1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a method for driving a plasma display panel that can eliminate moving picture noise in a 50 Hz driving method.
2. Description of the Related Art
Recently, a plasma display panel (PDP), which is one of flat panel displays, is in the limelight because it is expected to be easily capable of realizing a large-sized panel. The PDP displays an image by controlling a discharge period of each pixel according to digital data. The discharge period may be determined by the number of sustain pulses having subfield weight.
An alternate type PDP is a representative of such PDPs, and is provided with three electrodes and driven by an alternative voltage. The alternate type PDP is driven by an address-display separated (ADS) driving method so as to display an image. The ADS driving method can express a desired gray scale according to sequence of subfields, sub-field weight, and the number of sustain pulses.
However, the ADS driving method may cause problems due to motion artifacts, large area flicker, and variation in the number of gray scales. The motion artifacts are caused by dynamic false contour and motion blurring. The dynamic false contour is due to a non-linear method temporarily used for displaying gray scale, and the motion blurring is due to light emitting from each pixel during a time longer than an overall frame time.
FIG. 1 shows graphs illustrating a related art PDP driving method. In FIG. 1, a frame driven at a frequency of a 50 Hz is shown. A 50 Hz driving method is generally used in Europe and a 60 Hz driving method is used in Republic of Korea, USA, etc.
As shown in FIG. 1, the related art PDP driving method includes dividing a 20 ms frame driven at 50 Hz into two 10 ms frames driven at 100 Hz, and rearranging subfields included in each frame. For example, the 20 ms frame includes eight different subfields. A first frame of 10 ms consists of first, third, fifth and seventh subfields, and a second frame of 10 ms consists of second, fourth, sixth and eighth subfields. Thus, when the 20 ms frame driven at 50 Hz is modulated into two 10 ms frames driven at 100 Hz, large area flicker that is a large area screen flicker phenomenon occurring in the 50 Hz driving method can be prevented, and subfield weights accumulated on a retina by adjacent main frames in the 100 Hz driving are effectively dispersed thereby offsetting the dynamic false contour.
However, since the driving method shown in FIG. 1 allows an XGA single scan PDP panel and a HD PDP panel to have a limitation in the number of subfields, it is difficult to apply the 100 Hz driving method to the XGA single scan PDP panel and the HD PDP panel. Also, the lack of the number of the subfields causes a serious quantization in a low gray scale region Further, since one frame is divided into two frames, double false contour may be caused.
FIG. 2 is a schematic view exemplarily showing a related art PDP driving method.
As shown in FIG. 2, the related art PDP driving method divides one 50 Hz frame into two 50 Hz frames. In other words, the driving method of FIG. 1 divides one 50 Hz frame into two 100 Hz frames, whereas the driving method of FIG. 2 divides one 50 Hz frame into two 50 Hz frames. Accordingly, in the driving method of FIG. 2, though one frame is divided into two frames, the driving method is maintained in 50 Hz driving without any change. In other words, one 50 Hz frame is divided into two 100 Hz frames, but since data can be displayed only during half of each frame, the 50 Hz frame is resultantly divided into two 50 Hz frames.
Thus, when the 50 Hz frame is divided into two 50 Hz frames, the lowest brightness weight of the first frame (10 ms) is different than the lowest brightness weight of the second frame (10 ms), and the remaining brightness weights of the first frame are the same as those of the second frame. Also, the first and second frames are arranged having symmetric brightness weights. Accordingly, large area flicker occurring in the 50 Hz driving can be minimized.
However, since the related art PDP driving method of FIG. 2 divides one frame into two frames, double false contour may be caused. In other words, the division of the first and second frames functions to change 50 Hz into 50 Hz, but since real data is identically repeated in two frames to reproduce a moving picture, so that double false contour occurs, thereby lowering video resolution.