Ultraviolet pumped tricolor phosphor blend white emitting LEDs

Near-UV and violet emitting AlGaInN single quantum well LED structures were grown by MOCVD on sapphire substrates. On-wafer tests before processing gave an output power at 40 mA between 1.4 mW at 380 nm and 6.7 mW at 420 nm. LED chips with wavelengths between 380 and 404 nm were selected for manufacturing radial UV LEDs and white emitting LEDs. The UV to white converters were prepared from broad band red, green and blue emitting powder phosphors with individual luminescence peaks near 610, 550 and 460 nm, respectively. White luminescence conversion (LUCO) LEDs with a warm hue and color temperatures in the range 4000-4300 K are demonstrated.