Electromagnetic Sensing for Deterministic Finishing Gridded Domes

摘要

Electromagnetic sensing is a promising technology for precisely locating conductive grid structures that are buried in optical ceramic domes. Burying grid structures directly in the ceramic makes gridded dome construction easier, but a practical sensing technology is required to locate the grid relative to the dome surfaces. This paper presents a novel approach being developed for locating mesh grids that are physically thin, on the order of a mil, curved, and 75% to 90% open space. Non-contact location sensing takes place over a distance of 1/2 inch. A non-contact approach was required because the presence of the ceramic material precludes touching the grid with a measurement tool. Furthermore, the ceramic which may be opaque or transparent is invisible to the sensing technology which is advantageous for calibration. The paper first details the physical principles being exploited. Next, sensor impedance response is discussed for thin, open mesh, grids versus thick, solid, metal conductors. Finally, the technology approach is incorporated into a practical field tool for use in inspecting gridded domes.