Index matched fluidic packaging of high power UV LED clusters on aluminum substrates for improved optical output power
We present an improved cooling for a high power density UV LED module for a wavelength of 395 nm. The module consists of 98 LED chips soldered on a thick film printed alumina substrate on an area of 2.11 cm2. We investigated cooling by a commercial water cooler as well as by a surface micro cooler developed by our own. Further we describe a technology to replace alumina by aluminum as substrate material. A module consisting of 25 UV LEDs was optically characterized without and with liquid encapsulation. Finally we conducted numerical studies to develop an easily producible, sufficiently powerful, and robust water cooler. Based on the results we present a water cooler design with cooling channels embedded in the aluminum substrate of an LED module, removing the interface between LED substrate and heat sink.
Very high power density LED modules on aluminum substrates with embedded water cooling
We present optical measurements of an LED module consisting of 98 UV LEDs with an emission wavelength of 395 nm soldered onto a ceramic substrate within an area of 211 mm2. The module is mounted to a high performance mi-crostructured water cooler. This cooler enables a maximum optical power density of 45.9 W/cm2 at a forward current of 1350 mA and 447.9 W electrical input power. Further we describe the development of an LED module based on an aluminum substrate with thick film printed insulator and conductor layers and embedded, meander shaped water cooling channels. Numerical and experimental studies with different channel cross-sections are shown. Finally experimental results for this kind of UV LED module with 98 LED chips are presented and compared to the ceramic based module.
The role of forensic epidemiology in evidence-based forensic medical practice
Objectives This thesis is based on 4 papers that were all written with the same intent, which was to describe and demonstrate how epidemiologic concepts and data can serve as a basis for improved v ...