Thanks for your answer.
Yes, the brightness is the issue. As i could see the non-glossy Displays are brighter. Maybe with the glossy Displays i would have less ghosting, but then the mirror would be darker.
After everything i read, i decided to try an other glas, the Mirastar with just 3% transmission. So i wont change the Display now.
I will post photos when its here.

I will try my best to write in understandable english :)

Hey guys.
Saw the project, ordered some parts and now i have a Mirropane 4mm and notebook display non-glossy in use.
I’m not satisfied with the result. I can see the Display shining throw the glas.

So i’ve read a little bit about displays. Some are sayin that glossy Displays are better, cause of the better contrast and other say that non-glossy Displays are better. But why?
Coult somebody explain it to me what ist the better choice?