Analysis investigation for continuous and discrete athermal bondings on an eight-inch reflective mirror

Effects of continuous and discrete bondings with an RTV glue (DOW CORNING^® 6-1104) on an eight-inch reflective mirror have been carried out numerically. The finite element analysis and Zernike polynomial fitting are applied to the whole process. Under the integrated optomechanical analysis, the comparison of the optical aberrations, equivalent stresses and natural frequencies with various bondline thicknesses under the self-weight loading and temperature difference has also been investigated. The separated thermal and gravity effects on PV values with various bondline thicknesses for the discrete bonding are studied. It is found that the thermal effect has absolute influence than the gravity effect since the latter approaches zero for all bondline thicknesses. Besides, the simulation results have been verified by the analytical solution. It can be concluded that in the design of the bondline thickness, the bonding method and the temperature range should be considered simultaneously to reduce the temperature-induced stress and aberration and to increase the natural frequency.