Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2000-05-17
2003-02-18
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S583000, C313S584000, C313S585000, C313S586000
Reexamination Certificate
active
06522071
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma display panel in which a discharge of gas between glass substrates are utilized for displaying an image, and more particularly, to a discharge electrode in a plasma display panel.
2. Background of the Related Art
Having all the advantages of the clear picture and the variety of screen sizes of the cathode ray tubes, and of the light and thin liquid display panel, the plasma display panel is considered as the next generation display. In general, the plasma display panel is light as it weighs approx. ⅓ of the cathode ray tube of the same screen size, and thin as it has a thickness below 10 cm even for a large sized panel of 40 to 60″. Moreover, though the cathode ray tube or the liquid crystal display has a limitation on a size in displaying a digital data picture and a full motion picture on the same time, the plasma display panel has no such a problem. And, while the cathode ray tube is influenced from a magnetic force, the plasma display panel is not influenced from the magnetic force, permitting to provide a stable picture to the watchers. And, since the pixels are controlled in a digital fashion, with no distortion of images at corners of the screen, the plasma display panel can provide a picture quality better than the cathode ray tube. The plasma display panels, using a gaseous discharge inside of the panel in displaying an image, are used as TV receivers, monitors, indoor and outdoor signboards and the like having large sized displays, particularly, directing to displays of the HDTV(High Definition Television) age, since the plasma display panel has a simple fabrication process as provision of active element to every cell is not required, is easy to provide a large sized screen, and has a fast response speed. The plasma display panel is provided with two glass substrates sealed together having electrodes coated thereon perpendicular, and opposite to each other, and gas filled in a space between the two glass substrates. There are pixels at portions the electrodes are crossed. In operation, a voltage higher than 100 volts are provided between the perpendicular electrodes, to cause a glow discharge of the gas, for displaying an image by using a light provided in the discharge. There are a two electrode type, a triode type, and a four electrode type in the plasma display panels with respect to a number of electrodes each cell has, wherein the two electrode type has two electrodes to which addressing and sustain voltages are provided on the same time, and the triode type, called as a surface discharge type, is adapted to be switched or sustained by a voltage provided to a electrode at a side of a discharge cell.
A related art triode surface discharge type plasma display panel will be explained with reference to the attached drawings.
FIG. 1
illustrates a perspective view of a disassembled upper and lower substrates of the related art plasma display panel,
FIG. 2
illustrates a section of a related art plasma display panel,
FIG. 3
illustrates a plan view of scan electrodes and sustain electrodes of a related art plasma display panel,
FIG. 4
illustrates a section across line I-I′ in
FIG. 3
,
FIG. 5
illustrates wiring of scan electrodes and sustain electrodes of a related art plasma display panel, FIGS.
6
A~
6
D illustrate a discharge principle of a related art plasma display panel, and
FIG. 7
illustrates an electric field formed between a pair of discharge electrodes and spreading of a discharge.
Referring to
FIG. 1 and 2
, the related art triode surface discharge type plasma display panel has an upper substrate
10
and a lower substrate
20
bonded and sealed together to face each other. On the upper substrate
10
, there are scan electrodes
16
and
16
′ and sustain electrodes
17
and
17
′ parallel to each other, a dielectric layer
11
coated on the scan electrodes
16
and
16
′ and the sustain electrodes
17
and
17
′, and a protection film
12
. On the lower substrate
20
, there are address electrodes
22
, a dielectric film
21
on an entire surface of the substrate including the address electrodes
22
, partition walls
23
on the dielectric film
21
between the address electrodes
22
, and a fluorescent material
24
on surfaces of the partition wall
23
and the dielectric film
21
in each discharge cell. The upper substrate
10
and the lower substrate
20
are bonded together by frit glass, and a space between the upper and lower substrates
10
and
20
is filled with a mixture of inert gas, such as helium He and xenon Xe, to a pressure in a range of 400~500 Torr, to form a discharge space. In general, the inert gas filled in the discharge space of a D.C. plasma display panel is a mixture of helium and xenon (He—Xe), and the inert gas filled in the discharge space of an A.C. plasma display panel is a mixture of neon and xenon (Ne—Xe).
Referring to
FIGS. 3 and 4
, of the scan electrodes
16
and
16
′ and the sustain electrodes
17
and
17
′, the electrodes
16
and
17
are formed of transparent material, and the electrodes
16
′ and
17
′ are formed of a metal for enhancing light transmission of each discharge cell. The metal scan electrode and sustain electrode
16
′ and
17
′ are provided with a discharge voltage from a driving IC fitted outside of the panel, and the transparent scan electrode and sustain electrode
16
and
17
are provided with the discharge voltage to the metal electrodes
16
′ and
17
′, to cause a discharge between adjacent transparent electrodes
16
and
17
. The transparent electrode
16
or
17
is formed of indium oxide or tin oxide of a total width of approx. 300 &mgr;m, and the metal electrode
16
′ or
17
′ is a thin film consisting of three layers of chrome-copper-chrome. A width of the bus electrode
16
′ or
17
′ line has approx. ⅓ of a width of the transparent electrode
16
or
17
line.
FIG. 5
illustrates wiring of the scan electrodes Sm−1, Sm, Sm+1, - - - , Sn−1, Sn, Sn+1 and the sustain electrodes Cm−1, Cm, Cm+1, - - - , Cn−1, Cn, Cn+1 arranged on the upper substrate, wherein, while the scan electrodes are insulated from each other, all the sustain electrodes are connected in parallel. In
FIG. 5
, the section enclosed by the dashed line represents an effective surface an image is displayed thereon, and the other section represents a non-effective surface no image is displayed thereon. The scan electrodes on the non-effective surface are in general called dummy electrodes
26
, a number of which are not particularly limited.
The operation of the aforementioned triode surface discharge type AC type plasma display panel will be explained with reference to FIGS.
6
A~
6
D.
Referring to
FIG. 6A
, when a driving voltage is applied between the address electrode and the scan electrode, an opposed discharge is occurred between the address electrode and the scan electrode. The opposed discharge excites the inert gas in the discharge cell, so that a portion of the inert gas is divided to electrons, ions and excited species. As shown in
FIG. 6B
, a portion of the ions collides onto a surface of the protection film, which causes emission of secondary electrons from the surface of the protection film. The secondary electrons collide with the gas in a plasma state, to spread the discharge. As shown in
FIG. 6C
, when the opposed discharge between the address electrode and the scan electrode ends, wall charges with opposite polarities are generated on surfaces of the protection film over the sustain electrode and the scan electrode, respectively. And, as shown in
FIG. 6D
, when the driving voltage provided to the address electrode is cut off during the wall charges with opposite polarities build up at the scan electrode and the sustain electrode continuously, there is a surface discharge occurred in a discharge region on a surface of the dielectric laye
Jung Kyung Hun
Park Hun Gun
Fleshner & Kim LLP
LG Electronics Inc.
Patel Nimeshkumar D.
Roy Sikha
LandOfFree
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