• 한국정밀공학회지
• /
• 제32권3호
• /
• pp.299-305
• /
• 2015

In this paper, we propose a simple and low-cost fabrication method of polymer microlens using solvent-vapor-assisted reflow (SVAR). Metal molds for replication of polymer were fabricated using micro milling and the cylindrical shape of polymer was imprinted using hot-embossing process. The cylindrical shape of polymer was changed to hemispherical lens shape by SVAR. The characteristics of fabricated microlens were evaluated according to the condition of SVAR such as temperature and time. The focal length of polymer microlens could be controlled more easily in low-temperature and long-time condition than in high-temperature and short-time condition. That is, the level of concentrated light to focal point could be improved through the control of temperature and time. Also, we confirmed that toluene was more appropriate solvent than acetone in fabrication of PMMA polymer microlens using SVAR.

• 한국정밀공학회지
• /
• 제30권10호
• /
• pp.1111-1117
• /
• 2013

In this paper, the shape accuracy of the stamped hat-type product is quantified and analyzed with ultra high strength steel (UHSS) sheets. The shape of the hat-type product is designed in order to simplify the geometry of the side sill and the stamping methodology is proposed in order to verify the effect of the stamping procedure on the springback amount. Experiments and finite element analyses are conducted with four kinds of the forming sequences. The springback amounts are measured and compared according to the forming procedure with the embossing shape. Experimental result in company with analysis one illustrate that the springback amount is reduced with embossing in the padding operation. They also fully demonstrates the proposed forming procedure and the analysis method can be effectively applied to the process design for producing parts with ultra high strength steel.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2006년도 춘계학술대회 논문집
• /
• pp.86-90
• /
• 2006

Nanoimprint lithography (NIL) is a novel method to fabricate nanometer scale patterns. It is a simple process with low cost, high throughput and high resolution. NIL process creates patterns by the mechanical deformation of imprint resist and physical contact process. This physical contact process causes the stiction between the resist and the stamp. Stiction becomes a key issue especially in the stamps including narrow pattern size and wide area during NIL process development. The antistiction layer coating using fluorocarbon is very effective to prevent this problem and ensure successful NIL. In this paper, the concept of antistiction coating is explained and different preparation methods for nanoimprinting are briefly discussed.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.632-635
• /
• 2003

As a process technology of nano pattern with a new conception for economic and practical technology of alternative nano process. process technologies such as Embossing, Imprinting. Molding and Inking are beginning to make its appearance. Among these alternative processes, nano mold process is a process that is of benefit to mass production and keeps excellency of reproduction and high quality of parts. In this study, we experienced micro precision machining technology of nano stamper for the injection mold of optical disk with big capacity. Especially, Flatness and uniformity are important for nano stamper with global area, for the purpose of developing polishing technology of micro precision of Back polishing only being used for nano stamper, we carried out a basic study to secure flatness standards

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2001년도 추계학술대회 논문집
• /
• pp.287-291
• /
• 2001

In this study, we designed and constructed a multi-forming progressive die with a bending, embossing on the multi-stage and performed through the try out. Out of the characteristics of this paper that nothing might be ever seen before such as this type of research method on the all of processes of thin and high precision production part.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2002년도 학술대회논문집
• /
• pp.233-237
• /
• 2002

In consideration for evaluating urban lighting plan as culture of a society, preparing lighting plan while designing urban plan is a fundamental process. This study proposes a methodology, maintaining and embossing urban throughout preparing a long-term urban lighting plan considering overall urban space as well as improving competitive power for lighting to take an important role in total environmental design project.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.525-526
• /
• 2010

• 한국광학회:학술대회논문집
• /
• 한국광학회 2006년도 하계학술발표회 논문집
• /
• pp.185-186
• /
• 2006

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 The Korea-Japan Plastics Processing Joint Seminar
• /
• pp.7-13
• /
• 2003

Microlens arrays were fabricated using a novel fabrication technology based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep X-rays and subsequent thermal treatment. X-ray irradiation causes the decrease of molecular weight of PMMA, which in turn decreases the glass transition temperature and consequently causes a net volume increase during the thermal cycle resulting in a swollen microlens. A new physical modeling and analyses for micro lens formation were presented according to experimental procedure. A simple analysis based on the new model is found to be capable of predicting the shapes of micro lens which depend on the thermal treatment. For the replication of micro lens arrays having various diameters with different foci on the same surface, the hot embossing and the microinjection molding processes has been successfully utilized with a mold insert that is fabricated by Ni-electroplating based on a PMMA microstructure of micro lenses. Fabricated microlenses showed good surface roughness with the order of 1nm.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 춘계학술대회논문집
• /
• pp.465-469
• /
• 2003

Microlens arrays were fabricated using a novel fabrication technology based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep X-rays and subsequent thermal treatment. X-ray irradiation causes the decrease of molecular weight of PMMA, which in turn decreases the glass transition temperature and consequently causes a net volume increase during the thermal cycle resulting in a swollen microlens. A new physical modeling and analyses for microlens formation were presented according to experimental procedure. A simple analysis based on the new model is found to be capable of predicting the shapes of microlens which depend on the thermal treatment. For the replication of microlens arrays having various diameters with different foci on the same surface, the hot embossing and the microinjection molding processes has been successfully utilized with a mold insert that is fabricated by Ni-electroplating based on a PMMA microstructure of microlenses. Fabricated microlenses showed good surface roughness with the order of 1 nm.