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UV LEDs reliability tests for fluoro-sensing sensor application

Abstract:

The use of UV HB-LEDs for fluoro-sensing applications, as detection of substances in water is proposed for replace previous light sources. Developing devices to continuous environmental analysis requires that the used light sources must be robust, economic, and capable to operate correctly for long periods of time during 24 h/day. UV HB-LEDs have improvement over old light sources but need an analysis of reliability for this type of applications. In this paper a reliability analysis of two types of new commercial 3W UV HB-LEDs has been developed, in two different working conditions: continuous and cycled working of 1 min 30sON/30sOFF. Two sets of eleven LEDs at three accelerated temperature are tested. After 1500 h of test at 60 °C, 75 °C and 90 °C, we have not observed catastrophic failures, only LEDs luminosity degradation. The degradation is larger for LEDs working at continuous current than LEDs working at cycled current in all tests.