Reference

The screen disappears/darkens unexpectedly.

    The screen goes to sleep automatically after a certain period of time to reduce battery consumption.
  • The screen turns on again when you push the power button.

  • When you want to change the time before the screen goes to sleep, tap [ Apps & Widgets] - [ Settings] - [Display] - [Sleep] in that order to set the time.

  • If you set the time to a longer interval before going to sleep, the battery will be consumed faster.