How to Put Display to Sleep while using External Monitor?

[WunDaii]

I have a MacBook Air 2012 and an external HDMI monitor which I have connected. I want to use my external monitor as my main screen, but I want to use the trackpad and keyboard on the Air (so it must be open).

How do I keep the MacBook Air internal screen completely off and use the external monitor? I have turned the brightness all the way down but as many of you know, it does not turn the screen completely off. I'm afraid that even if it's that dim, it's still drawing a bit of power.

Any help is much appreciated, thanks!

 

[GGJstudios]

I'm afraid that even if it's that dim, it's still drawing a bit of power.

Why should you be concerned about the very little power required? Your MBA should be plugged in if you're using an external display, so the power requirements are not a concern.

 

[WunDaii]

Why should you be concerned about the very little power required? Your MBA should be plugged in if you're using an external display, so the power requirements are not a concern.

I meant power from the GPU (I think that's what it is). Also, it's not always plugged in, but power in terms of energy is not a concern.

 

[FreakinEurekan]

I have a MacBook Air 2012 and an external HDMI monitor which I have connected. I want to use my external monitor as my main screen, but I want to use the trackpad and keyboard on the Air (so it must be open).

How do I keep the MacBook Air internal screen completely off and use the external monitor? I have turned the brightness all the way down but as many of you know, it does not turn the screen completely off. I'm afraid that even if it's that dim, it's still drawing a bit of power.

Any help is much appreciated, thanks!

Under Lion & Mountain Lion there is not a way to totally disable the built-in screen other than using clamshell mode with external keyboard & mouse.