Copper sheet for Ground?

[ssniesle]

I apologies if this is elementary, but I took apart an ipad dock/stand and found that three of the control buttons on a pcb is attached to a 1"x3" copper sheet (which is glued to the plastic housing).
Is this used for ground? I don't understand why they would do this if it is ground, since there is another ground wire near by and I also don't understand how ground works in this case.
Please educate me.

Thank you

 

[CocaCola]

Likely a grounded shield, to block interference...

 

[ssniesle]

please explain

What would it be shielding? And can I attach this shield to any surface and still act as ground?

 

[davenn]

if it acting as a shield, it would be for RF shielding to lower the amount of RF being radiated by the iPad.
Shielsing would normally be around /close to the areas that radiated the most .
many items of electronics have RF shielding.... another common one is switch mode power supplies for laptops etc

Dave