This function deactivates the image transmission to the display by minimizing its brightness. 
This helps prevent accidental disclosure. However, the device stays on.
 
1.
When the device is on, press and hold the ON/OFF(11) button. The display goes out and 
the message Display Off appears.
2.
Turn the display back on with a short press of theON/OFF (11) button.
3.
When you press and hold the ON/OFF(11) button, the display shows the message 
Display Off with a countdown. Pressing & holding the button down for the duration of 
the countdown will power the device off completely.