ESD (Electrostatic Discharge) is the term used to describe the sensitivity of electronics components to static electrical charges. Many of these components such as some types of LEDS, computer chips, circuit boards etc. can be damaged beyond repair by an electrical discharge as low as 20 volts.
EMC (Electromagnetic Compatibility) is the capability of equipments or systems to be used in their intended environment within designed efficiency levels without causing or receiving degradation due to unintentional EMI (Electrostatic Interference.
The thin layer of metal shielding on top of the array is used to connect the surface of the switch to the ground of the phone. This reduces the electronic magnetic interference and eliminates the possibility of building up any high electric potential that could damage the phone. The shielding is integrated with the dome array and does not require any additional assembly. Since the shielding is soft tooled, it has a low tooling cost and is easy to modify.
Best Hardware Co., Ltd make used EMI/ESD in its’ metal dome arrays. For more details, please browse http://www.metal-domes.com/product/dome-array-EMI.htm, or contact now!