Dontech has an extensive array of high energy vacuum deposition systems for applying thin film transparent conductive coatings to different types of glass, plastic, and crystalline substrates. Processes include DC and AC magnetron sputtering and ion-enhanced (IAD) e-beam evaporation. Dontech’s conductive coatings are used in applications ranging from the very demanding requirements of an avionic cockpit display, through the less-demanding but similarly change-sensitive requirements of high end medical instrumentation, to the supply of tightly-toleranced raw material components for the touchscreen market.
Transparent conductive coatings include transparent conductive oxides (TCOs) such as indium tin oxide (ITO), metallics such as gold, copper, or silver-based layers, and alloys. Conductive coatings and substrate surfaces can be dielectrically enhanced (index matched) to maximize light transmission through the control of interface reflections, where reflection losses are converted to transmitted light. Dontech can index match the conductive coatings to air (n=1), to the optical substrate, and in the case of optical bonding applications, to an optical adhesive (n=1.41 through n>2.36). An index matched transparent conductive coating is essentially a conductive AR coating.
ITO coatings in particular offer excellent optical and environmental durability properties. Standard conductivities for ITO coatings range from < 1 ohm/sq to >500 ohms/sq. Visible light transmission of Dontech dielectrically enhanced conductive coatings can exceed 98% photopic transmission. Coating designs range from a simple single-layer of ITO applied to an optical substrate for the control of static charge buildup to a multilayer thin film coating fully dielectrically enhanced (e.g., integrated into a broad band AR coating) conductive coating. Dielectrically enhancing ITO coatings greatly expands the transmission band into a greater portion of the longer wavelengths of the NIR spectrum. In all cases, the coating performance is dependent on substrate and the conductivity of the coating.
Dontech designs and applies conductive coatings on both rigid and flexible (R2R and batches) substrates. We customize our coatings for the optical spectrum covering Visible through Near IR. For longer wavelengths (up to 25 microns) such as the Near IR through Mid IR, Dontech offers conductive optical grids.
Dontech designs and produces transparent conductive coatings to meet the following environmental and quality standards in addition to both internal and custom environmental and optical requirements:
Dontech manufactures a variety of transparent (Visible and part of the Near IR spectrum; out to 1600nm, dependent on substrate and coating conductivity) conductive coatings for optical EMI/RFI shielding (for low to moderate levels of EMI/RFI shielding requirements) and transparent heater applications. For applications at longer wavelengths or requiring greater levels of EMI/RFI shielding Dontech recommends conductive optical grids.
For EMI/RFI shielding applications, conductive coatings are typically grounded via a perimeter busbar, gasket, or tape to help terminate the optical conductive ground plane to the rest of the Faraday Cage. In transparent heater applications, the conductive coating makes contact with two isolated highly conductive busbars. When voltage is applied, the conductive coating generates heat across the surface of the substrate. Transparent heaters can be supplied with wires, connectors, and temperature feedback sensors.
Dontech has extensive engineering and technical support resources that can assist with your transparent conductive coating selection and design needs. Our technical staff have diverse backgrounds relevant to high-performance display and precision optics markets. For many of our top customers, we function as an extension of their engineering departments, supporting projects from concept to final system delivery. We will integrate our optical filters and other enhancing components into touchscreens, displays, and systems to the level that is needed by our customers.