• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.224-225
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• 2006

$BaTiO_3$ powder를 epoxy/solvent에 혼합한 슬러리와 solvent에 혼합한 슬러리의 분산 특성을 평가하기 위하여 분산제인 silane을 $BaTiO_3$ powder 표면에 코팅한 powder를 이용하여 분산실험을 진행하였다. Silane 표면 코팅 량에 따른 $BaTiO_3$ 슬러리와 $BaTiO_3$/epoxy 복합 슬러리의 분산 특성은 서로 다른 경향으로 나타남을 확인하였으며, silanae 최적 첨가량은 $BaTiO_3$/solvent 슬러리의 경우 0.3~0.5 wt%, $BaTiO_3$/epoxy/solvent 슬러리의 경우 1wt% 이상 첨가한 조건이었다. 또한 분산성 측정의 방법으로 점도 측정 방법과 함께 표면 거칠기 측정 방법의 가능성을 확인하였다.

• Journal of electromagnetic engineering and science
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• v.5 no.3
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• pp.140-145
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• 2005

In this paper, an experimental investigation for return loss and a software-based prediction for interference level of single-packaged filtering antenna composed of dielectric waveguide filter and PCB(Printed Circuit Board) slot antenna in transceiver module have been carried out with several different feeding structures in millimeter-wave regime. The implementation and embedding method of the existing air-filled waveguide filters working at millimeter-wave frequency on general PCB substrate have been described. In a view of the implementation of each components, the dielectric waveguide embedded in PCB and LTCC(Low Temparature Co-fired Ceramic) substrates has employed the via fences as a replacement with side walls and common ground plane to prevent energy leakage. The characteristics of several prototypes of filtering antenna embedded in PCB substrate are considered by comparing the wideband and transmission characteristics as a function of bent angle of transmission line connecting two components. In addition, as an essential to the packaging of transceiver module working at millimeter-wave, miniaturization technology maintaining the performances of independent components and the important problems caused by integrating and connecting the different components in different layers are described in this paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.3
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• pp.130-138
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• 2010

The thermal reliability of the closed-type BLDC motor for the high speed axial fans is analyzed by a numerical method in this paper. Since the module and the motor part are combined in a closed case, the heat generated from a rotor in the motor and the electronic components in the PCB module can not be effectively removed to the outside. Therefore the module will easily fail by high temperature. The accelerated-life testing was accomplished to formulate the life equation and numerical method is used to predict the inside temperature of the PCB module, which is one of the life equation parameter according to the environment. When the environment temperature of BLDC motor is 21, 35 and 50 $^{\circ}C$, the temperature in the PCB space is predicted as 73.4, 87.5 and 102.4 $^{\circ}C$. Then the life time with the temperature are calculated as 2,239, 863 and 328 hours.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.265-271
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• 2008

TCP(Tape Carrier Package), COG (Chip On Glass), COF(Chip On Film) are three methods for connecting LDI(LCD Driver IC) with LCD panels. Especially COF is growing its portion of market place because of low cost and fine pitch correspondence. But COF has a problem of the lead broken failure in LCD module process and the usage of customer. During PCB (Printed Circuit Board) bonding process, the mismatch of the coefficient of thermal expansion between PCB and D-IC makes stress-concentration in COF lead, and also D-IC bending process during module assembly process makes the level of stress in COF lead higher. As an affecting factors of lead-broken failure, the effects of SR(Solder Resister) coating on the COF lead, surface roughness and grain size of COF lead, PI(Polyimide) film thickness, lead width and the ACF(Anisotropic Conductive Film) overlap were studied, The optimization of these affecting manufacturing processes and materials were suggested and verified to prevent the lead-broken failure.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.494-499
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• 2007

