백색 발광다이오드의 특성에 대한 황색 형광체의 영향

• Published in: Biuletyn Uniejowski Vol. 40; no. 2; pp. 103 - 106
• Main Authors: 장호정(Ho Jung Chang), 손창식(Chang-Sik Son), 허재성(Jae Sung Hur)
• Format: Journal Article
• Language: Korean
• Published: 한국표면공학회 2007
• Subjects: 기계공학; Yellow phosphor; Luminance; White LED
• ISSN: 1225-8024; 2299-8403; 2288-8403

We have investigated the optical and electrical properties of surface mounted white light emitting diode (LED) chips prepared by using yellow phosphors on the blue LED chip. The yellow phosphor mixed with transparent epoxy was coated on the prepared LED chip. The optimum mixing conditions with epoxy and yellow phosphor is obtained at the mixing ratio of epoxy:yellow phosphor = 97:3 wt%. The maximum luminance and light emitting efficiency are above $80,000cd/m^2$ and 23.2 lm/W, respectively, at the bias voltage of 2.9 V. There was no distinct change in the luminance strength with changing of the yellow phosphor ratios. The current of the white LED chip is about 30 mA at 2.9 V.