• 한국정밀공학회지
• /
• 제26권9호
• /
• pp.135-142
• /
• 2009

In the present study replication of microstructured surfaces by microinjection molding was carried out. For a fabrication of mold inserts, nickel microstructures having various characteristic dimensions were fabricated by nickel electroforming onto Si mother microstructures. In addition, reverse nickel microstructures based on the electroformed nickel microstructures were successfully realized by electroforming with passivation process. The fabricated nickel microstructures were used as mold inserts for a replication of microstructured surfaces by microinjection molding. Microinjection molding experiment was carried out under three different processing conditions, which revealed effects of a packing stage and mold wall temperature. The microinjection-molded microstructured surfaces were characterized by using an atomic force microscope (AFM). It was found that mold wall temperature could enhance replication quality resulting in the precise microstructured surfaces.

• 대한기계학회논문집A
• /
• 제34권7호
• /
• pp.859-866
• /
• 2010

본 연구에서는 다단 마이크로 구조물의 대량성형을 위하여, 모듈화된 초소형몰드 시스템(MSMS)을 이용한 초소형 사출성형 공정을 수행하였다. 본 연구에서 적용된 초소형몰드 시스템은 여러 모듈들로 구성되어 있으며, 각 모듈들은 다양한 단면 마이크로 구조물을 가지고 있다. 초소형몰드 시스템의 모듈들은 X-선 리소그래피 공정 및 니켈 전주도금 공정으로 제작되었으며, 다양한 모듈들을 조합 및 결합함으로써 복잡한 형상을 가지는 초소형몰드 시스템을 효과적으로 구현할 수 있다. 이와 같은 초소형몰드 시스템을 적용함으로써, 본 연구에서는 다단 구조물의 표면에 마이크로 삼각 프리즘이 주기적으로 배열되어 있는 다단 마이크로 구조물의 초소형 사출성형 공정을 성공적으로 수행하였다.

• 소성∙가공
• /
• 제15권1호
• /
• pp.34-41
• /
• 2006

Microlens arrays were fabricated by a modified LIGA process composed of the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, both hot embossing and microinjection molding processes have been successfully utilized with the fabricated mold insert. Replicated microlenses showed very good surface roughness with the order of 1 nm. The focal lengths of the injection molded microlenses were successfully estimated theoretically and also measured experimentally.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
• /
• pp.23-28
• /
• 2005

Microlens arrays were fabricated using a modified LIGA process based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, the hot embossing and the microinjection molding processes have been successfully utilized with the fabricated mold insert. Fabricated microlenses showed good surface roughness than the mold insert. The focal lengths of the injection molded microlenses were successfully measured experimentally and also estimated theoretically.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2012년도 추계학술대회 논문집
• /
• pp.465-466
• /
• 2012

• 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.

• 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.