Plasma display device
View Patent ↗Initialization waveforms with different voltages are applied respectively to a predetermined subfield with a small number of sustain pulses, and a subfield with the smallest number of sustain pulses in subfields other than the predetermined subfield. This offers a plasma display device that achieves a correct write operation in all discharge cells even if discharge interference occurs between adjacent cells, and also achieves a high contrast.
1. A plasma display device comprising:
a plasma display panel in which a discharge cell is formed at an intersection of a scan electrode and a sustain electrode disposed in parallel and a data electrode disposed orthogonal to the scan electrode and the sustain electrode; and
a scan drive circuit for applying a voltage waveform to the scan electrode;
wherein
one field comprises a plurality of subfields including at least a luminescence sustain period and a write period,
the one field includes at least one set of successive two subfields including a predetermined subfield and a preceding subfield followed by the predetermined subfield,
the predetermined subfield has a smaller number of sustain pulses than that of the preceding subfield,
a number of sustain pulses applied to the discharge cell of each subfield from a beginning subfield to the preceding subfield followed by the predetermined subfield of the one field is gradually larger than a number of sustain pulses of a preceding subfield,
a number of sustain pulses applied to the discharge cell of each subfield from the predetermined subfield to the last subfield of the one field following the predetermined subfield of the one field is gradually larger than a number of sustain pulses of a preceding subfield,
the scan drive circuit applies, in the one field, only a first initialization waveform in an initialization period of the subfield having the smallest number of sustain pulses and only a second initialization waveform in an initialization period of the predetermined subfield, and
a peak voltage of the first initialization waveform applied to the subfield having the smallest number of sustain pulses is higher than a peak voltage of the second initialization waveform applied to the predetermined subfield.
2. The plasma display device of claim 1 , wherein each of a voltage of the first initialization waveform and a voltage of the second initialization waveform is determined by an average luminance level of input picture signal.
3. The plasma display device of claim 2 , further comprising an initialization voltage determination unit for determining the voltage of the first initialization waveform and the voltage of the second initialization waveform based on the average luminance level of input picture signal.
4. The plasma display device of claim 1 , wherein the subfield having the smallest number of sustain pulses, excluding the predetermined subfield, is a first subfield in the one field.
5. The plasma display device of claim 1 , wherein a voltage of the first initialization waveform increases gradually toward the peak voltage of the first initialization waveform, and a voltage of the second initialization waveform increases gradually toward the peak voltage of the second initialization waveform.
6. The plasma display device of claim 1 ,
wherein a voltage of the first initialization waveform increases in a positive direction toward the peak voltage of the first initialization waveform, and a voltage of the second initialization waveform increases in a positive direction toward the peak voltage of the second initialization waveform, and
wherein the voltage of the first initialization waveform includes a positive voltage being retained for all sustain electrodes, and a lamp voltage, which gradually decreases toward a voltage above a discharge start voltage with respect to all sustain electrodes, being applied to all scan electrodes.