Very strong plastic, glass you get the picture because of a mixture of pixels and electrons.
Sony
Its not working, switched off, or the LCD plasma screen is damanged in someway.....
nail polish remover.
There is a magnet in the holster that triggers a switch inside the phone to turn the screen off.
because it protects the screen from being scratched or damaged
Turn it off then turn it back on
mobile phones
Do the 'old favourite' of switching the phone off and on again. Switching the phone off - severs the connection to the internet.
You could purchase a kit off amazon has worked for many people or take to cell phone shop.
its the way they make it if you have a look on your phone on the inside of the case under the screen you should see and little hole with a little rubber nodge in it when that is pressd in it turns the screen off. well it does on mine anyways!
Plastic
phone that is touch screen that is not an i phone