On Thursday, August 15th, the UR SPIE student chapter will be concluding its annual Summer Colloquium series with a special doubleheader.
Speaker #1: Janghwan Bae
What: Vacuoles: Visual Performance in Intraocular Lenses
Abstract: In certain formulations of intraocular lenses, localized concentrations of water can accumulate over time with variable environment conditions. Since the index of refraction of water is significantly lower than that of the base polymer, the optical effects of these vacuoles can become visually significant. To assess the effect of vacuoles, the scattering behavior would be analyzed. And LightTools calculation is included. Experimentally, this effect can be seen with our scatterometer. As conclusion, the resolution of eye is not affected by vacuoles. But, there is the loss of light come up to retina. This can affect the visual contrast of human.
Speaker #2: Dennis Briggs
What: Accurately Measuring the Dynamic Coefficient of Friction in UltraForm Finishing
Abstract: UltraForm Finishing (UFF) is a deterministic subaperture computer numerically controlled grinding and polishing platform designed by OptiPro Systems. UFF is used to grind and polish a variety of optics from simple spherical to fully freeform, and numerous materials from glasses to optical ceramics. The UFF system consists of an abrasive belt around a compliant wheel that rotates and contacts the part to remove material. This work aims to accurately measure the dynamic coefficient of friction (m), how it changes as a function of belt wear, and how this ultimately affects material removal rates. The coefficient of friction has been examined in terms of contact mechanics and Preston’s equation to determine accurate material removal rates. By accurately predicting changes in m, polishing iterations can be more accurately predicted, reducing the total number of iterations required to meet specifications. We have established an experimental apparatus that can accurately measure m by measuring triaxial forces under translating loading conditions. Using this system, we will demonstrate m measurements for UFF belts during different states of their lifecycle and assess the material removal function from spot diagrams as a function of wear. Ultimately, we will use this system for qualifying belt-wheel-material combinations to develop a spot-morphing model to better predict instantaneous material removal functions.
Date: 08/15/2013
Time: 11:30 am – 12:30 pm
Where: Sloan Auditorium (Goergen 101)
**Important** Pizza will be provided in addition to snacks and beverages.
