Image Number 4 for United States Patent #6891667.
The invention describes a system and methods for filtering electromagnetic and visual transmissions and for minimizing acoustic transmissions. Various combinations of UV, IR, and yellow-tinted filters are applied in various physical configurations to a transparent substrate such as a plastic film or glazing of a window for modifying selected wavelengths of electromagnetic radiation. For instance a light filter may have a multi-layered metallic sputtered stack having a relatively low sheet resistance. The combination of filters prevents or attenuates the passage of selected wavelengths through the substrate as needed to address security risks. The combination of filters is useful to prevent unauthorized data collection and information exchange from or within buildings or otherwise prevent such unauthorized data collection and information exchange from, for example, computer monitors or screens, personal digital assistants, and local area networks.