A method of manufacturing a mechanical grating device, including the steps of: forming a spacer layer on a substrate; removing portions of the spacer layer to define an active region; forming a sacrificial layer in the active region; forming conductive reflective ribbon elements over the active region; annealing the mechanical grating device at an annealing temperature greater than 150 C. The electronic components housed inside the enclosure are covered with the ground conductor pattern. The interior of the housing can be sealed against leaks, for example, by providing the housing in two portions with a gasket provided between the portions.