  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.
