• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.191-194
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• 2004

본 연구에서는 광 스케너 반사경(mirror)의 torsion bar모양을 변화시키고, 반사경 밑 양단에 magnet를 장착시켜 낮은 구동전압에서 동작되게 함으로써 Scanner의 효율을 개선하였다. torsion bar의 모양은 I형에서 S형 타입으로 변화시킴으로써 일반적인 광 스케너의 공진주파수(50Hz)보다 낮은 주파수(35.8Hz)에서 높은 반사각(약$10^{\circ}$)을 얻을 수 있었다. 또한 광 스케너에 일반적으로 사용되는 정전 액튜에이터 대신 자기 액튜에이터를 사용함으로써 공기 중의 먼지나 습기 등 외부요인을 감소시켰다.

• Journal of Magnetics
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• v.18 no.2
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• pp.163-167
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• 2013

We fabricated prototype cantilevers for mechanically detected high-frequency ESR measurement. Cantilevers are fabricated from silicon-on-insulator (SOI) wafers using standard MEMS techniques such as lithography, wet etching, and plasma etching. Using commercial SOI wafers, fabrication cost and the number of processes can be substantially reduced. In this study, three types of cantilevers, designed for capacitive and optical detection, are shown. Capacitive type with lateral dimensions of $3.5{\times}1.6mm^2$ is aimed for low spin concentration sample. On the other hand, optical detection type with lateral dimensions of $50{\times}200{\mu}m^2$ is developed for high-sensitive detection of tiny samples such as newly synthesized microcrystals.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.320-321
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• 2003

위성통신 및 무선통신에서 안테나의 수신 감도를 향상시키기 위한 노력은 계속되어 왔다. 안테나의 지향성을 높이기 위하여 다수의 동형 단위 안테나들을 일정 방향으로 배열하여 안테나를 기계적으로 회전시키지 않고, 고정된 다수의 동형 단위 안테나들에서 방사되는 전파의 위상을 전자적으로 변화시켜 방사 빔을 주사하는 방법, 즉 위상배열 안테나(Phased Array Antenna)를 널리 사용하고 있다. 위상배열 안테나의 단위 안테나에서 방사되는 전파의 위상을 변화시키기 위해선 실시간 시간지연 시스템이 필요하다. (중략)

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.203-209
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• 2004

Compliant bi-stable mechanism allows two stable states within its operation range staying at one of the local minimum states of the potential energy. Energy storage characteristics of the bi-stable mechanism offer two distinct and repeatable stable states, which require no power input to maintain it at each stable state. This paper suggests an equivalent model of the chevron-type bi-stable microactuator using the equivalent spring stiffness in the rectilinear and the rotational directions. From this model the range of spring stiffness where the bi-stable mechanism can be operated is analyzed and compared with the results of the FEA (Finite Element Analysis) using ANSYS for the buckling analysis, both of which show a good agreement. Based on the analysis, a newly designed chevron-type bi-stable MEMS actuator using hinges is suggested for the latch-up operation. It is found that the experimental response characteristics of around 36V for the bi-stable actuation for the 60$mu extrm{m}$ stroke correspond very well to the results of the equivalent model analysis after the change in cross-sectional area by the fabrication process is taken into account. Together with the resonance frequency experiment where 1760Hz is measured, it is shown that the chevron-type bi-stable MEMS actuator using hinges is applicable to the optical switch as an actuator.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.1
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• pp.54-61
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• 2012

In this paper, the pose estimation method for the satellite GTB (Ground Test Bed) using vision/MEMS IMU (Inertial Measurement Unit) integrated system is presented. The GTB for verifying a satellite system on the ground is similar to the mobile robot having thrusters and a reaction wheel as actuators and floating on the floor by compressed air. The EKF (Extended Kalman Filter) is also used for fusion of MEMS IMU and vision system that consists of a single camera and infrared LEDs that is ceiling landmarks. The fusion filter generally utilizes the position of feature points from the image as measurement. However, this method can cause position error due to the bias of MEMS IMU when the camera image is not obtained if the bias is not properly estimated through the filter. Therefore, it is proposed that the fusion method which uses the position of feature points and the velocity of the camera determined from optical flow of feature points. It is verified by experiments that the performance of the proposed method is robust to the bias of IMU compared to the method that uses only the position of feature points.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.195-198
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• 2002

