Characterisation of a deep-ultraviolet light-emitting diode emission pattern via fluorescence

TL;DR

This paper introduces a fluorescence-based method to characterize the emission pattern of deep-UV LEDs, enabling accurate measurement despite camera sensitivity limitations, and distinguishes packaging types effectively.

Contribution

A novel fluorescence technique for measuring deep-UV LED emission patterns using visible light conversion and standard CMOS cameras.

Findings

Emission pattern matches Lambertian distribution with 99.6% accuracy.

Method can differentiate between LED packaging types.

Technique overcomes camera sensitivity limitations in deep-UV detection.

Abstract

Recent advances in LED technology have allowed the development of high-brightness deep-UV LEDs with potential applications in water purification, gas sensing and as excitation sources in fluorescence microscopy. The emission pattern of an LED is the angular distribution of emission intensity and can be mathematically modelled or measured using a camera, although a general model is difficult to obtain and most CMOS and CCD cameras have low sensitivity in the deep-UV. We report a fluorescence-based method to determine the emission pattern of a deep-UV LED, achieved by converting 280 nm radiation into visible light via fluorescence such that it can be detected by a standard CMOS camera. We find that the emission pattern of the LED is consistent with the Lambertian trend typically obtained in planar LED packages to an accuracy of 99.6$\%$. We also demonstrate the ability of the technique to distinguish between LED packaging types.