Pulse width modulation for multi-pixel density oled display

A non-transitory computer-readable medium storing software for driving an organic light emitting diode (OLED) display having a first plurality of pixel lines having a first pixel density and a second plurality of pixel lines having a second pixel density higher than the first pixel density, the software comprising instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform operations comprising:

• driving the first and second plurality of pixel lines with corresponding drive signals at a frame rate at which frames are displayed, where during each of the frames the drive signals have a pixel on time during which pixels in the pixel lines driven by the drive signals emit light and a pixel off time during which pixels in the pixel lines driven by the drive signals are dark,
• wherein the pixel on times and the pixel off times are varied between the drive signals of the first plurality of pixel lines and the drive signals of the second plurality of pixel lines to reduce variations in luminance between the first plurality of pixel lines and the second plurality of pixel lines.