, but has a disadvantage that it should equip external resistance to limit the current because the electrode is exposed in the discharge space.
In an AC-type PDP, an electrode is not exposed directly but covered with a dielectric substance, so displacement current flows. Since the electrode is covered with a dielectric substance, electric current can be limited naturally. Also, because the electrode can be protected from ion impact during the discharge, the AC-type PDP has a longer lifetime compared to the DC-type PDP.
The AC-type PDP can be classified into an opposite discharge type and a surface discharge type. The opposite discharge type has a problem that the life span is short due to degradation of fluorescent substances caused by the ion impact. In the surface discharge type, on the other hand, the discharge is collected in a panel opposite to the fluorescent substances in order to minimize the degradation of fluorescent substances and thus overcome the structural disadvantage of the opposite discharge type. Nowadays, most PDP devices adopt the surface discharge type.
Meanwhile, among various flat display devices, the PDP can easily realize a wider and thinner screen. Because of this advantage, the PDP in today has broad applications by being increasingly used for a real time display screen in stock trading markets, a display screen for a conference and a wall frame television with a wide screen.
FIG. 1
is a diagram showing a layout of a surface discharging AC type PDP using three electrodes. Particularly, the diagram in
FIG. 1
shows an array of the electrodes.
Referring to
FIG. 1
, the surface discharging AC type PDP includes a front substrate
11
and a rear substrate
11
A. An X electrode
12
and a Y electrode
13
are formed in a row direction. An address electrode
14
is formed in a direction where the X electrode
12
and the Y electrode
13
cross to each other.
Also, a cell
15
is constructed on a point where each of the electrodes is crossing. Especially, the X electrode
12
is a scan electrode used for scanning a screen. The Y electrode
13
is a sustain electrode used for sustaining a discharging state. The address electrode
14
is used for inputting data.
The address electrode
14
formed in each cell is supplied with an address voltage by being connected to an address driver. The X electrode
12
is connected to an x electrode driver and supplied with a scan voltage. The Y electrode
13
is supplied with a sustain voltage by being connected to a Y electrode driver.
The X and Y electrodes and the address electrode are constructed and a matrix form.
FIG. 2A
is a cross-sectional view of the surface discharging AC type PDP with the three electrodes in accordance with a preferred embodiment of a prior art.
Referring to
FIG. 2A
, the front panel includes a front electrode having a front substrate
21
, a pair of transparent electrodes being positioned with a predetermined distance from the front substrate
21
, a pair of bus electrodes being formed on top of each transparent electrode
22
, a transparent dielectric layer
23
limiting discharge current-by being formed on the front electrode, a protection layer
24
for protecting the transparent dielectric layer
23
being formed beneath the transparent dielectric layer
23
. The front electrode constitutes X and Y electrodes shown in FIG.
1
. For example, one transparent electrode
22
and the bus electrode
22
A constitute the X electrode while the other transparent electrode
22
and the bus electrode
22
A constitute the Y electrode.
A rear panel includes a rear substrate
21
A, an address electrode
25
formed on the rear substrate
21
A in a direction of acrossing the front electrode, a white dielectric layer
26
for protecting the address electrode
25
and simultaneously reflecting visible rays emitted from a discharging space
29
by being formed entirely on the rear substrate
21
A including the address electrode
25
, a barrier rib
27
for preventing the cross-talk phenomenon occurring between cells neighboring the address electrodes
25
being formed in a stripe shape and a fluorescent substance
28
emitting visible rays by being formed on the white dielectric layer
26
and at lateral sides of the barrier rib
27
.
The discharging space
29
where inert gas is added and sealed is formed in a space provided when the front panel and the rear panel are connected.
Referentially, rig.
2
A shows the front substrate
21
rotated in 90° for a conventional purpose. Discharge cells are isolated through the barrier rib
27
in a stripe shape.
The following will describe procedures until the discharge cells luminesce based on the above structure of the PDP.
Firstly, in connection with the discharge cell to be lighted, a predetermined voltage is supplied to a space between the Y electrode and the address electrode
25
so to induce discharge between the two electrodes. Due to this type of discharge, a positively ionized ion and an electron are stored into surfaces of the fluorescent substance
28
and the protection layer
24
as wall-charges.
In the discharge cell stored with the wall-charges, a voltage is supplied to the X electrode. Once the voltage is supplied, then, there occurs another discharge between the Y electrode and the X electrode.
Afterwards, the discharge occurs repeatedly due to the X and Y electrodes as they are supplied with an alternate electric field. This repeated discharge is called sustain discharge. Ultraviolet rays emitted by the sustain discharge are changed into visible rays as the ultraviolet rays excite the fluorescent substance
28
. The visible rays are then transmitted through the front substrate
21
and emitted to outside.
As described in the above, a conventional PDP has the barrier rib
27
for preventing erroneous discharge between left and right cells.
Generally, the barrier rib
27
has a stripe shape being placed in a parallel direction to the address electrode
25
. The conventional PDP, however, does not have a barrier rib for preventing charge movements between upper and lower calls. Therefore, a distance between the bus electrodes is set to be sufficiently large to prevent the charge movements between the upper and lower cells, thereby preventing reciprocally erroneous discharge between the cells.
The barrier rip having the strip shape is compelled to isolate each cell into two regions. That is, the two, regions are isolated into a section including a transparent electrode causing ultraviolet rays emitted due to the main discharge to react with a fluorescent substance so to emit visible rays and a black stripe region for preventing occurrences of the discharge further to prevent emission of visible rays. The region including the transparent electrode is responsible for realizing an image by emitting the visible rays.
A ratio of emitting visible rays per cell increases in proportion to an increase in an area of the discharge region in one cell. Therefore, the luminescence efficiency is also improved.
However, in the conventional PDP having the stripe shape and the barrier rib, if the area of the region for the discharge increases, there easily occurs erroneous discharge b
Han Seong-Hoon
Oh Dong-Ki
Song Bok-Sik
Hyundai Plaxma Co., Ltd.
Patel Vip
Sheridan Ross PC
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