• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.934-937
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• 2001

It is well-known that the micro fabrication technology of micro parts are the high energy beam or silicon-based micro machining method such as LIGA Process, Laser machining, photolithography and etching technology. But, for fabricating complex 3-D structure it is better to use mechanical machining. This machining method by the mechanical machine tool with nanometer accuracy is getting attention in some field-especially micro optics machining such as grating, holographic lens, micro lens array, fresnel lens, encoder disk etc.. In this study, we survey the micro fabrication by mechanical cutting method and set up the mechanical micro machining system. And we carried out micro cutting experiments for micro parts with v-shape groove.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.581-582
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• 2000

본 논문에서는 적외선과 같이 주파수가 Tera Hz 영역인 극초고주파에서 사용할 수 있는 Horn형 안테나의 제조를 위한 독창적인 방법을 제시하고 실험적인 검증을 하였다. 파장이 $10{\mu}m$ 부근인 전자기파에 대응될 수 있는 안테나의 구조에 대한 시뮬레이션을 하였으며 이를 기준으로 안테나 어레이를 제조하기 위한 기초실험을 하였다. 기존에 사용되던 LIGA-like 공정과는 대조적으로 Columnar illumination 방법을 사용하였으며 $300{\mu}m$ 두께의 SU-8에 대하여 수직벽을 제조할 수 있었고 기판 위치에 일정한 각도를 줌으로서 경사면을 갖는 구조를 제조하였으며 기판을 회전시킴으로서 원뿔형의 Horn형 안테나 어레이를 제조할 수 있는 방안을 제시하였다.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.204-205
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• 2002

Co(P) 합금은 전기화학적으로 제조되는 강자성 재료 중 그 자기적 특성이 우수하여 이미 1960년대부터 연구가 진행되었으며$^{1)}$ 1980년대까지는 주로 무전해도금에 의해 제조되다가$^{2.3)}$ 1990년대 이후부터는 LIGA(Lithographie Galvanoformung Abformung) 공정이나 패터닝 공정과의 공정 통합의 용이성 때문에 전기도금방식이 주류를 이루고 있다.$^{4.5)}$ 그러나 전기도금에 의해 제조된 대부분의 Co(P) 합금은 P의 함량이 과다하여 비정질상태로 존재하며 추가적인 열처리 공정이 요구되고 자기적 성질도 좋지 못한 단점이 있었다. (중략)

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.245-250
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• 2005

Recently, micro machining technology for high precision mold becomes more interested for mass production of high performance optical parts micro-grooved on the surface, which is under very active development due to its effectiveness in the view point of optical performance. Mechanical micro machining technology now has more competitiveness on lithography, MEMS or LIGA processes which have some problems to fabricate especially cylinder type of groove in such as lenticular lens for illumination angle modulation system. In this study. a lenticular lens mold with U-type micro groove is fabricated making utilizing of the benefit of the mechanical micro machining technology. A shaping machining process is adapted using 3 axis degree of freedom micro machining system and single crystal natural diamond tool. A brass and a electroless nickel materials are used for mold fabrication. Machining force, chip shape and machined surface are investigated from the experiment and an optimal machining condition is found based on the examined problems from the micro cutting process.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.55-61
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• 1998

Recently, the needs of machining technologies of very small parts have been increasing with advent of micro-revolution. These technologies have mostly used the method applied to semi-conductor production process such as LIGA, etc. But they have serious difficulties to settle down in terms of workpiece materials, machining thickness, 3-dimensional structure. Therefore. mciro-machining technology using EDM(Electrical Discharge Machining) was proposed. It is very difficult to machine the micro-parts (microshaft, microhole) using conventional machining. Micro-machining using BDM can machine the micro-parts easily because it requires little machining force. This MEDM(Micro-EDM) need the capabilities to move a electrode and control a discharge energy precisely, and the gap control strategy to maintain the optimal discharge condition is necessary. Therefore, in this study, the new EDM machine with high precision motion stage and high-performance EDM device was developed. Using this MEDM machine, we have machined microshaft and microhole with various shapes and sizes.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.192-193
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• 1998

At Rutherford Appleton Laboratory(RAL), a high-repetition rate ps exicmer laser-plasma x-ray source has been developed for x-ray lithography with a calibrated output of up to 1 watt X-ray average power at 1nm wavelength. In a previous reports this compact x-ray source was used to print 0.18$\mu$m lines for a gate on Si-FET devices and deep three-dimensional structure with 100$\mu$m length, 25$\mu$m width, and 48 $\mu$m depth for a nanotechnology. The deep X-ray lithography is called as LIGA thchnology and getting a wide interest as a new technology for a nano-device. In this report all this works are summarized.

• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2094-2104
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• 2006

As demands for complex microstructures with high aspect ratios have increased, the existing methods, MEMS and LIGA, have had difficulties coping with the number of masks and fabricable heights. A microstereolithography technology can meet these demands because it has no need of masks and is capable of fabricating high aspect ratio microstructures. In this technology, 3D part is fabricated by stacking layers, 2D sections, which are sliced from STL file, and the Dynamic Image Projection process enables the resin surface to be cured by a dynamic image generated with $DMD^{TM}$ (Digital Micromirror Device) and one irradiation. In this paper, we address optical design process for implementing this microstereolithography system that takes the light path based on DMD operation and image-formation on the resin surface using an optical design program into consideration. To verify the performance of this implemented microstereolithography system, complex 3D microstructures with high aspect ratios were fabricated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.11a
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• pp.249-254
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• 2004

광의 효율적 사용을 위해 표면에 마이크로 그루브가 새겨진 고성능 광학 부품의 개발이 활발하고, 이들 부품의 다량 생산을 위한 초정밀 금형제조기술이 각광을 받고 있다. 최근의 초정밀 미세 기계가공의 경우 간단한 공정으로 이러한 마이크로 그루브 금형을 제작할 수 있다. 특히 조명각 변조용 렌티큘러 렌즈와 같이 실린더형 그루브 금형의 경우에는 기존의 Lithography, MEMS, LIGA 등 광 에너지를 이용한 다른 제조방법들에서는 가공하기 어려운 점이 있으나, 기계가공에서는 쉽게 제작가능한 장점이 있다. 본 연구에서는 이러한 미세기계가공기술의 장점을 활용하여 U 형 마이크로 그루브를 가진 Lenticular 렌즈용 금형을 가공하고자 하였다. 가공에는 3 축 구동의 초정밀 미세 복합가공기와 단결정 천연 다이아몬드공구가 사용되었고, 가공방식은 마이크로 세이핑 공정을 적용하였으며, 가공 금형 재료에는 Brass와 무전해 Nickel이 사용되었다. 실험을 통하여 금형가공시의 절삭력, 칩 형상, 가공표면 등의 분석이 수행되었으며 이를 기반으로 여러 가지 가공문제점을 해결하고, 최종적으로 양호한 렌티큘러렌즈용 금형을 가공하였다.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.116-125
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• 2006

MEMS and LIGA technologies have been used for fabricating microstructures, but their shape is not 3D because of difficulty for preparation of many masks. To fabricate 3D microstructures, microstereolithography technology based on Digital Micromirror Device($DMD^{TM}$) was introduced. It has no need of masks and is capable of fabricating high aspect ratio microstructures. In this technology, STL file is the standard format as the same of conventional rapid prototyping system, and 3D parts are fabricated by layer-by-layer according to 2D section sliced from STL file. The UV light source is illuminated to DMD which makes bitmap images of 2D section, and they are transferred and focused on resin surface. In this paper, we addressed optical design of microstereolithography system in consideration of light path according to DMD operation and image-forming on the resin surface using optical design program. To verify the performance of implemented microstereolithography system, 3D microstructures with complexity and high aspect ratio were fabricated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.95-98
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• 2006

LCD-BLU (Back Light Unit) is one of kernel parts of LCD unit. The fabrication method of a 3-D micro mold patterned with micro-lenses for the LGP (Light Guiding Plate), one of the most important parts of LCD-BLU, was presented. Instead of dot pattern made by etching, 3-D optical pattern design with $50{\mu}m$ micro-lens was applied in the present study. The micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP. The positive micro-lens patterned injection mold with different aspect ratios (i.e. 0.3 and 0.4) was fabricated with modified LiGA with thermal reflow process. The brightness of LCD-BLU increased as aspect ratio of micro-lens increased.