Above the display you'll find a blue LED that flashes brightly when the phone is asleep
The blue light is turned on (to indicate that the phone is powered on) and the screen is turned off to save the battery after the phone has not been in use for some time.
That blue led is an option that you can activate under the settings>Screen menu.
If is enable, the phone will show the screen protector (date, time and other simbols like sms, missed calls, etc) until around 15mins, then the screen is off and the blue led is getting in action until you touch any button or receive any sms or call, etc
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