EMI, RFI, ESD Shielding

However, despite the many clear benefits that plastic hold over metals, they have one clear disadvantage. They can completely unsafe to EMI, RFI and ESD interface and provide no protection against electrostatic discharge. This layer facilitates the cancellation or dissipation of electrostatic build up on a person’s finger. All factors mentioned bellow would lead to a major electronic failure.

Electric charge could travel around the perimeter of a membrane switch then ground itself through LCD displays or other circuit board components. Furthermore, rapid electrical discharge across the front of a membrane switch could include the current behind it.

Some electronic devices can emit or be affected by receiving low level electromagnetic interference if they are not properly protected. There will be impact like waveform distortion on the operating electronic devices.

Shielding structure includes both independent and switch integrated protective RFI/EMI shields to guard against digital interface while grounding vagrant electrostatic charges attenuating both incoming and outgoing RFI. Switch integrated system also serves as grounding paths for ESD charges.

Fortunately membrane switches can incorporate shielding by aluminum foil, sputtered ITO (indium-tin oxide), screen printed conductive, metal mesh or coated polyester that protects against the induced current caused by the electromagnetic and radio frequency interference.

RFI shielding – protection from radiated electronic broadcast noise – 10Khz to 1000Mhz

EMI shielding – protection from DC electricity to 300Ghz

ESD shielding – protection from electrostatic discharge damage