GoToSleep

Widget is able to lock the screen classic.
You can OFF the screen without pressing the power key when you tap the widget on the screen.
Android 2.2 or higher
You must configure the device administrator.

I tried to priority programs and the lightness of the design of the widget.
I think that I can use without having to worry about the capacity of the body.

If you want to uninstall, please go after the device administrator set to OFF.