• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.599-600
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• 2008

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.254-255
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• 2004

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.04a
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• pp.15-19
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• 2003

Polymeric micro lens arrays with diameters of $13\~96\;{\mu}m$ fabricated using the micro-compression molding with electro formed mold inserts. In the present study, the electro forming process was used to make the metallic micro-mold insert for micro-molding of microlens array. The wettability property of the fabricated mold insert was examined by measuring the contact angle of the polymer melt on the mold insert. Microlenses were compression-molded with the fabricated mold insert. The effects of the molding temperature and wettability property on the replication quality of the molded lenses were analyzed experimentally.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.491-492
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• 2009

We have fabricated a microlens integrated silicon (Si) structure for optical interconnects. To form microlenses, the Si wafer was wet-etched with $SiN_x$ mask in a HF:$HNO_3:C_2H_4O_2$ solution and then the holes were filled with a AZ9260 photoresist. The focal length of microlens increased in proportional to its radius of curvature (ROC). For the ROC of $100-161{\mu}m$, the focal lengths were obtained approximately between $160{\mu}m$ and $310{\mu}m$, in an agreement with the simulated values using a ray tracing method.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1682-1683
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• 2011

Through-silicon microlens array has been implemented using glass thermal reflow process. Design, numerical analysis, fabrication, and measurement results are discussed. Microlenses with six different volumetric dimensions were successfully fabricated and characterized. Radius of curvature of each microlenses were measured with less than 1% deviation compared to calculated value. Measured average roughness of the microlens surface was 16.5 nm.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.21-26
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• 2006

A optical head unit for nano optical probe array was developed. The optical probe array is generated by Talbot effect. The shape and thickness of microlens array(MLA) were designed to minimize the spot size at the foci of MLA. To increase the optical efficiency of the system and obtain the large tolerance for fabrication, aperture size was theoretically optimized. Then microlens illuminated aperture array(MLIAA) as an optical head unit was fabricated using a ultra violet(UV) molding process on aluminum aperture array. In this process, Al aperture array was fabricated separately using the photolithography and reactive ion etching(RIE) process. Optical properties of the generated optical probes were measured and compared at Talbot distance from the aperture array having a diameter of $1{\mu}m$ and MLIAA.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1332-1336
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• 2003

An experimental method is presented to maximize the replication quality of UV-molded micro-optical components. It is important to maximize the replication quality, because one can obtain the replicated micro-optical components with desired properties by accurate control of the shape. In the present study, a simple technique to avoid micro-air bubbles was first suggested. The effects of the UV-curing dose and the compression pressure on the replication quality of UV-molded structure were examined experimentally. Finally, as a practical application of the process design method, microlens arrays with diameters between 8 ${\mu}m$ and 96 ${\mu}m$ were fabricated by the present method, and the replication quality and the optical properties of the replicated microlens were measured and analyzed.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.743-746
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• 2000

Plastic microlenses play an important role in reducing the size, weight, and the cost of the systems in the fields of optical data storage and optical communication. In the present study, plastic microlens arrays were fabricated using micro-compression molding process. The design and fabrication procedures for mold insert were simplified by using silicon instead of metal. A simple but effective micro compression molding process, which uses polymer powder, were developed for microlens fabrication. The governing process parameters were temperature and pressure histories and the micromolding process was controlled such that the various defects developing during molding process were minimized. The radius and magnification ratio of the fabricated microlens were $125{\mu}m$ and over 3.0, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.33-39
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• 2003

A new microlens fabrication technique, the excimer laser lithography is developed. This bases on the pulsed laser irradiation and the transfer of a chromium-on-quartz reticle on to the polymer surface with a proper projection optics system. An excimer laser lithography system with 1/4 and 1/20 demagnification ratios was constructed first, and the photoablation characteristics of the PMMA and Polyimide were experimentally examined using this system. For two different shapes of microlenses, a spherical lens and a cylindrical lens, fabrication techniques were investigated. One for the spherical lens is a combination of the mask pattern projection and fraction effect. The other for the cylindrical lens is a combination of the mask pattern projection and the relative movement of a specimen. The result shows that various shapes of micro optical components can be easily fabricated by the excimer laser lithography.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.94-97
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• 2002

Micromolding methods are most suitable for mass production of plastic microlens and lens array with low cost. Among the procedures related with micromolding of microlens array, fabrication of mold insect which contains micro cavity of lens shape is the most important stage. In this study, nickel mold inserts for 45 $\mu\textrm{m}$ and 95 $\mu\textrm{m}$ diameters lens way were fabricated using electroforming process. The mother for metal mold inset was made using reflow method. A micro compression molding with polymer powders was used to test the qualities of the metal mold insets. Micro lens profile and surface roughness was measured by interferometric technique and AFM, respectively. The final molded lens replicated the mother well, and had good surface quality.