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"LDI"

Fabrication of 660 nm Wavelength SMD Type Semiconductor Laser Diode Package Using Silicon Molding on BT Resin Circuit Board
Beom Jin Kim, Pil Hong Jeong, Jae Min Lee, Dong Hwan Won, Jeong Ho Lee, Heon Min Lee, Ku Yun Jeong, Keon Park, Kawan Anil, Soon Jae Yu, Yeon Sik Chae, Sung Bae Park
J Electr Electron Mater 2025;38(3):272-277.   Published online May 1, 2025
DOI: https://doi.org/10.4313/JKEM.2025.38.3.5
SMD-type 660 nm wavelength semiconductor laser diode device is fabricated using silicon resin molding technology and fabricated a BT resin printed circuit board. BT resin electrode structure printed circuit boards with soldering electrode pads and through holes for heat dissipation were fabricated. The SMD process is an injection molding technique in which the chip is molded from silicon material and then cut by a dicing process to complete the beam emission surface. The fabricated SMD-type semiconductor laser diode exhibits a good near-field beam pattern with no scattering/dispersion caused by the printed circuit board or silicon molding in the emitted laser beam, or reflections around the chip. It was also confirmed that the heat generated at 20 mA operation has good heat dissipation characteristics through the through-hole heat dissipation structure.
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Design and Evaluation of Dye-Sensitized Solar Cell Submodule for Self-Powered Smart Liquid Crystal Window
Byeong-yun Oh
J Electr Electron Mater 2024;37(5):494-499.   Published online September 1, 2024
DOI: https://doi.org/10.4313/JKEM.2024.37.5.4
The possibility of a dye-sensitized solar cell (DSSC) submodule was evaluated as an independent power source that can drive a smart liquid crystal window (SLW) that selectively blocks sunlight when electricity is applied. In order to save energy and increase the functionality of buildings, SLW operation was supplied directly from DSSC submodule, rather than connecting to the existing power system and external power sources. It was confirmed that the SLW can control light transmittance through self-generation using the DSSC submodule composed of 6 cells at low light of 2,500 lux. These results imply that there is a high possibility of combining smart windows and DSSCs suitable for window-type building-integrated photovoltaic (BIPV) systems. DSSCs, which can self-generate power in low light, are expected to increase their usability in urban BIPV systems through combination with smart window technology.
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Building Integrated Photovoltaics: Technical and Aesthetic Prospects
Polgampola Chamani Madara, Hasnain Yousuf, Muhammad Aleem Zahid, Suresh Kumar Dhungel, Youngkuk Kim, Junsin Yi
J Electr Electron Mater 2024;37(2):154-163.   Published online March 1, 2024
DOI: https://doi.org/10.4313/JKEM.2024.37.2.5
The energy demand in the world is expected to exceed 740 million TJ by 2040 and our dependence on fossil fuels needs to be switched to sustainable and renewable energy sources like solar energy. Building Integrated Photovoltaic (BIPV) is one of the best approaches to extracting solar energy. There are more than 200 BIPV products in the market currently but when it comes to integrating these products into the technical aspects such as buildings’ structural integrity, thermal, daylight retainment and aesthetic prospects to be considered. The share of BIPV integration potential of different building types in the world of residential, agricultural, industrial, commercial and other buildings account for 66%, 4.8%, 8.1%, 19.9%, and 1.2% accordingly. Many solar technologies developed to achieve architectural requirements, but the main problem is the trade-off between efficiency and aesthetic appeal, which is less than 10% in coloured and transparent solar modules. This paper discusses the different applications of solar photovoltaics (PV) in building architecture, technical requirements, and different module technologies. The article provides a comprehensive guide for researchers and designers working on the development of BIPV integrations.
