• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.49 no.7
• /
• pp.1-9
• /
• 2012

In this paper, resistance temperature detector (RTD) integrated into the LED package is proposed in order to solve the temperature dependence of LED's optical properties. To measure the package temperature in real time, the RTD type temperature sensor having excellent accuracy and linearity between temperature change and resistance change was adopted. A stable metallic film is required for long term reliability and stability of the RTD type temperature sensor. Therefore, deposition and annealing condition for the film were determined. Based on the determined condition, the RTD type temperature sensor with the sensitivity of about $1.560{\Omega}/^{\circ}C$ was fabricated inside the LED package. In order to configurate the LED package system keeping the constant brightness regardless of the temperature, additional conversion circuit and control circuit boards were fabricated and added to the fabricated LED package. The proposed system was designed to compensate the light intensity caused by temperature change using the variable duty rate of driving current. As a result, the duty rate of PWM signal which is the output signal of the configurated system was changed with the temperature change, and the duty rate was similarly varied with the target duty rate. Consequently, it was focused the fabricated RTD can be used for compensating the optical properties of LED and the LED package which exhibits constant brightness regardless of the temperature change.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.12
• /
• pp.982-987
• /
• 2011

In this study, $Ge_8Se_{(2+x)}Te_{(6-x)}$ thin film amorphous-to-crystalline phase-change rate was evaluated in using a nano-pulse scanner. The focused laser beam with a diameter <10 ${\mu}m$ was illuminated in the power (P) and pulse duration (t) ranges of 1-31 mW and 10-460 ns, respectively, with subsequent detection of the responsive signals reflected from the film surface. We also evaluated the material characteristics, such as optical absorption and energy gap, crystalline phases, and sheet resistance of as-deposited and annealed films. The result of experiments showed that the thermal stability of the Ge-Se-Te film is largely improved by adding Se.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.12
• /
• pp.1619-1625
• /
• 2018

Portable electronic devices secondary batteries can cause fire and explosion due to micro-current change in addition to the situation of short-circuit inrush current, safety can not be secured with a general operation limited current fuse. Therefore, in secondary battery, it is necessary for the protector to satisfy both the limit current type operation in the open-short-circuit inrush current and the current detection operation characteristic in the micro current change situation and for this operation, a fuse for the current detection type secondary battery protection circuit can be applied. The purpose of this study is to design a protection device that operates stably in the hazardous situation of small capacity secondary battery for portable electronic devices through the design of low melting fuse elements alloy of sensing type fuse and secures stability in abnormal current state. As a result of the experiment, I-T and V-T operation characteristics are satisfied in a the design of the alloy of the current sensing type self-contained low melting point fuse and the resistance of the heating resistor. It is confirmed that it can prevent accidents of short circuit over-current and micro current change of secondary battery.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.5
• /
• pp.295-299
• /
• 2018

In this work, we conducted a study on cell strings of high efficiency and high power solar cell modules via simulation. In contrast to the conventional module manufacturing method, the simulation was performed by connecting cutting cells divided into four parts from 6-in size using the electrically conductive adhesive (ECA). The resistance of the ECA added in series connection was extracted using an experimental method. This resistance was found to be $3m{\Omega}$. Based on this simulation, we verified the change in efficiency of the string as a function of the number of cutting cell connections. Consequently, the cutting cell efficiency of the first 20.08% was significantly increased to 20.63% until the fifth connection; however, for further connections, it was confirmed that the efficiency was saturated to 20.8%. Connecting cutting cells using ECA improves the efficiency of the string; therefore, it is expected that it will be possible to fabricate modules with high efficiency and high power.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.384-384
• /
• 2012

PRAM switching device by using current pulse modulation was investigated to verify its possibility for 3D architecture. In this work, two phase change materials connected in series having a different crystallization temperature are used. Its structural for different phase change material was evaluated by electrical resistance. We confirmed that Germanium-Antimony-Tellurium (GST) alloy and Germanium- Copper-Tellurium (GCT) alloy material were selected according to crystallization temperature, ${\sim}180^{\circ}C$ for switching and ${\sim}240^{\circ}C$ for memory devices, respectively. From this research, it is expected that phase change switching device could have advantages of process in terms of material similarity and structural simplification.

