uhhh yes… sorry, how stupid from me…
I switch the display an and off with the WIFI-Powerplug.
There a many ways to fullfill somebodys needs. For me the Wifi-Plug and the small script was ein easy way to deploy that. The goal was to switch the Display complete powerless to save energie.
Not only switch the display to dark or switch of the HDMI-Port.
It works very good and im happy with that solution.