Patent ID: 7623125

Claim:
A display drive device which drives a display panel comprising a plurality of display pixels based on display data composed of digital signals, said display drive device comprising: a gradation voltage setting circuit which performs voltage division of a highest reference voltage and a lowest reference voltage that are supplied, and produces a plurality of gradation voltages corresponding to each luminosity gradation of the display data; a gradation conversion circuit which produces a display signal voltage of a different voltage level for each luminosity gradation of the display data based on the plurality of gradation voltages produced by the gradation voltage setting circuit, wherein two different voltage levels of the display signal voltage are produced for the luminosity gradations in a predetermined period; and a display signal voltage output circuit which applies the display signal voltage produced by the gradation conversion circuit to the display pixels; wherein a center voltage of the two voltage levels of the display signal voltage at a highest luminosity gradation of the luminosity gradations of the display data is set to a potential higher than the center voltage at a lowest luminosity gradation of the luminosity gradations by only an amount corresponding to a correction voltage that is set based on characteristics of the display pixels; wherein a difference of voltage level for the center voltage between a first highest gradation voltage and a second highest gradation voltage which correspond to the two voltage levels of the display signal voltages at the highest luminosity gradation, and a difference of voltage level for the center voltage between a first lowest gradation voltage and a second lowest gradation voltage which correspond to the two voltage levels of the display signal voltages at the lowest luminosity gradation are set to an equivalent value; wherein a first voltage range comprised of the difference between the first highest gradation voltage and the first lowest gradation voltage, and a second voltage range comprised of the difference between the second highest gradation voltage and the second lowest gradation voltage are changed by only an amount corresponding to a change of the highest reference voltage or the lowest reference voltage, when at least one of the highest reference voltage or the lowest reference voltage is changed; and wherein a change characteristic value of the center voltage is maintained constant for each luminosity gradation of the display data.