Picture of two heads

Open Access research that challenges the mind...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including those from the School of Psychological Sciences & Health - but also papers by researchers based within the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

Beam divergence measurements of InGaN/GaN micro-array light-emitting diodes using confocal microscopy

Griffin, C. and Gu, E. and Choi, H.W. and Jeon, C.W. and Girkin, J.M. and Dawson, M.D. and McConnell, G. (2005) Beam divergence measurements of InGaN/GaN micro-array light-emitting diodes using confocal microscopy. Applied Physics Letters, 86 (4). ISSN 0003-6951

[img]
Preview
PDF (strathprints000116.pdf)
strathprints000116.pdf

Download (471kB) | Preview

Abstract

The recent development of high-density, two-dimensional arrays of micrometer-sized InGaN/GaN light-emitting diodes (micro-LEDs) with potential applications from scientific instrumentation to microdisplays has created an urgent need for controlled manipulation of the light output from these devices. With directed light output these devices can be used in situations where collimated beams or light focused onto several thousand matrix points is desired. In order to do this effectively, the emission characteristics of the devices must be fully understood and characterized. Here we utilize confocal microscopy to directly determine the emission characteristics and angular beam divergences from the individual micro-LED elements. The technique is applied to both top (into air) and bottom (through substrate) emission in arrays of green (540 nm), blue (470 nm), and UV (370 nm) micro-LED devices, at distances of up to 50 µm from the emission plane. The results are consistent with simple optical modeling of the expected beam profiles.