Abstract: A hermetically-sealed enclosure including at least two wall elements of substantially congruent shapes, and a spacer system that defines an interior space between the wall elements. The enclosure also includes a bridge element that has one or more flexible metal foil layers extending between adjacent, respective edges of the wall elements to isolate the interior space from a surrounding environment. The bridge element is substantially free of step discontinuities in total thickness along the intended weld path, and the bridge element is bonded to each of the wall elements via an ultrasonic weld to form a continuous bond line.