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.
