Membrane Switch Shielding Options

There are a number of shielding options available for membrane switches including:

• Environmental contamination
• Radio frequency interference (RFI)
• Electromagnetic interference (EMI)
• Electrostatic discharge (ESD)
• Shock and Vibration
• Excessive heat

The shielding layer may take the form of an inert wrap, sheet, gasket or seal; but it may also be a conductive element integrated in the membrane switch circuitry. It is often located above the active circuit layer, therefore underneath the graphic overlay. The keypad, LCD and LED screen can all be protected individually or in combination.

EMI, RFI and ESD Membrane Switch Shielding

Often, the shielding layer can function to channel potentially harmful electrostatic discharge (ESD) away from the electronic components or protect internal electronics from radio frequency interference (RFI) or electromagnetic interference (EMI) by reflection or absorption. Shielding may take the form of copper mesh, aluminum foil or even be polyester and incorporated into the graphic overlay itself.

Membrane Switch Gaskets and Moisture Barriers

A gasket or seal may be used to protect from moisture, liquid or chemical infiltration of the membrane switch, offering a simple and inexpensive solution. An integrated perimeter gasket is recommended in all cases where the keypad assembly may be subjected to high levels of humidity and other extreme environmental conditions.
Typically a gasket will have a minimal width of 0.125". Foam and various materials can improve the effectiveness of the gasket.