Open AccessThe physical characteristic study on luminance uniformity and temperature for power GaN LEDs chip
Author(s) -
Huan-Ting Chen,
Yijun Lu,
Yue Gao,
Cheng Zhong,
陈忠,
Zhuang Rong-Rong,
Xiaofang Zhou,
Huamin Zhou,
周海光
Publication year - 2012
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.61.167104
Subject(s) - current crowding , luminance , light emitting diode , materials science , luminous flux , current density , optoelectronics , current (fluid) , optics , diode , heat sink , illuminance , luminous intensity , physics , thermodynamics , light source , quantum mechanics
In this paper, we study the relationship among current density distribution, heat and temperature based on current continuity equation, ohm law and three-dimensional heat transfer model. The relationship between luminance distribution and current spreading of GaN blue light emitting diode (LED) is studied. Luminance distribution is proved to be an effective method of distinguishing the performance of current spreading. Because of the close relationship among temperature, luminance distribution and current density, a qualitative method of optimizing electrode structure and current spreading is proposed. With different currents and heat sink temperatures, the current non-uniformity and the luminance distribution of LED are analyzed. Temperature or current density crowding results in heat accumulation, increase of non-radiative recombination and the restriction of the emitting photons, hence thermal flux is an important factor influencing the luminance distribution. Through carrier transport mechanism, the reason for the temperature influence on luminance distribution is explained. Optimized contact electrode structure can improve current spreading and luminance uniformity, also considerably increase the reliability of high power LED.