Low Cost Optical Finishing of Transparent Ceramics

Glass and polymer coatings applied to sapphire or other hard transparent ceramics offer several very low-cost approaches for optical finishing. In Phase I, MSI will investigate (A) polishing the applied coatings, (B) bonding of polished glass faceplates,(C) replicating optically smooth surfaces using polished mandrels, and (D) very thin coatings as applied. The resulting windows will be characterized with the objectives to achieve high in-line transmittance, low haze, and angular image resolution qualityof less than 1 milliradian. All processes developed will be compatible with the PVB bonding/autoclaving used for assembling transparent armor systems. In the Phase I Option, the most promising approaches will be further optimized and preliminaryproduction cost estimates will be made. In Phase II, MSI will scale-up the most successful low-cost optical finishing processes to 12 x 14 inch windows while the optical quality is increased to at least 80% in-line transmission and less than 5% haze.Commercialization of this technology will be facilitated through MSI's on-going business relationship with Raytheon Optical Systems, Inc.This program will provide new low-cost methods for achieving optically transparent hard ceramic windows by eliminatingthe expensive and time consuming polishing of the sapphire or ALON itself. As a result, transparent armor will be available at substantially reduced costs, thereby opening up new markets for these products. By so expanding the range of applications, thecost of light-weight, large-area transparent armor panels for military land vehicles and aircraft will be further reduced. Commercial personnel security vehicles will also benefit from the technology developed in this program. The sapphire and/or ALONtransparent armor will offer protection against small caliber armor piercing projectiles at substantially reduced weight and thickness.