Papers by Author: Chun Chieh Chen

Abstract: Owing to the fast development in photonic, telecommunication, and opto-electronic industries, the demand for various micro-lens arrays is rapidly growing. The slow tool servo technique was applied on an ultra-precision diamond turning machine in the present research in conjunction with the tool path generating algorithm for aspheric micro-lens array fabrication. An aspheric lens array of 100% filling factor was successfully produced and the form accuracy and surface roughness were better than 0.15μm and 3nm for all the obtained lenses.

Abstract: Micro lens array is widely used in photonics and telecommunication products, including back-light module of flat panel display devices and white-light LED illumination. The ultra precision diamond shaping method together with tool servo technique was studied and developed in this research to generate elliptical micro lens array. Each elliptical micro lens has radii in X and Y direction of 1.0 mm and 1.5 mm respectively. A high filling-factor (100 %) elliptical micro lens array with form accuracy better than 0.15μm and surface roughness around 5nm Ra was successfully fabricated.

Abstract: Stainless steel and other ferrous metals are normally classified as not diamond turnable for the unacceptable tool wear caused by the thermal-chemical reaction between diamond and ferrous metals. In the present research, stainless steel specimens were plasma nitrided at a relatively low temperature (<450oC) to prevent the depletion of Cr content at the austenite matrix and to give a hardened layer where Fe atoms are bonded to nitrogen atom to form γ’-Fe4N. Diamond turning experiments were subsequently carried out under the following machining conditions: single crystal diamond tool, cutting speed up to 180 m/min, cut depth up to 5μm and light mineral oil as the cutting fluid. The results showed that, given the same machining conditions, while rapid tool wear and poor surface finish were obtained when turning the as-received stainless steel, surfaces with Ra better than 3nm and no obvious tool wear were achieved when turning the plasma nitrided specimens