Mevicon Inc.

A large portion of the Mevicon's research effort has been focused on improving the surface accuracy/figure of the formed thin film shells. This work is looking at both realizing further improvements in the as formed shape and surface figure. In developing and demonstrating active control strategies (primarily boundary control) to maintain the desired shape of thin film formed shells regardless of the operating environment. This work is directly relevant to increasing the wavelength range over which single surface thin film shells can be used.

The ultimate achievable residual error for a form stiffened shell is a factor of the initial and environmental induced errors, and the degree to which that error can be corrected, such as by techniques discussed here. While form stiffened thin film shells are noticeably stiffer than baseline films, they are still susceptible to environmentally induced disturbances. Much like current trends in modern terrestrial optics (Wilson, 1999), this necessitates a requirement for active control. A variety of control approaches can be considered to achieve and then maintain the desired surface figure including normal (contactive and distributed), internally reacted global shape control, boundary control (continuous and discrete) and/or down stream correction. An overview of the potential global shape control approaches and their applicability to doubly curved shells was provided by Flint and Denoyer (2003) Of all the approaches, discrete boundary control is felt to offer the best combination of near term realizability and minimizing growth in areal density. Numerical underpinning for boundary control and preliminary experimental results were provided by Lindler (2004).