Energy-efficient window coatings transmittable to wireless communication signals and methods of fabricating thereof

Abstract

Described are energy-efficient signal-transparent window assemblies and methods of fabricating thereof. These assemblies remain IR-blocking properties while allowing signal penetration and remain substantially transparent within the visible spectrum with no features detectable to the naked eye. This performance is achieved by isolating conductive layers into discrete cells via gap patterning. The second coating stack's line widths are at least 0.4 micrometer greater than the gaps among the primary stacks. The thickness of the primary stack increases from zero to full thickness near the gap, with a sidewall transition length exceeding 0.2 micrometers. The fabrication process involves lithography for patterning, PVD coating, and post-clean and high-temperature treatments. In some examples, a transparent organic thin layer is provided between the second coating stack and the primary stack or the substrate. Additionally, a thick dry-photoresist method in a special lithography process could significantly reduce manufacturing cost.