Electromagnetic interference (EMI) refers to environmental factors that disrupt, obstruct, limit, or otherwise degrade the effective performance of electrical equipment. RFI (Radio frequency interference) refers to high-frequency electromagnetic waves that emanate from electronic devices. Electromagnetic fields are produced whenever electricity passes through a medium (such as a wire, circuit, or air). Common sources of EMI include power lines, computers, electrical instruments, household appliances, and cell phones as well as geomagnetic or atmospheric conditions such as lightning storms.

The most effective way to control the level of EMI/RFI immunity or radiation an instrument exhibits is with shielding. Shielding, through the use of properly grounded conductive materials, reduces electromagnetic fields by reflecting and/or absorbing the energy. EMI suppression on displays (computers or instruments) is generally achieved by coating glass panels with low-resistance transparent conductive oxides, applying mesh screens, or both. JDSU industry-leading 0.25 ohm/square sheet resistance provides the highest suppression available from an optical coating. A display bus bar is a silver coating around the perimeter of the display that provides the required grounding. Typical applications include air traffic control systems, medical instrumentation, computer systems, avionics instrumentation, industrial monitoring systems, measurement instrumentation, and secure communications.