Driving apparatus of display panel
View Patent ↗An apparatus for driving a display panel can execute quality image display. To allow discharge cells operating as pixels of the display panel to repeatedly perform sustain discharge, a fall period of a last sustain pulse of sustain pulses repeatedly applied to row electrodes includes a first voltage drop period in which a voltage value gently drops, a voltage constant period which follows the first voltage drop period and in which the voltage value remains constant for a predetermined period, and a second voltage drop period which follows the voltage constant period and in which the voltage value drops more gently than in the first voltage drop period.
1. An apparatus for driving a display panel for each of a plurality of sub-fields constituting each field of an input image signal, said display panel including a plurality of row electrodes corresponding to display lines, a plurality of column electrodes so arranged as to intersect said row electrodes, respectively, and capacitive discharge cells each formed at a point of intersection between said row electrode and said column electrode and operating as a pixel, comprising:
reset means for repeatedly applying a predetermined number of times a reset pulse to all of said row electrodes at the start of at least one of said sub-fields thereby allowing all of said discharge cells to repeatedly reset discharge so as to initialize the condition of said discharge cells;
address means for applying a scan pulse to said row electrode in each of said sub-fields and a pixel data pulse corresponding to said input image signal to said column electrode, thereby allowing each of said discharge cells to selectively discharge so as to set said discharge cell to either a light-on mode or a light-off mode; and
light emission sustain means for repeatedly applying a sustain pulse to said row electrode in each of said sub-fields thereby allowing only said discharge cell in said light-on mode to repeatedly sustain discharge;
wherein:
only the last sustain pulse of the sustain pulses applied to said row electrode in each sub-field has a fall period constituted by a first sustain voltage drop period in which the voltage value gently lowers, a sustain voltage constant period which follows said first sustain voltage drop period and in which the voltage value remains constant for a predetermined period, and a second sustain voltage drop period which follows said sustain voltage constant period and in which the voltage lowers more gently than in said first sustain voltage drop period; and
a reset-pulse fall period in which a voltage value of the last reset pulses repeatedly applied to said row electrode in said sub-field is decreasing includes a first reset voltage drop period in which the voltage value gently lowers, a reset voltage constant period in which the voltage value remains constant for a predetermined period, and a second reset voltage drop period in which the voltage lowers more gently than in said first reset voltage drop period.
2. An apparatus according to claim 1 , wherein said light emission sustain means sets said row electrode to a high impedance state during said predetermined period so as to keep the voltage value of said last sustain pulse constant during said voltage constant period.
3. An apparatus for driving a display panel for each of a plurality of sub-fields constituting each field of an input image signal, said display panel including a plurality of row electrodes corresponding to display lines, a plurality of column electrodes so arranged as to intersect said row electrodes, respectively, and capacitive discharge cells each formed at a point of intersection between said row electrode and said column electrode and operating as a pixel, comprising:
address means for applying a scan pulse to said row electrode in each of said sub-fields and a pixel data pulse corresponding to said input image signal to said column electrode, thereby allowing each of said discharge cells to selectively discharge so as to set said discharge cell to either a light-on mode or a light-off mode; and
light emission sustain means for repeatedly applying a sustain pulse to said row electrode in each of said sub-fields thereby allowing only said discharge cell in said light-on mode to repeatedly sustain discharge, said sustain pulse having a rise period in which the voltage rises to a first voltage from a second voltage and a fall period in which the voltage drops to said second voltage from said first voltage, wherein:
only the last sustain pulse of the sustain pulses applied to said row electrode in the sub-field has said fall period, said fall period having a first voltage drop period in which the voltage drops to a third voltage from said first voltage, a voltage-constant period which follows said first voltage drop period and in which the voltage remains at said third voltage, and a second voltage drop period which follows said voltage-constant period and in which the voltage drops to said second voltage from said third voltage, and the voltage on said row electrode is held at said second voltage after said second voltage drop period.
4. An apparatus according to claim 3 , wherein a discharge for erasing a part of the wall charge formed inside the discharge cell occurs in said fall period of said last sustain pulse.
5. An apparatus according to claim 4 , wherein said third voltage is equal to or less than a half of the difference between said first voltage and said second voltage.
6. An apparatus according to claim 4 , wherein the difference between said third voltage and said second voltage is equal to or less than the difference between said first voltage and said third voltage.