현재의 광통신, 이동통신 및 디지털 시대에서는 보다 소형화되고, 대용량의 데이터 저장 및 다기능 소자에 대한 요구가 많아지고 있다. 이러한 전자 산업 환경에서 MEMS 소자는 여러 요구조건을 만족시킬 수 있는 특징을 갖추고 있으며 실제 소자의 제작에 있어서 MEMS 소자를 이용하여 여러 물리 및 화학 센서 및 Actuator 제작에 응용이 되어지고 있고 Optical switch, Gyroscope, 적외선 어레이 센서, 가속도 센서, 위치 센서 등 여러 분야에서 실용화가 진행되어지고 있다. MEMS 구조물의 packaging 방법에 있어서는 내부 MEMS 소자의 동작을 위한 외부 환경으로부터의 보호를 위하여 Hermetic sealing에 대한 요구를 만족시켜야 한다. 본 발표에서는 이와 같은 MEMS device의 진공 패키지를 구현함에 있어서 기판 내부에 수동소자를 실장할 수 있는 LTCC 기술을 이용하여 진공 패키징하는 방법에 대하여 소개한다. 본 기술을 이용하는 경우 기존의 Hermetic sealing 이외에 향후 적층 기판 내부에 수동소자를 내장시켜 배선 길이 및 노이즈 성분을 감소시켜 더욱 전기적 성능을 향상시킬 수 있는 장점이 있게된다. 본 논문에서는 LTCC 기판을 이용하여 패키징 시킨 후, 내부 진공도에 영향을 줄 수 있는 계면들에서의 시간에 따른 진공도 변화의 특성치를 측정하여 LTCC 기판의 Hermetic sealing 특성에 관하여 조사하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.258-259
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• 2004

• Progress in Medical Physics
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• v.25 no.2
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• pp.116-121
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• 2014

Next future, The bio technology will be a rapidly developing. This paper is the scattering beam measurement of the red blood cell (RBC) and the fabrication of the micro cell biochip using the bio micro electro mechanical system (Bio-MEMS) process technology. The Major process method of Bio-MEMS technology was used the buffered oxide etchant (BOE), electro chemical discharge (ECD) and ultraviolet sensitive adhesives (UVSA). All experiments were the 10 times according to the process conditions. The experiment and research are required the ultraviolet expose, the micro fluid current, the cell control and the measurement of the output voltage Vpp (peak to peak) waveform by scattering angles. The transmitting and receiving of the laser beam was used the single mode optical fiber. The principles of the optical properties are as follows. The red blood cells were injected into the micro channel. The single mode optical fiber was inserting in the guide channel. The He-Ne laser beam was focusing in the single mode optical fiber. The transmission He-Ne laser beam is irradiating to the red blood cells. The manufactured guide channel consists of the four inputs and the four outputs. The red blood cell was allowed with the cylinder pump. The output voltage Vpp waveform of the scattering beam was measured with a photo detector. The receiving angle of the output optical fiber is $0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$. The magnitude of the output voltage Vpp waveform was measured in the decrease according to increase of the reception angles. The difference of the output voltage Vpp waveform is due differences of the light transmittance of the red blood cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1050-1053
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• 2002

This paper presents metal structure that is fabricated using UV-LIGA process with PMER N-CA3000. In order to fabricate metal structure with high aspect ratio, the systematic optimization method was adopted and then the structure of $36{\mu}m$ thick mold with aspect ratio 7:1 (trench) and $32{\mu}m$ thick nickel structure was obtained. This structure is applied to the fabrication of optical switch.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.263-266
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• 2007

We report a nickel optical MEMS switch, being able to rotate through a large angle and to accommodate multiple channels. The proposed optical switch consists of a thin nickel mirror and two torsion springs supporting the mirror. The torsion springs are designed using a finite element method (FEM) such that plastic deformation of the thin nickel is avoided during the large torsion actuation. For switching speed improvement, transient vibration of the released mirror is suppressed by optimizing the mirror design and a fast switching response of $200\;{\mu}s\;(pull-down)/300\;{\mu}s\;(pull-up)$ is demonstrated.