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EMI (Electromagnetic Interference) Shielding Properties of Barium-Based Ferrite Thin Films Prepared by Spin Spray Method
Hye Ryeong Oh, Yeon-ju Park, Woo-sung Lee, Chan-sei Yoo, Myong-jae Yoo, Intae Seo
J Electr Electron Mater 2024;37(2):195-201.   Published online March 1, 2024
DOI: https://doi.org/10.4313/JKEM.2024.37.2.11
The low-temperature deposition of BaNi(2-x)CoxFe16O27 thin films with a Ba hexaferrite structure for electromagnetic shielding was studied. The BaNi(2-x)CoxFe16O27 thin films produced through the spin spray process were suitable for thin film deposition on a flexible substrate because it crystallized well at low temperature below 90℃. The change in shielding characteristics depending on the Co content of the BaNi(2-x)CoxFe16O27 thin film was investigated, and excellent shielding characteristics with S21 of -1 dB were obtained in a wide frequency range of 26~40 GHz when the Co content was 0.4 or more. The purpose of this study is to analyze changes in shielding properties caused by change in Co content in relation to phase changes in BaNi(2-x)CoxFe16O27 and obtain basic data for developing excellent flexible electromagnetic wave shielding materials.
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Analysis of Power Pattern According to Load Types
Mi-yong Hwang, Seung-joon Cho, Soon-hyung Lee, Yong-sung Choi
J Electr Electron Mater 2023;36(4):369-375.   Published online July 1, 2023
DOI: https://doi.org/10.4313/JKEM.2023.36.4.7
In this paper, we compared and analyzed the power load patterns of dormitory buildings and office buildings to use them as basic data (demand analysis and capacity design) for the design and operation of microgrids for multi-use facilities, and the following conclusions were got. During the daytime on regular weekdays, the power consumption load pattern of office buildings was relatively large at 264.0~332.3 kWh, and during the evening hours, the power consumption load pattern of dormitory buildings was relatively large at 233.0~258.3 kWh. In the case of vacation, during the daytime on weekdays, the power consumption load pattern of office buildings was relatively large at 279.1~407.4 kWh, and in the evening, the power consumption load pattern of dormitory buildings was relatively high at 280.1~394.1 kWh. During the daytime on regular weekends, the power consumption of dormitory-type buildings was relatively high at 133.5~201.6 kWh, and it was found that the power consumption of dormitory-type buildings appeared relatively high at 187.5~252.1 kWh. During a vacation in the daytime on weekends, the power consumption of dormitory-type buildings was found to be 186.5 kWh~ and 218.6 kWh. The increase in power consumption during a vacation (December-February) compared to normal (April-June) was thought to be due to an increase in electricity demand, and the reason for the higher power consumption in dormitory buildings during the vacation was due to reduced working hours in office buildings.
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A Study on the Manufacture of Gas Insulated Switchgear Spacer Using APG Molding Process
Chanyong Lee, Jaesung Bae, Han-gu Cho, Sangmook Lee, Jaehyeong Lee
J Electr Electron Mater 2022;35(4):386-391.   Published online July 1, 2022
DOI: https://doi.org/10.4313/JKEM.2022.35.4.11
The gas insulation switchgear, which is a device for protecting a power system, cannot be supported by the insulation gas itself in a charge unit stored in a metal container. Therefore, molding technology is required to manufacture a gas insulation switch spacer. The APG method injection molding simulation was performed by applying the variables obtained through the physical properties of an epoxy composite used for manufacturing an insulating spacer to a moldflow software. After varying the temperature conditions of heater in the simulation, the thermal characteristics and the degree of hardening of the spacer were analyzed, based on which the optimum process conditions are presented.
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Simulation for Injection Molding of Insulation Spacers for Gas-Insulated Switches Using Thermosetting Epoxy Resin
Jaesung Bae, Wonchang Lee, Hongsub Jee, Byungyou Hong, Jaehyeong Lee
J Electr Electron Mater 2021;34(6):426-432.   Published online November 1, 2021
DOI: https://doi.org/10.4313/JKEM.2021.34.6.4
Injection molding is used in many industrial fields such as home appliances, vehicle parts, and electronic device parts because various resins can be molded, leading to mass production of complex shapes. Generally, the empirical prediction method is used to set the initial processing conditions of injection molding. However, this approach requires a lot of cost and its presented solution is not accurate. In this paper, injection molding was simulated through the MoldflowTM in order to manufacture the spacer for gas insulated switch. Through the simulation, the flow of the resin with respect to the diameter of the inlet was analyzed. It was found that the process was possible at a higher resin temperature as the diameter of the inlet increased. In addition, through thermal analysis during injection of the resin, it was confirmed that a stagnation phenomenon occurred at the insert portion during injection molding, and the temperature of the resin was higher than that of the mold. As in this paper, if the spacer is manufactured by optimizing the injection hole and the temperature of the injection process based on simulation, it is expected that the spacer can be manufactured with high productivity.
