High-impact resistance optical sensor windows

摘要

Recent field experience with optical sensor windows on both ground and airborne platforms has shown a significant increase in window fracturing from foreign object debris (FOD) impacts and as a by-product of asymmetrical warfare. Common optical sensor window materials such as borosilicate glass do not typically have high impact resistance. Emerging advanced optical window materials such as aluminum oxynitride offer the potential for a significant improvement in FOD impact resistance due to their superior surface hardness, fracture toughness and strength properties. To confirm the potential impact resistance improvement achievable with these emerging materials, Goodrich ISR Systems in collaboration with Surmet Corporation undertook a set of comparative FOD impact tests of optical sensor windows made from borosilicate glass and from aluminum oxynitride. It was demonstrated that the aluminum oxynitride windows could withstand up to three times the FOD impact velocity (as compared with borosilicate glass) before fracture would occur. These highly encouraging test results confirm the utility of this new highly viable window solution for use on new ground and airborne window multispectral applications as well as a retrofit to current production windows. We believe that this solution can go a long way to significantly reducing the frequency and life cycle cost of window replacement