If the display on your iPhone continues dimming, it's due to technologies that modify the screen's colors or brightness based on battery capacity.
Manually adjust the brightness levels
Manually adjust the brightness levels
– Your iPhone's screen brightness is automatically adjusted to your surroundings by default.
– If you don't prefer this feature, you can turn it off by manually adjusting the brightness.
– To do so, go to the Accessibility tab in the Settings app on your iPhone.
– Tap Display & Text Size in Accessibility.– Scroll to the bottom of display and text Size and turn on the Auto-Brightness option by turning the switch next to it.
The brightness levels on your iPhone will not change automatically. You'll have to do it manually in the Control Center by using the brightness bar.
Turn off Attention-Aware Feature.
Turn off Attention-Aware Feature.
– An iPhone with Face ID, it may be darkening the screen when it detects that you are not looking at it in order to conserve battery life.
– Try turning off this smart feature for a day.– You can achieve this by disabling Attention-Aware Features.
– Go to Settings , next go to Accessibility.– Click on Face ID & Attention.– Then disable this feature.