Extraction efficiency enhancement in ultra-violet LEDs based on spin on glass microlenses
Date Issued
2015
Date
2015
Author(s)
Liu, Chi-Min
Abstract
In this paper, we present a cost-effective method to fabricate spin on glass microlens array (SOG MLA) on ultra-violet light emitting diodes (UV LEDs). SOG microlens array was formed by thermal reflow technique and multiple replication processes which can reduce the cost of solution process. In our experiments, we fabricated different diameter size SOG microlens arrays whose diameter of each size was about 200, 150, 100 and 50 μm. The light extraction efficiency is improved by 7.31%, 10.35%, 14.01% and 21.86%, respectively. We also fabricated the different shape SOG microlenses, which was circular, square and hexagonal. The light extraction efficiency is improved by 7.31%, 9.6% and 13.8% for circular, square and hexagonal SOG MLA, respectively. By applying optimized lens pattern, an increase of 21.86% in improved light extraction efficiency is achieved experimentally, without detrimental effect to the electrical performance of the UV LEDs.
Subjects
spin on glass
microlens array
ultra-violet light emitting diode
light extraction efficiency
replication process
Type
thesis
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