Dontech (Doylestown, PA) Therma Klear™ transparent heaters provide the warmth necessary to extend the operating temperature of liquid crystal displays (LCDs) in cold environments (e.g. from 0° to below -40°C). A Therma Klear heater is composed of an electrically conductive thin-film coating on a visually transparent substrate. When current flows across the coating, it generates heat. Dontech manufactures heaters using different types of crystalline materials (e.g. zinc sulfide or germanium), glass, acrylic, and polycarbonate substrates. By index-matching, 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).