Experimental testing and FEM simulation for thermal imprinting of micro/nano glass-optical devices

Thermal imprinting of glass-optical devices and its numerical simulation using the finite element method were investigated. The constitutive equation of the glass material was estimated using compression creep tests based on conventional thermoviscoelastic theory. The relaxation modulus of D263 glass was approximated by the generalized Maxwell model. For glass thermal imprinting, a glassy carbon die was used on which line and space or microlens array patterns were machined with a focused ion beam (FIB). The optimum molding-temperature condition that gives precise transcription profile was investigated in detail. Finite element analyses were performed to simulate the experimental glass thermal imprinting. In comparing experimental and numerical results, the transcription heights of groove or microlens obtained by experimental tests approximately agreed with numerical values. Finite element analyses using thermoviscoelastic property of glass are reliable in estimating suitable conditions for glass thermal imprinting.