How to turn off the screen on a tablet with android?

Question

Android

The situation is this: there is not the latest Samsung Galaxy Tab P1000 with cyanogen 4.4.2 installed on it. I am writing "tablet phone", because in terms of its form factor it tends to be a tablet, and the android calls itself a phone (even stock 2.3.2
) in which sleep mode (if it is on android); b) the application must be active and assume that the user is carefully considering the screen.
That is, it seems that it should be some kind of demon that works in the background and allows the user to use the tablet for its intended purpose.
I tried to use applications that manipulate permissions - it doesn’t work ... If we consider the option "open the case, disconnect the cable, connect it if necessary", then it would be wiser to run the emulator on the computer, since the frequency of using the unfortunate device is small (three times a day), but he needs to work ...
PS The question is removed - another application has been delivered, the existence of which I did not even suspect.

Answer 1

Turning off the backlight will help save battery.
You can find many applications in google play by the keyword Backlight.
https://play.google.com/store/search?q=backlight&c=apps

Answer 2

You make an application (service) that keeps the wakelock (so that the system does not decide to change the brightness of the backlight) and writes the value 0 to the backlight driver interface in sysfs.

Answer 3

What cyanogen was used?