The German Ferdinand-Braun-Institut, abbreviation FBH and its subsidiary UVphotonics NT will present their latest UV LEDs at the "2018 UV LED Technology and Applications International Conference" in Berlin from April 22nd to 25th.
With the increase of efficiency and output power, together with its small size, UV LEDs are used in more and more applications, including the disinfection of water, air and surfaces, and the curing of synthetic materials. UV LEDs can be quickly switched and dimmed, and heat dissipation is effectively radiated by the heat sink. Unlike mercury lamps, UV LEDs consist of non-toxic substances whose wavelengths can be flexibly adjusted over a wide spectral range.
They discovered a degradation mechanism during development: During the first few hours of operation, there will be electromigration of hydrogen in the UV-B LED structure, which is accompanied by a drop in the optical power of the device.
After a corresponding design adjustment, a UV-B LED with an L50 lifetime of 8,000 hours can be created. The optimization of the device has further improved the reliability of the LED and it is expected that the L50 lifetime will be significantly extended. In addition, the output power at 350mA can be increased to 30mW.
At the conference, FBH scientists will also demonstrate a compact diode laser light source for the deep ultraviolet spectral range with an emission wavelength of 222 nm, where LEDs are difficult to achieve. The device converts light from a gallium nitride-based high-power diode laser into the ultraviolet spectral range by frequency multiplication (one-pass), and may be miniaturized. The wavelength-stabilized narrow-band light source is particularly suitable for spectral applications such as absorption and Raman spectroscopy and can be applied to medical diagnostics and material analysis.