Byungjin Ma

Korea Electronics Technology Institute

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Kwanhun Lee

Korea Electronics Technology Institute

Jemin Kim

Korea Advanced Institute of Science and Technology

Kwanhoon Lee

Korea University

Soohaeng Cho

Solid (South Korea)

Yongjo Park

Korea University

Youngchul Shin

Seoul National University of Science and Technology

Joonseok Kang

Sungkyunkwan University

Young‐Min Kim

Sungkyunkwan University

Suh Won-Bae

Shinhan University

SungSoon Choi

Korea Electronics Technology Institute

Cooperative Institutions

Samsung (South Korea)

Korea Electronics Technology Institute

Inha University

Seoul National University

Government of the Republic of Korea

Korea University

Korea Institute of Materials Science

Yonsei University

Sungkyunkwan University

Korea Advanced Institute of Science and Technology

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Reliability estimation of plastic LED package with different types of silicone encapsulant and adhesive

2012 4th Electronic System-Integration Technology Conference (2012)

Jemin Kim Byungjin Ma Kwanhun Lee

To estimate reliability of plastic LED packages based on different types of silicone encapsulant and adhesive, we designed two plastic LED package models using normal refractive index (NRI) silicone or high refractive index (HRI) silicone as encapsulant with epoxy or silicone as bonding adhesive. And then, thermal acceleration tests were performed during 1,000 hours in three different temperatures and optical characteristics were measured at every 250 hours. Exponential decay of luminous flux of plastic LED package was assumed and extrapolation was used to analyze the time-to-failure (TTF) of plastic LED packages. From TTF data, statistical analysis was performed and the reliability parameters such as acceleration factor (AF) and B 10 lifetime at 40°C were estimated according to what types of silicone encapsulant and bonding adhesive were applied in plastic LED packages with 90% confidence.

Plastic packaging

10.1109/estc.2012.6542203

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熱過渡応答を用いたフリップチップ発光ダイオードにおけるはんだボイドの研究【Powered by NICT】

IEEE Conference Proceedings (2016)

Byungjin Ma Kim Chang Wan Lee Kun Hyung Suh Won-Bae Kwanhun Lee

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Modeling and simulation of efficiency droop in GaN-based blue light-emitting diodes incorporating the effect of reduced active volume of InGaN quantum wells

Current Applied Physics (2017)

Han‐Youl Ryu Guen-Hwan Ryu Young‐Hwan Choi Byungjin Ma

Auger effect

Quantum Efficiency

Indium gallium nitride

10.1016/j.cap.2017.06.014

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Citations (17)

Comparison of effect of epoxy and silicone adhesive on the lifetime of plastic LED package

Electronic Materials Letters (2013)

Jemin Kim Byungjin Ma Kwanhun Lee

Plastic packaging

Electronic Packaging

10.1007/s13391-013-0024-2

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Citations (16)

Investigation on solder voids in flip-chip light-emitting diodes using thermal transient response

Byungjin Ma Chang‐Wan Kim Kun Hyung Lee Suh Won-Bae Kwanhun Lee

In order to reduce the cost of the LED packages and to minimize the thermal budget, the chip-on-board (COB) packages and the chip-scale package (CSP) LEDs, based on flip-chip die bonding process, have been developed. Although the flip-chip die bonding process for the COB and the CSP LEDs is useful to decrease the thermal resistance, a precise process control for minimizing voids in solder joint and an in-line inspection for bonding quality check are needed for reliability. We proposed a simple in-line void inspection method based on the thermal transient response of LED junction temperature. In order to carry out the feasibility test, we made three LED package groups showing different solder void qualities. By measuring voltages at two points in time domain, we could distinguish the LED packages showing a poor solder void quality.

Void (composites)

Chip-scale package

Surface-mount technology

Electronic Packaging

Temperature cycling

10.1109/therminic.2016.7749064

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Citations (2)

Evaluation of the internal quantum efficiency in light-emitting diodes

Journal of the Korean Physical Society (2015)

Byungjin Ma Kwan Hun Lee

Quantum Efficiency

Electrical efficiency

LED lamp

10.3938/jkps.67.658

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Citations (5)

Performance and reliability of SC-type optical fixed attenuators for optical network system

ICEIC : International Conference on Electronics, Informations and Communications (2008)

Jemin Kim Byungjin Ma Kwanhun Lee

The void and delamination on the surface of the SC-type optical fixed attenuators under damp heat condition were detected and analyzed. We improved them by modifying cleaning process, housing structures and materials of parts. Then the performance and reliability of old and new models were checked. The results of several environmental tests such as damp heat and mechanical test showed that the improved model had the advantages of production cost and environmental characteristics analyzed by using statistical method such as T-test.

Void (composites)

Delamination

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Citations (8)

Formation of vertical ridge structure in 660nm laser diodes for high power single mode operation

Journal of Vacuum Science & Technology B Microelectronics and Nanometer Structures Processing Measurement and Phenomena (2005)

Soohaeng Cho Sang-Bum Lee Joonseok Kang Byungjin Ma Changyun Lee

We report a method for formation of a ridge with almost vertical sidewalls in the fabrication of ridge stripe AlGaInP laser diode structures, which cannot be easily achieved when a conventional wet-etch process is used, for high power operation with a fundamental transverse mode. By depositing additional oxides protecting layers on the sidewalls after the dry-etch process, a wet-etch process, which is necessary to remove the plasma-induced damaged portion of the etched region, can be safely applied and the vertical ridge shape maintained. Using this method, the ideally rectangular ridges were obtained and the single mode operation of 660nm laser diode with up to 270mW output power was successfully achieved.

Laser diode

Mode (computer interface)

Dry etching

10.1116/1.2006133

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Citations (1)

熱散逸のためのアルミニウム基板上に被覆した窒化アルミニウム厚膜の作製と特性評価【Powered by NICT】

Ceramics International (2016)

Hahn Byung-Dong Yun-A Kim Cheol-Woo Ahn Choi Jong-Jin Ryu Jungho

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Temperature dependence of the color rendering index of a phosphor-conversion white light-emitting diode

AIP Advances (2019)

Guen-Hwan Ryu Byungjin Ma Han‐Youl Ryu

We experimentally investigated the temperature dependence of the color rendering index (CRI) of a phosphor-conversion (PC) white light-emitting diode (LED) composed of a GaN-based blue LED chip and yttrium aluminum garnet doped with Ce3+ (YAG) phosphor. For the 15 CRI values from R1 to R15, 12 CRI values were found to increase with temperature from 20 to 80 °C. The general CRI (Ra) was increased from 84.6 to 86.1 as the temperature increased from 20 to 80 °C. R9 which represents the color rendering property for the deep red was found to increase by more than 10% and some CRI values exhibited more than 20% increase in this temperature range. This increasing behavior of CRI with temperature is contrary to the case of a multi-chip-based white LED, where the Ra was reported to decrease with increasing temperature. The improvement in the CRI with temperature for the PC white LED is attributed to the relative increase of the spectral power distribution (SPD) in the wavelength range from 460 to 520 nm and the overall broadening of SPD with increasing temperature. As a result of the increase in the CRI with temperature, the PC white LEDs are expected to be advantageously used for stable high-temperature operation of LED lighting.

Color temperature

Color rendering index

Atmospheric temperature range

10.1063/1.5066351

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Citations (3)