Enhanced light extraction from UV LEDs using spin-on glass microlenses. (1st April 2016)

• Record Type: Journal Article
• Authors: Liu, Chi-Min; Su, Guo-Dung J
• Is Part Of: Journal of micromechanics and microengineering. Volume 26:Number 5(2016:May)
• Publication Date: 2016-04-01
• Subjects: spin-on glass -- microlens array -- ultra-violet light-emitting diode -- light extraction efficiency -- replication process; Microelectromechanical systems -- Periodicals; Micromechanics -- Periodicals; 621.38105
• DOI: 10.1088/0960-1317/26/5/055003
• Languages: English
• ISSNs: 0960-1317

Abstract

Abstract: In this paper, we present a cost-effective method for fabricating spin-on glass (SOG) microlens arrays (MLAs) on ultra-violet light-emitting diodes. The SOG MLA is formed using thermal reflow molds and multiple replication processes, which can reduce the cost of the solution process. In this paper, we fabricate SOG MLA of different sizes, where the diameter of each microlens is approximately 50, 100, 150, and 200 μ m. In each case, the light extraction efficiency is improved by 21.86%, 14.01%, 10.35%, and 7.31%, respectively. We also discuss the effects of different-shaped SOG microlenses, namely circular, square, and hexagonal. The light extraction efficiency is improved by 7.31%, 9.60%, and 13.80% for the circular, square, and hexagonal SOG MLAs, respectively. By applying an optimized lens pattern, an increase in light extraction efficiency of 21.86% is achieved.