Patent ID: 7705810

Claim:
An organic electro-luminescent display (OELD) device for processing multi-color gray-scale data, comprising: a four-color converting part to generate gamma-converted RGB data by performing gamma conversion with respect to primary RGB gray-scale data by multiplying each component of the primary RGB gray-scale data by a value of an inverse of a corresponding maximum gray-scale level, to extract a white color component from the gamma-converted RGB data, to generate four-color RGBW data by subtracting the white color component from the gamma-converted RGB data and by adding white gray-scale data to the gamma-converted RGB data, and to perform reverse gamma conversion on the four-color RGBW data to generate compensated RGBW gray-scale data; a data driving part to process the compensated RGBW gray-scale data provided from the four-color converting part to generate four-color signals in an analog type; a scan driving part to generate scan signals in sequence; and an OELD panel to emit light with a color in response to the four-color signals from the data driving part and the scan signals from the scan driving part, wherein a white extracting part is configured to determine which color data of the gamma-converted RGB data has a minimum value and to compare the minimum value with a predetermined value relative to the maximum gray scale level and corresponding to a half luminance of the maximum gray scale level, the white extracting part generates the minimum value of the gamma-converted RGB data as the white color component if the minimum value is smaller than the predetermined value, and the white extracting part generates the predetermined value as the white color component if the minimum value is larger than the predetermined value.