Screen-printed phosphor coatings for white LED emission

We demonstrate the possibilities offered by the screen-printing technique to create thick layers of rare earth doped phosphors on glass slides for light-emitting diodes (LEDs). Using commercial LEDs, the effect of the layer thickness and phosphor concentration on luminescence emission and chromaticity are investigated. The advantages offered by screen-printed multi-phosphors systems are also revealed through a feasibility study permitting to tune the chromatic coordinate of the global light emission by modifying the phosphors characteristics independently.