the.com/backlit screen
the reason you can read in the dark and can't sleep afterward.
means a display lit from behind by an LED or fluorescent panel, so the image glows instead of just reflecting ambient light.
from predecessors like early LCDs relied on reflected light and were unreadable in dim rooms; engineers added a light source behind the liquid crystal layer in the 1990s, and backlighting became standard as laptops, phones, and TVs chased brightness and clarity.
blue lightbacklit screens skew blue, suppressing melatonin at night
oled differenceoled pixels self-light, no backlight panel needed
power drainthe backlight is often a phone's biggest battery cost