EMI/RFI Shielding for Optics

Dontech designs and fabricates these products for transparent EMI/RFI shielding of electronic displays and optics:

• Transparent Conductive Coatings (ITO and TCO's from < 1 to 500 ohms/sq)
• Stainless Steel Woven Meshes (50 opi to 250 opi)Copper Meshes (woven and etched)
• Custom Meshes
• Conductive Platings

Dontech manufactures a variety of EMI/RFI shielding solutions including transparent conductive oxide coatings such as indium tin oxide (ITO), metal (e.g., gold) and metal-ITO alloys, on different types of glass and plastic substrates. Conductive coatings and substrate surfaces can be dielectrically enhanced (index matched) to maximize light transmission through the control of interface reflections. Reflection losses are converted to transmitted light. Dontech can index match the conductive coatings to air (n=1), to the optical substrate, and to an optical adhesive (n=1.43 through n>2.36). ITO coatings offer excellent optical properties, very good environmental durability with low to moderate levels of shielding. Standard conductivities for ITO coatings range from < 1 ohm/sq to >250 ohms/sq.

For higher shielding applications, Dontech manufactures shielding solutions with optical fine wire meshes (i.e., copper or stainless steel). The mesh is typically a plane weave with either square or rectangular apertures. The weaving looms for Dontech mesh have been specially tooled to allow for very high uniformity which is important for both moiré control and aesthetic purposes. The wire mesh is electroplated, fusing the wire crossovers, to improve the uniformity and conductivity of the mesh while minimizing surface reflections. Additionally, the outer plating layer is conductive and corrosion resistant, which greatly improves the galvanic stability of the material. Standard Dontech mesh is available from 50 through 255 openings per inch, allowing for a broad range of both shielding and optical solutions.

All of Dontech's EMI/RFI shielding optical filters can be supplied with conductive gaskets, tapes, and mounting frames. Conductive gaskets include form in place, strip and die cut conductively loaded elastomers, metalized fabric over foam and metal-based gaskets (e.g., finger stock, knitted mesh gaskets).