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.
Highlights
Recent developments in light-emitting diode (LED) technology have produced deep-ultraviolet aluminium gallium nitride (AlGaN) LEDs with wavelengths ranging between 220–280 nm emitting in the 100 mW range [1]
The LED can be used to directly illuminate the specimen without use of any lenses, but this begs the question of homogeneity of specimen illumination and the emission pattern of the LED in air is of interest when assessing the suitability of an LED as an excitation source in optical microscopy
This technique allows for a broader measurement of the emission pattern of the LED and results are shown in figure 3 along with standard deviation error bars on the y-axis
Summary
Recent developments in light-emitting diode (LED) technology have produced deep-ultraviolet aluminium gallium nitride (AlGaN) LEDs with wavelengths ranging between 220–280 nm emitting in the 100 mW range [1]. These LEDs have applications in sterilisation, water purification [2] and gas-sensing [3]. Deep-UV LEDs have potential applications as excitation sources in fluorescence microscopy. One of the major weaknesses of using deep-UV LEDs for microscopy is low transmission through glass, making deep-UV illumination sources difficult to adapt into standard epifluorescence microscopes. The LED can be used to directly illuminate the specimen without use of any lenses, but this begs the question of homogeneity of specimen illumination and the emission pattern of the LED in air is of interest when assessing the suitability of an LED as an excitation source in optical microscopy
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
