Defines the amount of time the backlight stays on as long as there is no activity on the computer and you have external power attached.
Options for Backlight Turns Off After are Disabled, 1 minute, 2 minutes, 3 minutes, 4 minutes, or 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes.
Disabled
Device Settings > Screen > Backlight - External Power > Backlight Turns Off After