You can turn on and off the keyboard backlight by changing the keyboard backlight settings.
The settings window appears. Follow the on-screen instructions to change the settings.
You can set the keyboard backlight to automatically turn on and off according to ambient light intensity.
If you enable this function, you can also set a time period to turn off the keyboard backlight after inactivity of keyboard operations.
Ambient light intensity is measured by the ambient light sensor. Blocking the ambient light sensor may turn on the keyboard backlight.