500Hz QD-OLED 1440p Monitor: MSI MAG 272QP X50 PD26 Review

The entire OLED premium comes down to pixels. An IPS panel paints every frame on top of a backlight that never stops shining. Liquid crystals twist to block that light wherever the image needs to go dark, but some of it always leaks through. That leak is why black looks gray and why you can trace the screen's edges across a dark room. An OLED panel skips the backlight entirely. Every pixel produces its own light, so a black pixel is simply a pixel that has shut itself off and is emitting nothing

How Does OLED Technology Work?