OLED screens produce excellent contrast because each pixel makes its own light, but static elements shown for a long time can leave faint permanent marks, known as burn-in. Makers counter this with subtle measures like shifting pixels slightly, dimming unchanging areas and evening out wear.
These safeguards, built into phones, TVs and monitors, make burn-in unlikely for normal use over a device's life. Risk remains for extreme cases with fixed bright images shown constantly, so the measures matter most there. For most people they work invisibly, letting OLED's picture quality be enjoyed without the worry that once accompanied the technology.