• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.145-151
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• 2014

The glass used for mobile display windows is required to have high strength. Chemical strengthening by means of ion exchange is widely used glass. The depth of the layer and the compressed stress are affected by tempering temperature and time. The purpose of this study is to investigate the range of DOL and CS, which to less breakage during reliability tests such as the ball drop test, hole drop test, 3-point bending test, drop test, and tumble test with Soda-lime Glass.

• Transactions of Materials Processing
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• v.11 no.2
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• pp.103-107
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• 2002

With the great demand for WDM (Wavelength Division Multiplexing) optical communications, optical switches are expected to become one of the dominant components in future networks. Conventional mechanical switches suffer from poor reliability and large size; however, many micromachined optical switches with moving mirrors have been proposed for high scale OXC (Optical Crossconnect) or ADM (Add/Drop Multiplex) because of the low power consumption and high reliability of these switches. In this paper, we introduce the technological trends of optical switches using MEMS, related micromachining technologies and their characteristics.

• Journal of Applied Reliability
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• v.5 no.2
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• pp.261-272
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• 2005

In evaluation of electronic reliability on the PCB(Printed Circuit Board), electrochemical migration is one of main test objects. The phenomenon of electrochemical migration occurs In the environment of the high humidity and the high temperature under bias through a continuous aqueous electrolyte. In this paper, the generating mechanism of electrochemical migration is investigated by using water droll acceleration test under various waters. The waters used in the water drop test are city water, distilled water and ionic water. It found that the generated velocity of electrochemical migration depended on the temperature of water and the electrolyte quantity which included in the various waters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.4
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• pp.214-217
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• 2017

An IGBT (insulated gate bipolar transistor) device has an excellent current-conducting capability. It has been widely employed as a switching device to use in power supplies, converters, solar inverters, and household appliances or the like, designed to handle high power. The aim with IGBT is to meet the requirements for use in ideal power semiconductor devices with a high breakdown voltage, an on-state voltage drop, a high switching speed, and high reliability for power-device applications. In general, the concentration of the drift region decreases when the breakdown voltage increases, but the on-resistance and other characteristics should be reduced to improve the breakdown voltage and on-state voltage drop characteristics by optimizing the design and structure changes. In this paper, using the T-CAD, we designed the NPT-IGBT (non punch-through IGBT) and FS-IGBT (field stop IGBT) and analyzed the electrical characteristics of those devices. Our analysis of the electrical characteristics showed that the FS-IGBT was superior to the NPT-IGBT in terms of the on-state voltage drop.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.1-7
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• 2015

In this study, properties of Pb-free solders for automotive electronics parts were discussed. Lead-free solders for electronics became important after RoHS (Restriction of the use of certain Hazardous Substances) to avoid environmental pollution. Also the growing electronic rate in automotive parts and ELV (End-of Life Vehicles) make Pb-free solder for automotive electronics to be inevitable trend. Definitely, Pb-free solder for automotive electronics should have good wettability, basic strength, but need more reliability than other solders, since it has harsh condition like high temperature, humidity and engine vibration. Thus, shear strength test, thermal shock, drop test and many others are needed to ensure the high reliability. This study describes the properties and requirements of Pb-free solders for automotive electronics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.83-88
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• 2007

The reliability characteristics of class-E RF power amplifier are studied, based on the degradation of MOSFET electrical characteristics. The class-E power amplifier operates as a switch mode operation to achieve high efficiency. This operation leads to high voltage stress when MOSFET switch is turned-off. The increase in threshold voltage and decrease in nobility caused by high voltage stress leads to a drop in the drain current. In the class-E power amplifier the effects caused by the degradation of MOSFET drain current is a drop of the power efficiency and output power. But the small inductor in the class-E load network allows the reliability to be improved. After $10^{7}\;sec$. the drain current decreases 46.3% and the PAE(Power Added Efficiency) decreases from 58% to 36% when the load inductor is 1mH. But when the load inductor is 1nH the drain current decreases 8.89% and the PAE decreases from 59% to 55%.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.157-162
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• 2003

Piezoelectric ink jet offers a promising combination of productivity, reliability and uniformity that are appropriate for jetting organic electronic materials. Spectra is manufacturing a printhead specifically for display manufacturing. This printhead contains a robust material set and is intended to allow calibration of individual nozzles to meet uniformity requirements of+/-2% for display manufacture.

• Journal of the Korean Society of Safety
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• v.23 no.2
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• pp.37-44
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• 2008

The safety assessment for facility industry is now being periodically performed. For the purpose of scientific safety management, QRA(Quantitative Risk Assessment) is also being performed, and reliability data of the facilities is essential to perform the assessment. Generally, the existing safety assessment is performed by using the values announced in other industry processes, which result in the drop of reliability. In order to solve this problem, there is an urgent need to establish reliability database for the facilities. The most appropriate method is to perform a direct reliability analysis towards the facilities undergoing safety assessment. In this study, in compliance with the assessment method and procedure of OREDA-2002 handbook, the facility reliability data are collected, which include the calendar time and operational time in terms of different facility items, the number of failures in terms of different failure mode, the mean, standard deviation, lower limit and upper limit of failure rate, and the failure rate. And the data process method for this special occasion is also proposed when the number of failure is 0.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.144-149
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• 2009

The safety assessment for facility industry is now being periodically performed in Korea. For the purpose of scientific safety management, QRA(Quantitative Risk Assessment) is also being performed, and reliability data of the facilities is essential to perform the assessment. The necessary reliability data for QRA have been generally announced the values in other process industries, which results in the drop of risk reliability. The most appropriate method is to perform a direct reliability analysis towards the facilities undergoing safety assessment. In this study, the distinction between homogeneous sample estimation and multi-sample estimation of reliability data clarify using 2-Bayes theory.

• Journal of the Korea Society of Computer and Information
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• v.23 no.3
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• pp.9-16
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• 2018

In this paper, I purpose one of the development methods for portable Automatic field Test Equipment(ATE) with VME form factor. Almost portable ATE have not used to standards form factor and they are connected by mechanical non-rigid general connectors and wire harnesses among the components. Furthermore, it is hard to reuse developed board. So, it decreases to reusability of developed board and it is hard to maintenance of ATE. Even those things have weakness for vibration and drop test especially in portable ATE. The XK9A1 ATE using VME form factor has environmental reliability through vibration, drop, temperature test. It consists of 5 developed board called the control board, the wire & wireless communication board, the power supply board, the load board and the mother board. It is connected by two wire harnesses between mother board and extern circular connectors. The control board send the data and address to other board though each 16-bit data and 20-bit address line. You can develop the function board what you want to using those data & address line when it comes to needing other function board.