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A Study on Reliability of Liquid-Crystal for Smart Window
Byung-kyu Park, Sun-geum Kim, Seung-woo Lee, Gye-choon Park, Jin Lee
J Electr Electron Mater 2020;33(6):471-474.   Published online November 1, 2020
DOI: https://doi.org/10.4313/JKEM.2021.33.6.8
In recent years, the challenge of higher energy efficiency has emerged as urban buildings have become taller, and the area of window glasses has increased. To address the problem of energy efficiency in buildings, research on smart windows is being actively conducted. In this study, an accelerated experiment for thermal stability was conducted to fabricate a liquid crystal cell applicable to external windows. It was confirmed from the study that the function is maintained even in a high-temperature external environment through the change in transmittance by voltage. Compared with the initial transmittance, after the passage of time, the smart window cell to which the sealant was applied showed a small change in transmittance of 1~2%. This result confirmed the thermal stability of the liquid crystal-based smart window.
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Optimal Design of Coverglass Pattern in Building-Integrated Photovoltaic for Improved Yearly Electrical Energy
Taehyeon Kim, Seung-chul Lee, Woo-sang Park
J Electr Electron Mater 2020;33(4):297-302.   Published online July 1, 2020
DOI: https://doi.org/10.4313/JKEM.2021.33.4.9
A coverglass pattern was designed to improve the annual electrical energy production of a building-integrated photovoltaic (BIPV) module installed in the exterior walls of buildings. The transmittance pattern was calculated using ray tracing, and the results were derived by optimizing the simulation using Taguchi’s method. We obtained the optimal pattern by analyzing the conventional patterns for improving the transmittance and derived design factors by quantifying the pattern. By calculating the influence of electrical energy on each design factor, we obtained the optimal coverglass pattern that produced the maximum annual electrical energy. The annual electrical energy production improved by approximately 11.79% compared to the non-patterned coverglass.
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AZO Transparent Electrodes for Semi-Transparent Silicon Thin Film Solar Cells
Jiyoon Nam, Sungjin Jo
J Electr Electron Mater 2017;30(6):401-405.   Published online June 1, 2017
Because silicon thin film solar cells have a high absorption coefficient in visible light, they can absorb 90% of the solar spectrum in a 1-μm-thick layer. Silicon thin film solar cells also have high transparency and are lightweight. Therefore, they can be used for building integrated photovoltaic (BIPV) systems. However, the contact electrode needs to be replaced for fabricating silicon thin film solar cells in BIPV systems, because most of the silicon thin film solar cells use metal electrodes that have a high reflectivity and low transmittance. In this study, we replace the conventional aluminum top electrode with a transparent aluminum-doped zinc oxide (AZO) electrode, the band level of which matches well with that of the intrinsic layer of the silicon thin film solar cell and has high transmittance. We show that the AZO effectively replaces the top metal electrode and the bottom fluorine-doped tin oxide (FTO) substrate without a noticeable degradation of the photovoltaic characteristics.
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Simultaneous Realization of Electromagnetic Shielding and Antibacterial Effect of Al Doped ZnO Thin Films onto Glass Substrate
Hyung Jin Choi, Soon Gil Yoon
J Electr Electron Mater 2016;29(5):279-283.   Published online May 1, 2016
In this study, we intended to achieve both antibacterial properties and electromagnetic shielding using the Al-doped ZnO (AZO) films. FTS (Facial Target Sputtering) magnetron sputtering was used for the AZO thin films instead of the conventional RF sputtering because the FTS sputtering could avoid the damage for the plasma as well as fabrication of thin films with a high quality. The 300-nm thick AZO thin films grown on glass substrate showed a resistivity of about 7 × 10-4 Ω-cm and a transmittance of about 90% at a wavelength of 550 nm. AZO thin films were investigated for the electromagnetic shielding effectiveness measured by 2-port network method at 1.5 ~ 3 GHz. The AZO (300 nm)/glass films showed an EMI shielding effectiveness of approximately 27 dB. An antibacterial effect was measured by the film attachment method (JIS Z 2801). The percent reductions of bacteria by AZO films were 99.99668% and 99.99999% against Staphylococcus aureus and Escherichia coli, respectively.