• Journal of Industrial Convergence
• /
• v.21 no.8
• /
• pp.35-42
• /
• 2023

Recently, electronic devices with bendable electronic devices based on flexible substrates are being sold, and therefore, the purpose of this study is to evaluate the possibility of flexible substrates of conductive transparent tapes. As a transparent electrode, carbon nanotube (CNT) was formed by the coating method developed by the research team, and samples coated up to 5 times were fabricated. The surface resistance and transmittance of the substrate were measured, and both resistance and transmittance decreased as the number of CNT coatings increased. After the tape was detached from the glass, the surface resistance slightly increased in all samples, and the transmittance increased by about 10% in all measured wavelength ranges because the glass was removed. Next, the tape coated with CNT twice was used to a bending test 20,000 times under the condition of a radius of curvature of 2 mm. The electrical and optical properties before and after bending did not change, which means that there was no change in CNT properties due to bending.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2371-2373
• /
• 2000

This paper presents a new vector control scheme for induction motor. An exact knowledge of the rotor flux position is essential for a high-performance vector control. The position of the rotor flux is measured in the direct scheme and estimated in the indirect schemes. Since the estimation of the flux position requires a priori knowledge of the induction motor parameters, the indirect schemes are machine parameter dependent. The rotor and stator resistance among the parameters change with temperature. Variations in the parameters of induction machine cause deterioration of both the steady state and dynamic operation of the induction motor drive. Several methods have presented to minimize the consequences of parameter sensitivity in indirect scheme. In this paper, new estimation scheme of rotor flux position is presented to eliminate sensitivity due to variation in the resistance. The simulation is executed to verify the proposed vector control performance and to compare its performance with that of indirect vector control.

• Journal of Sensor Science and Technology
• /
• v.23 no.4
• /
• pp.266-271
• /
• 2014

Chemical sensors are used in various industrial facilities such high-risk and prevent the leakage of substances, important in life and environmental protection and the safe use of industry, used for management. In particular, high-temperature environments such as power generation equipment of the rotating part due to leakage generated by the various oil, power plants Shut Down, fire, work environment (exposure to various chemical solution and gas leak) and various water, air and soil pollution causes. Thus, over the long term through various channels such as crops and groundwater contamination caused by the slow, serious adverse effect on the ecosystem. In this paper, synthetic lube oil and high pressure hydraulic fluid leakage and immediately detect a new Printed Electronic implementation of technology-based film-type sensors, and its performance test. Thus, industrial accidents and environmental pollution and for early detection of problems, large accidents can be prevented. Experimental results of the synthetic lube oil and high pressure hydraulic fluid solution after the contact time depending on the experiment and the oil solution of the sensor material of the conductive porous PE resistance value by a chemical reaction could be confirmed that rapid increase. Also implemented in the film-type oil sensor electrical resistance change over time of the reaction rate and the synthetic lube oil is about 2 minutes or less, the high pressure hydraulic fluid is less than about 1 minute was. Therefore, more high-pressure hydraulic fluid such as a low volatility synthetic lube oils are the resistance change and the reaction rate was confirmed to be the slowest.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.4
• /
• pp.390-395
• /
• 2004

In order to analyze the physical and chemical characteristics of home production porcelain insulators by change of the alumina addition amount, 360001bs ball socket type suspension insulators which were manufactured in 1989, 1995 and 2001 removed in transmission line and an experiment was performed. By the result, 8 wt.％ alumina that influences the mechanical properties and arc resistance properties in case of insulators that were manufactured in 1989 was contained, and the relative density and the fracture toughness of insulators appeared by 94.2％ and 1.4 ㎫$.$ $M^{\frac{1}{2}}$, respectively. However, 12 wt.％ alumina was contained in case of insulators that were manufactured in 1995, and the relative density and the fracture toughness of insulators appeared preferably lower by 92％ and 1.3㎫$.$ $M^{\frac{1}{2}}$, respectively. Amount of alumina was contained most by 17 wt.％ in case of insulators that were manufactured in 2001. It was confirmed that the electrical and mechanical characteristics such as the relative density and the fracture toughness appeared excellently by 96％ and 1.7㎫$.$ $m^{\frac{1}{2}}$, respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.915-922
• /
• 2017

The study on the thermal and oil resistance rubber composite, 2016. [6] predicted the lifetime of Fluorocarbon Rubber by accelerating aging at high temperature ($150^{\circ}C$, $175^{\circ}C$, $200^{\circ}C$). general rubber products are likely to exhibit different properties depending on the degradation factors such as temperature, humidity, ozone, light, emulsion, mechanical and electrical stress. To solve these problems, We compared the rate of change about tensile strength, elongation rate, volume change rate, weight change rate, thickness change rate, thermal conductivity in low temperature promoting aging on the basis of predictive lifetime of high temperature promoting aging. As a result of the review, the required life expectancy was satisfied, but there was a slight difference in the rate of change between the high-temperature promoted aging life result and the low temperature promoted aging life result. The cause was a reduction in "tensile strength / elongation" and an increase in "volume / weight / thickness" caused by the main chain decomposition of fluorine rubber due to aging at high temperature promoting aging. However, the low temperature promoting aging was caused by the curing reaction of fluorine rubber at $80^{\circ}C$. The tensile strength / elongation and volume / weight / thickness changes were small.