No. 22Technology3 minviews 24
Published by GK Library Annex
My phone screen gets brighter without me touching it
You only moved from under the covers to the window, and the screen reacted before you touched it.
When you carry the phone you were using under dark covers over to a window, the screen brightens on its own. Since you did not touch anything, it can look like a glitch, but the phone measured the light around it and changed the brightness by itself. A tiny part near the top of the screen does that job.
A tiny eye above the screen measures the room
Most phones have a very small part called an ambient light sensor near the front camera. Its job is to keep measuring how bright the room is.
In dark places it lowers the screen to reduce glare, and in sunlight it raises the brightness so you can read the text. The same brightness looks washed out under the sun, so the phone turns it up to match the surroundings. On iPhone this feature is called Auto-Brightness, and Android phones usually include it as auto brightness or adaptive brightness. So a screen that changes by itself is a sign that it is working properly.
It can remember your adjustments
If you nudge the automatic brightness down by hand, some phones remember that choice and make the screen a little dimmer next time in similar light. Adaptive Brightness on Android is a well-known example. So it may be uneven for the first few days and then gradually match your taste. When you enter a tunnel or an elevator, the screen changes a beat late because it usually waits a moment so it does not flicker with every passing shadow.
If a finger, a thick case, or a lifted screen protector covers the sensor, it can misread the room as dark and suddenly dim the screen. If the screen dims for no reason, check the top of the screen first.
Things that are easy to mix up
Auto-brightness is different from night mode, which tints the screen yellow. One changes brightness, and the other changes color temperature.
Some people worry that auto-brightness drains the battery faster, but since it lowers brightness in the dark, it is closer to saving power. Also, when a phone gets hot, it may dim the screen on purpose to reduce heat. In that case, let it cool in the shade for a while.
To turn auto-brightness off, on iPhone go to Settings, then Accessibility, then Display & Text Size. On Android, you can usually turn it off in the display settings.
Related reads
The screen brightens on its own because the ambient light sensor on the front measured the light around it and adjusted the brightness.
Notes and references · Apple Support · Android Help. Apple Support: iPhone Auto-Brightness uses the ambient light sensor to adjust screen brightness, and the display may dim if the device gets too hot. Android Help: Adaptive Brightness adjusts brightness based on your surroundings and your own adjustments.
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