A data conversion unit comprising: a transformation portion configured to transform R (red), G (green) and B (blue) sub-pixel data signals of input image data into R, G, B and W (white) sub-pixel data signals; a brightness reinforcement portion configured to reinforce brightness of the transformed W sub-pixel data signal based on a distribution of color pixel data signals of the input image data in accordance with brightness; and a RGB reinforcement portion configured to selectively perform saturation reinforcement for the transformed RGB sub-pixel data signals according to a color attribute pattern of each color pixel data signal of the input image data, wherein the RGB reinforcement portion includes: a color attribute pattern analyzer configured to analyze the color attribute pattern for each of color pixel data signals using spatially adjacent color pixel data signals of the input image data to determine whether said each of color pixel data signal corresponds to chromatic or achromatic color; a saturation gain generator (143, 144) configured to selectively generate different saturation gain values according to the analyzed resultant of the color attribute pattern analyzer; and a RGB adjuster configured to adjust the RGB sub-pixel data signals using the selectively generated saturation gain value. a transformation portion configured to transform R (red), G (green) and B (blue) sub-pixel data signals of input image data into R, G, B and W (white) sub-pixel data signals; a brightness reinforcement portion configured to reinforce brightness of the transformed W sub-pixel data signal based on a distribution of color pixel data signals of the input image data in accordance with brightness; and a RGB reinforcement portion configured to selectively perform saturation reinforcement for the transformed RGB sub-pixel data signals according to a color attribute pattern of each color pixel data signal of the input image data, wherein the RGB reinforcement portion includes: a color attribute pattern analyzer configured to analyze the color attribute pattern for each of color pixel data signals using spatially adjacent color pixel data signals of the input image data to determine whether said each of color pixel data signal corresponds to chromatic or achromatic color; a saturation gain generator (143, 144) configured to selectively generate different saturation gain values according to the analyzed resultant of the color attribute pattern analyzer; and a RGB adjuster configured to adjust the RGB sub-pixel data signals using the selectively generated saturation gain value. a color attribute pattern analyzer configured to analyze the color attribute pattern for each of color pixel data signals using spatially adjacent color pixel data signals of the input image data to determine whether said each of color pixel data signal corresponds to chromatic or achromatic color; a saturation gain generator (143, 144) configured to selectively generate different saturation gain values according to the analyzed resultant of the color attribute pattern analyzer; and a RGB adjuster configured to adjust the RGB sub-pixel data signals using the selectively generated saturation gain value.