There are times when I wish to entirely turn off the monitor on my Acer Extensa 5620-6419 laptop computer. I investigated this issue quite carefully over a period of several months, posting queries on this forum, the Launchpad forum, and the Ubuntu Brainstorm site.
There were no suggestions or answers posted. I did see a few "scripts" posted but I was reluctant to try such commands in my Terminal, not really knowing what the outcome would be.
Strictly by accident I found the answer - and it is so simple that it's ridiculous!
Just click on Fn + F6. That turns off the monitor and the backlight; typing any key or clicking a mouse button immediately turns on the monitor again.
Now I did find one anomaly: if Firefox or OpenOffice Word Processor is open in the Desktop when you click Fn + F6, when you reactivate the monitor the cursor is frozen. (The only way to correct that is to hit Fn + F4 which either "suspends" or "hibernates" [I'm not sure which] the computer. When you reactivate the computer by pressing the power button, the cursor is active again.) But the "fix for this is to click on Fn + F6 from an empty Workspace. Then the cursor does not freeze and you can then switch to your desired workplace where you may have Firefox or OpenOffice active.
Of course I do not know if this key combination will work on all laptop computers but it can't hurt to try it!
You may ask, as someone did on Ubuntu Brainstorm, WHY I would want to turn off the monitor and my answer is the same as the other person's answer on Ubuntu Brainstorm: I often use my computer as my de facto internet radio and, when so using it, I wish to have the monitor, including the fluorescent back light, turned off completely. This not only saves energy, it will also prolong the monitor's life as I often play the "radio stations" for many hours. (The screensaver option can turn off the screen but it does NOT turn off the backlight.)
[By the way, I see absolutely NO reason to pay $150.00+ for an "internet radio," which will be restricted to only ONE portal when you can use an older computer - or even a new "budget-priced" computer - converted to Ubuntu for the same purpose - and this will NOT be restricted to just one portal; you can "tune" to any station via its own web page or from any portal you choose. Plus you have the ability to do lots of other things as well which, of course, you cannot do with an "internet radio." The only reason I could see to buy one of those items is for their cosmetics - many of them are really good looking, and some of them even sound good too. (Of course good amplified computer speakers eliminate that advantage.)]
I hope others will reply to let me know if this key combination is universal or just restricted to my machine.
I apologize for this rather long-winded post but I do hope that the knowledge of this simple Fn + F6 key combination will help anyone who wishes to completely turn off his laptop monitor.
I have one final question - why didn't anyone else know about Fn + F6? I never saw this solution posted anywhere!