Method of operating an organic light emitting display device, and organic light emitting display device

A method of operating an organic light emitting display device including a red sub-pixel, a green sub-pixel, a blue sub-pixel and a white sub-pixel, the method comprising:

• increasing a first gamma voltage for the red, green and blue sub-pixels to increase a sum of maximum luminances of the red, green and blue sub-pixels;
• decreasing a second gamma voltage for the white pixel to decrease a maximum luminance of the white sub-pixel;
• calculating a ratio of a first accumulated driving amount of the red, green and blue sub-pixels to a second accumulated driving amount of the white sub-pixel;
• determining a ratio of first data of the red, green and blue sub-pixels to second data of the white sub-pixel with respect to a white portion of RGB (red, green, blue) input data in inverse proportion to the ratio of the first accumulated driving amount to the second accumulated driving amount;
• converting the RGB input data into RGBW (red, green, blue, white) data based on the ratio of the first data to the second data with respect to the white portion;
• and
• driving the red, green, blue and white sub-pixels based on the increased first gamma voltage, the decreased second gamma voltage and the RGBW data.

A method of operating an organic light emitting display device including a red sub-pixel, a green sub-pixel, a blue sub-pixel and a white sub-pixel, the method comprising:

• converting RGB (red, green, blue) input data received from a host device into RGBW (red, green, blue, white) data;
• adjusting a first gamma voltage for the red, green and blue sub-pixels and a second gamma voltage for the white pixel based on a ratio of an aperture size of the red, green and blue sub-pixels to an aperture size of a pixel, a ratio of a maximum luminance of the white sub-pixel to a sum of maximum luminances of the red, green and blue sub-pixels, and a ratio of a first accumulated driving amount of the red, green and blue sub-pixels to a second accumulated driving amount of the white sub-pixel;
• and
• driving the red, green, blue and white sub-pixels based on the adjusted first gamma voltage, the adjusted second gamma voltage and the RGBW data.

An organic light emitting display device, comprising:

• a display panel including a red sub-pixel, a green sub-pixel, a blue sub-pixel and a white sub-pixel;
• a gamma voltage generator configured to generate a first gamma voltage for the red, green and blue sub-pixels and a second gamma voltage for the white pixel, the first and second gamma voltages being adjusted such that a sum of maximum luminances of the red, green and blue sub-pixels is substantially equal to a luminance of a white color displayed by the organic light emitting display device;
• a data converter configured to adjust, with respect to a white portion of RGB (red, green, blue) input data, a ratio of first data of the red, green and blue sub-pixels to second data of the white sub-pixel based on a first accumulated driving amount of the red, green and blue sub-pixels and a second accumulated driving amount of the white sub-pixel, and configured to convert the RGB input data into RGBW (red, green, blue, white) data based on the adjusted ratio of the first data to the second data;
• and
• a source driver configured to drive the red, green, blue and white sub-pixels based on the first gamma voltage, the second gamma voltage and the RGBW data.