Windows 10 isn't supported on that model (ie Acer don't have Windows 10 drivers for it, and it's not on their Windows 10 upgrade support list:
http://www.acer.com/ac/en/GB/content/windows10-eligible-models
If it's a driver issue, Microsoft may fix the problem with a driver update which, when available, will be delivered via automatic updates.
Strictly speaking though, you should not have installed Windows 10 if that model is not officially supported. You should have checked the Acer website first, then you would have known not to upgrade just yet.
If you can't tolerate the problem and no new driver is forthcoming, buy an external webcam that's supported on Win10.