Wnat is the terminology for the layers of a display screen.

@luca8078 for the touchscreen most commonly have three layers. The top is the film layer. It is usually a polyester layer that is coated with a conductive material underneath. That is what actually measures the change is capacitance when you touch it. As you can tell, this is two layers already. Your Film and Electrode layer. Last layer on this, is the glass substrate. That glass layer has a also conductive material coated on the top of it. You need this so that the electrical charge can get through all of these layers and to the surface of the touch screen. You need that charge for your screen to work.

Now for the display you commonly have the

Cover glass

Polarizer

Color Filter

Liquid crystal layer with the TFT board

Polarizer

Backlight

All this of course is mounted in the panel assembly housing.

Now this is very general and technology changes. So, each screen technology may have a few different layers etc. That is the importance to know what device a panel actually belongs to.

For some good explanation, here is some easy reading LCD Basics