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A transparent poly methyl methacrylate (PMMA) optical micro-pyramid array-pattern is designed and fabricated using an injection modeling technique. The device`s optical characteristics are tested and analyzed theoretically. In the optical pattern generated using the fabricated PMMA pattern, the components, due to not only refraction but also diffraction, are observed simultaneously. Wave optic modeling and analysis reveals that the energy ratio between the diffraction and refraction in the optical pattern are dependent on the critical dimension of the optical pattern such that the refraction and diffraction tend to be directly and inversely proportional to the pattern dimension, respectively.

The specular hologram is one type of hologram, and it consists of many arcs. They are very easy to fabricate and can even be machined by hand and a compass. In this study, we designed two squares having different depths and consisting of many arcs, after which we machined the arcs using end-mill technology. The width of the machined arcs showed high repeatability. Moving tracks were observed on the bottom surface, and top burrs were noted. In spite of them, the phenomenon of the specular hologram was observed when an observer and a light source stood on the same side. The two squares seemed to have different depths when they were observed from the left and right directions. In this study, it was verified that a specular hologram can be manufactured by end-mill technology. Key Words : End-mill(엔드밀), Specular Hologram(스페큘러 홀로그램), Machining(가공), Arc(호) * Dept. of Nano Manufacturing Technology, KIMM # Corresponding Author : Dept. of Nano Manufacturing Technology, KIMM E-mail : jeonec@kimm.re.kr** Dept. of Nano-Mechatronics, UST Korea*** School of Elec. and Info. Eng., Korea Univ.**** School of Mechanical Eng., Pusan National Univ.

Ultra-fine planing and micro punching are separately used for improving surface roughness and machining dot patterns, respectively, of metal molds. If these separate machining processes are applied for machining of identical molds, there could be an aligning mismatch between the machine tool and the mold. A hybrid machining system combining ultra-fine planing and micro punching was newly developed in this study in order to solve this mismatch; hybrid process technology was also developed for machining dot patterns on a mirror surface of a metal mold. The hybrid machining system has X, Y, and Z axes, and a cam axis for ultra-fine planing. The cam axis and attachable and removable solenoid actuators for micro punching can make large and small sizes of dot patterns, respectively. Ultra-fine planing was applied in the first place to improve the surface roughness of a metal mold; the measured surface roughness was about 20nm. Then, micro punching was applied to machine dot patterns on the same mold. It was possible to control the diameter of the dot patterns by changing the input voltage of the solenoid actuator. Before machining, severe inhomogeneous plastic deformation around the machined dot patterns was also removed by annealing heat treatment. Therefore, it was verified that metal molds with dots patterns for optical products can be machined using a hybrid machining system and the hybrid process technology developed in this study.