What is an EMI Shielding Window?
An EMI shielding window is an optically transparent, electrically conductive barrier that significantly reduces the amount of electro-magnetic radiation that might pass through it. These shielding windows are commonly surrounded by non-transparent barriers that are more effective EMI shields, but do not offer the optical transmission needed to allow visible light to pass through the barrier. Between the EMI shielding window and the non-optically transparent barrier there is often a conductive busbar made of a highly conductive coating, such as an epoxy based paint that is highly filled with conductive silver particles, or a deposited metal film.
EMI Shielding Windows are utilized in many different applications that require electro-magnetic separation between two regions while maintaining at least a minimum optical transmission. There are a number of reasons why you would do this. In emergency medical environments where EMI sources are not guaranteed to be denied entry, it is imperative that EMI sensitive equipment be shielded properly to ensure that they function as intended. To prevent equipment malfunction on the battlefield, many different pieces of EMI sensitive military equipment must be shielded from known and unknown EMI sources. Many different kinds of equipment need to be shielded either so that they can be protected from external EMI sources or so that their internally generated EMI does not interfere with external equipment, or cause harm to people.
There are three generally accepted types of EMI shielding windows. The three different types each have their own strengths and weaknesses. There are knitted wire mesh screens, woven mesh screens and transparent conductive coatings. All three types generally use either clear plastic or glass sheets as the substrate. Both the knitted and woven wire mesh screens rely on small diameter wires (between .001” and .0045” diameter) combined with typically 10 to 30 openings per inch for knitted wire mesh or 80 to 150 mesh (wires per inch) for woven wire mesh to determine the optical transmission of the EMI shield. The third type of coating is referred to as an Electrically Conductive Transparent Coating (ECTC) and does not use wires. ECTC’s utilize deposited electrically conductive material onto the surface of an optically transparent substrate.
For more information about EMI Shielding Windows please call 800.426.2864 or email us.
Abrisa Technologies is a recognized global supplier of high quality, fabricated glass components, optical thin film coatings, and custom glass solutions for a wide variety of industries. From our US based Abrisa Industrial Glass fabrication facility in Santa Paula, CA and our ZC&R Coatings for Optics division in Torrance, CA we serve diverse industries such as microelectronics and displays, semiconductor, military, automotive, aerospace, medical, biomedical and scientific R&D. We provide custom specialty flat glass and coating products for applications such as: flat panel display, touch and gesture recognition; visible to IR imaging and surveillance; entertainment, indoor and outdoor lighting; advanced instrumentation; and photonics.