Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1999-11-19
2001-11-27
Hjerpe, Richard (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S060000, C345S061000, C345S067000, C315S169100, C315S169400
Reexamination Certificate
active
06323830
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a driving method for reducing the dynamic image false contour effect of the plasma display panel. In the present invention, there are several sub-fields included in a frame, and each sub-field comprises: a reset period, a addressing period and a sustaining period. The sustaining period of each sub-field can be further divided into: (1) a first sustaining period, (2) a first erasing period, (3) a second erasing period and (4) a second sustaining period. The first erasing signal is applied onto the sustaining electrode and the scanning electrode of the first display line during the first erasing period, and the second erasing signal is applied onto the sustaining electrode and the scanning electrode of the second display line during the second erasing period. Two separated erasing signals sequentially applied onto two neighboring display lines can reduce the chance to erase extra cells which should be sustained in the second sustaining period.
BACKGROUND OF THE INVENTION
Recently, due to the fast development in electro-optic techniques, the related studies and techniques of plasma display panels (to be abbreviated as PDP here below) have been developed rapidly and suitable for 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 as a home entertainment equipment to replace the traditional display devices.
In general, a high resolution of color PDP with 1028×1024 pixels (SXGA) requires profound techniques of manufacturing process in order to fabricate the fine-pitched barrier ribs and to produce the luminescent materials (such as phosphor) that are essential for PDP fabrication. Furthermore, a high speed driving method is required to activate the pulses and drive the high resolution picture. However, the dynamic false contour of the image appears when the conventional driving method is used in dynamic image display. In other words, when the dynamic image is moving, the abrupt changes of image brightness and the distortion of the image contour take place in some regions of the display, due to the fixed sequence of the sub-field signals in the prior art.
In the prior art, the accumulated brightness level is determined by a plurality of sub-fields which have the sustaining periods of different time duration. However, when the video image is displayed on the PDP driven by the conventional manner with fixed order of time ratio sequence, the abrupt changes of image brightness level will cause the distortion and error as so called “dynamic image false contour” effect.
In order to reduce the “dynamic image false contour” effect, one prior art is shown on the FIG.
1
A and FIG.
1
B. The
FIG. 1A
is a schematic diagram illustrating the conventional example of display cells in the prior art.
FIG. 1B
is a timing diagram illustrating the timing of signal sequences related to the display cells in FIG.
1
A. In
FIG. 1A
, X's and Y's denote the cell display signals in the display matrix and also play the roles of display electrodes. X's and Y's can both be grouped into odd electrodes and even electrodes.
FIG. 1B
is a timing diagram illustrating the timing of signal sequences in accordance with the X's and Y's electrodes in
FIG. 1A
, wherein, sequence X includes a rest period, an addressing period, a sustaining period which comprises an erasing period; similarly, sequence Y also includes a reset period, an addressing period, a sustaining period which also comprises an erasing period. Afterwards, sequence Y succeeds with a sustaining period in which sequence Y differs and is complementary with sequence X. In this conventional method, however, signals X's can be even or odd, but they are all erased simultaneously during one erasing period in sequence X. This erasing method will lead to the heavy loss of wall charge accumulated in the Y cells during the single erasing period, then the Y cells can not be maintained in light emission status during the second sustaining period.
BRIEF DESCRIPTION OF THE INVENTION
In order to overcome the problems that have been previously discussed above, the present invention has been proposed and relates to a driving method for reducing the dynamic image false contour for display panels, and more particularly, to a driving method that is useful in the display technique of plasma display panels and can prevent the abrupt changes of image brightness and the distortion of dynamic image false contour and effectively improve the moving picture quality.
Accordingly, it is the main object of the present invention to provide a driving method for reducing the dynamic image false contour for display panels that can prevent the abrupt changes of image brightness and the distortion of dynamic image false contour and effectively improve the moving picture quality.
In addition, it is another object of the present invention to provide a signal process circuit device of the driving method for reducing the dynamic image false contour for display panels that can prevent the abrupt changes of image brightness and the distortion of dynamic image false contour and effectively improve the moving picture quality.
To accomplish the foregoing objects, the present invention provides a driving method in which the erasing period of the sustaining period of the image sequence is separated into an odd erasing period and an even erasing period in order to completely execute the operation during the erasing period. In other words, the driving signal of the dynamic image display utilizes the dual erasing period method to completely execute the erase operation, prevent the dynamic image distortion and achieve better moving picture quality.
It is preferable that the odd erasing period or the even erasing period of the dual erasing period can be realized by using a scanning electrode Y and a data electrode D to compose a pair of erasing signals.
It is preferable that the odd erasing period of the sustaining period comprises a first erasing signal which is realized by using an odd scanning electrode Y
odd
and an odd data electrode D
odd
to compose a pair of erasing signals; the even erase period comprises a second erasing signal which is realized by using an even display electrode Y
even
and an even data electrode D
even
to compose a pair of erasing signals. In such a manner, the erasing period and the even erasing period can be realized to complete the erasing image signal to effectively reduce the dynamic image contour of the display panels during the sustaining period.
It is preferable that the first erasing signal which is realized by using an odd scanning electrode Y
odd
and an even data electrode D
even
to compose a pair of erasing signals and the second erasing signal which is realized by using an even scanning electrode Y
even
and an odd data electrode D
odd
to compose a pair of erasing signals can be used to reduce the dynamic image false contour of the display panels.
In the meantime, the present invention further provides a signal process circuit device of the driving method which comprises a plurality of scanning IC's including a plurality of connected transistor switches used to generate a plurality of scanning electrode signals Y's; wherein the output of the plurality of scanning IC's is connected in parallel with an inverter circuit composed of a plurality of transistors.
It is preferable that the plurality of transistors switches connected by the plurality of scanning IC's can be categorized into IC's for scanning odd drivers and IC's for scanning even drivers.
It is preferable that the signal process circuit device of the driving method further comprises a plurality
Acer Display Technology Inc.
Hjerpe Richard
Nguyen Kevin M.
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