Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2000-04-17
2003-12-09
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S062000, C345S063000, C345S065000, C345S066000, C345S067000, C345S204000, C345S214000, C345S690000, C313S484000, C313S514000, C315S169400, C315S167000
Reexamination Certificate
active
06661394
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plasma display panel (PDP) using a radio frequency discharge, and more particularly to a driving circuit for a radio frequency PDP that is capable of effectively matching an impedance between a radio frequency signal generator and the plasma display panel.
2. Description of the Related Art
Recently, a plasma display panel (PDP) feasible to the fabrication of large-scale panel has been available for a flat panel display device. The PDP includes discharge cells corresponding to color pixels of matrix type and controls a discharge interval of each discharge cell to display a picture. More specifically, after the PDP selected discharge cells to be displayed by an address discharge, it allows a discharge to be maintained in a desired discharge interval at the selected discharge cells. Thus, in the discharge cells, a vacuum ultraviolet ray generated during the sustaining discharge radiates a fluorescent material to emit a visible light. In this case, the PDP controls a discharge-sustaining interval, that is, a sustaining discharge frequency of the discharge cells to implement a gray scale required for an image display. As a result, the sustaining discharge frequency becomes an important factor for determining the brightness and a discharge efficiency of the PDP. For the purpose of performing such a sustaining discharge, a sustaining pulse having a frequency of 200 to 300 kHz and a width of about 10 to 20 &mgr;s has been used in the prior art. However, the sustaining discharge is generated only once at a extremely short instant per the sustaining pulse by responding to the sustaining pulse; while it is wasted for a step of forming a wall charge and a step of preparing the next sustaining discharge at the remaining major time. For this reason, the conventional three-electrode, face-discharge, and AC PDP has a problem in that, since a real discharge interval is very short in comparison to the entire discharge interval, the brightness and the discharge efficiency become low.
In order to solve such a problem of low brightness and low discharge efficiency, we has suggested a method of utilizing a radio frequency discharge employing a radio frequency signal of hundreds of MHz as a display discharge. In the case of the radio frequency discharge, electrons perform an oscillating motion by the radio frequency signal to sustain the display discharge in a time interval when the radio frequency signal is being applied. More specifically, when a radio frequency signal with a continuously alternating polarity is applied to any one of the two opposite electrodes, electrons within the discharge space are moved toward one electrode or the other electrode depending on the polarity of the voltage signal. If the polarity of a radio frequency voltage signal having been applied to the electrode before the electrons arrive at the electrode is changed when electrons are moved into any one electrode, then the electrons has a gradually decelerated movement speed in such a manner to allow their movement direction to be changed toward the opposite electrode. The polarity of the radio frequency voltage signal having been applied to the electrode before the electrons within the discharge space arrive at the electrode is changed as described, so that the electrons make an oscillating motion between the two electrodes. Accordingly, when the radio frequency voltage signal is being applied, the ionization, the excitation and the transition of gas particles are continuously generated without extinction of electrons. The display discharge is sustained during most discharge time, so that the brightness and the discharge efficiency of the PDP can be improved. Such a radio frequency discharge has the same physical characteristic as a positive column in a glow discharge structure.
FIG. 1
is a perspective view showing the structure of a discharge cell of the above-mentioned radio frequency PDP employing a radio frequency discharge. In
FIG. 1
, the discharge cell
26
includes radio frequency electrodes
12
provided on an upper substrate
10
, data electrodes
16
and scanning electrodes
20
provided on a lower substrate
14
in such a manner to be perpendicular to each other, and barrier ribs
22
provided between the upper substrate
10
and the lower substrate
14
. The radio frequency electrodes
12
apply a radio frequency signal. The data electrodes
18
apply a data pulse for selecting cells to be displayed. The scanning electrodes
20
are provided in opposition to the radio frequency electrodes
12
in such a manner to be used as opposite electrodes of the radio frequency electrodes
12
. Between the data electrodes
18
and the scanning electrodes
20
is provided a dielectric layer
18
for the charge accumulation and the isolation. The barrier ribs
22
shut off an optical interference between the cells. In this case, the barrier ribs
22
are formed into a lattice structure closed on every side for each discharge cell so as to isolate the discharge space. This is because it is difficult to isolate a plasma for each cell unlike the existent face-discharge due to the opposite discharge generated between the radio frequency electrodes
12
and the scanning electrodes
20
. Also, the barrier ribs
22
have a more enlarged height than the conventional barrier ribs for the sake of providing a smooth radio frequency discharge between the scanning electrodes
20
and the radio frequency electrodes
12
. A fluorescent material
24
is coated on the surface of the barrier rib
22
to emit a visible light with an inherent color by a vacuum ultraviolet ray generated during the radio frequency discharge. The discharge space defined by the upper substrate
10
, the lower substrate
14
and the barrier ribs
22
is filled with a discharge gas.
As shown in
FIG. 2
, the discharge cells
26
having the configuration as described above are positioned at each intersection among data electrode lines X
1
to Xm, scanning electrode lines Y
1
to Yn and radio frequency electrode lines RF. In
FIG. 2
, the data electrode lines X
1
to Xm consist of the data electrodes
16
of the discharge cells
26
. The scanning electrode lines Y
1
to Yn consist of the scanning electrodes
20
, and the radio frequency electrode lines RF consist of radio frequency electrodes
12
. A driving method of the discharge cell
26
of
FIG. 1
will be described below. A data pulse DP is applied to the address electrode
16
and a scanning pulse SP is applied to the scanning electrode
20
to generate an address discharge. By this address discharge, charged particles are produced at a discharge space. The charged particles make a radio frequency discharge with the aid of a radio frequency pulse RFS applied to the radio frequency electrode
12
and a center voltage Vc of a radio frequency voltage applied to the scanning electrode
20
constantly. In this case, an ultraviolet ray generated by the radio frequency discharge radiates a fluorescent material
24
to emit a visible light. When an erasure pulse is applied to the scanning electrode
20
, the charged particles becomes distinct to stop the radio frequency discharge.
In order to cause a radio frequency discharge from the radio frequency PDP including the discharge cells as described above, a radio frequency signal having a sufficient power must be applied to radio frequency electrode lines RF of the panel. A conventional PDP driving circuit including a radio frequency driving circuit for obtaining this purpose is shown in FIG.
3
.
Referring to
FIG. 3
, the conventional radio frequency PDP driving circuit includes an analog to digital (A/D) converter
30
for converting an input analog image signal into a digit signal, an image signal processor
32
for converting the digit signal from the A/D converter
30
into a bit signal to re-arrange the same for each bit, a data driver
34
for outputting a driving signal according to a data signal inputted from the image signal processor
32
to data electrode lines of a PDP
4
Fleshner & Kim LLP
Kovalick Vincent E.
LG Electronics Inc.
Shalwala Bipin
LandOfFree
Driving circuit for radio frequency plasma display panel does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Driving circuit for radio frequency plasma display panel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Driving circuit for radio frequency plasma display panel will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3124507