Also flickering. Yes, it's a problem for OLED displays. One might assume (like I did) that if you don't have a backlight, you couldn't have that problem in an active-matrix display, but because OLEDs tend to have quite wild shifts in color over their full dynamic range OLEDs are usually driven with some sort of dual-sweep scanout which turns the pixels off completely between frames for dim outputs. As I understand it, the drive regime for these is somewhere between a DMD (clever PWM for brightness control, purely digital) and a normal TFT (purely analog control).