Method for driving a plasma display panel
The present method is to drive a plasma display panel which displays a frame composed of a plurality of sub-fields having different weights of luminance. The method comprises using plural kinds of application voltage waveforms different in light emission luminance, as pulse voltages for sustain discharges in display of each sub-field, and adjusting the number of waves in each of the plural kinds of application voltage waveforms according to the weight of luminance set for each sub-field, thereby performing gradation display.
1. A method for driving a plasma display panel displaying a frame composed of a plurality of subfields, comprising:
applying first and second sustain pulses having at least two kinds of waveforms different in luminance, the second sustain pulse having a higher luminance than the first sustain pulse, and the first and second sustain pulses being applied according to a weight of luminance to be given to the sub-fields at a predetermined constituent ratio in a sustain period of at least one sub-field; and
adjusting the constituent ratio of the first and second sustain pulses according to a maximum luminance of the frame to be displayed wherein, if the maximum luminance of the frame to be displayed is lower than a luminance of a maximum gradation corresponding to the number of sub-fields, a constituent ratio of the first sustain pulse is increased such that the luminance of the maximum gradation decreases.
2. The method of claim 1 , wherein the first sustain pulse has a rectangular waveform and the second sustain pulse has a waveform in which a voltage changes in two or three stages.
3. The method of claim 1 , wherein the first sustain pulse has a rectangular waveform and the second sustain pulse has a waveform with a larger amplitude than the rectangular waveform of the first sustain pulse only at a rising part of the second sustain pulse.
4. The method of claim 1 , wherein, when a frame having low maximum luminance is displayed, the sustain period consists of a waveform having relatively low luminance among plural kinds of sustain pulses and, when a frame having high maximum luminance with respect to other frames is displayed, a constituent ratio of sustain pulses having relatively high luminance with respect to other sustain pulses is increased such that a luminance of a maximum gradation increases.
5. The method of claim 1 , wherein a total number of the first and second sustain pulses included in the frame to be displayed is decreased according to an increase of a display rate of a screen of the plasma display panel in addition to the adjustment of the constituent ratio of the first and second sustain pulses in the sustain period of at least one of the plurality of sub-fields.