Reference

Combinations and Functions with the Fn Key

Press and hold down the Fn key and another key simultaneously to perform a keyboard shortcut action.

For example, to adjust the LCD brightness: Fn+F5 → Press and hold down the Fn key, then press the F5 key.

Some keyboard functions can only be used while Windows is running.

Press the button repeatedly to adjust the LCD brightness of your computer screen. [Details]

To decrease lighting intensity, press the Fn+F5 keys.

To increase lighting intensity, press the Fn+F6 keys.

Changes the size of an image or a document displayed on the running app.
To zoom out, press the Fn+F9 keys.

To zoom in, press the Fn+F10 keys.

This function may not be available depending on the apps you use.

Works differently depending on the apps you use. Refer to the help file included with the app for more information.

For information on shortcut keys combined with the (Window) key, etc., refer to Windows Help and Support. [Details]