• 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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.834-840
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• 2010

Photo lithography process is very important technology to fabricate highly integrated micro patterns with high precision for semiconductor and display industries. Up to now, mask type lithography process has been generally used for this purpose; however, it is not efficient for small quantity and/or frequently changing products. Therefore, in order to obtain higher productivity and lower manufacturing cost, the mask type lithography process should be replaced. In this study, a maskless lithography system using the DMD(Digital Micromirror Device) is developed, and the exposure condition and optical properties are analyzed and simulated for a single beam case. From the proposed experimental conditions, required exposure experiments were preformed, and the results were investigated. As a results, 10${\mu}m$ spots can be generated at optimal focal length.

• Journal of Information Display
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• v.11 no.2
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• pp.76-83
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• 2010

This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.38-39
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• 2000

마치 살아있는 것처럼 움직이는 영상을 보고자 하는 인류의 욕구가 19세기에 다양한 광학 기구들을 낳게 했는데, 이 중의 하나가 영화이다. 이러한 필름을 기초로 한 투사기술은 그러한 인간의 욕구를 작게나마 해소시켰지만, 수평선 저 너머에서 일어나는 일을 동시에 눈으로 보고 싶어하는 꿈을 실현시켜 주진 못했다. 하지만 이러한 생방송을 할 수 없는 필름기술의 한계는 CRT라고 하는 전자 투사 디스플레이(electronic projection display)의 도움으로 극복되었다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.67-68
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• 2007

• The Optical Journal
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• s.98
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• pp.60-66
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• 2005

프로젝터와 프로젝션 TV는 공통적으로 광학엔진내에 신호 처리된 영상 정보를 표시해주는 CRT(Cathode Ray Tube), LCD(Liquid Crystal Device), LCoS(Liquid Crystal on Silicon), 디지털 마이크로 미러 디바이스(Digital Micromirror Device;DMD)등의 디스플레이 소자가 사용된다. 최근 이러한 디스플레이 소자는 소형화·경량화 되어지는 추세에 있으며 무겁고 두꺼운 CRT보다는 LCD를 이용한 프로젝션 시스템들이 속속 출시되고 있다. LCoS 및 DMD를 이용한 시스템들도 출시 또는 개발되고 있는 실정이다. 특히, 현재까지는 LCD가 주류였지만, 고해상도 구현에 유리한 반면, 개발속도가 느린 LCoS에 비해 하이 콘트라스트(High Contrast) 구현에 탁월하고 개발 속도가 빠른 DMD를 이용한 프로젝션 시스템의 개발 및 출시가 주로 진행되고 있다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.268-269
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• 2003

삼성전자는 LCD 방식에 이은 3세대 프로젝션 모델로 평가받는 DMD (Digital Micromirror Device) 기술을 채용한 43‘’, 50‘’, 61‘’ DLP (Digital Light Processing) 프로젝션 TV를 개발 시판하고 있다. DMD 기술이란 921,600개의 미세한 거울들이 신호에 따라 반사각도를 조절하며 이미지를 구현하는 기술이다. 삼판식 프로젝션 시스템의 단점을 개선, 경박단소와 저가격화를 위하여 단판식을 이용하는 DLP 프로젝션 TV 의 경우 Red, Green, Blue 로 이뤄진 칼라휠을 회전시킴으로서 DMD 위에 연속적으로 삼색의 영상을 재생하여 색을 분리 합성한다. (중략)

• 전기의세계
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• v.45 no.9
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• pp.37-41
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• 1996

MEMS 기술에 의해 개발되고 있는 많은 제품들 가운데 가장 잠재력 있고 큰 시장을 가진 대형 projector의 개발은 핵심 chip이 현재 DMD(Digital Micromirror Device), AMA(Actuated Mirror Array), 그리고 GLV(Grating Light Valve) 방식으로 진행되고 있으며 TI사가 개발 중인 DMD projector가 상품화에 근접해 있으며 고화질의 시제품을 SID(Society for Information Display) 국제 전시회에 출품하여 전세계 연구원들의 이목을 끌었으며 앞으로 어떻게 수율을 높이고 광학계의 단순화를 이루어 제작비를 낮추는 가가 관심의 초점이다. MEMS 연구를 하는 한 사람으로서의 사견으로도 이 제품이 성공하여야 범세계적으로 일어나고 있는 MEMS 기술이 더욱 확실한 신기술로서의 지위를 갖고 연구되리라 믿는다.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.148-149
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• 2007

We present the design and fabrication prcoess of a two-axis tilting micromirror device driven by the electrostatic vertical comb actuator. A high aspect-ratio comb actuator is fabricated by multiple DRIE process in order to achieve large scan angle. The proposed fabrication process enables a mirror to be fabricated on the wafer-scale. By bonding a double-side polished (DSP) wafer and a silicon-on-insulator (SOI) wafer together, all actuators on the wafer are completely hidden under the reflectors. Nickel lines are embedded on a Pyrex wafer for the electrical access to numerous electrodes of mirrors. An anodic bonding step is implemented to contact electrical lines with ail electrodes on the wafer at a time. The mechanical angle of a fabricated mirror has been measured to be 1.9 degree and 1.6 degree, respectively, in the two orthogonal axes under driving voltages of 100 V. Also, a $8{\times}8$ array of micromirrors with high fill-factor of 70 % is fabricated by the same fabrication process.

• Design & Manufacturing
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• v.15 no.4
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• pp.65-71
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• 2021

In the early days of laser invention, it was simply used as a measuring tool, but as lasers became more common, they became an indispensable processing tool in the industry. Short-wavelength lasers are used to make patterns on wafers used in semiconductors depending on the wavelength, such as CO2 laser, YAG laser, green laser, and UV laser. At first, the hole of the PCB board mainly used for electronic parts was not thin and the hole size was large, so a mechanical drill was used. However, in order to realize product miniaturization and high integration, small hole processing lasers have become essential, and pattern exposure for small hole sizes has become essential. This paper intends to analyze the characteristics through patterns by exposing the PCB substrate through DMD and polygon scanner, which are different optical systems. Since the optical systems are different, the size of the patterns was made the same, and exposure was performed under the optimal conditions for each system. Pattern characteristics were analyzed through a 3D profiler. As a result of the analysis, there was no significant difference in line width between the two systems. However, it was confirmed that dmd had better pattern precision and polygon scanner had better productivity.