screen burn-in; ghost image
Permanent discoloration on a display where a static image has been shown for too long. Common in OLED and plasma screens.
See also: 焼き付き
The screen burn-in on my smartphone has gotten worse.
Displaying the same screen for a long time can cause screen burn-in.
Compound of 画面 (screen) and 焼け (burning, from 焼ける). Literally 'screen burn'.