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Regular Paper : Temperature Dependence on the Partial Discharge of Epoxy Molding Ignition Coil According to Applied Voltage
Jong Yeol Shin, Jin Woong Hong
J Electr Electron Mater 2015;28(2):85-91.   Published online February 1, 2015
A gasoline engine automobile uses high voltage generation of the ignition coil, igniting and burning mixed fuel in the combustion chamber, which drives the engine. When the electronic control unit intermits a current supplied to the power transistor, counter electromotive force with a low voltage is generated by self induction action in the ignition primary coil and a high voltage is induced by mutual induction action with the primary ignition coil in the second ignition coil. The high voltage is supplied to the ignition plug in the combustion chamber, causing a spark, igniting the compressed mixed fuel. If a very small defect occurs inside the insulating material when a voltage is applied in said ignition coil, the performance of the insulation material will get worse and breakdown by a partial discharge of corona discharge. Thus, in this experiment, we are to contribute to improve the performance and ensure the reliability of the ignition coil by investigating partial discharge characteristics according to the change of voltage and temperature when a voltage is applied to the specimen of the epoxy molding ignition coil.
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Regular Paper : Analysis of the LIGBT-based ESD Protection Circuit with Latch-up Immunity and High Robustness
Jae Chang Kwak
J Electr Electron Mater 2014;27(11):686-689.   Published online November 1, 2014
Electrostatic discharge has been considered as a major reliability problem in the semiconductorindustry. ESD reliability is an important issue for these products. Therefore, each I/O (Input/Output) PADmust be designed with a protection circuitry that creates a low impedance discharge path for ESDcurrent. This paper presents a novel Lateral Insulated Gate Bipolar (LIGBT)-based ESD protection circuitwith latch-up immunity and high robustness. The proposed circuit is fabricated by using 0.18 um BCD(bipolar-CMOS-DMOS) process. Also, TLP (transmission line pulse) I-V characteristic of proposed circuitis measured. In the result, the proposed ESD protection circuit has latch-up immunity and highrobustness. These characteristics permit the proposed circuit to apply to power clamp circuit. Consequently, the proposed LIGBT-based ESD protection circuit with a latch-up immune characteristiccan be applied to analog integrated circuits.
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Electric Field Strength and Shielding Effectiveness Comparison According to the Size of Shielding Facility
Ho Jae Kang, Chang Su Huh, Jeong Ju Bang, Jin Su Choi, Woo Chul Park
J Electr Electron Mater 2014;27(4):221-225.   Published online April 1, 2014
In modern times, threat of high power electromagnetic wave is increasing. When the electrical grid and communication network are attacked by these high power electromagnetic wave, the whole infrastructure is paralyzed. To protect the infrastructure from these high power electromagnetic wave threat, the shielding facility that can block high power electromagnetic wave is constructed. Also shielding effectiveness evaluation about the constructed facility is important. But, because of space efficiency and saving of construction cost to construct the actual shielding facility, the shielding room wall is generally adjacent to exterior concrete structures. As space between shielding facility wall and concrete structures is very small, arranging the transmitting antenna exterior shielding facility is realistically difficult. Therefore, in this research, The shielding effectiveness measurement plan in the state of exterior narrow space of HEMP shielding facility is presented. And to apply this plan, The influence of shielding effectiveness according to the size of the shielding facility is analyzed.
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Molding and Evaluation of Ultra-Precision Chalcogenide-Glass Lens for Thermal Inaging Can1era Using Thermal Deforn1ation Compensation
Du Hwan Cha, Jeong Ho Kim, Hye Jeong Kim
J Electr Electron Mater 2014;27(2):91-96.   Published online February 1, 2014
Aspheric lenses used in the thermal imaging are typically fabricated using expensive single-crystal materials (Ge and ZnS, etc.) by the costly single point diamond turning (SPDT) process. As a potential solution to reduce cost, compression molding method using chalcogenide glass has been attracted to fabricate IR optic. Thermal deformation of a molded lens should be compensated to fabricate chalcogenide aspheric lens with form accuracy of the submicron-order. The thermal deformation phenomenon of molded lens was analyzed ant then compensation using mold iteration process is followed to fabricate the high accuracy optic. Consequently, it is obvious that compensation of thermal deformation is critical and useful enough to be adopted to fabricate the lens by molding method.
