system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What do OLED screens do that make them an improvement over LCD screens?
gpt
Traditional LCD screens use a backlight, the LCD pixels change the color of that light as it passes through them. The backlight makes these screens thicker, and the LCD pixels can't block all the light from the backlight so the display isn't capable of displaying true black.

OLEDs emit their own light, there is no backlight. This means the screen can be much lighter and thinner (even to the point of being flexible) and can display true black as each pixel emits no light at all when turned off.