Patent ID: 8120554

Claim:
An organic light emitting display comprising: a pixel portion comprising a plurality of pixels defined by a plurality of scan lines, a plurality of data lines, a plurality of power source lines and a plurality of frequency supplying lines, wherein each pixel is configured to emit light based at least in part on a data signal transmitted through one of the data lines and a periodic frequency signal transmitted through one of the frequency supplying lines, wherein within each of a plurality of sub-frames of a frame the periodic frequency signal has a voltage transition which repeats within each sub-frame with an interval of time between each voltage transition, wherein the duration of the interval of time within each sub-frame is different, and wherein the instantaneous brightness of the light emitted is different in different sub-frames and is based at least in part on the duration of the interval of time between each voltage transition of the periodic frequency signal in each sub-frame; a data driver configured to feed the data signal to a data line of a particular pixel; a scan driver configured to feed the scan signal to a scan line of the particular pixel; and a frequency supply configured to supply the frequency signal to a frequency supplying line of the particular pixel, wherein the frequency signal is periodic and has different frequencies and different numbers of periods in different sub-frames, wherein each pixel represents gradation on the basis of a brightness sum of light emitted from the organic light emitting diode in every sub-frame of one frame, wherein the data signal includes a digital data signal having i bits corresponding to each sub-frame, where i is a positive integer, wherein the frequency supply is configured to supply the frequency signal corresponding to each sub-frame to the frequency supplying line, and wherein the frequency supply comprises: a shift register part configured to generate a starting signal and a bit selection signal corresponding to each sub-frame, a counter part configured to start in response to the starting signal and generate 1 st through N th frequency signals at different frequencies according to input clock signals, and a selector configured to select one of the 1 st through N th frequency signals supplied from the counter in correspondence to the bit selection signal, and supply the selected frequency signal to the frequency supplying line.