The thermal reliability of the closed-type BLDC motor for the high speed axial fans is analyzed by a numerical method in this dissertation. Since the module and the motor part are combined in a closed case, the heat generated from a rotor in the motor and the electronic components in the PCB module can not be effectively removed to the outside. Therefore the module will easily fail by high temperature. The accelerated-life testing was accomplished to formulate the life equation and numerical method is used to predict the inside temperature of the PCB module, which is one of the life equation parameter according to the environment. The experiment for measuring the surface heat flux of the electronic components is carried out to apply the boundary condition of numerical study. When the environment temperature of BLDC motor is 21, 35 and $50^{\circ}C$, the temperature in the PCB space is predicted as 73.4, 87.5 and $102.4^{\circ}C$. Then the life time with the temperature are calculated as 2,239, 863 and 328.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.3
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• pp.28-39
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• 1994

We experimented on memory multichip modules to increase the packing density of memory devices and to improve their electrical characteristics. A 128K$\times$8bit SRAM module was made of four 32K$\times$8bit SRAM memory chips. The memory multichip module was constructed on a low-cost double sided PCB(printed circuit boared) substrate. In the process of fabricating a multichip module. we focused on the improvement of its electrical characteristics. volume, and weight by employing bare memory chips. The characteristics of the bare chip module was compared with that of the module with four packaged chips. We conducted circuit routing with a PCAD program, and found the followings: the routed area for the module with bare memory chips reduced to a quarter of that area for module with packaged memory chips. 1/8 in volume, 1/5 in weight. Signal transmission delay times calculated by using transmission line model was reduced from 0.8 nsec to 0.4 nsec only on the module board, but the coupling coefficinet was not changed. Thus, we realized that the electrical characteristics of multichip packages on PCB board be improved greatly when using bare memory chips.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.572-573
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• 2010

Vibration analysis of Fine-pitch Ball Grid Array (FBGA) packages mounted on a Printed Circuit Board (PCB) subjected to harmonic excitation is performed by using finite element method (FEM). A finite element model of a memory module is composed of three main parts, packages, simplified solder balls and bare PCB. At first, natural frequencies and mode shapes of the developed model were confirmed experimentally. Secondly, the harmonic excitation experiment for the module was carried out at the first natural frequency of the memory module, and it was verified with the simulation by using mode superposition method at a constant acceleration.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.271-272
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• 2019

본 논문은 친환경 전기차용에 적용되는 있는 고밀도 LDC(Low-Voltage DC-DC Converter) 전력변환장치의 PCB구조와 스위칭소자에 따른 PCB의 발열특성을 해석한다. 전력변환장치 PCB사이에 알루미늄 플레이트를 적용하여 다면 방열경로를 통한 PCB방열특성을 비교하고, 또한 기존 Si-FET와 낮은 온 상태 도통저항을 가지는 GaN-FET 반도체디바이스를 적용한 전력변환장치의 PCB 방열특성을 시뮬레이션을 통해 비교 및 검토하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.22-27
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• 2009

In this paper, an automatic functional inspection system EVT (Emulated Vision Tester) for LCD drive module PCB has been proposed and implemented. Typical automatic inspection system such as probing methods and vision-based systems are widely known and used, however, there exist undetectable defects due to critical timing factors which they may miss to catch from LCD equipments. Especially typical vision-based systems have inconsistency on acquisition of images so that distinction between gray scales can be difficult which results in low level of performance and reliability on the inspection results. The proposed EVT system is pure hardware solution. It directly compares pattern signals from a pattern generator to output signals from LCD drive module. It also inspects variety of analog signals such as voltage, resistance, wave forms and so forth. The EVT system not only shows high performance in terms of reliability and processing speed but reduces costs on inspection and maintenance. Also, full automation of entire production line can be realized when EVT is applied in in-line inspection processes.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.609-610
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• 2006

As developing the information society, Lighting Emitted diode(LED) which is light source for illumination of next generation is attracted public attention. LED have many problem as narrow light view angle, high price, drift phenomenon of color coordinate, high heating problem for lower power, lower weight and small size. So, many researches have continued in a illumination as LED module type. in this problem, heating problem is very important and difficult and that is caused in decreasing phenomenon of brightness and drift phenomenon of color coordinate. so the problem of heating is urgent question for illumination of LED. In this paper, structural design of PCB changed as two type for solving the heating problem. also the properties of heating is analysed and optical properties is measured with heating image camera and spectrometer according to change in this design.