Compact and efficient RGB to RGBW data conversion method and its application in OLED microdisplays

In many electronic information displays, a colour pixel comprises three spatially distinct sub-pixels containing red, green and blue (RGB) colour filters. The option of adding a fourth white (W) sub-pixel that allows light to pass through unfiltered can significantly improve the optical efficiency of the pixel that, in turn, increases the power efficiency of the display. Such a display is called an RGBW display, and the required transformation of data format from incoming RGB to pixel RGBW is termed as “RGB to RGBW conversion.” This paper reports a method of RGB to RGBW conversion that is highly compact and efficient in terms of system resources while retaining image quality. It processes incoming data through a new colour space conversion algorithm in order to reduce the average power consumption with no noticeable visual artefacts. We explain the method and demonstrate its cost-effective and power-effective implementation for the specific case of an organic light emitting diode microdisplay.