Microformability of optical glasses for precision molding

We investigated macroscopic and microscopic deformation of optical glasses K-PSK100 and K-PG375 for precision molding. The materials are characterized by a low glass transition temperature T_g; T_g is 663 K for PSK100 and 616 K for PG375. The materials exhibit Newtonian viscous flow above T_g. We studied the temperature dependence of the normal viscosity and evaluated the microformability by the geometrical transferability of a V-grooved die shape to the material. The dies were made of (100)Si and the width of the V-groove W_g was 0.1-2.0μm. After die-forming, we measured the transferred shape of the material with AFM and analyzed the curvature r of the tip of the deformed specimen and the formed and filled area to the V-groove R_f. As a result, we found that the materials exhibit superior microformability due to the homogeneity on a nanometer scale and will be applied to micro- or nano-forming and thus contribute to mass production of micro/nano-devices.