Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
1999-11-19
2001-01-09
Vu, David (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C345S055000, C345S076000
Reexamination Certificate
active
06172465
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for driving a plasma display, and more particularly to a method for reducing dynamic false contour of the plasma display.
BACKGROUND OF THE INVENTION
Recently, due to the fast development in electro-optic techniques, the related studies and techniques of the plasma display panel (to be abbreviated as PDP here below) have grown rapidly and compatible with multimedia applications. The advantages of PDP, in contrast to liquid crystal displays now in use, include better moving picture quality and image display characteristics. In addition, the thickness of a PDP is much thinner than that of a conventional cathode ray tube (CRT) television set. The PDP thus catches the eyes of scientists and researchers and have become a popular field of research. We believe that PDP will soon become popular for home use replacing the traditional CRT displays.
In general, one field for displaying one frame is divided to a plurality of sub-fields, and a PDP represents gray scale with sub-fields. That is, different light emission time of discharging in each sub-field is used to display different bright brightness of a pixel. Please refer to
FIG. 1
showing the sequence of sub-fields used in the prior art. Typically, one field includes eight sub-fields ranging from SF
0
to SF
7
, and the brightness levels of brightness are divided to 2
8
, that is, 256 grades. Each sub-field signal comprises an address period, a sustain period, and a reset period. The sustain periods of these sub-fields SF
0
, SF
1
, SF
2
, SF
3
, SF
4
, SF
5
, SF
6
, and SF
7
, are at a ratio of 1:2:4:8:16:32:64:128. The 256 intensity levels are achieved by selectively combining the sub-fields to turn the PDP on.
Nevertheless, the abrupt change of image brightness appears when the brightness level of the image is changed. For instance, a signal having a brightness level
128
is on the left of the emitting pattern and a signal having a brightness level
127
is on the right of the emitting picture. When an image is moved from left direction to right direction, the abrupt change of image brightness will appear and further lead to a dynamic false contour in a certain part of the image. Therefore, it is inconvenient and inefficient for applications and has a lot to be improved.
SUMMARY OF THE INVENTION
In order to overcome the problem discussed above, a method for driving plasma display panel to avoid the abrupt change of image brightness and the distortion of dynamic image contour.
Accordingly, an object of the present invention is to provide a method for improving the moving picture quality.
Another object of the present invention is to provide a method for eliminating the dynamic false contour of a PDP.
Moreover, it is still another object of the present invention to provide a driving method for avoiding the abrupt change of image brightness.
Furthermore, it is still another object of the present invention to provide a circuit of a PDP for avoiding the abrupt change of image brightness and reducing the distortion of dynamic image contour.
To accomplish the foregoing objects, the present invention provides a method for driving a plasma display panel (PDP) in which the sub-field signals of the odd-numbered scanning lines are first applied and the sub-field signals of the even-numbered scanning lines are later applied. The plasma display panel has a first substrate and a second substrate facing each other. At least two scanning lines are formed on the first substrate and sequentially numbered as either one of an odd-numbered scanning line and an even-numbered scanning line, each of the scanning lines has a first electrode and a second electrode disposed in parallel with each other. A plurality third electrodes are disposed on the second substrate and extending orthogonally to the first and second electrode for defining a cell among each first, second, and third electrode. The first electrode and second electrode of the odd-numbered scanning line is defined as an odd-numbered first electrode and an odd-numbered second electrode, and first electrode and second electrode of the even-numbered scanning line is defined as an even-numbered first electrode and an even-numbered second electrode. A light emission is executed by carrying out a addressing discharge utilizing a memory function for cells of these scanning lines and by carrying out a sustain discharge for sustaining the addressing discharge.
According to the present invention, the driving method includes steps of (a) executing a reset discharge for all cells of the odd-numbered scanning line by applying reset signals on the odd-numbered first electrode and the odd-numbered second electrode, (b) executing the addressing discharge for all cells of the odd-numbered scanning line selected by either one of the odd-numbered first electrode and the odd-numbered second electrode to receive addressing signals from the third electrode, and (c) executing the sustaining discharge for all cells of the odd-numbered scanning line by alternatively applying driving signals on either one of the odd-numbered first electrode and the odd-numbered second electrode. The method further includes steps of (d) executing a reset discharge for all cells of the even-numbered scanning line by applying reset signals on the even-numbered first electrode and the even-numbered second electrode, (e) executing said addressing discharge for all cells of the even-numbered scanning line selected by either one of the even-numbered first electrode and the even-numbered second electrode to receive addressing signals from the third electrode, and (f) executing said sustaining discharge for all cells of the even-numbered scanning line by alternatively applying driving signals on either one of the even-numbered first electrode and the even-numbered second electrode.
In the meantime, the present invention further provides a signal circuit including a timing controller used to determine the clock pulses for the driving signals of the sub-fields, a scanning driver of scanning lines connected to the timing controller for generating the scanning line signals, and a scanning driver for sustaining scanning lines that is connected to the timing controller and used to sustain the scanning line signals. The signal circuit further includes a data driver connected to the timing controller for driving the data of the image signals.
REFERENCES:
patent: 5998414 (1999-04-01), Awamoto et al.
Acer Display Technology Inc.
Sun Raymond
Vu David
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