Abstract
The lifetime of ultraviolet high-power light-emitting diodes (UV HP-LEDs) is an open issue due to their high current density, high temperature, and UV radiation. This work presents a reliability study and failure analysis of three high-temperature accelerated life tests (ALTs) for 13,500 h with 3 W commercial UV LEDs of 365 nm at a nominal current in two working conditions: continuous mode and cycled mode (30 s on/30 s off). Arrhenius–Weibull parameters were evaluated, and an equation to evaluate the lifetime (B50) at any junction temperature and other relevant lifetime functions is presented. The Arrhenius activation energy was 0.13 eV for the continuous mode and 0.20 eV for the cycled mode. The lifetime at 50% survival and 30% loss of optical power as a failure definition, working at Ta = 40 °C with a multi-fin heat sink in natural convection, was over 4480 h for the continuous mode and 19,814 h for the cycled mode. The need to add forced convection for HP-LED arrays to achieve these high-reliability values is evidenced. The main source of degradation is the semiconductor device, and the second is the encapsulation silicone break.
Highlights
The market and applications of ultraviolet high-power light-emitting diodes (UV HP-LEDs) have rapidly increased in the last years
We developed temperature accelerated life tests (ALTs) to analyze the lifetime of a commercial 3 W, 365 nm UV LED with the high external quantum efficiency of UV LEDs [7]
The results obtained are the lifetime parameters of this commercial 3 W UV-A LED
Summary
The market and applications of ultraviolet high-power light-emitting diodes (UV HP-LEDs) have rapidly increased in the last years. A simpler power supply, eco-friendly characteristics, and the use of a simpler power supply of UV HP-LEDs have led to their preference over ultraviolet lamps, introducing other new applications [1,2,3,4]. UV LEDs have lower power per device, from less than one watt to a few tens of watts, compared to lamps used in industrial applications, ranging from a few to 3000 watts [5]. Report by Yole Développement [6] identified that in 2018, the UV light source market share was 74.7%. UV lamps and 25.3% UV LEDs, with a total market share of over USD 0.2 billion, which could more than double to USD 0.5 billion in 2024. The applications of UV-A LEDs with wavelengths from 320 to 400 nm include resin curing, photocatalytic water and air purification [8], high-resolution microscopes, industrial inspection, fluorescence light [9], biological research [10], sanitary radiation for sterilization and disinfection [11], and printing
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.