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Fast Switching Properties of TN Cell With Graphene Quantum Dots
Dai Hyun Kim
J Electr Electron Mater 2014;27(2):110-114.   Published online February 1, 2014
In this study, we report the doping effect of graphene quantum dots (QDs) in nematic liquid crystal (NLC) system on rubbed polyimide (PI) surface. The good LC alignment and high thermal stability in QD-LC cell system on rubbed PI surfaces can be measured. Also, the low threshold voltage of QD-TN cell was observed about 2.77 V. The fast response time of 13.2 ms for QD-TN cell can be achieved. Finally, the good voltage holding ratio of QD-TN cell on rubbed PI surface was measured.
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Technology Education : Regular Paper ; Evaluation of Thermography Camera Using Molded Optical Lens for Medical Applications
Seong Mi Ryu, Hye Jeong Kim
J Electr Electron Mater 2013;26(8):624-628.   Published online August 1, 2013
With the recent development of less-costly uncooled detector technology, expensive optics are among the remaining significant cost drivers in the thermography camera. As a potential solution to this problem, the fabrication of IR lenses using chalcogenide glass has been studied in recent years. We report on the molding and evaluation of a ultra-precision chalcogenide-glass lens for the thermography camera for body-temperature monitoring. In addition, we fabricated prototype thermography camera using the chalcogenide-glass lens and obtained the thermal image from the camera. In this work, it was found out that thermography camera discerned body-temperature between 20 and 50℃ through the analysis of thermal image. It is confirmed that thermography camera using the chalcogenide-glass lens is applicable to the body-temperature monitoring system.
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Fabrication and Evaluation of Chalcogenide Glass for Molding
Heung Su Park, Du Hwan Cha, Hye Jeong Kim, Jeong Ho Kim, Hyun Yong Lee
J Electr Electron Mater 2012;25(2):135-139.   Published online February 1, 2012
In this study, we synthesized the chalcogenide glass(Ge19Sb23Se58) for infrared optics by melt-quenching method and verified the effect of cooling condition on the glass properties. The structural and optical properties of the glass were analyzed by XRD, FT-IR and SEM image. The glass synthesized under the cooling temperature of 980℃ shows transmittance of 58% at 8∼12 ㎛, which was decreased as the cooling temperature was decreased. In addition, thermal and hardness also were measured. From the analysis results, we ascertained the feasibility as a molding materials for infrared optics.
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High Voltage and Discharge Engineering : Frequency Spectrum Analysis of Series Arc and Corona Discharges
Gyung Suk Kil, Kwang Seok Jung, Dae Won Park, Sun Jae Kim, Ju Seop Han
J Electr Electron Mater 2010;23(7):554-559.   Published online July 1, 2010
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Development of White LED Lamp Having High Color Uniformity With Transfer Molding Technology
Soon Jae Yu, Do Hyung Kim
J Electr Electron Mater 2010;23(1):38-41.   Published online January 1, 2010
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The Improvement of Matching of Amplifier Input Transistor for Display Driver IC
Hyeon Cheol Kim, Yong Han Roh
J Electr Electron Mater 2008;21(3):213-216.   Published online March 1, 2008
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A Study on Influence of PV and Ra with Re-Ir Coating of WC Core Surface for Glass Molding Lens
J Electr Electron Mater 2007;20(9):808-811.   Published online September 1, 2007
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Temperature Rise Test and Temperature Distribution Analysis of Pole Mount Mold Transformer with One-body Molding
J Electr Electron Mater 2006;19(12):1154-1159.   Published online December 1, 2006
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High Voltage Engineering : The Thermal Analysis of Pole Mount Mold Transformer with One-body Molding by Duct Condition
Han Gu Jo, Un Yong Lee, Yeong Du Park
J Electr Electron Mater 2004;17(3):348-352.   Published online March 1, 2004
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